Pectin Supplementation Improves Probiotic Survival and Preserves Bioactive Compounds of Fermented Pear Juice

Fruit and vegetable juices are ideal probiotic carriers and pectin supplementation is promising for probiotic survival. In this study, we investigated the effects of high- and low-methoxyl pectin on Lacticaseibacillus casei 37 and Lactobacillus helveticus 76 in fermented pear juice (PJ) regarding fermentation, viability, and functionality. Our results showed that pectin protected probiotic viability at 4 °C for 28 days, with viable cell counts reaching 8.39–8.63 log colony-forming units/mL. Furthermore, it promoted phenolic compound release (e.g., gallic acid and protocatechuic acid), raising total phenolic content by 8.3–21.9% and total flavonoid content by 79.6–140.3%. It significantly enhanced DPPH, ABTS radical scavenging activity, and FRAP antioxidant capacity. In vitro digestion revealed that pectin supplementation elevated the survival rate of probiotics in simulated gastric juice by 6.2–66.4%. Additionally, correlation analysis linked specific phenolics (p-coumaric acid, epicatechin, rutin) to antioxidant activity. An addition of 0.3% low-methoxyl and 0.2% high-methoxyl pectin was considered the optimal treatment, benefiting probiotic viability, phenolic accumulation and antioxidant stability of fermented PJ under cold storage and gastrointestinal environment. Thus, pectin is an effective carrier for high-viability, high-antioxidant probiotic fermented PJ beverages.