New Salad & Vegetable Crops

From Australia’s sub-Antarctic Islands

A report for the Rural Industries Research and Development Corporation by Iain Dawson, Australian National Botanic Gardens

December 1998

RIRDC Publication No 98/145 RIRDC Project No ANC-2A

ISBN 0 642 57857 5 ISSN 1440-6845

New Salad & Vegetable Crops from Australia’s Sub-Antarctic Islands Publication no 98/145 Project no. ANC-2A

The views expressed and the conclusions reached in this publication are those of the author and not necessarily those of persons consulted. RIRDC shall not be responsible in any way whatsoever to any person who relies in whole or in part on the contents of this report.

This publication is copyright. However, RIRDC encourages wide dissemination of its research, providing the Corporation is clearly acknowledged. For any other enquiries concerning reproduction, contact the Publications Manager on phone 02 6272 3186.

Researcher Contact Details Iain Dawson Australian National Botanic Gardens Clunies Ross Road ACTON ACT 2601

GPO Box 1777 CANBERRA ACT 2601

Phone: 02 6250 9450 Fax: 02 6250 9599 email: [email protected] Internet: http://www.anbg.gov.au

RIRDC Contact Details Rural Industries Research and Development Corporation Level 1, AMA House 42 Macquarie Street BARTON ACT 2600 PO Box 4776 KINGSTON ACT 2604

Phone: 02 6272 4539 Fax: 02 6272 5877 Email: [email protected] Website: http://www.rirdc.gov.au

Published in December 1998 Printed on environmentally friendly paper by the DAFF Copy Centre

Foreword

In recent years Australia has seen a dramatic increase in diversity in fruit and vegetable markets. This is partly due to the general acceptance of ethnic contributions to Australian cuisine and partly to promotion of health benefits attributed to the consumption of a wide range of fresh plant products.

After the discovery by the Royal Navy in the 18th century of the role of fresh fruit and vegetables in the prevention of scurvy, sailors in southern oceans used to visit a number of small islands in the sub-Antarctic to replenish their supplies of leafy green vegetables. These included the Kerguelen Cabbage and the Macquarie Cabbage. In recent times researchers based on Macquarie Island have also regularly consumed a cress like plant, Callitriche antarctica.

This project considers the feasibility of introducing these three species to the Australian consumer market. Three key issues are investigated: prospects for acclimatisation and mass production, sensory analysis to judge consumer reaction to the ‘new’ products, and chemical analysis of their nutritional value.

This report, the latest addition to RIRDC’s diverse range of over 250 research publications, forms part of our New Plant Products R&D program which aims to foster the development of new industries through the introduction of new crops.

Peter Core Managing Director Rural Industries Research and Development Corporation

iii

Acknowledgments

The author wishes to acknowledge the assistance of colleagues at the Australian National Botanic Gardens in the preparation of this report. Particular thanks are due to Susan Walker, Stuart Donaldson and Catherine Jordan. Professor Heather Greenfield, Dr Eileen Emmerson, and Dr MaryAnn Keszi and their associates are also thanked for their important contributions.

Valuable information was also provided by Dr Hans van der Sander of Bean Sprouts Australia Pty, Sydney. The Australian Antarctic Division provided the seed of Pringlea antiscorbutica. The author also acknowledges the financial assistance provided by Rural Industries Research and Development Corporation, without which it is unlikely that the research would have been possible.

Insert photo of Pringlea antiscorbutica here

Contents

Executive Summary ...... vii

1. INTRODUCTION...... 1

2. PLANT MATERIAL ...... 3 2.1 THE PLANT SPECIES ...... 3 2.2 THEIR NATURAL ENVIRONMENT...... 3 2.3 PROPERTY RIGHTS ...... 4 3. CULTIVATION...... 5 3.1 ACCLIMATISATION ...... 5 3.2 PROPAGATION ...... 5 3.3 OPTIMAL GROWTH CONDITIONS...... 7 4. SUITABILITY FOR HUMAN CONSUMPTION ...... 12 4.1 PRIOR EVIDENCE OF SUITABILITY FOR HUMAN CONSUMPTION...... 12 4.2 FLAVOUR PROFILING ...... 12 4.3 CHEMICAL COMPOSITION ...... 13 4.4 TOXICITY AND PHARMACOLOGY...... 14 5. DISCUSSION ...... 15

6. RECOMMENDATIONS...... 17

7. REFERENCES...... 18

8. APPENDIX 1: FLAVOUR PROFILING ...... 19 8.1 OBJECTIVES...... 21 8.2 METHODOLOGY...... 21 8.3 RESULTS AND DISCUSSION ...... 22 8.4 CONCLUSIONS ...... 26 9. APPENDIX 2: NUTRIENT COMPOSITION ...... 31 9.1 PLANTS...... 33 9.2 COOKING METHODS...... 33 9.3 ANALYSES ...... 33 9.4 QUALITY CONTROL ...... 34 9.5 RESULTS ...... 34 9.6 CONCLUSION ...... 35 9.7 REFERENCES...... 35

v About the Author

Iain Dawson is Assistant Director of Living Collections at the Australian National Botanic Gardens (ANBG) where he is in charge of the Horticultural Research Unit. The ANBG charter is to grow, study and promote the native flora of Australia. Projects of the Horticultural Research Unit are concerned with conservation and sustainable use of Australian plants.

vi Executive Summary

Three species of edible plant from Australia’s sub-antarctic islands have been assessed for their suitability for production and sale in mainland Australia and Tasmania. Propagation and growth were assessed in controlled environment experiments. Appeal to consumers was assessed by an expert tasting panel, and nutritional characteristics were determined by chemical analyses. The major findings and recommendations are:

Callitriche antarctica: • easily propagated by division • survives a wide range of temperature • has potential to become an environmental weed • grows best at about 13°C • can be grown either in hydroponics or in solid media • is susceptible to aphid infestations • is visually appealing to consumers • can be consumed raw • scored highly for taste • is a rich source of potassium and a useful source of vitamin C, carotenoids and iron

Recommendation: Despite its attractiveness as a food crop it would be unwise to introduce this plant because of its high potential to become an environmental weed. It should however be further investigated for potential pharmaceutical uses.

Pringlea antiscorbutica: • seed germinates easily at ca. 20°C • stratification at lower temperature accelerates germination • optimum growth temperature is probably between 13 and 17°C • survives outdoors in Canberra • is susceptible to aphid infestations • could be grown as either a sprout crop or a leafy vegetable crop • most likely use is as a garnish • can be consumed either raw or cooked • is visually appealing to consumers • scored highly for taste • contains high levels of potassium, and useful levels of carotenoids • contains high levels of vitamin C, even when cooked

Recommendation: This crop has significant potential and deserves further investigation, including field growth trials in a cool location, and toxicological studies.

Stilbocarpa polaris: • can be propagated by rhizome cuttings • grows very slowly • requires temperatures below 20°C • is susceptible to aphid, slug and snail damage

vii • has less visual appeal than the other species • must be cooked to make palatable • scored well for taste, but less well for texture • has higher starch content than the other species, but lower vitamin content • has high potassium content • cooking reduces its nutritional value

Recommendation: This crop grows too slowly to be commercially practicable. Despite having a pleasant flavour it is less visually appealing than the other species. No further work is recommended at present

viii 1. Introduction

In 1994 a Horticultural Task Force submitted its report 'Strategies for growth in Australian horticulture' which predicted a need to increase horticultural production from $3 billion to $5 billion by the end of the century in order to service domestic and export demand. Increased consumption of up to 50% more per capita would result from competitive pricing, product diversification and value added convenience packaging. In particular increased consumption of more unusual horticultural produce was expected, and this would be driven by marketing campaigns.

In recent years the Australian market has already seen a dramatic increase in product diversity. For example, a few years ago it was unusual to find lettuce varieties other than the crisphead type, whereas today there are several different types available, as well as other leafy vegetables such as rocket and English spinach which are marketed in the same niche. This diversity has come about through consumer demand in a social and political climate where ethnicity is promoted and valued, there is more international travel and experience of other culinary cultures, and a greater awareness of the health benefits of increased fruit and vegetable consumption and supposed benefits from biologically active compounds found in some foods ('functional foods'). In addition there is undoubtedly a fashion component in what is consumed. There is also a growing awareness in the community of the value of conserving genetic diversity which includes the preservation of 'heritage' germplasm through the production of old varieties of crop and their wild relatives.

Macquarie and Heard Islands are both located to the south of continental Australia in latitudes that are essentially climatically inhospitable for permanent human occupation but which nevertheless are capable of providing sufficient food from plant and animal sources to sustain human life for significant periods of time. Three plant species are of particular interest as food, namely Stilbocarpa polaris, Pringlea antiscorbutica and Callitriche antarctica. The Australian National Botanic Gardens collected these species on expeditions in 1989 and 1993, and they have since been grown in special cold growth room facilities in Canberra.

