Effect of Three Concentration Processes on the Physicochemical Properties and Flavor Characteristics of Anoectochilus Roxburghii Juice

This study investigated the effects of atmospheric‐pressure concentration (APC), vacuum concentration (VAC), and freeze‐concentration (FC) methods on the physicochemical properties, bioactive compounds, and flavor profile of Anoectochilus roxburghii juice. The results indicated that after concentration, APC caused the most significant color change in A. roxburghii juice (ΔE = 3.06), while FC was best at retaining the original color (ΔE = 0.45). However, FC juice showed a lower clarification index, indicating better stability. Additionally, the pH value decreased in all groups after concentration. The pH of the normal pressure group dropped from 5.33 to 5.18, representing the most significant reduction. Meanwhile, FC juice exhibited over 85% preservation rates for both total flavonoids and total phenolics, with only a 2.37% loss of kinsenoside. This performance was significantly superior to that of the VAC and APC juices. Different concentration methods all resulted in a decrease in the antioxidant capacity of A. roxburghii juice, with FC juice showing the lowest degree of antioxidant capacity loss. Its total antioxidant capacity was 1.49 μmol/mL, with a retention rate of 97.98%. This retention rate was 9.97% and 14.37% higher than that of the VAC group and the APC group, respectively. In contrast, electronic tongue analysis detected elevated bitterness (response value > 8.30) and astringency (5.97) in APC juice compared to the other groups. The taste profiles of VAC and FC juices closely aligned, whereas APC processing resulted in a significant divergence from FS. Therefore, our findings provide theoretical insights for optimizing A. roxburghii juice processing methodologies.