Quality of green beans (Phaseolus vulgaris L.) influenced by microwave and hot water pasteurization

This research investigated the influence of 915 MHz microwave-assisted thermal pasteurization and conventional hot water pasteurization (F9010=10 min) on chlorophylls, greenness (a*), ascorbic acid, and the growth of spoilage microorganisms in green beans in storage at 10, 7, and 2 °C for up to 100 days. Frozen cut green beans were processed in vacuum-sealed containers flushed with N2. The beans suffered 28.3% and 33.9% losses of chlorophyll a, 9.2% and 15.3% losses of ascorbic acid during the microwave and hot water processing, respectively. During storage, slower spoilage (21 days at 10 °C, 42 days at 7 °C, and 100 days at 2 °C), superior preservation of chlorophyll (47–50%), ascorbic acid (47–62%), and a lower increase in a* (2.8–5.2) were obtained in samples processed with microwave-assisted thermal pasteurization. Paenibacillus spp. were identified as the predominant bacteria in the spoiled green beans pasteurized with both methods. The results highlighted the potential of microwave pasteurization for producing safe, high-quality vegetable products.