Abstract

Background: In the food industries, several oligosaccharides have received increasing attention as key components for functional foods and nutraceutical products. Prebiotics are non-digestible oligosaccharides which have been shown to have properties that can modulate gastrointestinal problems and improve gut health and well-being. Recent researches much pay attention to find alternative sources, improve specific properties and proof on health benefits of these prebiotics. Methods: This is the summary of research works have been done by our research group on prebiotics and gut health in Thailand. These works aimed to study sources of prebiotics from fruits and vegetables in Thailand, production by enzymatic synthesis of prebiotics, purification by microbial fermentation and membrane technology and applications of the prebiotics in nutraceuticals and functional foods. Results: Among the 30 parts of 14 plants, six appear to have the highest potential for commercialization based on extract yield and the amount and type of indigestible oligosaccharides. These include dragon fruit, palm flesh, palm embryo, jackfruit flesh, jackfruit seed, and okra pod. At least three of them, dragon fruit, jackfruit flesh and seed, were confirmed on their prebiotic property by selectively in vitro colonic microflora fermentation in an artificial colon system. Among 52 LAB isolates for production of GOS, BFP32 showed highest intracellular β-galactosidase activity and GOS yield. It was identified as Lactobacillus pentosus var. plantarum by 16S rDNA sequencing. Composition of GOS consisted of oligosaccharides with having DP of 3, 4 and 5. A mixture of GOS was purified successful by sequential bacterial and yeast fermentation whereas nanofiltration could be used for partial purification. Prebiotic index (PI) of the GOS produced was1.19 in batch culture. A crude extract from tubers of Jerusalem artichoke (Helianthus tuberosus L.) had transfructosylating activity for biosynthesis of FOS from sucrose. Optimal conditions for production of FOS were 0.26 U FTase, incubated with 0.46 M sucrose as substrate at pH 5.4 and 35ºC for 144 h. A maximum yield of scFOS (DP<5) was obtained (54.46%). The scFOS showed prebiotic property with PI of 1.29 in batch culture. Four formulas of canned tuna in spring water and tuna in mayonnaise and pouched tuna in salad cream and tuna in thousand island cream with added inulin were developed for commercial production. An addition of 5 % inulin for tuna in spring water and 7 % inulin for tuna in mayonnaise, tuna in thousand island and tuna in salad cream are recommended. The highest prebiotic index (PI) scores of tuna in spring water and tuna in salad cream added 5% inulin were 1.82 and 0.93, respectively in three-stage continuous culture. In clinical study of tuna products, it was found that 5% inulin addition helps on improve bowel regularity. By-product from rubber wood sawdust could be used as alternative source of XOS. Among eight edible commercial mushrooms, Schizophyllum commune had highest total β-glucan content (59.87% dry basis). Conclusions: Research on prebiotics in Thailand had two mainly approaches including by extraction from natural occurring in fruits and vegetables and by enzymatic approach using hydrolysis and transferase activities from agricultural by-products and low cost raw materials. Prebiotic researches are covered in vitro, in vivo in rat and being investigated in clinical study related to gut health functional and immunity.

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