Influence of whey protein hydrolysate addition to whey permeate batch fermentations for producing lactic acid

Addition of whey protein hydrolysate (WPH) to whey permeate fermentations, by Lactobacillus helveticus. to produce lactic acid was investigated. Three to four percent (w/w) supplementation with WPH solution (10% w/w protein) was required to obtain high lactose conversion and lactic acid yield in a f ermentation time of 30-40 h. At this percentage supplementation, the nitrog en content of the media was 0.06-0.09% w/w. The bacteria used around 0.02% w/w nitrogen during fermentation. thus there was an abundance of unused nit rogen remaining at the end of fermentation. At 3-4% supplementation, it was calculated that around 36-47% of whey protein concentrate produced from wh ey would be required to supplement the whey permeate fermentation in the fo rm of the hydrolysate. (C) 2001 Elsevier Science Ltd. All rights reserved.