Effect of pulsed light on enzyme inactivation, colour, firmness, surface morphology, and bioactive compounds in fresh and dried whole red chilies (Capsicum annuum var. longum)

Abstract

The effect of pulsed light on enzymatic activity and biochemical stability of red chillies was investigated. Balancing and reducing the a_w and moisture content to 0.6 a_w and 0.35 a_w is crucial to attain biochemical stability. Upon drying at 60 °C/5 h + 40 °C/2 h and 70 °C/11 h + 55 °C/4 h + 40 °C/2 h the enzymes inactivated to more than 30 %, respectively. Hence, to completely inactivate the enzymes, a technology has been introduced i.e., pulsed light treatment (PLT), which employed 0.53–2.59 J·cm⁻². The stability of red chillies was evaluated based on the quality attributes such as enzyme activity, total phenolics, flavonoids, antioxidant capacity, ascorbic acid, capsiacinoids, and carotenoids. After treatment at fluence of 2.59 J·cm⁻², there was >90 % inactivation of PPO and POD. Based on kinetic modelling, it is showed PLT better preserved the colour, texture, morphology, and bioactive compounds in 0.6 and 0.35 a_w than 0.85 a_w red chillies. Morphological studies determined the changes in red chillies after PLT. FTIR and GCMS analysis revealed the structural and compositional changes occurring after PLT. Therefore, drying combined with PL can be a potential alternative method to blanching along with maximizing the availability of bioactives.