Quality evaluation and microbial enumeration of plant based probiotic yoghurt from powdered milk and tiger nut milk

Abstract

Some commercial yoghurt manufacturers have promoted the usage of artificial thickening and binding agents in the production of yoghurt. These substances, most of which are chemically synthesized could be dangerous. The purpose of this research is to assess the physicochemical characteristics of yogurt made from full cream milk, skimmed milk, and tiger nut milk. It also aimed to estimate the total aerobic plate count, total coliform count, and total mold count of the products for microbiological analyses. The powdered milk samples were reconstituted into liquid and the sorted-clean tiger nut was blended in order to extract the milk. Tiger nut milk proportion of 20 to 30 % was incorporated into the liquid milk before fermentation. The harvested yoghurt was assayed for sensory, physicochemical and microbial analyses. The result obtained showed a level of significant difference (p < 0.05). Among the samples produced, sample G has the least acceptable value 5.00 while sample C had the highest acceptable value 7.05 across the sensory scores. The values obtained from the physicochemical analysis showed that pH value ranged from 3.67 to 4.97. For TDS and titratable acidity (TA), the values ranged from 4.53 to 6.72 x 10² ppm and 0.62 to 0.87 respectively. None of the yoghurt samples had coliform growth on the medium after the incubation period while total viable count ranged from 78.67 to 227.33 cfu/ml and total mould count ranged from 16.67 to 56.67 sfu/ml at a dilution factor of 10². Tiger nut milk can be used in the production of yoghurt as a possible substitute because of its nutritional content and health advantages. Therefore, it is imperative to assert that the use of tiger nut milk in the manufacturing of yoghurt will improve the quality of yoghurt and ultimately result in a desired product.