Bioactivity of water soluble extracts and some characteristics of white cheese during the ripening period as effected by packaging type and probiotic adjunct cultures

Abstract

In this study, the chemical composition, proteolysis and in vitro angiotensin-converting enzyme-(ACE)-inhibitory and antioxidant activities of white cheeses made using probiotic adjunct cultures (Bifidobacterium bifidum DSMZ 20456 and Lactobacillus acidophilus DSMZ 20079) were investigated. The cheeses were ripened in a vacuum package or brine for 120 d at 4 °C. The cheese samples maintained the probiotic characteristics of the viable cells as >106 cfu/g even after ripening for 120 d. The proteolysis degrees in terms of water-soluble nitrogen/total nitrogen (WSN/TN), trichloroacetic acid-soluble nitrogen/total nitrogen (TCA-SN/TN) and phosphotungstic acid-soluble nitrogen/total nitrogen (PTA-SN/TN) values in the cheeses increased throughout the ripening. The highest levels of proteolysis were found in cheese made using Lb. acidophilus DSMZ 20079 and ripened in a vacuum package. ACE-inhibitory activity of the water soluble extracts (WSEs) of the cheeses increased significantly (P < 0·05) throughout the ripening (IC50 values 82·78–140·99 μg/ml). Use of Lb. acidophilus DSMZ 20079 and packaging under vacuum significantly increased the percentage of ACE inhibiting activity. WSEs had DPPH scavenging activity (the IC50 values were 2·41–5·39 mg/ml and the inhibition values were 5·10–10·38%), increasing up to 60 d ripening. In the present study, it was observed that Lb. acidophilus DSMZ 20079 was more effective than Bifido. bifidum DSMZ 20456 in terms of the cheese characteristics investigated.