This project was suggested because: • these species were known to be edible (see below) and thought to be rich in vitamin C. • adaptation to extremely low light levels meant that they were likely to be rich in chlorophyll and could possibly contain significant amounts of minerals. • Stilbocarpa has a fleshy rhizome that might contain significant amounts of carbohydrate. • their flavour and texture were judged to be quite pleasant • their unusual origins would make it relatively simple to promote them in the market. • biologically active compounds have been found in related species of all three species so it was possible that they would contain similar compounds and might be promoted as a 'functional food' or 'nutraceutical'. In Callitriche, for example, these include iridoid glucosides and verbascocide. The former have liver protecting qualities and the latter has anti-inflammatory, anti-microbial and anti-tumour effects.

1 However, before there was any attempt at commercialisation there were some fundamental questions that needed to be answered. These included: • could they be grown in Australia in commercial quantities? • would consumers like their taste? • what were the nutritional benefits of consumption?

The Australian National Botanic Gardens therefore approached the Rural Industries Research and Development Corporation who agreed to financially support a preliminary investigation of these species. Propagation and growth trials were conducted by the Australian National Botanic Gardens in Canberra, and the food analysis was subcontracted to staff of the Department of Food Science and Technology at the University of New South Wales.

2 2. Plant Material

2.1 The plant species The main references for the taxonomy and ecology of the plant species are 'The Flora of Australia (1993) Volume 50, Oceanic Islands' and Selkirk et al (1990). Other information is from Clark and Dingwall (1985).

Callitriche antarctica Engelm. ex Hegelm. This is a prostrate, mat forming, amphibious herb. It grows to about 3 cm high. It is widespread on Macquarie and Heard Islands and is locally dominant in and around pools and in seal wallows. It grows in very wet peat, gravel, loam and sand or in water. It is limited by low water availability, high wind velocities and by competition with taller growing species. It is also found on most other sub-antarctic islands and in the southern parts of South America. There is also an unconfirmed report for an occurrence in Tasmania. The whole plant is edible. In appearance it is similar to the common cress (Lepidium sativum) in size, but with a growth habit and flavour more like water cress (Nasturtium officinale).

Pringlea antiscorbutica R.Br. ex Hook.f. (Kerguelen Cabbage) This is a perennial, fleshy, rhizomatous herb. The stem is prostrate and up to 1 m long. The most palatable parts are the leaves which are fleshy and 5-8 cm long by 4-6 cm wide. It is a monotypic genus confined to the islands to the south of the Indian Ocean, including Heard (Aus.), Macdonald (Aus.), Kerguelen (Fr.), Crozet (Fr.), Prince Edward (S.A.), and Marion (S.A.). On Heard Island it is common and widespread on deeper soils away from seal and penguin colonies. It is a member of the Cruciferae, the same family as cabbage, broccoli, cauliflower radishes and cress. Unlike most of the other plants in the family, which are insect pollinated, it has adapted to wind pollination in response to the strong winds and relative lack of insects in its habitat.

Stilbocarpa polaris (Hombr. & Jacquinot ex Hook.f.) A.Gray (Macquarie Island Cabbage) This is a perennial herb with a tuft of leaves arising from a fleshy rhizome. The leaves can be up to 45 cm in diameter and the plant can grow to 2 m tall. The edible parts are the rhizome and leaf stalks. The rhizome is about 4 cm in diameter and up to 60 cm long. The leaf stalks are up to 50 cm long and moderately hairy. Although this species only grows on the sub- antarctic islands of Macquarie (Aus.), Auckland (N.Z.), Campbell (N.Z.) and Antipodes (N.Z.) it is locally abundant on all except the most exposed sites and can form pure stands. Its growth is limited by very wet conditions and by extreme wind velocities. It grows in moist peat. Stilbocarpa belongs to the Araliaceae, which includes several other species of economic interest, including several ornamental species, ginseng, and the edible Tetrapanax from which rice paper is made.

2.2 Their natural environment Pringlea antiscorbutica plants and seed were obtained from Heard Island. The other two species were propagated vegetatively from plants obtained from Macquarie Island.

Heard Island was discovered in 1833 by the British, and again in 1853 by Americans. It was annexed to Australia by Britain in 1947. It is administered by the Commonwealth government as an external territory. It is uninhabited, and it is unique in that it is the only

3 unmodified sub-antarctic island ecosystem in the world. It has therefore been nominated for the World Heritage List.

It lies at 53 °S about 2000 km SW of Australia to the south of the Indian Ocean. The main part of the island is roughly circular and about 25 km in diameter. It is to the south of the Oceanic Polar Front (the zone where cold polar water flowing north-eastwards meets warmer southward moving water) and is therefore colder than Macquarie Island (which is to the north of the OPF) and has more severe and more frequent frosts. In addition the island is mountainous and approximately 90% is permanently covered in ice. The annual mean temperature is only 1°C. It is also wetter than Macquarie Island with 1360 mm of precipitation and 276 raindays at sea level (the highest point on the island is 2745 m ) Cloud cover reduces solar radiation to only 11% of the potential. Strong winds blow continuously. Soils in the lower lying, vegetated areas, are poorly developed. They are derived from basalt. There are only 12 species of higher plants on the island, one of which (a grass) is introduced.

Macquarie Island was discovered by sealers in 1810, and was included as part of Tasmania in 1825. There are no permanent residents of the island, but a research station has been maintained there since 1948. It is entirely Crown Land and is administered as a nature reserve by the Tasmanian government.

The island lies at latitude 54 °S about 1500 km SSE of Tasmania. It is approximately 35 km long and 5 km wide. The maximum altitude is 433m, and most of the island is an undulating plateau between 200 and 300m high. Soils on the plateau, which is mostly vegetated, are gravelly loams, with acid peaty soils elsewhere. It is to the north of the Oceanic Polar Front and the effect of the ocean is to ameliorate the climate so that temperatures only vary within a narrow range (mean January 7 °C, July 3 °C). Despite the southerly location frost is relatively light. The mean minimum at the research station (near sea level) is above freezing for all months of the year and the record lowest temperature is only -8.9 °C (warmer than Canberra!). Strong westerly winds blow almost continuously (mean wind speed 33 kph) and mean daily sunshine is only 2 hours, cloud cover blocking about 80% of the potential radiation. Rain falls on 320 days of the year (mean annual precipitation 895 mm) and the relative humidity is always high (mean 89%). The higher plant flora of Macquarie Island is more diverse than that of Heard Island, but still only consists of 41 species, 5 of which are introduced.

Soils on both islands are poorly developed and often boggy and waterlogged. There may be local enrichment of soils by bird and seal colonies. Photoperiod (duration of daylight hours) varies from a minimum of 7.1 to a maximum of 16.9 hours, which, for comparison, is similar to Holland (as is potential solar radiation).

2.3 Property rights Under the terms of the International Convention on Biological Diversity (Article 15 -Access to Genetic Resources) Australia does not have exclusive rights to the unimproved genetic material of any of these species. Pringlea antiscorbutica also grows on territory controlled by South Africa and France. Stilbocarpa polaris is shared with New Zealand. Callitriche antarctica grows in several other southern hemisphere countries.

4 3. Cultivation

Commercial development of these species will depend on the ability to produce large quantities of plants and quickly grow them to marketable size. This section therefore deals with propagation methods, the optimal requirements for rapid growth, and the definition of the range of environmental conditions under which they will grow satisfactorily. The latter is important not only to determine locations suitable for production for the consumer market but also where stock plant material or seeds can be produced to supply growers.

3.1 Acclimatisation These species all grow naturally in environments of relatively cold temperatures, high rainfall, high soil moisture content, low light and strong winds. Adaptation to such conditions does not preclude successful acclimatisation to different or less extreme conditions.

Stilbocarpa antarctica can be grown outdoors in Canberra. Pringlea antiscorbutica has been less successful but does survive, despite research evidence that it is unable to adapt to high vapour pressure deficits or restricted soil water availability (Dorne and Bligny, 1993). Slugs and snails have been major pest problems in outdoor beds. Callitriche antarctica has not yet been grown outdoors in Australia (except perhaps for an unconfirmed record of a natural occurrence in Tasmania).

3.2 Propagation

3.2.1 Callitriche antarctica The easiest method of propagation for this species is by division. The individual plants readily produce adventitious roots at nodes. Small plugs of plants will rapidly colonise a standard seedling tray under a wide range of environmental conditions (see below).

Flowering occurred under our standard growing conditions (described below) and seeds were produced. The flowers and seeds are barely noticeable on casual inspection, the latter being about 1mm in diameter. No attempt was made to germinate these seeds.

