KEFİRİN VE QUARK PEYNİRİN FONKSİYONEL VE BESLEYİCİ ÖZELLİKLERİ ÜZERİNE ULTRASONİK UYGULAMANIN ETKİLERİ
Project no. 1354 · Status: Kapanmış · 2018
Summary
Bioactive peptides have hormone or drug-like activity that can modulate physiological functions by binding to receptors on target cells and have potential effects in the prevention of chronic and degenerative diseases that pose a risk of nutrition due to their high bioactivity and easy metabolism in humans. Compared with conventional heat treatment techniques, non-thermal processing techniques also have significant effects on the structure and interactions of proteins. In this project, the effects of non-thermal ultrasonication on semi-skimmed pasteurized cow's milk, its whey protein-casein-enriched form, and kefir and quark obtained from these milks on protein characterization, protein digestibility, antioxidant activity and angiotensin converting enzyme (ACE) inhibition under in vitro digestion condition were investigated. When the results were evaluated, the protein hydrolysis rate did not change in the milk and the products obtained from these milks, depending on the increased amount of protein in the protein-enriched milk (p>0.005). In addition, the degree of protein hydrolysis in K and Q obtained with ultrasound applied milk and protein milk was statistically different from the control samples (p<0.005). In SDS-page imaging after in vitro digestion, no attenuation of protein bands was observed in K and Q samples obtained from ultrasonicated milk compared to non-ultrasounded samples. In all examples, it appears that during digestion, casein (27-35 kDa) is completely hydrolyzed, with alpha-lactoferrin, BSA and immunoglobulins hydrolyzed by pepsin in the stomach and by small intestinal peptidases. Antioxidant activity of ultrasonicated (US) milk was higher when compared to protein enriched milk (PS) and untreated cow's milk (p<0.05). The same finding was not observed between kefir and quark (K, Q) obtained from ultrasonicated (UK, UQ) and untreated milk. DPPH activity was found to be higher in UK and UQ samples compared to K and Q samples (p<0.05). While the highest ACE inhibition activity was observed in PUK and PUQ samples (p<0.05), it was determined that protein enrichment of milk did not affect ACE inhibition, and this activity increased with kefir and quark production compared to control milk (p<0.05). Anahtar kelimeler: ultrasonication, in vitro digestion, protein digestibility, antioxidant activity, ADE inhibition,