INDIGENOUS PLANTS IN THE LIMPOPO PROVINCE: POTENTIAL FOR THEIR COMMERCIAL BEVERAGE PRODUCTION by ISAAC TEBOGO RAMPEDI submitted in accordance with the requirements for the degree of DOCTOR OF PHILOSOPHY in the subject ENVIRONMENTAL MANAGEMENT at the UNIVERSITY OF SOUTH AFRICA SUPERVISOR: PROF JANA OLIVIER DECEMBER 2010 i STUDENT NUMBER: 0734-731-6 DECLARATION I declare that INDIGENOUS PLANTS IN THE LIMPOPO PROVINCE: POTENTIAL FOR THEIR COMMERCIAL BEVERAGE PRODUCTION is my own work and that all the sources that I have used or quoted have been indicated and acknowledged by means of complete references. ________________________ _____________________ SIGNATURE DATE (MR I T RAMPEDI) ii ACKNOWLEDGEMENTS I am grateful to Professor Jana Olivier, my research supervisor, for her excellent guidance, commentary and constructive engagement during the course of the study. The National Research Foundation (NRF) as well as the University of South Africa (UNISA), through the Thuthuka Research Funding Programme, are acknowledged for financial support (GUN 207 3321). I am also indebted to the following people and their organisations for the positive role they played during the course of the research project: • All the local traditional chieftaincies in the Limpopo province who provided permission to conduct research in areas falling within their jurisdiction are acknowledged. • All the individuals who assisted with data collection for surveys in the various rural communities of Venda, former Gazankulu (Mopani) region as well as Sekhukhuneland are deeply thanked. • Dr Aubrey Parsons is thanked for sharing some of his expertise and assistance with sensory analyses on some of the selected beverages. • Rosemary Du Preez, Agronomist and researcher at the Agricultural Research Council (ARC), Institute of Subtropical and Tropical Crops (ISTC) in Nelspruit, is acknowledged for collaboration and allowing me to read some of her work related to my study as well as constructive feedback. • Karen De Jager, Researcher at the Agricultural Research Council (ARC), is thanked for collaboration and assistance with respect to the formulation of some of the concept products (liqueurs) piloted for the research project. • Daisy Madisha, Researcher and biotechnologist at the Agricultural Research Council (ARC) and ITSC, is acknowledged for providing some of the snowball leads in the Venda study area in the Limpopo province. • Prof Dr James Simon, Director of the New Use Agriculture and Natural Plant Products (NUANPP) programme at Rutgers University, New Brunswick is acknowledged for specialist training and interesting exposure gained on phytochemistry and the commercialisation of natural plant-based products during a study visit in the USA in 2008. • Dana Robberste in the School of Environmental Sciences at UNISA Florida Campus is thanked for administrative support regarding the Thuthuka Research Grant (GUN 207 3321). • I wish to convey my sincere thanks to all members of the College of Agriculture and Environmental Sciences (CAES) as well as the Centre for African Renaissance at UNISA who were willing to participate in the study by playing a role in the sensory characterisation and evaluation of selected beverages. • Makro Centurion Store (Liquor Section) and their Head Office are acknowledged for granting permission to undertake market surveys and sensory analyses amongst some of their customers. • All participating respondents in the various rural communities surveyed for the research in the Limpopo province and for assistance in the collection of voucher specimens and the preparation of (samples) traditional beverages for nutrient characterisation and evaluation as well as sensory analyses, are deeply thanked. • I am grateful for the support of my wife, Tshepo and my daughters, Tsholofelo and Boikanyo. • I wish to acknowledge the positive and moulding role played by my parents (Klaas Mashalane Rampedi and Mandy Mmapula Rampedi) in my early educational phase in Naledi Township, Soweto and the values of hardwork, faith and perseverance that they have inculcated. iii ABSTRACT South Africa has over 19 500 different indigenous plant species. Most of these are of ethnobotanical significance and are still used by local rural communities as medicine, food and for making beverages. The relatively little research that has been conducted on indigenous plant species has focused mainly on their medicinal potential. However, in view of the rapidly growing size of the global and local beverage industry and their constant search for new products, beverage-making indigenous plant species may have commercial development potential. To date, no detailed studies have been conducted on these plants, especially in the species-rich Limpopo province. The aim of this study