3.2.2 Pringlea antiscorbutica A large quantity of fresh seed was obtained from three locations on Heard Island.

The seed was collected in March 1997 and air dried. In April 5 replications of 20 seeds were sown on damp filter paper (3 ml distilled water) in petri dishes at each of 3 temperatures (4, 10 and 20°C), sealed with parafilm, and left to germinate in darkness. Seeds were inspected for germination daily for the first week then every two days. After 7 days germination had started at 20°C but not at the lower temperatures. After 18 days there was still no germination at the lower temperatures but 38% of seeds at 20°C had germinated. After a further 18 days (total 36) no more seeds had germinated in any treatment. Three petri dishes from the 4°C treatment were transferred to 20°C. Thirteen days later 50% had germinated, and by the twentieth day 93% had germinated. A similar result was achieved when the remaining seeds from 4°C were transferred to 20°C two weeks after the first batch was transferred.

5 Three petri dishes from the 10°C treatment were also transferred to 20°C thirty six days after the start of the trial. After 20 days 28% of these had germinated, and after 30 days this had risen to 75%. Again, a similar result was achieved when the remaining 2 petri dishes were transferred to 20°C two weeks after the first transfer.

Smoked water (Kirstenbosch ‘Instant Smoke Plus’ Seed Primer) was added to 3 of the petri dishes at 20°C on day 36 of the trial. This increased total germination to 87% (from 38%) after 20 days, whereas only one more seed had germinated in the untreated petri dishes in the same period. After 30 days the latter had reached 68%.

A second trial compared 3 treatments. These were i. 23°C, ii. 4°C for 14 days then transferred to 23°C, and iii. 4°C for 26 days followed by transfer to 23°C. At 23°C (i.)the germination rate after 21 days was 92%. In (ii) seven days after transfer (to 23°C after 14 days at 4°C) the germination rate was 93%. Sixty six percent of seeds transferred to 23°C after 26 days at 4°C (iii) had germinated after only 5 days. One day later 92% had germinated. A short period of preconditioning at low temperature therefore appears to accelerate germination. The germination rate is close to the rates needed for commercial sprout production.

In these trials the optimum temperature was clearly ca. 20°C, though stratification at lower temperature increased the final germination rate. The beneficial effect of the addition of smoked water is surprising, given that fire would not be a feature of the Heard Island environment, and merits further investigation.

In a further trial germination at 23°C was compared with germination at 20/10°C (12h/12h), using large batches of seed (200 per plate) in an effort to simulate the methods used in the bean sprouting industry. At the higher temperature results were similar to those in the first trial at 20°C, but after germination the seeds quickly turned brown and died if not removed from the plates. Very few seeds germinated in the diurnal cycle treatment.

3.2.3 Stilbocarpa polaris Transverse sections (0.5 to 2 cm thick) were cut from the fleshy rhizome and placed in a pine bark and sand based potting mix in 6 cm diameter pots. The cuttings were placed in the growth chamber described above. This procedure was used several times. Typically more than 50% of these cuttings survived, thicker cuttings being more likely to survive than thin ones.

No fresh seed of this species was available. Flowering occurred in plants in the growth chamber and in the outdoor plot in January but no seed was set. A small quantity of seed that had been stored in sealed containers at 4°C for several years had previously been tested at the ANBG seed store after treatments which included leaching for 4 months, soaking in detergent for 10 minutes, freezing for 1 day, or no pretreatment. Germination was attempted at 10 to 15°C but with no success even after several months. Although it could be argued from comparison with the Pringlea data that the germination temperature could have been sub- optimal it was comparable with that of the natural environment of Macquarie Island.

3.3 Optimal growth conditions

ANBG has maintained all three species for several years in a specially designed growth chamber which mimics their natural environment. This runs with a day/night temperature range of 12 to 8°C, which is somewhat warmer than the natural habitats. Light is provided by fluorescent, incandescent and metal halide sources. The light intensity is 60 - 80 μmol.m-2.sec-1.

Although all three species have survived and grown satisfactorily in this specially constructed growth chamber commercial production will require more rapid plant growth. Survival outdoors in a cool location at ANBG is also no indicator of possible growth rates. A series of controlled environment laboratory (phytotron) experiments were therefore carried out to determine the optimum conditions for growth. General details of the operational controls of the phytotron can be found in Morse and Evans (1962).

Further information on the species environmental limits was obtained by growing them for various periods in partially controlled greenhouse environments. Greenhouse conditions were controlled by automatically operated (thermostat/timer) evaporative coolers, heaters, and shade/thermal screen mechanisms (Ludwig Svensson/Living Shade Pty Ltd). During the months of September, October and November when the greenhouse trials took place the air temperature averaged 15.0 °C and the pot temperature 14.5 °C. The mean air temperature rose from 12 °C in early September to 18 °C in mid November. The temperature range during this period was 3.0 - 31.8 °C.

Additional storage/experimental space was created by modifying an existing cool room by adding two 400W metal halide lamps and one 60W incandescent lamp. These give a light intensity of approximately 100 μmol.m-2.sec-1. The temperature was maintained at 15 °C and the photoperiod was 24 hours.

3.3.1 Callitriche antarctica This species is a prostrate, mat-forming herb which may be either terrestrial or aquatic. It is obviously tolerant of high nutrient levels as it frequently grows in seal wallows. This study needed information to not only maximise growth rates but also to allow production in a commercially appropriate manner. Three experiments were conducted to examine growth in potting mix versus hydroponics at a range of temperatures. Fresh weights were taken in preference to dry weights to gauge commercial productivity.

In the first experiment small plugs (ca. 2 cm diameter) of Callitriche were taken from seedling trays and transplanted to 9 cm square pots containing a pine bark based potting mix. The composition of the potting mix was:

7 Composted pinebark fines 70% Washed river sand 30% Osmocote (8-9 months) low P formula 3.0 kg/m3 3 Lime (CaCO3) 3.0 kg/m Dolomite 3.0 kg/m3 Iron sulphate, slow release formula 0.8 kg/m3 Trace elements (Microma) 0.7 kg/m3

Twelve pots were placed in each of three temperatures in naturally lit phytotron cabinets (‘C’ type, Morse and Evans, 1966). The temperature regimes are summarised in the following table:

Day Night temperature Thermoperiod Photoperiod Mean temperature temperature (°C) (°C) (h) (h) (°C)

12 6 12/12 12 9 16 10 12/12 12 13 20 14 12/12 12 17

In the discussion of results the treatments are identified by their mean temperature.

After 8 weeks in these conditions the fresh weights were 1.88±0.31g at 9°C, 3.31±0.59g at 13°C, and 2.25±0.26g at 17°C.

In a second experiment plants were grown in a hydroponic solution (half strength Hoagland’s No. 2, Hewitt, 1966) in 8 litre plastic containers. After initial adaptation to aquatic habit ca. 15g fresh weight (measured after draining and blotting with paper towels)of Callitriche was placed in the containers in each of the three temperatures in the phytotron cabinets (conditions as described above). Fresh weight gain after 45 days was 12.0 g at 9°C, 25.1 g at 13°C, and 17.4 g at 17°C, so the optimum for growth is likely to be ca. 13°C.

A third experiment, in which increased nutrient concentrations were used, was abandoned after several attempts due to severe filamentous and other algal contamination. Despite these problems Callitriche was observed to grow well even in double strength Hoagland’s No 2 nutrient solution.

Apart from these experiments Callitriche was found to survive high greenhouse temperature(>28 °C) for durations of several hours.

In a commercial situation this species could be grown either as a terrestrial plant, in which case the consumer could cut off the above ground parts as required, or as a hydroponic plant, in which the whole plant would be eaten. The difficulty with the latter would be maintaining cultures free of algae and bacteria. Growth as sprouted seed is also potentially possible, which would simplify the control of algae, but we were unable to test this method due to the unavailability of seed during the period of these studies.

The species is susceptible to aphid infestations.

The tolerance of this species to a wide range of temperature and nutrient conditions, its ability to rapidly colonise habitats by vegetative means, as well its ability set seed under some

8 conditions would suggest that this species has high environmental weed potential. This would be of particular concern in vulnerable alpine and wetland environments. If this were to happen the environmental and economic costs would not justify the potential commercial returns. As a consumer product it would be difficult to maintain the strict control of growth necessary to prevent this. It is therefore reluctantly recommended that this species should not be considered for further development.

3.3.2 Pringlea antiscorbutica Insufficient mature plants were available for experimentation so fresh seed supplies were obtained from Heard Island. This delayed the experimental program and resulted in the use of quite small plants, however in retrospect this may not have been a disadvantage as the smaller plants may prove to be most suitable for consumers. This is discussed further below.

Seed was germinated as detailed above and transplanted into 5 cm diameter plastic pots containing the standard potting mix described previously. Plants were divided between three temperatures in naturally lit cabinets in the phytotron (‘Type C’ cabinets, Morse and Evans, 1962). Although these cabinets are lit by sunlight the effect of 2 layers of glass is to reduce radiation by about 50%. The experiment was conducted between November and March. The temperature regimes and other environmental conditions are listed in the following table:

Day Night Thermoperiod Photoperiod Mean temperature (°C) temperatur temp (h) (h) e (°C) eratu re (°C)

12 6 12/12 12 9 16 10 12/12 12 13 20 14 12/12 12 17

For the discussion of results the treatments are identified by their mean temperature.

