Integrating mulberry juice and Lactiplantibacillus plantarum TAR4 fermentation to improve antioxidant, anti-inflammatory, and hypoglycemic potential of modified cottage cheese

Mulberry (Morus nigra) is recognized for its nutrient-dense and health benefits. This study aimed to enhance the bioactivities (antioxidant, anti-inflammatory, hypoglycemic) of modified cottage cheese by incorporating mulberry juice and fermenting with Lactiplantibacillus plantarum TAR4 (LAB). Initially, enzyme treatments (pectinase, amylase) on mulberry juice assessed total phenolic content (TPC), flavonoids content (TFC), DPPH activity (DPPH), ferric reducing antioxidant power (FRAP), albumin denaturation inhibition (ADI) and α-amylase inhibition (AI) activities. Optimal mulberry juice, showing highest bioactivities, was added to cheese. Bioactivity stability during simulated in-vitro digestion was tested. Results showed that pectinase-treated mulberry juice had highest DPPH (37.01 ± 0.24%), FRAP (84.38 ± 1.73 mg Fe²⁺/g dried mulberry), ADI (30.47 ± 0.57%), and AI (71.11 ± 2.55%). Adding 5% (w/w) mulberry juice significantly increased TPC, TFC, ADI, and AI in cheese (p < 0.05). Post-intestinal digestion, mulberry cheese maintained high TPC (15.77 ± 0.07 mg GAE/g cheese) and FRAP (3.75 ± 0.17 mg Fe²⁺/g cheese), while LAB-fermented mulberry cheese (mulberry-LAB) exhibited superior AI activity (54.4 ± 0.9%). No significant differences were found in TFC, DPPH and ADI between mulberry and mulberry-LAB cheeses post-intestinal digestion. This study recommends integrating mulberry juice and L. plantarum TAR4 fermentation to enhance the bioactivities of modified cottage cheese, offering a novel approach to boost nutritional and functional properties.