Optimisation of production conditions of casein hydrolysate with high bioactivity and its usability as food additive

Bioactive peptides are obtained by hydrolyzation of proteins. Casein, one of the milk proteins, is known as a primary source of bioactive peptides. In this thesis, it was demonstrated that casein protein with high bioactive peptide content can be produced under optimum conditions with maximum activity values and can be used as a food additive. First, the appropriate endopeptidase enzyme was decided (Alcalase®, Neutrase® and rTrypsin®) and then exopeptidase enzyme combinations were tried to increase the bioactivity. The most suitable endopeptidase was determined as hydrolysate conditions with Neutrase ultrasound pretreatment at 12 hours incubation (total peptide content 258.0 mg Tryptone/g sample, antihypertensive potential 77.6%, antioxidant potential 686.8 µmol Trolox/mL sample, metal binding 31.4%, alpha amylase inhibition 67.1%, lipase inhibition 40.9%). The simultaneous use of Protana™ Prime and Flavourzyme® enzymes was found to be suitable for the use of exopeptidase (total peptide amount 447.2 mg Tryptone / g sample, antihypertensive potential 50.5%, antioxidant potential 622.3 µmol Trolox / mL sample, metal binding 34.1%, alpha amylase inhibition 92.7%, lipase inhibition 40.4%). Incubation time, enzyme concentration and ultrasonic time were evaluated as optimization factors. The highest bioactivity values were observed at 12 hours incubation, 30 minutes ultrasound and 0.5 mL enzyme concentration. Hydrolysate with high bioactivity values obtained under optimum conditions was added to ayran samples at 1%, 5% and 10% and composition, sensory and bioactivity analyses were evaluated on the 1st, 7th and 14th days and 1% and 5% concentrations were preferred as a result.