Measurements were made at the start of the experiment and after 55 days and 110 days. The total fresh weight per plant at the start of the temperature treatments was 0.89 ±0.06 g. The results are shown in the following table:

9°C 13°C 17°C LSD (0.05)

Leaf area per plant at 55 days (cm2) 38.9b 50.7ab 66.3a 15.8 Fresh weight increase per plant 0 - 55 days (g) 8.1b 12.7a 12.7a 4.4 Leaf fresh weight increase per plant 55 - 110 days (g) 7.8a 6.9a 4.7b 1.7 Mean leaf size at 55 days (cm2) 2.7b 3.9a 4.6a 0.9 Leaf dry weight per plant at 55 days (g) 0.46c 0.64b 0.85a 0.18 Leaf dry weight per plant at 110 days (g) 1.4a 1.6a 1.0b 0.4

Equipment failure prevented the re-measurement of leaf area after 110 days of growth, but up to 55 days the growth was greatest at 17 °C. Leaf fresh weight increased faster at lower temperatures, but this may indicate the effects of the plant not being well adapted to the

9 higher vapour pressure deficit at 17 °C. Interestingly leaf dry weight increased with temperature up to 55 days but in the second half of the experiment the lower temperatures resulted in greater dry weight. The reasons for this are not clear. It may be that light levels were higher towards the end of the experiment or the physiology of the leaves changes as the plants mature. This requires further investigation.

This species is susceptible to aphid, slug and snail infestations.

3.3.3 Stilbocarpa polaris This species was difficult to evaluate in the time available. Although propagation was relatively easy, growth rates were low and no seed was available, resulting in very few plants being available for experiments. In addition the need for sufficient material for sensory and chemical analysis resulted in no material being available for destructive harvesting methods, limiting the types of data available from growth trials. The initial expectation was that the petioles (leaf stems) would be the main edible portion, so leaf numbers and maximum petiole length measurements were taken. In fact the rhizome proved to be the desirable organ, but growth was so slow that no measurements of weight or dimensions were practical.

The optimum temperature for growth was investigated by growing plants in phytotron cabinets. Plants were grown in 150 mm diameter plastic pots in the standard potting mix detailed above. Nutrients were supplemented by watering with half strength Hoagland’s No. 2 once per week. Plants were placed in each of six treatments, all naturally lit but with different photoperiods. These were:

Day Night temperature Thermoperiod Photoperiod Mean temperature temperature (°C) (°C) (h) (h) (°C)

17 9 variable (sine ) 16 13 23 15 variable (sine ) 16 19 29 21 variable (sine ) 16 25 12 6 12/12 12 9 16 10 12/12 12 13 20 14 12/12 12 17

For simplicity these treatments are identified by their mean temperature and photoperiod below. Photoperiod extension was by low intensity incandescent lamps as described by Morse and Evans (1962). The experiments were all performed in winter light conditions in Canberra. The plants at 25°C/16 h and at 17°C/12h had all died after 70 days, and those at 19°C/16h were dying. The latter were all dead by the second harvest at 150 days. There were no losses at 13°C/16h, 13°C/12h or 9°C/12h. However there were no significant differences in leaf number (mean 23.1, an increase of 16.6 during the trial), maximum petiole length (mean 148 mm, the same as at the start of the trial), or maximum leaf diameter (mean 153 mm, 59 mm greater than at the start) after 150 days of growth. Only one plant flowered during the experiment, in the 13°C/16h treatment.

10 Although inconclusive it appears that this species is unable to tolerate lengthy periods with day temperature in excess of 20°C, at least in the relatively bright light conditions in phytotron cabinets (50 - 70% of daylight).

Despite the extremely dry summer of 1997/98 some plants have survived outdoors in Canberra in heavily shaded conditions, though growth was impaired.

Spider mite is a serious pest as the plant’s morphology makes control difficult. Outdoors it attracts slugs and snails.

Flowering also occurred in our growth room after 6 months in a photoperiod of 10 hours, and also outdoors where the photoperiod varies between 9h 41m and 14h 21m. In both situations flowers opened in January. No conclusions can therefore be made about environmental signals that promote flowering. In both locations flowering did not occur in all plants and no viable seed was set.

The slow growth rate, exemplified by leaf numbers only increasing by only about 3 per month, and the unmeasurable increases in rhizome size, will prevent the commercial use of this species.

11 4. Suitability for Human Consumption

4.1 Prior evidence of suitability for human consumption

4.1.1 Stilbocarpa polaris There are numerous references to Stilbocarpa polaris being used for human food. Some of these indicate that large amounts were consumed over several months with no ill effects. Describing the living conditions of sealers in 1820 Bellinghausen noted that consumption of "wild cabbage" (Stilbocarpa polaris) was an effective remedy against scurvy and this made life more tolerable than in South Georgia where there is no equivalent plant. The plants were prepared by scraping the stalks and roots, chopping them finely and making a cabbage flavoured stew with them (Debenham, 1945). Sailors stranded after the wreck of the Bencleugh in 1877 used Macquarie "cabbage" as a vegetable which was described as having the flavour of cabbage and parsnip (Thomson, 1912). Another early visitor was Sinclair (1877 - 1878) who describes his Christmas dinner on Macquarie Island as consisting of "corned beef and an herb that grows here which we call cabbage, potatoes, elephant (seal) tongue, curried parakeets, penguins tongues, hearts and livers, which are first rate, preserved meat, a roly-poly made of blackcurrant jam....so you see we did not fare so bad" (Sinclair manuscript journal quoted in Cumpston 1968.). Obviously by this time it was considered normal for visitors to the island to eat the 'cabbage'. There is also a report of a sealing party being stranded for 4 months in 1910 without provisions that survived well on seal meat, mutton birds and Stilbocarpa polaris (in J. S. Cumpston, op cit p229). Blake, a member Mawson’s Australasian Antarctic Expedition, describes eating sea elephants heart and the stems of Stilbocarpa polaris in 1913.

4.1.2 Pringlea antiscorbutica Daily use of this plant was made by the 1839-43 British expedition to the Antarctic when it visited Kerguelen. It was used either cooked alone or boiled with the ship's beef, pork or pea soup. It is named after Sir John Pringle (1707-1782) a British physician and founder of modern military medicine, who did pioneering work on the prevention of scurvy (Vitamin C deficiency). The specific epithet refers to its antiscorbutic properties.

4.1.3 Callitriche antarctica Although no written records have been found for the suitability of this species for human consumption it resembles the commonly consumed watercress species. It is regularly consumed by scientists and other visitors to sub-antarctic islands with no apparent ill effects. Biologically active compounds verbascocide and iridoid glucosides have been identified in Callitriche stagnalis (Damtoft et al., 1994). Evidence of their biological activity is found in numerous papers (eg Recio et al, 1994; Herbert et al, 1991).

4.2 Flavour profiling Descriptive flavour profiles for each of the three species were needed to assess their likely public acceptance. This part of the project was sub-contracted to Dr MaryAnn Filadelfi- Keszi whose report, containing the details of the methodology and results, is presented in Appendix 1. Briefly, Pringlea and Callitriche were tasted raw, and Pringlea and Stilbocarpa were tasted cooked by eight trained panellists, selected to include a range of

12 cultural backgrounds. (The Stilbocarpa was also tasted raw but was considered by the panel (and by the two scientists) to be too fibrous to bother with a full assessment.). Pringlea antiscorbutica was cooked by plunging into boiling water, boiling for 5 minutes and draining. Stilbocarpa polaris was cooked by plunging into boiling water, boiling for 20 minutes and draining. The panel were able to characterise the appearance, aroma, flavour by mouth, texture and aftertaste of each food sample both qualitatively and quantitatively. All plant materials were consumed within an hour or two of harvest.

The overall ‘score’ out of ten for the appearance of each of the foods was:

Species Organ Preparation Score Callitriche antarctica whole plant raw 7.69 Pringlea antiscorbutica leaves raw 7.75 Pringlea antiscorbutica leaves boiled 7.43 Stilbocarpa polaris leaves and stems boiled 4.00 Stilbocarpa polaris crown boiled 4.69

A subjective interpretation of this is that the Callitriche and Pringlea have considerable visual appeal, but the Stilbocarpa looks somewhat less appetising.

The scores for the other four characteristics (aroma, flavour-by-mouth, texture and aftertaste) were consolidated to give an overall score to describe the overall sensory effects of consuming the foods. The scores were as follows:

Species Organ Preparation Score Callitriche antarctica whole plant raw 7.63 Pringlea antiscorbutica leaves raw 7.31 Pringlea antiscorbutica leaves boiled 7.19 Stilbocarpa polaris leaves, stems and crowns boiled 6.63

A subjective summary of this is that all the foods can be considered very palatable.

