Vinegar base production from waste pineapple juice

Abstract

The effects of sugar concentration, aeration, addition of the yeast nutrients ammonium phosphate and ammonium sulphate, and variation in the number of yeast cells in the inoculum on fermentation rate and efficiency and yeast growth in the alcoholi fermentation process were studied.
Aeration gave a substantial initial increase in the rate of cell growth and the rate of alcohol production, but after 24 hr the amount of alcohol produced was the same as with no aeration.
Addition of ammonium phosphate or ammonium sulphate had no effect on alcohol production or cell population.
When inoculum size was increased sixfold to 54 x 106 cells per ml, the time for completion of fermentation of juice with and without added sugar was reduced, in the former case from 40 hr to 16 hr.
The rapid fermentation method involving large inoculum was not assessed on flavour of the vinegar stock produced.