Synergistic use of ultrasound and hot water to extend the postharvest shelf-life of blueberries

Blueberries are valued for their rich content of antioxidants and bioactive compounds but are highly perishable due to their fragile structure and high moisture content. This study investigated the effectiveness of ultrasound (US) and hot water (HW) treatments, applied individually and sequentially, in maintaining quality and extending the shelf life of fresh blueberries. Fruits were subjected to HW immersion (50°C, 5 min), US treatment (28 kHz, 10 min), or a combined HW + US treatment, then stored at 4 ± 1°C for 14 days. Quality parameters, including microbial load, firmness, surface color (L a b*), total phenolic content, antioxidant activity, and sensory attributes, were evaluated. The combined HW + US treatment showed superior effects compared with individual treatments and the control, achieving greater microbial inhibition, reduced firmness loss, delayed color degradation, and higher retention of phenolics and antioxidant activity. Sensory analysis further confirmed improved appearance, texture, and odor. Overall, the integration of ultrasound with mild heat treatment represents an eco-friendly and scalable postharvest technology that preserves bioactive compounds and sensory quality, offering a sustainable solution for the fresh produce industry.