4.3 Chemical composition The chemical analysis was sub-contracted to Professor Heather Greenfield and her associates at the Department of food Science and Technology, University of New South Wales. Full details of the methods used and results of the compositional analysis are given in Appendix 2.

The material analysed was raw and cooked Pringlea antiscorbutica, raw Callitriche antarctica and cooked Stilbocarpa polaris. Preparation methods were the same as for flavour profiling. All plant materials were prepared for testing within a few hours of picking.

The results are typical of green leafy vegetables, i.e. a high water content, traces of fat and available carbohydrate, low levels of protein and small amounts of dietary fibre. As expected the plants were rich sources of potassium, and also contained useful levels of iron (although bioavailability from these plant sources may be low).

Thiamin and riboflavin were at low levels. Vitamin C was at appreciable levels in Pringlea antiscorbutica and the levels were only about 20% lower in the cooked plant. Callitriche

13 antarctica had useful levels of vitamin C, but vitamin C was not detected in Stilbocarpa polaris (boiled) presumably due to the long period of boiling needed for this plant to become edible. The plants were all good sources of carotenoids but levels in Stilbocarpa polaris were lower presumably due to the long period of cooking needed.

From a nutritional point of view these plants would be useful if consumed as part of a mixed diet. The only reservation is that Stilbocarpa polaris requires long cooking to render it edible; this reduces the vitamin levels in the food considerably.

4.4 Toxicity and pharmacology No investigation of toxicity was made for any of these foodstuffs, primarily because of the expense involved. Whilst their long history of human consumption would suggest there are no ill effects from consumption it would nevertheless be prudent to investigate this further (see ‘Recommendations’ below). Similarly investigation for pharmaceutical effects was beyond the scope of this study. It is known that overseas interest has been shown in the essential oil of Pringlea antiscorbutica.

14 5. Discussion

All three species were considered to be quite palatable by the tasting panel, and all had useful nutritional qualities. However, the poor growth rate of Stilbocarpa, and the considerable weed potential of Callitriche will halt their further development for the time being. Research may be able to improve the growth rate of Stilbocarpa to commercially acceptable levels but this must be considered as a long term project. The rapid rate of vegetative propagation of Callitriche could result in its rapid colonisation of large parts of south eastern Australia even if sterile forms could be developed.

Pringlea antiscorbutica however does appear to have potential for further development. It will be difficult to grow in most locations in Australia as there is research evidence that it is unable to adapt to high vapour pressure deficits or restricted soil water availability (Dorne, A. J. and Bligny, R. 1993). However, when grown with an unlimited supply of water, as in these experiments, it has proved adaptable to temperatures considerably higher than those in its native habitat. Some plants have even survived outdoor planting in Canberra. It is likely that production will be possible in Tasmania or south-eastern mainland Australia in cool locations. A possible scenario is the establishment of seed production facilities (which require perennial growth) in the coolest locations, with winter production from seed for consumption closer to large population centres. It is expected that this new crop will expand the range and increase volumes of vegetable consumption rather than take away market share from existing crops.

The product offered to the consumer is likely to be either sprouted seeds or the complete rosettes of young plants, as the end use is likely to be as a garnish rather than as a green vegetable. The nearest comparisons are with products such as mustard or radish spouts or water cress.

Accurate data on market size for specialty crops such as sprouted seeds, watercress, rocket etc is not available. Personal observation in supermarkets and restaurants suggest that these markets are not insignificant. Even for important crops such as lettuce and spinach the statistics are notoriously inaccurate and are believed to grossly underestimate production due to cash transactions by growers. The smaller the size of the crop the greater the error. The worst inaccuracies are for leaf bunching crops that have multiple harvests per annum where volumes may be as much as 90% higher than those reported. Traditional crops appear to have had rather static production in recent years. In contrast 'new' crops such as Chinese Cabbage have been growing rapidly in importance but the lack of adequate statistics makes prediction of market size for new crops particularly difficult. Specialty crops also tend to have higher value than traditional crops which are often in oversupply.

A visit to the Sydney based company ‘Bean Sprouts Australia Pty Ltd’ (Hans van der Sander) provided the following information on the sprout industry. Approximately 80% of the industry is in NSW, and the biggest single product by far is mung bean, though there are many other crops produced such as onion, alfalfa and mustard sprouts. The mung bean seed comes from Queensland and Victoria, alfalfa from South Australia. Onion seed is obtained from the USA and China. There are three major producers in Sydney.

15 Production systems vary according to the crop. Some crops (eg mung bean) only require a moist environment for a few days. The sprouting temperature is usually 19°C. Some species are pregerminated in revolving drums then moved to beds, others are germinated directly in plastic punnets used to package the products for supermarket shelves. In all cases the speed of germination is important and the maximum permissible appears to be about 7 days.

Apart from maintaining hygienic conditions the main production problems are the quality of seed (hard seed) and uniformity of sprouting (the ideal characteristics are: size range 50 - 70 mm, no secondary roots, whiteness). Shelf life is considered a minor problem which is mainly a matter of educating retailers. The details of nutritional quality are not important to consumers. (For example although research shows that white sprouts are better than green ones consumers prefer green). In NSW about 30 tonnes per week (final product) is produced from about 12 tonnes of seed. Total consumption of mung bean sprouts is estimated to be about 75 tonnes per week. This is all for the domestic market. Alfalfa accounts for a further 30 tonnes per week.

Apart from the fresh sprout industry there are large international markets for seed for the various crops that are grown.

As a signatory the International Convention on Biological Diversity Australia does not have exclusive access to Pringlea, so no property rights can be asserted for the common form of the species. However, a selection process for speed of germination and vigour may result in forms that can be protected either under patent or plant breeders rights laws.

16 6. Recommendations

Pringlea antiscorbutica should be further investigated as a potential food crop. An industry partner should be recruited to undertake growth trials in a commercial setting. The location of this trial should probably be in Tasmania where the climate should ensure the survival of the crop. A research project currently under way at the Tundra Biology Unit, Department of Botany, University of Queensland is currently investigating the detailed physiology of this species and may provide information that will facilitate accelerated growth of the crop. ANBG is a partner in this project. In addition an examination of the properties of the essential oil derived from this species would be desirable, and before any public release its toxicology should also be fully investigated.

Callitriche antarctica, despite its attractiveness as a food crop and its high growth rate, presents too great a risk of becoming an environmental weed to be widely grown at this stage. Further work on its biology is beyond the scope of this project but is ecologically desirable. In addition this crop has potential pharmaceutical benefits which should be further investigated.

Stilbocarpa polaris grows too slowly to be considered for further development at this stage. Despite having a pleasant flavour it is not as visually appealing as the other species and no further work is recommended at present.

17 7. References

Clark M. R. and Dingwall P.R. (1985) Conservation of Islands of the Southern Ocean. International Union for Conservation of Nature and Natural Resources, Cambridge, U.K.

Cumpston J. S.(1968) Macquarie Island. ANARE.

Damtoft S, Jensen S R, Thorsen, Molgard, P and Olsen C E (1994) Iridoids and verbascocide in Callitrichaceae, Hippuridaceae and Lentibulariacea. Phytochemistry 36 (4):927-929.

Debenham F. (ed.) (1945) The Voyage of Captain Bellinghausen to the Antarctic Seas, 1819-21, p.364.

Dorne A. J. and Bligny R. (1993). Physiological adaptation to subantarctic climate by the Kerguelen cabbage, Pringlea antiscorbutica R. Br. . Polar Biology 13:55-60

Flora of Australia (1993) Volume 50 Oceanic Islands 2. Australian Government Publishing Service, Canberra.

Herbert J M, Maffrand J P , Taoubi K, Augereau J M, Fouraste I, and Gleye J. (1991) Verbascocide isolated from Lantana camara, an inhibitor of protein kinase C. J. Natural Products 54(6):1595-1600.

Hewitt E J (1966) Sand and Water Culture Methods in the Study of Plant Nutrition. 2nd edition, pp. 187-193. Commw. Agric. Bureau: Farnham Royal, U. K.

Morse R N and Evans L T (1962) Design and development of CERES - an Australian phytotron. J. Agric. Eng. Res. 7: 128-140.

Recio M C, Giner R M, Manez S and Rios J L (1994) Structural considerations on the iridoids as anti-inflammatory agents. Planta Med. 60(3):232-234.

Selkirk P M., Seppelt R D and Selkirk D R (1990) Subantarctic Macquarie Island: environment and biology. Cambridge University Press, Cambridge, UK.

Thomson J I (1912) Voyages and Wanderings in Far-Off Seas and Lands, London.

