Effects of Thermal and Non-Thermal Sterilization Methods on the Phytocompounds, Flavor Profile, and Antioxidant Properties of High Acidity Mulberry Vinegar

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This study examined the effects of three sterilization techniques—heat, microwave, and high hydrostatic pressure (HHP)—on the phytochemicals, flavor, and antioxidant properties of high-acidity mulberry vinegar. High-acidity vinegar is valued for its unique sensory properties, preservation potential, and potential health benefits, yet its quality can be significantly impacted by processing methods. Understanding how sterilization affects high-acidity vinegar is crucial for optimizing its functional and nutritional properties while maintaining consumer appeal. Thermal processing (TP) involved heating samples at 85 °C for 15 min, while microwave heating (MH) was performed at 600 W for 40 s. HHP treatments subjected samples to pressures of 400 MPa, 500 MPa, and 600 MPa at ambient temperature (~25 °C) for 15 min. Results showed that total soluble solids (TSS) remained stable at approximately 6.90% across treatments, confirming effective sterilization, especially with HHP. pH values were consistent (3.53–3.55), while total acidity varied, with HHP treatments achieving lower acidity (5.00 g/L). Phytochemical analysis indicated the control (CK) treatment preserved the highest total anthocyanin content (TAC), but HHP500 maintained notable levels. HHP treatments also yielded the highest total phenolic (TPC) and total flavonoid content (TFC), highlighting non-thermal sterilization’s advantage in preserving health-promoting compounds. Antioxidant activity, particularly DPPH, was best retained in HHP samples. HHP500 showed minimal reductions in key phenolic acids, with decreases of 6.16% in p-hydroxybenzoic acid and 7.81% in total phenolic acid. Volatile organic compound analysis revealed increased ester production, with ethyl acetate peaking at 1775.71 μg/L in HHP600. Overall, HHP at 500 and 600 MPa proved superior for producing high-quality mulberry vinegar, supporting the demand for minimally processed, health-focused food products.