Characteristics of Unripened Cow Milk Curd Cheese Enriched with Raspberry ( Rubus idaeus ), Blueberry ( Vaccinium myrtillus ) and Elderberry ( Sambucus nigra ) Industry By-Products.

The aim of this study was to apply raspberry (Ras), blueberry (Blu) and elderberry (Eld) industry by-products (BIB) for unripened cow milk curd cheese (U-CC) enrichment. Firstly, antimicrobial properties of the BIBs were tested, and the effects of the immobilization in agar technology on BIB properties were evaluated. Further, non-immobilized ( NI ) and agar-immobilized ( AI ) BIBs were applied for U-CC enrichment, and their influence on U-CC parameters were analyzed. It was established that the tested BIBs possess desirable antimicrobial (raspberry BIB inhibited 7 out of 10 tested pathogens) and antioxidant activities (the highest total phenolic compounds (TPC) content was displayed by NI elderberry BIB 143.6 mg GAE/100 g). The addition of BIBs to U-CC increased TPC content and DPPH - (2,2-diphenyl-1-picrylhydrazyl)-radical scavenging activity of the U-CC (the highest TPC content was found in C-Ra NI 184.5 mg/100 g, and strong positive correlation between TPC and DPPH - of the U-CC was found, r = 0.658). The predominant fatty acid group in U-CC was saturated fatty acids (SFA); however, the lowest content of SFA was unfolded in C-Eld AI samples (in comparison with C, on average, by 1.6 times lower). The highest biogenic amine content was attained in C-Eld AI (104.1 mg/kg). In total, 43 volatile compounds (VC) were identified in U-CC, and, in all cases, a broader spectrum of VCs was observed in U-CC enriched with BIBs. After 10 days of storage, the highest enterobacteria number was in C-Blu NI (1.88 log 10 CFU/g). All U-CC showed similar overall acceptability (on average, 8.34 points); however, the highest intensity of the emotion "happy" was expressed by testing C-Eld NI . Finally, the BIBs are prospective ingredients for U-CC enrichment in a sustainable manner and improved nutritional traits.