H L de Kock and A Minnaar
Department of Food Science, University of Pretoria, Pretoria, 0002 South Africa
In South Africa we are blessed with one of the world’s finest fauna and flora. Yet the number of examples of significant local commercial foods based on our indigenous flora and fauna are few and the number of food products even less. The former is just about limited to game meat, biltong, indigenous goat milk, sorghum beer and sorghum meal, and the latter to rooibos tea, Amarula and ostrich meat. Europe is South Africa’s most important export market. There are numerous potential novel food applications for indigenous animal and plant materials from Southern Africa arising from their unique sensory attributes. Our research approach is to characterise, modify and then develop the functional attributes of these underutilised foodstuffs with the aim of satisfying the consumer-driven growth markets for desirable, natural and health –promoting food products and ingredients, both locally and internationally.
This presentation will review our recent sensory research to quantify and understand the sensory properties, both positive and negative, of indigenous sorghum, millet, cowpeas, marama beans and wild medlar fruit (“umviyo”). This includes the effects of cultivar and/or processing methods on sensory quality. A specific emphasis of the research is on the effects of phenolic compounds, e.g. condensed tannins in sorghum grain, that potentially provide health and nutrition benefits but may also produce negative sensory qualities such as bitterness and astringency. It was found that not all tannin containing sorghums were bitter and astringent. One of the tannin sorghums studied was perceived as similar to tannin-free sorghums even though it had twice the phenol content.
Another example is research that quantified the acceptance of the novel sensory properties of a juice made from the wild medlar fruit before and after repeated exposure. The assessment was done by consumers unfamiliar with the fruit, but with or without knowledge about the nutritional properties (vitamin C content and antioxidant activity) of the product. The ultimate aim is to develop a strategy to effectively induce consumer acceptance of underutilised indigenous foods, both locally and in major export niche markets.
Keywords: Indigenous, South Africa, sorghum, repeated exposure, wild medlar