Goat whey fermentation by Kluyveromyces marxianus and Lactobacillus rhamnosus release tryptophan and tryptophan-lactokinin from a cryptic zone of alpha-lactalbumin.

Angiotensin-I-Converting Enzyme (ACE) inhibitors peptides were produced from unsupplemented acid goat whey fermented aerobically for 168 h by Kluyveromyces marxianus and Lactobacillus rhamnosus. This yeast-lactobacillus association is GRAS. Two novel lactokinins were identified: NYW and W with IC50 of 20 and 0.86 mum respectively. They both were resistant toward simulated gastrointestinal digestion. In addition, WLAHK was found in the hydrolysate. These three sequences belong to f(99-110) of alpha-la which seems to be a lactokinin cryptic zone. W was the major molecule released by the fermentation process. Considering that W is the precursor of serotonin, the hydrolysate produced could be of interest for the generation of functional health ingredient involved in regulation of affective disorders and hypertension.

Crude goat whey fermentation by Kluyveromyces marxianus and Lactobacillus rhamnosus: contribution to proteolysis and ACE inhibitory activity.

Unsupplemented acid goat whey containing 0.96% protein and 2.76% lactose was fermented aerobically with 32 microflora extracted from various raw milk cheeses and dairy products. These microflora were screened for their ability to hydrolyse whey proteins (alpha-lactalbumin and/or beta-lactoglobulin) and to generate peptides inhibitors of Angiotensin I Converting Enzyme. Five microflora were able to degrade whey protein. The most efficient microflora was able to fully hydrolyse alpha-lactalbumin and to a lesser extend beta-lactoglobulin. It was extracted from Bamalou des Pyrenées cheese. Micro-organisms involved consisted of yeast Kluyveromyces marxianus and lactobacillus Lactobacillus rhamnosus. Both were able to produce ACE inhibitory peptides after whey fermentation.