Valorization of second cheese whey enriched with apple pomace for the production of innovative fermented products

Second cheese whey (SCW) is the primary by-product of the whey processing, which has received particular attention due to its significant environmental impact as a source of pollution. Due to its compositional profile and richness in lactose, SCW is an underexplored by-product and its valorization is not widely practiced being difficult to manage. This study aimed to exploit SCW as a potential ingredient for the development of new food products, such as enriched dairy products. To achieve this goal, twelve fermented formulations were produced and compared using milk, SCW, and their 50:50 mixture as substrates for fermentation. Three lactic bacterial (LAB) strains were selected, and the effect of apple pomace (AP), a by-product of juice processing, incorporated into the substrates during fermentation was investigated. The results showed that the growth of LAB was enhanced in the presence of AP, and a progressive increase in the total phenolic content and antioxidant activity was observed as the percentage of AP increased from 4 % to 12 %. HPLC analysis, in particular, revealed elevated concentrations of quercetin glycosylated derivatives in SCW-based fermented products, with the highest levels observed in samples containing 12 % AP. A chemometric approach was applied to identify groupings within the dataset. Strong correlations were consistently found between spectrophotometric assays and the polyphenol concentration measured by chromatography. Furthermore, the sensory evaluation results confirmed a higher overall acceptability score for products fermented with SCW and 12 % AP.