8. Appendix 1: Flavour Profiling

The following appendix is an edited version of a report commissioned especially for this project.

19 Keszi Research Company Pty Ltd ACN 070 525 101

PO Box 3322 Narellan NSW 2567 Tel/Fax 02 / 4658-0188 E-mail [email protected]

FLAVOUR PROFILING OF THREE SUB-ANTARCTIC PLANTS

PREPARED BY

Dr MaryAnn Filadelfi-Keszi

FOR

Iain Dawson Horticultural Research Australian Nature Conservation Agency Australian National Botanic Gardens GPO Box 1777 Canberra, ACT 2601

24 November 1997

20 Executive Summary

Eight trained panellists conducted a comprehensive quantitative descriptive analysis (QDA) session to profile the key characteristics (attributes) in appearance, aroma, flavour-by-mouth, texture, aftertaste and overall amplitude of three sub-antarctic plant species, raw Callitriche antarctica (Cress), raw and cooked Pringlea antiscorbutica (Kerguelen Cabbage), and cooked Stilbocarpa polaris (Macquarie Island Cabbage).

In addition to the five appearance descriptors, 21 descriptors were developed for the raw Callitriche Antarctica (Cress).

Five appearance descriptors and 22 other descriptors for the aroma, flavour-by-mouth, texture, aftertaste, and overall amplitude were developed for raw Pringlea antiscorbutica (Kerguelen Cabbage) .

In contrast, five appearance descriptors and 31 other descriptors for the aroma, flavour-by- mouth, texture, aftertaste, and overall amplitude were developed for cooked Pringlea antiscorbutica (Kerguelen Cabbage).

Eight appearance descriptors were developed to describe the leaf/stem and crown areas in the appearance of Stilbocarpa polaris. Thirty-four other descriptors were developed to describe the aroma, flavour-by-mouth, texture, aftertaste, and overall amplitude of Stilbocarpa polaris.

8.1 Objectives To develop a descriptive flavour profile for three raw and cooked sub-antarctic plant species.

8.2 Methodology On 11 November 1997, at the trained panel facility in the Department of Food Science and Technology at the University of New South Wales, Kensington, eight trained panellists conducted a comprehensive quantitative descriptive analysis (QDA) session to profile the key characteristics (attributes) in appearance, aroma, flavour-by-mouth, texture, aftertaste and overall amplitude of three sub-antarctic plant species.

After development of the descriptors or attributes, panellists individually rated the intensities of each attribute. Data from each panellist were collected on a master sheet. The mean scores obtained from combining the individual intensity scores were then used to graph the plant profiles. Appearance descriptors were not graphed as the individual attributes were not rated.

The plant species evaluated included:

Raw Callitriche antarctica (Cress), raw and cooked Pringlea antiscorbutica (Kerguelen Cabbage), and cooked Stilbocarpa polaris (Macquarie Island Cabbage).

21 8.3 Results and Discussion

8.3.1 Raw Callitriche antarctica (Cress) Tabulated mean attribute scores are included in Table 8.1.

The appearance (visual) key attributes that were agreed to by consensus to describe raw Callitriche antarctica included very basic terms such as green, healthy/wholesome, delicate tear-drop leaves and thin trailing stem. Panellists gave the appearance amplitude (overall impression of the appearance) a score of 7.69 out of 10.

The other key attributes that were advanced by the trained panel to describe Callitriche antarctica were:

AROMA: PERCEIVED BY SNIFFING

GREEN/GRASSY: AS FRESHLY MOWED GRASS CLEAN/REFRESHING: FRESH AND INVIGORATING SPINACH/SILVERBEET: SELF-EXPLANATORY EARTHY: CHARACTERISTIC OF WET CLAY/SOIL AROMA AMPLITUDE: OVERALL IMPRESSION OR BALANCE/BLENDEDNESS OF THE AROMA ATTRIBUTES

FLAVOUR-BY-MOUTH: PERCEIVED BY PLACING FOOD IN MOUTH AS IN EATING

GRASSY/LEAFY: AS FRESHLY MOWED GRASS OR CRUSHED FOLIAGE MUSTARD GREEN: SELF EXPLANATORY MUSHROOMY/EARTHY: SELF EXPLANATORY ALLIUM: GREEN SPRING ONION FLAVOUR SWEET: SELF EXPLANATORY SPINACH/SILVERBEET: SELF EXPLANATORY F-B-M AMPLITUDE: OVERALL IMPRESSION OR BALANCE/BLENDEDNESS OF THE FLAVOUR ATTRIBUTES

TEXTURE: MOUTHFEELS

CRISP: FRESH AND FIRM TENDER/SOFT: EASILY CRUSHED, MALLEABLE STRINGY STEMS: FIBROUS STEMS SUCCULENT: THICK FLESHY TISSUES TEXTURE AMPLITUDE: OVERALL IMPRESSION OR BALANCE/BLENDEDNESS OF THE TEXTURE ATTRIBUTES

AFTERTASTE: FLAVOURS OR MOUTHFEELS 5 MINUTES AFTER SWALLOWING

ASTRINGENT: SHARP, CAUSING CONTRACTION OF ORAL TISSUES, DRY MOUTH MUSTARDY/LEAFY: SELF EXPLANATORY AFTERTASTE AMPLITUDE: OVERALL IMPRESSION OR BALANCE/BLENDEDNESS OF THE AFTERTASTE ATTRIBUTES

OVERALL AMPLITUDE: OVERALL IMPRESSION OR THE BALANCE/BLENDEDNESS OF THE AROMA, FLAVOUR , TEXTURE, AND AFTERTASTE ATTRIBUTES

8.3.2 Raw Pringlea antiscorbutica (Kerguelen Cabbage) Table 8.2 contains the tabulated mean attribute scores for the raw Pringlea antiscorbutica.

Green, leafy, attractive, and succulent were put forward to describe the raw Pringlea antiscorbutica. Panellists rated the appearance amplitude of Pringlea antiscorbutica as 7.75 out of 10.

The other key attributes developed by the trained panel to describe raw Pringlea antiscorbutica are given below:

AROMA: PERCEIVED BY SNIFFING

NASTURTIUM: SELF EXPLANATORY RADISH: SELF EXPLANATORY CAPERS: SELF EXPLANATORY PIQUANT: PUNGENT/TART AROMA CARDAMOM: SELF EXPLANATORY AROMA AMPLITUDE: OVERALL IMPRESSION OR BALANCE/BLENDEDNESS OF THE AROMA ATTRIBUTES

FLAVOUR-BY-MOUTH: PERCEIVED BY PLACING FOOD IN MOUTH AS IN EATING

HORSERADISH/RADISH: SELF EXPLANATORY CHIVE: SELF EXPLANATORY SHARP/SPICY HOT: PUNGENT, SEASONED, HIGHLY FLAVOURED BITTER: SELF EXPLANATORY F-B-M AMPLITUDE: OVERALL IMPRESSION OR BALANCE/BLENDEDNESS OF THE FLAVOUR ATTRIBUTES

TEXTURE: MOUTHFEELS

SUCCULENT/FLESHY: THICK FLESHY TISSUES LEAFY: FOLIAGE (SPINACH TYPE OF FEEL) FIRM: NOT SOFT CHEWY: CONSISTENCY REQUIRING MASTICATION TEXTURE AMPLITUDE: OVERALL IMPRESSION OR BALANCE/BLENDEDNESS OF THE TEXTURE ATTRIBUTES

AFTERTASTE: FLAVOURS OR MOUTHFEELS 5 MINUTES AFTER SWALLOWING

RADISH: SELF EXPLANATORY SPICY HOT: PUNGENT SALIVARY: PROMOTING HIGH SALIVATION IN MOUTH BITTER: SELF EXPLANATORY AFTERTASTE AMPLITUDE: OVERALL IMPRESSION OR BALANCE/BLENDEDNESS OF THE AFTERTASTE ATTRIBUTES

OVERALL AMPLITUDE: OVERALL IMPRESSION OR THE BALANCE/BLENDEDNESS OF THE AROMA, FLAVOUR , TEXTURE, AND AFTERTASTE ATTRIBUTES

23 8.3.3 Cooked Pringlea antiscorbutica (Kerguelen Cabbage) Tabulated mean attribute scores are included in Table 8.3.

The appearance of cooked Pringlea antiscorbutica was described in similar terms to the raw Pringlea antiscorbutica. The terms were still green, leafy, attractive, and succulent. The amplitude, however, decreased slightly to 7.43 out of 10.

