Microbiological assessment of tigernut milk as a potential probiotic product

Abstract

This study aimed at developing starter cultures as probiotic from spontaneous fermented tigernut milk (SFTM) by the natural flora. Fermented tiger nut milk (FTM) was produced from these varieties – small dried brown, big dried brown and fresh yellow tiger nuts. Microbiological analysis of SFTM and pasteurized fermented tiger nut milk (PFTM) were carried out using Nutrient agar, De Mann Rogosa and Sharp and Malt Extract Agar for isolation of aerobic bacteria, lactic acid bacteria and yeast respectively. The pH of SFTM and PFTM, and titratable acidity of the lactic acid produced were investigated. Lactic acid bacteria (LAB) Lactococcus lactis (LC) and two species of yeast Pichia sp. PM13 and Pichia Kudriazevii CBS 245 were obtained from FTM at different fermentation periods. LAB were found to predominate the microflora of the FTM with their count ranging between 2.2 x 10⁴ - 6.5 x 10⁴ (SFTM) and 4.6 x 10⁵ - 7.9 x 10⁶ (PFTM) and pH ranged 4.3- 6.5. The quantity of lactic acid produced by the LAB isolate ranged between 0.46 g/l - 1.92 g/l and hydrogen peroxide between 0.16 g/l – 0.51 g/l. Thus, the propagation and selection of known starter cultures as a probiotic microbes might bring about uniformity of product.

Keywords: Tiger nut milk; Lactic acid bacteria, Spontaneous, Starter Culture; Probiotic Product