was, therefore to evaluate the potential of indigenous plants for commercial beverage production. In order to achieve this, a survey was conducted in the Limpopo province to identify beverage-making plants and to document beverage preparation methods. Selected beverages were analysed and evaluated for their nutrient and sensory characteristics and a market product acceptability survey was conducted to identify those beverages with the greatest potential for development. Sixty three different beverage-plant species were identified in three study areas within the Limpopo province. These were used for the preparation of teas, fruit juices and alcoholic beverages. Plants that received further research attention were selected on the basis of their status as indigenous plants, frequency of use, nature of harvesting methods and availability. Some of the selected beverages were found to be rich in nutrients, especially with respect to vitamin C and mineral content. Furthermore, sensory analyses and market surveys indicated that four species, namely, Doyvalis caffra, Garcinia livingstonei, Grewia flavescens and Englerophytum magalismontanum have potential for further development for the beverage industry while Athrixia phylicoides has commercialisation potential as a herbal tea. However, further research is required to improve and refine preparation methods and to ensure compliance with quality standards. The availability of sufficient plant material for the industry must also be ensured. This research has indicated that South African indigenous plants have untapped market potential for the beverage industry which, if developed sustainably, could contribute to economic growth of the rural parts of South Africa. KEY TERMS Beverage-making indigenous plant species, commercial development potential, snowball sampling, tests, dietary reference intakes, teas, fruit juices, beer, spirits, new products, sensory analyses, aroma, flavour, product acceptability, hedonic scale, Limpopo province. iv LIST OF ABBREVIATIONS ARC, Agricultural Research Council ASNAAP, Agribusiness in Sustainable African Natural Plant Products ACL, Amarula Cream Liqueur AOAC, Association of Official Analytical Chemists CGI, Clanwilliam General Info CARA, Conservation of Agricultural Resources Act CWNG, Cosmetic Workshop and Natures Goodness CYP450, Cytochrome P450 DA, Department of Agriculture DEAT, Department of Environmental Affairs and Tourism DRIs, Dietary Reference Intakes EU, European Union FAO, Food and Agricultural Organisation F/G, Fructose/Glucose IKS, Indigenous Knowledge System IPUF, Indigenous Plant Use Forum ICONS, Institute of Conservation and Natural History of the Soutpansberg ISCW, Institute of Soil, Climate and Water ISTC, Institute of Subtropical and Tropical Crops IAP, Invasive Alien Plant LSOER, Limpopo State of the Environment Report MDA, Malondialdehyde GC, Gas Chromatography v HPLC, High Performance Liquid Chromatography ICP-OES, Inductively Coupled Plasma Optical Emission Spectrometry NEMBA, National Environmental Management Biodiversity Act (NEMBA) NGOs, Non-Governmental Organisations PPECB, Perishable Products Export Control Board RAI, Recommended Adequate Intake RDA, Recommended Dietary Allowance RTD, Ready-To-Drink RCKB, Research Centre Knowledge Base RE, Retinol Equivalents RTCB, Rooibos Tea Control Board TP, Total Polyphenol SABS, South African Bureau of Standards SADC, Southern African Development Co-operation SAHTA, South African Honeybush Tea Association SANBI, South African Institute of Biodiversity SAWB, South African Weather Bureau Stats SA, Statistics South Africa SOD, Super-Oxide Dismutase TNC, Total Non-Structural Carbohydrates UV, Use Value vi TABLE OF CONTENTS CHAPTER 1: RESEARCH BACKGROUND ON INDIGENOUS PLANT-BASED BEVERAGES 1.1 INTRODUCTION 1 1.2 LITERATURE CONTEXTUALISATION OF THE STUDY AND RESEARCH MOTIVATION 2 1.3 RESEARCH AIM AND OBJECTIVES 6 1.4 SCOPE AND LIMITATIONS OF THE RESEARCH 6 1.5 ORGANISATION OF THE THESIS 7 CHAPTER 2: LITERATURE REVIEW ON BEVERAGE-MAKING INDIGENOUS PLANTS AND ASSOCIATED DRINKS 2.1 INTRODUCTION 8 2.2 INDIGENOUS TEAS 8 2.2.1 Rooibos tea, Aspalathus linearis 8 2.2.1.1 Botanical aspects 9 2.2.1.2 Production and product development trends 10 2.2.1.3 Market development aspects 16 2.2.2 Honeybush tea, Cyclopia species 17 2.2.2.1 Medicinal and current research findings 18 2.2.2.2 Development of honeybush into an agricultural crop 20 2.2.2.3 Markets for honeybush tea 21 2.2.3 Bush tea, Athrixia phylicoides 24 2.2.3.1 Botanical and ethnobotanical aspects 24 2.2.3.2 Geographical distribution and harvesting practices 24 2.2.3.3 Traditional medicinal uses and current research findings 25 2.3 ALCOHOLIC BEVERAGES 27 2.3.1 African beers 27 2.3.1.1 Sorghum beer 27 2.3.2 Indigenous spirits and wines