The remaining key attributes were:

AROMA: PERCEIVED BY SNIFFING

NASTURTIUM: SELF EXPLANATORY RADISH: SELF EXPLANATORY CAPERS: SELF EXPLANATORY CARDAMOM: SELF EXPLANATORY NUTTY: SELF EXPLANATORY BUTTERY: SELF EXPLANATORY SPINACH: SELF EXPLANATORY OVER-BOILED POTATO: OVER COOKED POTATO AROMA AMPLITUDE: OVERALL IMPRESSION OR BALANCE/BLENDEDNESS OF THE AROMA ATTRIBUTES

FLAVOUR-BY-MOUTH: PERCEIVED BY PLACING FOOD IN MOUTH AS IN EATING

HORSERADISH/RADISH: SELF EXPLANATORY CHIVE: SELF EXPLANATORY SHARP/SPICY HOT: PUNGENT, SEASONED, HIGHLY FLAVOURED BITTER: SELF EXPLANATORY BUTTERY: SELF EXPLANATORY NUTTY: SELF EXPLANATORY SPINACH: SELF EXPLANATORY OVER-BOILED POTATO: OVER COOKED POTATO VEGETABLE STOCK: SOUP-LIKE FLAVOUR MADE FROM VARIOUS VEGETABLES F-B-M AMPLITUDE: OVERALL IMPRESSION OR BALANCE/BLENDEDNESS OF THE FLAVOUR ATTRIBUTES

TEXTURE: MOUTHFEELS

SUCCULENT/FLESHY: THICK FLESHY TISSUE LEAFY: FOLIAGE (SPINACH TYPE OF FEEL) FIRM: NOT SOFT CHEWY: CONSISTENCY REQUIRING MASTICATION TEXTURE AMPLITUDE: OVERALL IMPRESSION OR BALANCE/BLENDEDNESS OF THE TEXTURE ATTRIBUTES

AFTERTASTE: FLAVOURS OR MOUTHFEELS 5 MINUTES AFTER SWALLOWING RADISH: SELF EXPLANATORY SPICY HOT: PUNGENT BITTER: SELF EXPLANATORY ASTRINGENT: SHARP CAUSING CONTRACTION OF ORAL TISSUES, DRY MOUTH AFTERTASTE AMPLITUDE: OVERALL IMPRESSION OR BALANCE/BLENDEDNESS OF THE AFTERTASTE ATTRIBUTES

OVERALL AMPLITUDE: OVERALL IMPRESSION OR THE BALANCE/BLENDEDNESS OF THE AROMA, FLAVOUR , TEXTURE, AND AFTERTASTE ATTRIBUTES

24 8.3.4 Cooked Stilbocarpa polaris (Macquarie Island Cabbage) Tabulated mean attribute scores can be found in Table 8.4.

The appearance of the cooked Stilbocarpa polaris was arranged into the leaf/stem and crown areas. The leaf/stem area was described as hairy, green, and fibrous. The amplitude score for this area was 4.00 out of 10.

The crown area was described as variegated olive green, knobby, and fibrous. The amplitude score for the crown was 4.69.

The aroma, flavour-by-mouth, texture, aftertaste, and overall amplitude follow:

AROMA: PERCEIVED BY SNIFFING

LEGUMES: SELF EXPLANATORY ARTICHOKE HEARTS: SELF EXPLANATORY CELERY LEAVES: SELF EXPLANATORY BRASSICA: CABBAGE, BROCCOLI, ETC (SULPHUR-LIKE) CARROT: SELF EXPLANATORY AROMA AMPLITUDE: OVERALL IMPRESSION OR BALANCE/BLENDEDNESS OF THE AROMA ATTRIBUTES

FLAVOUR-BY-MOUTH: PERCEIVED BY PLACING FOOD IN MOUTH AS IN EATING

LEAF/STEM

BITTER/TANNIN: SELF EXPLANATORY CELERY: SELF EXPLANATORY CARROT: SELF EXPLANATORY LEGUME/BROAD BEAN: SELF EXPLANATORY GLOBE ARTICHOKE: SELF EXPLANATORY PHENOLIC: ANTISEPTIC/DISINFECTANT TYPE OF FLAVOUR AMPLITUDE: OVERALL IMPRESSION OR BALANCE/BLENDEDNESS OF THE FLAVOUR ATTRIBUTES

CROWN

LEGUME/BROAD BEAN: SELF EXPLANATORY GLOBE ARTICHOKE: SELF EXPLANATORY ROOT VEGETABLE (CARROT/PARSNIP): SELF EXPLANATORY BRASSICA: SELF EXPLANATORY BITTER/TANNIN: SELF EXPLANATORY AMPLITUDE: OVERALL IMPRESSION OR BALANCE/BLENDEDNESS OF THE FLAVOUR ATTRIBUTES

TEXTURE: MOUTHFEELS

LEAF/STEM

HAIRY: THREAD-LIKE FEEL FIBROUS: NUMEROUS FIBRES CHEWY: CONSISTENCY REQUIRING MASTICATION PITHY: SOFT FIBROUS AMPLITUDE: OVERALL IMPRESSION OR BALANCE/BLENDEDNESS OF THE TEXTURE ATTRIBUTES

CROWN

PITHY/FLESHY: SOFT FIBROUS TENDER: SOFT

25 FIBROUS: NUMEROUS FIBRES AMPLITUDE: OVERALL IMPRESSION OR BALANCE/BLENDEDNESS OF THE TEXTURE ATTRIBUTES AFTERTASTE: FLAVOURS OR MOUTHFEELS 5 MINUTES AFTER SWALLOWING

BITTER: SELF EXPLANATORY ASTRINGENT: SHARP, CAUSING CONTRACTION OF ORAL TISSUES, DRY MOUTH ARTICHOKE: SELF EXPLANATORY SWEET: SELF EXPLANATORY AFTERTASTE AMPLITUDE: OVERALL IMPRESSION OR BALANCE/BLENDEDNESS OF THE AFTERTASTE ATTRIBUTES

OVERALL AMPLITUDE: OVERALL IMPRESSION OR THE BALANCE/BLENDEDNESS OF THE AROMA, FLAVOUR , TEXTURE, AND AFTERTASTE ATTRIBUTES

8.4 Conclusions

Flavour descriptors (attributes) were developed for three sub-antarctic plant species through a consensus process using eight trained panellists. The three sub-antarctic species evaluated were raw Callitriche antarctica (Cress), raw Pringlea antiscorbutica (Kerguelen Cabbage), cooked Pringlea antiscorbutica, and cooked Stilbocarpa polaris (Macquarie Island Cabbage).

In addition to the five appearance descriptors, 21 descriptors were developed for the raw Callitriche Antarctica (Cress).

Five appearance descriptors were developed for raw Pringlea antiscorbutica (Kerguelen Cabbage) and 22 others for the aroma, flavour-by-mouth, texture, aftertaste, and overall amplitude.

Cooked Stilbocarpa polaris (Macquarie Island Cabbage) was arranged into a leaf/stem area and a crown area. Eight appearance descriptors were developed to describe these two areas in the appearance of Stilbocarpa polaris. Thirty-four other descriptors were developed to describe the aroma, flavour-by-mouth, texture, aftertaste, and overall amplitude of Stilbocarpa polaris.

26 TABLE 8.1: Tabulated mean attribute scores for Raw Callitriche antarctica (Cress).

AROMA

1 GREEN/GRASSY 4.44 2 CLEAN/REFRESHING 5.00 3 SPINACH/SILVERBEET 3.44 4 EARTHY 2.44 5 AROMA AMPLITUDE 4.38

FLAVOUR-BY-MOUTH

6 GRASSY/LEAFY 6.13 7 MUSTARD GREEN 4.13 8 MUSHROOM/EARTHY 3.75 9 ALLIUM 1.69 10 SWEET 1.06 11 SPINACH/SILVERBEET 1.25 12 F-B-M AMPLITUDE 6.06

TEXTURE

13 CRISP 5.25 14 TENDER/SOFT 5.63 15 STRINGY STEMS 3.63 16 SUCCULENT 3.50 17 TEXTURE AMPLITUDE 5.75

AFTERTASTE

18 ASTRINGENT 4.81 19 MUSTARDY/LEAFY 3.38 20 AFTERTASTE 4.56 AMPLITUDE

21 OVERALL AMPLITUDE 7.63

27 TABLE 8.2: Tabulated mean attribute scores for raw Pringlea antiscorbutica (Kerguelen Cabbage)

AROMA

1 NASTURTIUM 6.38 2 RADISH 6.19 3 CAPERS 4.13 4 PIQUANT 5.13 5 CARDAMOM 1.38 6 AROMA AMPLITUDE 6.69

FLAVOUR-BY-MOUTH

7 HORSERADISH/RADISH 7.38 8 CHIVE 4.25 9 SHARP/SPICY HOT 5.00 10 BITTER 2.50 11 F-B-M AMPLITUDE 7.25

TEXTURE

12 SUCCULENT/FLESHY 6.63 13 LEAFY 6.25 14 FIRM 5.63 15 CHEWY 4.88 16 TEXTURE AMPLITUDE 6.31

AFTERTASTE

17 RADISH 5.50 18 SPICY HOT 4.00 19 SALIVARY 4.00 20 BITTER 1.63 21 AFTERTASTE AMPLITUDE 6.13

22 OVERALL AMPLITUDE 7.31

28 TABLE 8.3: Tabulated mean attribute scores cooked Pringlea antiscorbutica (Kerguelen Cabbage).

AROMA

1 NASTURTIUM 4.00 2 RADISH 3.38 3 CAPERS 3.13 4 PIQUANT 3.63 5 CARDAMOM .38 6 NUTTY 2.63 7 BUTTERY 2.88 8 SPINACH 4.38 9 OVER-BOILED POTATO 2.13 10 AROMA AMPLITUDE 6.50

