Physico-chemical and microbiological changes in tigernut milk under ambient storage conditions.

Abstract

The keeping quality of tigernut milk under ambient, tropical conditions (30±20C, 70±5%RH) was studied. Fresh tigernut was soaked and milled and the slurry obtained was filtered. The filtrate (tigernut milk) was filled into sterile plastic bottles, pasteurized and kept at ambient conditions for two weeks during which some physical, physico-chemical and microbiological changes were monitored. The colour of the milk was creamy throughout the period of storage though two distinct layers were observed after 24 hours due to separation of solids from liquid. The odour remained pleasant for up to five days after which it became unpleasant and turned offensive on the day-12. The pH, soluble and total solids decreased all through storage while the total titratable acidity and moisture contents increased. The microbial content started increasing on day-2, reached a maximum value on day-9 and started decreasing. Generally, the milk remained stable for two days before significant changes commenced.

Keywords: Tigernut, milk, physical, physico-chemical, microbiological.