Effect of pulsed light technology on microbial quality, enzyme activity and physicochemical attributes of green chilies (Capsicum annuum var. longum) at different levels of water activity

The shelf life of green chillies is very low due to high-water activity (a_w = 0.90 ± 0.01). Balancing a_w and moisture content is crucial for maintaining freshness, quality and extending shelf life of green chillies. To attain microbial and biochemical stability, the a_w should be reduced to 0.6 and 0.3, respectively. Hence, a controlled drying process was introduced. The 0.6 a_w (62 ℃/360 min + 35 ℃/60 min) and 0.3 a_w (75 ℃/600 min + 40 ℃/240 min) green chillies improved bioactives retention, colour and texture; but could not completely prevent the growth of microorganisms. Therefore, post-drying, a decontamination process i.e., pulsed light (PL) treatment of 0.53 to 2.59 Jcm⁻² (1.7–2.1 kV/120–360 s) was employed. Along with microbial decontamination and enzyme inactivation, PL preserved better physicochemical characteristics in 0.6 and 0.3 a_w than 0.9 (fresh) green chillies. While, there is 89.8%, 89.0%, 88.8%, and 93.3% retention of phenolics, antioxidants, flavonoids, and capsaicinoids, respectively, in 0.3 a_w green chillies at PL fluence of 2.59 J cm⁻² fluence. Alongside, ascorbic acid, carotenoids, and chlorophyll showed 30%, 19%, and 26% loss, respectively, in 0.6 a_w green chillies at 2.59 J cm⁻². Drying followed by PL treatment ensured that the green chillies were safe for consumption, and met regulatory standards while maintaining their quality attributes. Therefore, integrated approach combining drying followed by PL decontamination would be the suitable method for preserving the quality of the green chillies.