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

Abstract

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-RaNI 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-EldAI samples (in comparison with C, on average, by 1.6 times lower). The highest biogenic amine content was attained in C-EldAI (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-BluNI (1.88 log10 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-EldNI. Finally, the BIBs are prospective ingredients for U-CC enrichment in a sustainable manner and improved nutritional traits.

Effect of Blueberry Pomace Addition on Quality Attributes of Buttermilk-Based Fermented Drinks during Cold Storage

“…Consequently, BM containing BP exhibits substantial antioxidant activity, positioning it as a novel dairy product with notable health benefits. Our research agrees with those of previous reports, which described that the addition of berry industry by-products contained higher radical scavenging activity due to the higher amount of phenolic compounds [ 31 , 37 ]. Also, similar findings were presented by Najgebauer-Lejko and Sady [ 42 ] where BM flavored with strawberry and rhubarb exhibited higher radical scavenging activity (0.88 mmol of TE/kg) compared with the control sample.…”

“…Additionally, both the blueberry concentration and storage duration significantly influenced the b* values, along with their interactions. Conversely, no statistically significant changes were detected in the redness coordinate (a*) for fortified BM samples, consistent with findings by Starkute et al [ 31 ].…”

“…Similarly, Saberi et al [ 37 ] observed significantly higher total phenolic content values in fortified yogurts with grape pomace and flaxseed oil compared to a control yogurt during storage. Similar tendencies were observed in the study of Starkute et al [ 31 ], where the total phenolic content and antioxidant activity significantly increased in enriched samples, demonstrating the potential of raspberry, blueberry, and elderberry industry by-products for enhancing the nutritional and functional properties of unripened cow milk curd cheese. Various factors such as berry variety, cultivation region, and extraction and drying methods can influence phenolic compound levels [ 38 ].…”