Detoxification of Meghalayan cherry (Prunus nepalensis) kernel and its effect on structural and thermal properties of proteins.

Valorizing food wastes and by-products can improve economic and environmental sustainability of the food production chain. In this regard, Meghalayan cherry kernels are a good source of proteins, but the presence of toxic compounds like amygdalin, makes them underutilized. Therefore, the present study was focused on detoxifying Meghalayan cherry kernel using thermal, soaking and ultrasound treatments and studying their impact on the structural and thermal characteristics of protein isolate. The results showed that all three treatments significantly reduced amygdalin content, with complete detoxification achieved after 30 and 60 min at 70 °C and 60 °C, respectively, in ultrasound, and after 90 and 120 min at 70 °C and 60 °C, respectively, in soaking + thermal treatment. The detoxification treatments significantly affected the protein content and weight-loss of Meghalayan cherry kernel. Fluorescence spectroscopy and FTIR showed alterations in Meghalayan cherry kernel protein isolate (MCKPI) secondary and tertiary structure. The fluorescence intensity was observed at 340 nm for native and detoxified protein isolate, and the lowest peak for MCKPI-US depicts conformational changes. The fading of bands in SDS-PAGE confirms structural changes due to thermal and sonication effects. SEM images demonstrated that more cracks and porous structures were seen in treated MCKPI than native MCKPI. Detoxification treatment increased thermal stability, resulting in lesser weight loss and higher denaturation temperature than native MCKPI. In this study, ultrasound treatment demonstrated the most pronounced effects on the detoxification of MCKPI and its thermal and structural properties, suggesting that Meghalayan cherry kernel is one of the most promising substrates for zero-waste bioprocess development.