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.
ABSTRACT
There is scarce data on the influence of fermentation with lactic acid bacteria (LAB) on the quality and safety of edible mushrooms. The aim of this study was to ferment Suillus luteus, Boletus edulis, Cantharellus cibarius, and Rozites caperata with LAB strains (Lacticaseibacillus casei LUHS210 and Liquorilactobacillus uvarum LUHS245) and to evaluate the influence of this technology on colour characteristics, pH, mould/yeast count, liking, emotional response, volatile compound (VC) profile, and the formation of biogenic amines (BA). Additionally, ultrasonication or prolonged thermal treatment were applied before fermentation. The LUHS245 strain showed better preservation properties in the case of fungal inhibition; however, prolonged thermal treatment and/or ultrasound pre-treatment ensure safer fermentation. Mushroom species and type of pre-treatment had a significant effect on colour coordinates and pH (p ≤ 0.0001). A greater variety of VC was identified in pre-treated and fermented samples. Significant differences were found between the emotions induced in consumers. The lowest sum of BA was found in thermally pre-treated and fermented R. caperata, while the highest was in ultrasonicated and fermented B. edulis. Finally, despite good overall acceptability, it is important to select appropriate LAB strains for the fermentation of edible mushrooms to ensure their safety in the case of BA formation.
