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Accepted Manuscript Evaluating the sensory properties of unpolished Australian wild rice Tiparat Tikapunya, Robert J. Henry, Heather Smyth PII: S0963-9969(17)30722-6 DOI: doi:10.1016/j.foodres.2017.10.037 Reference: FRIN 7085 To appear in: Food Research International Received date: 1 June 2017 Revised date: 5 October 2017 Accepted date: 19 October 2017 Please cite this article as: Tiparat Tikapunya, Robert J. Henry, Heather Smyth , Evaluating the sensory properties of unpolished Australian wild rice. The address for the corresponding author was captured as affiliation for all authors. Please check if appropriate. Frin(2017), doi:10.1016/j.foodres.2017.10.037 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. ACCEPTED MANUSCRIPT Evaluating the sensory properties of unpolished Australian wild rice Tiparat Tikapunya1,2 , Robert J Henry1, Heather Smyth1,3 1 Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Centre for Nutrition and Food Science, Brisbane, QLD 4072, Australia 2 Food Science and Technology Program, Faculty of Agriculture and Technology, Lampang Rajabhat University, Lampang, Thailand. 3 Corresponding author ACCEPTED MANUSCRIPT 1 ACCEPTED MANUSCRIPT ABSTACT Australian wild rices are genetically distinct from commercially cultivated rices and present new opportunities for the development of improved rice cultivars. Before use in rice breeding, the eating and cooking properties of Australian wild rice must first be understood as these are key factors in determining rice quality and consumer acceptance. Samples of Australian wild rice (taxa B) were collected and evaluated together with a commercial Canadian wild rice (Zizania aquatic L), Oryza sativa L.cv. Nipponbare, and selected commercial rices including long grain, medium grain, basmati, red basmati, and red rice. Cooking profiles were established, physical traits were measured and conventional descriptive analysis techniques were used to compare the sensory properties of the unpolished rices. Twenty six descriptors, together with definitions, were developed with a panel of twelve experienced assessors including aroma, flavour, texture and aftertaste attributes. Results reveal that the Australian wild rice had a mild aroma and flavour similar to that of red rice and red basmati but without the lingering aftertaste. In terms of texture, the wild rice was firmer, and somewhat crunchy and chewy rather than soft and fluffy despite requiring a longer cooking time. The sensory, physical and cooking profiles indicate that Australian wild rice has a high potential for commercialization in itself and provides a suitable genetic source for breeding programs, particularly in the coloured rice market. Keywords: Australian wild rice, sensory, descriptive analysis, rice quality, cooking profile ACCEPTED MANUSCRIPT 2 ACCEPTED MANUSCRIPT 1. INTRODUCTION Rice is the only cereal crop cooked and consumed mainly as whole grains and therefore the eating characteristics of the whole rice grain is much more important than for any other crop food (Hossain et al., 2009). Consumers from developed countries demand rice with good cooking and eating characteristics, but in many developing regions where rice is a staple food, nutritional value is more important (Sattari et al., 2015). For many decades, scientists and plant breeders have devoted much attention to improving the quality of cultivated rice. More recently, researchers are turning to wild rice species to source new quality and production traits for incorporation into improved commercial cultivars (Henry et al., 2016). Australian wild rices offer a potentially valuable source of novel alleles for rice breeding purposes due to their diversity and relative isolation from cultivated rice (Brozynska et al., 2017) No research has been conducted on consumer traits of Australian wild rice except for our earlier work on the physical properties of the grain (Tikapunya et al., 2016). An improved understand of the qualities of Australian wild rices will be required to fully realise their potential for commercial breeding and production purposes. Advances in the analysis of the genetic and molecular basis of rice quality (Anacleto et al. 2015) and consumer preferences will assist in positioning these wild rices in the most receptive market. The physical properties of three Australian wild rices collected from Cairns, Queensland, Australia have been evaluated (Tikapunya et al., 2016). The results revealed that Oryza australiensis had ACCEPTEDa relatively short grain and MANUSCRIPT was similar in shape to commercially