Assessment of Quality Indices in Japanese Quince (Chaenomeles japonica L.) Juice and Concentrate: Evaluating the Impact of Hydrolytic Enzymes and Clarifiers

Research background. Japanese quince (Chaenomeles japonica L.) is known for its relatively high levels of bioactive compounds, including phenolics, vitamin C, organic acids, dietary fibers, and pectins. Its acidic nature makes Japanese quince juice (JQJ) a potential alternative to lemon juice, offering preservative and acidifying properties in various products. Experimental approach. This study aimed to evaluate the effects of different hydrolytic enzymes (EnartisZym 1000 S, EnartisZym RS, EnartisZym EZ Filter) and the clarifying agent bentonite from “Neoclar AF” (bentonite/activated carbon) on the quality indicators of JQJ and its concentrate (JQJC). Juice was extracted from frozen fruits, followed by clarification, filtration, and concentration through open water evaporation at 60 °C to achieve approximately 50 Brix %. Results and conclusions. The findings demonstrated that hydrolytic enzymes and clarifiers effectively reduced pectin content in JQJ and JQJC by 68.5 % and 57.0 %, respectively, significantly improving their clarity by 85.9 % and 64.9 %. The highest clarity was observed in samples treated with EnartisZym 1000 S and bentonite (0.028) compared to the control. Enzymatic treatment had a minimal impact on phenolic content, with enzyme-treated JQJ containing an average of 318.3 mg/100 mL and JQJC 3.12 g/100 g, compared to 326.2 mg/100 mL and 3.34 g/100 g in untreated samples, respectively. Vitamin C retention was high, with enzyme-treated JQJ containing 68.3–69.4 mg/100 mL and JQJC 231.4–236.9 mg/100 g, compared to 72.8 mg/100 mL and 244.9 mg/100 g in untreated samples, indicating that enzymatic treatment and mild processing effectively preserved ascorbic acid content. The DPPH• radical scavenging activity was significantly higher in enzyme-treated JQJ, though it decreased during juice concentration. In both JQJ and JQJC, FRAP values were lower in enzyme-treated samples than in controls. Based on generalized scores acquired from AHP analysis, the enzyme EnartisZym EZ Filter, possessed both cellulolytic and pectolytic activities, was found to be the most efficient, ensuring the quality characteristics of JQJC nearly similar to those commercially available on the market such as lemon juice concentrate Novelty and scientific contribution. This study provides valuable insights into the potential of JQJC as a natural acidifying alternative to lemon juice, addressing a gap in existing research. The obtained data demonstrate that JQJC not only offers preservative and acidifying properties but also retains significant nutritional benefits, making it a promising ingredient for food applications. As an innovative niche product, JQJC has the potential to enhance food preservation and quality naturally. Future research should further explore its applications in various food formulations to maximize its functional and commercial potential.