Kocher, G.S.Dhillon, Sunjit Kaur2020-07-102020-07-102020http://krishikosh.egranth.ac.in/handle/1/5810149004The honey which goes waste during processing as well as storage was selected as the substrate for the present study on the basis of evaluation of physico-chemical parameters such as total soluble solids, total sugars, reducing sugars, moisture content, refractive index, acidity, pH, specific gravity, nitrogen content, phosphorus content, phenols, antioxidant activity, total yeast count and total microbial count. The study of yeast growth dynamics on the basis of absorbance measurements, haemocytometric count and consumption of reducing sugars led to the selection of Saccharomyces cerevisiae KY069279 as the best suited strain for growth on honey in comparison to other three yeast strains viz. S. cerevisiae MTCC 11815, D7 and Meyerozyma caribbica PY1. The yeast strain S. cerevisiae KY069279 showed the maximum growth rate (0.16 log cells/h), sugar consumption rate (0.078 g/h) and yield (0.054 log cells/h/g sugar consumed) on honey. Effect of addition of various supplements like grape juice, apple juice, yeast nitrogen base (YNB) and resins was studied whereby, addition of yeast nitrogen base led to the completion of fermentation in 8 days. Hence, YNB was chosen as the preferred nitrogen source for fermentation on honey. Optimization of mead fermentation parameters like initial brix, inoculum size, YNB concentration and acidity was carried out using Response Surface Methodology. The model revealed that an initial sugar level of 15°B, inoculum size 10%, YNB concentration 20.03 % and acidity 0.2% were statistically the optimum conditions for honey fermentation scale up experiments with a desirability of 95.7%. An ethanol content of 8.79% (v/v) with an ethanol yield 0.486 g/g and fermentation efficiency of 95.23 % was observed during the scale up experiments carried out at 3L scale. The prepared mead was evaluated for the physico-chemical parameters over a period of 90 days at regular intervals of one month. Shelf life studies revealed that the mead retained its quality over a tested period of three months. Sensory analysis by a panel of 6 panelists categorized mead at 0 day and mead at 90 days as ―moderately liked‖ and ―liked very much‖ with mean scores of 7.31 and 8.01, respectively on the 10 point Hedonic scale suggesting that mead sensory quality increased during storage. Highest antioxidant activity in terms of AEAC value was observed in case of packaged honey (33%), followed by waste honey (28%) and mead (22%) w.r.t ascorbic acid (100 % v/v). Organoleptic evaluation of dehydrated samples by gas chromatography mass spectroscopy listed esters, alcohols, volatile fatty acids, acetates, amines, amides, terpenes and lactones as the major constituents of mead.ennullThesis