Enhancing freeze resilience of baker's yeast and designing its product formulation

Abstract

Trehalose loading and cold acclimatization strategies were utilized to enhance the freeze resilience of baker's yeast (Saccharomyces cerevisiae) isolate and production protocol for formulation was planned. Loading with 1.0M trehalose following 7 days of incubation prompted increase in intracellular trehalose content from 0.3% to 4.71%. Comparative freeze resistance investigations uncovered that 14 day cold acclimatized culture displays extreme cell viability (193cfu/ml) under refrigerated conditions. The 28 days acclimatized culture indicated 36.29% sugar content followed by 1.0M trehalose loaded culture (29.44%). In 1.0M trehalose loaded culture, greatest trehalose content (4.71%) and least invertase activity (29.79 nmol/min/ml) was observed. Biomass production of baker's yeast was done at conditions pre-optimized in our laboratory: pH-6.0, aeration-120 rpm and temperature-30⁰C utilizing unclarified molasses as carbon source and corn steep liquor (CSL) as a nitrogen source. Best dough rising capacity was shown by 14 days cold acclimatized strain. Product formulation as cream yeast and dried (lyophilized and plate dried) yeast was done, out of which cream yeast was found appropriate for bread making while nutritional profiling of dried yeast formulations revealed it as a good source of protein, minerals and essential amino acids.