Physicochemical, nutritional, and phytochemical profile changes of fermented citrus puree from enzymatically hydrolyzed whole fruit under cold storage

This study aimed to investigate the microbial viability, edible qualities, and flavor volatiles of enzymatically hydrolyzed 'Orah' (Citrus reticulata Blanco) puree separately using Lactobacillus paracasei JLPF-176 (LP) and Bifidobacterium infantis JYBI-373 (BI) as starters during fermentation and storage. The results showed that fermented enzymatically hydrolyzed citrus puree contains sufficient viable counts (6–8 log CFU/mL) during fermentation and storage. Probiotics fermentation increased the content of organic acids, total phenolic content (TPC), total flavonoid content (TFC), antioxidant capacities, and flavanones. Storage led to an increase in soluble sugars (fructose and glucose) and a decrease in organic acid (l-tartaric acid). During the early storage weeks, the TPC, polymethoxylated flavones (PMFs), and flavanones of citrus puree fermented by LP were obviously increased, resulting in higher antioxidant capacity based on the DPPH and FRAP methods. Correspondingly, the antioxidant capacity (ABTS and FRAP) of citrus puree fermented by BI was decreased continuously during storage, which was related to the decrease in the TFC and tangeretin. A total of 24 volatile compositions were identified, and storage tended to decrease the sensory properties of citrus puree by probiotic fermentation. Overall, this study provides a potential method to innovate whole citrus fruit processing technology and improve its nutritional value.