Abstract:
Tiger nut and millet are indigenous crops in Ghana. These crops have been on the radar recently due to their versatile applications in food processing and their increase in consumption by low-income households. The nut is rich in fermentable carbohydrates and resistant starch, rich in fiber and micronutrients, and it is an ideal candidate for synbiotic foods. The objective of this study was to utilize whole tiger nut in dairy-cereal based beverage, make the product synbiotic, and assess the nutritional, physicochemical profile, microbial quality, and shelf life of the drink. The tiger nut-millet agglomerate was prepared by incorporating cellulase hydrolyzed tiger nut fibrous co-product (TNF), and non-hydrolyzed TNF (10% and 15%) into millet with a varying fermentation time of 12 and 24 hours. The agglomerate functional properties (i.e. Water Absorption Capacity (WAC), Bulk Density (BD), Swell Index) and textural characteristics (hardness, resilience, cohesiveness, adhesiveness gumminess and chewiness) were objectively measured in triplicates. The drink produced from composite tiger nut milk: dairy in a ratio of 40%:60% was inoculated with probiotics (Lactobacillus casei). The drink was analyzed in triplicate for physicochemical, proximate, and microbiological quality. Accelerated shelf-life study with the Arrhenius model was used to predict the shelf life of the drink. The obtained data were subjected to analysis of variance (ANOVA) in Minitab version 17. Agglomerate prepared from dough fermented at 12 hours had excellent textural and functional characteristics hence was selected for the synbiotic drink production. The moisture content of the product decreased with tiger nut incorporation, while sodium, potassium, magnesium, phosphorus, zinc, vitamin E, protein and total carbohydrate together with crude fibre increased with tiger nut incorporation. The products were microbiologically safe with no count for E. coli, Staphylococcus aureus, and yeast and moulds after five days of storage with increasing acidity. The shelf life observed for all the products at a University of Ghana http://ugspace.ug.edu.gh
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pH limit of 3.5 was five days, four days and three days at a storage temperature of 5℃, 25℃ and 35℃, respectively. Lactobacillus casei counts in the product increased by 1 log cycle each day for both refrigerated and room temperature samples. Incorporation of whole tiger nut and a known probiotic into dairy cereal-based beverage will increase the nutritional content of the product as a functional food. Consuming this product will provide consumers with the health benefits associated with the consumption of the whole tiger nuts based probiotic products
