Preservative Potential of Aqueous Garlic Extract on the Biochemical Characteristics and Organoleptic Qualities of Functional Soymilk

Abstract

Soymilk, a plant-based milk, is a cheap alternative to dairy milk. It has a short shelf life and is highly perishable. This study examined the effect of aqueous garlic extract on the shelf life of soymilk to produce a functional food with a longer shelf life. The microbial count, pH, and titratable acidity of the refrigerated soymilk samples were determined weekly for 21 days as well as the organoleptic properties. Microorganisms isolated from the soymilk samples during storage were also identified using standard methods. Bacillus spp., Staphylococcus spp., Streptococcus spp., and Aspergillus niger were identified during storage and the total viable count obtained for the freshly prepared soymilk was lower compared to the acceptable standard of bacterial limit (4.30 log CFU/ml) for Soy foods. The preserved soymilk's initial and final fungal count ranged from 4.46 - 4.79 and 8.30 - 8.70 log CFU/ml respectively. The score for taste decreased with an increase in the concentration of garlic extract. However, the overall acceptability of the soymilk samples was not significantly different (p > 0.05) with the addition of garlic extract. Incorporating 3 and 4% aqueous garlic extract into soymilk, as a preservative, increased the product's shelf life beyond 7 days. Thus, garlic extract could be explored as a potential preservative in extending the shelf life of soymilk.