cultivated rices. Two wild taxa more closely related to domesticated rice (Brozynska et al., 2017) taxa A (medium grain) and taxa B (long grain) were slender in shape. The grain colour of these wild rices varied from light red brown to dark brown compared with cultivated rice which was lighter and brighter. The physicochemical characteristics of the wild rice species were also studied in order to better understand the functionality of these wild rices (data 3 ACCEPTED MANUSCRIPT unpublished). Starch profiles for the wild rices revealed a higher amylose content compared to commercial cultivars indicating wild rice might be beneficial to human health by contributing to slower digestion rates. These preliminary results suggest that Australian wild rice may have potential for commercialisation, particularly in the unpolished (coloured) rice market. The market demand for unpolished (coloured) rice grains has been increasing due to the association between rice colour and nutritional valve. Prior to using Australian wild rice in breeding programs or indeed developing a commercial Australian wild rice cultivar, it will be important to understand the cooking behaviours and sensory properties of these unique rice species. This study focussed on profiling the cooking, sensory and eating properties of unpolished Australian wild rice (specifically taxa B) and benchmarking these qualities against commercial unpolished Canadian wild rice (Zizania aquatica L.), Oryza sativa L.cv. Nipponbare, and seven unpolished standard commercial rice cultivars. 2. MATERIALS AND METHODS 2.1 Samples Samples were identified in the field as part of the work described by Brozynska et al. (2017). A total of ten unpolished rice types were selected for sensory analysis and are listed in Table 1. The two paddy rice samples (Oryza sativa L.cv. Nipponbare and wild rice (taxa B)) were o collected and storedACCEPTED at (4 C) until used. Eight MANUSCRIPT unpolished commercial rices were purchased from a local market and stored at room temperature in air-tight plastic bags until sensory evaluation could take place. All samples were tested within 8 months of purchase or collection. 4 ACCEPTED MANUSCRIPT 2.2 Sample preparation and presentation The paddy of Oryza sativa L.cv. Nipponbare and wild rice (taxa B) were dehusked manually. Unpolished rice (30 g) was added to distilled water with a rice-to-water ratio of 1:4 in a beaker (250 ml) and covered with an aluminium foil. Beakers were placed in a water bath (100 ± 1oC). Cooking time was measured from when the contents of the beaker reached 100oC and a minimum cooking time (MCT) was established (Mohapatra & Bal, 2006) for each rice type individually (approximately 11-31 min). Cooked rice samples were strained (using a colander) and immediately sub-samples (5 g) were distributed into plastic sample cups (30 ml) (coded with a 3-digit blinding code), sealed with a lid and placed on a tray in a humidified warming oven (70oC) before being presented for sensory assessment. All samples were served for tasting within 30 min of cooking. Samples were presented to panellists for assessment on white trays together with a plastic tea spoon and coded with 3-digit blinding codes. During formal evaluation, samples were assessed in triplicate, with samples presented according to a balanced presentation design (latin square) within each replicate block. To ensure samples were warm during sensory assessment, samples were served directly from the warming oven, one at a time, upon panellist request during formal assessments. No more than 10 samples were assessed within a 2 hour period. 2.3 Measurement of rice physical properties ACCEPTED MANUSCRIPT The grain size of uncooked samples was measured (Cruz & Khush, 2000) and the length of 20 unpolished rice grains of each sample were measured using a digital Vernier caliper before and after cooking. The elongation ratio was calculated as a proportion of the length of cooked rice to length of uncooked rice. The number of burst grains was counted across 100 unpolished cooked rice grains for each sample. Cooked rice grains were analyzed in 5 ACCEPTED MANUSCRIPT triplicate for color (CIE L c h color space) using a chromameter CR 310 (Konica Minolta, Japan). 2.4 Sensory panel and evaluation method The sensory panel was selected based on availability of individuals from a pool of panelists who had been previously tested for sensory acuity and were experienced in sensory descriptive studies. Four male and 8 female panellists participated, aged 37-66 years old (mean age

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