FLAVOUR-BY-MOUTH

11 HORSERADISH 4.25 12 CHIVE 2.75 13 SHARP/SPICY 1.50 14 BITTER 1.63 15 BUTTERY 3.13 16 NUTTY 2.88 17 SPINACH 5.63 18 OVER-BOILED POTATO .87 19 VEGETABLE STOCK 2.88 20 F-B-M AMPLITUDE 7.25

TEXTURE

21 SUCCULENT 6.50 22 LEAFY 6.25 23 FIRM 4.25 24 CHEWY 4.38 25 TEXTURE AMPLITUDE 7.00

AFTERTASTE

26 RADISH 2.88 27 SPICY HOT .88 28 BITTER 2.44 29 ASTRINGENT 1.56 30 AFTERTASTE AMPLITUDE 5.63

31 OVERALL AMPLITUDE 7.19

29 TABLE 8.4: Tabulated mean attribute scores Cooked Stilbocarpa polaris(Macquarie Island Cabbage).

AROMA

1 LEGUMES 5.88 2 ARTICHOKE HEARTS 4.56 3 CELERY LEAVES 3.75 4 BRASSICA 3.63 5 CARROT 2.69 6 AROMA AMPLITUDE 5.63

FLAVOUR-BY-MOUTH

LEAF STEM

7 BITTER/TANNIN 5.63 8 CELERY 3.75 9 CARROT 3.13 10 LEGUME/BROAD BEAN 3.63 11 GLOBE ARTICHOKE 3.38 12 PHENOLIC 3.13 13 LEAF/STEM AMPLITUDE 3.50

CROWN

14 LEGUME/BROAD BEAN 5.50 15 GLOBE ARTICHOKE 5.75 16 ROOT VEGETABLES 5.13 17 BRASSICA 4.06 18 BITTER/TANNIN 3.19 19 CROWN AMPLITUDE 6.50

TEXTURE

LEAF/STEM

20 HAIRY 6.00 21 FIBROUS 6.13 22 CHEWY 5.44 23 PITHY 4.00 24 LEAF/STEM AMPLITUDE 3.69

CROWN

25 PITHY/FLESHY 6.25 26 TENDER 5.38 27 FIBROUS 2.38 28 CROWN AMPLITUDE 5.44

AFTERTASTE

29 BITTER 5.44 30 ASTRINGENT 4.75 31 ARTICHOKE 3.75 32 SWEET .88 33 AFTERTASTE AMPLITUDE 4.38

34 OVERALL AMPLITUDE 6.63

30 9. Appendix 2: Nutrient Composition

The following is an edited version of a report especially commissioned for this project.

NUTRIENT COMPOSITION OF THREE SPECIES OF SUB-ANTARCTIC PLANTS

A report

Eileen Emmerson, Heather Greenfield and Rosario Sagum, Department of Food Science and Technology, University of New South Wales, Sydney NSW 2052.

32 9.1 Plants The three species provided for analysis were:

• Pringlea antiscorbutica (analysed raw and cooked)

• Callitriche antarctica (analysed raw)

• Stilbocarpa polaris (analysed cooked)

9.2 Cooking Methods Pringlea antiscorbutica was cooked by plunging into boiling water, boiling for 5 minutes and draining.

Stilbocarpa polaris was cooked by plunging into boiling water, boiling for 20 minutes and draining.

9.3 Analyses Nutrients analysed and methods of analysis were:

• Moisture (vacuum-drying, Wills et al. 1983) • Ash (muffle furnace ashing, Wills et al. 1983) • Protein (LECO nitrogen analysis, AOAC Method no. 968.06, protein conversion factor used 6.25 • Fat (acid hydrolysis; Wills et al. 1983) • Sugars (HPLC, Wills et al. 1983) • Starch (enzymatic hydrolysis followed by HPLC; Wills et al. 1983) • Total dietary fibre (gravimetric method, AOAC Method No. 985.29, modified by running two blanks throughout the entire procedure) • Energy (calculated from Atwater factors as described by Greenfield & Southgate, 1992) • Minerals: sodium, potassium, calcium, iron, magnesium, zinc, manganese, copper (atomic absorption spectroscopy of acid solutions of ash, Wills et al. 1983); phosphorus by colorimetry of the same ash solution (AOAC Method No. 931.01) • Vitamins: thiamin (thiochrome method, AOAC Method 957.17); riboflavin (fluorimetry, AOAC Method No. 970.605); Vitamin C (ascorbic acid plus dehydroascorbic acid, fluorimetry, AOAC Method No. 967.22), carotenoids (column chromatography, AOAC Method No. 970.64).

33 9.4 Quality Control All analyses were performed in duplicate, results were accepted if within 10% of the mean. The sum of the proximates fell between 98 g – 103 g, representing a satisfactory total recovery from 100 g plant material analysed. For protein, fat, minerals and ash SRM 1548 Total Diet was used for data quality assurance.

9.5 Results The results for the proximate composition of the total of four foods analysed are given in Table 11.1. The results are typical of green leafy vegetables, i.e. a high water content, traces of fat and available carbohydrate, low levels of protein and small amounts of dietary fibre.

Table 9.1. Nutrient composition per 100 g edible portion.

Pringlea Pringlea Callitriche Stilbocarpa antiscorbutica, antiscorbutica, antarctica, polaris, raw boiled raw boiled

Water (g) 92.9 95.3 92 91 Protein (g) 3.6 3.8 2.2 1 Fat (g) 0.9 0.9 0.4 1 Carbohydrates (g) Glucose 1.1 0.6 0.6 1 Fructose 0.4 0.4 0.4 1 Sucrose 0 0 0 1 Maltose 0 0 0 0 Lactose 0 0 0 0 Starch 0.6 0.4 2.7 4 Energy (kJ) 129 121 114 165 Ash (g) 2 0.9 1.6 1 Dietary fibre (g) 0.3 0.3 0.4 1

The results for minerals are shown in Table 11.2. As expected the plants were rich sources of potassium, and also contained useful levels of iron (although bioavailability from these plant sources may be low).

The results for vitamin levels are shown in Table 11.3. Thiamin and riboflavin were at low levels. Vitamin C was at appreciable levels in Pringlea antiscorbutica and the levels were only about 20% lower in the cooked plant. Callitriche antarctica had useful levels of vitamin C, but vitamin C was not detected in Stilbocarpa polaris (boiled) presumably due to the long period of boiling needed for this plant to become edible. The plants were all good sources of carotenoids but levels in Stilbocarpa polaris were lower presumably due to the long period of cooking needed.

34 Table 9.2 Mineral and vitamin composition (per 100 g edible portion)

Pringlea Pringlea Callitriche Stilbocarpa antiscorbutica antiscorbutica, antarctica, polaris, , raw boiled raw boiled

Minerals (mg) Na 10 6 22 19 K 290 203 290 241 Ca 23 20 19 23 Fe 2 1 3 1 Mg 35 26 30 40 Zn 2.8 2 3.4 3 Mn 8.5 8.7 7.4 2.2 Cu 0.4 0.3 0.6 0.7 P 77 47 38 60 Vitamins Thiamin (mg) 0.006 0.006 0.006 Trace Riboflavin (mg) * Trace Trace Trace Trace Vitamin C (mg) 197 154 42 0 Carotenes (μg) β-carotene 162.8 147.9 121.5 33 α-carotene 1228.7 1205.4 1698.5 87.8 Cryptoxanthin 29.2 25.7 139 21.5

(* Trace = < 0.006)

9.6 Conclusion From a nutritional point of view these plants would be useful if consumed as part of a mixed diet. The only reservation is that Stilbocarpa polaris requires long cooking to render it edible; this reduces the vitamin levels in the food considerably.

9.7 References AOAC (1990) Official methods of analysis of the Association of Official Analytical Chemists. 2 vols. 15th ed. Washington, DC: AOAC.

Greenfield, H. & Southgate, D.A.T. (1992) Food composition data. Production, management and use. Barking UK: Elsevier Applied Science.

Wills, R.B.H., Scriven, F.M. & Greenfield, H. (1983) Nutrient composition of stone fruit (Prunus spp.) cultivars: apricot, cherry, nectarine, peach and plum. J.Sci. Food Agric. 34: 1383-9.