Impact of different peeling treatments on the isomerization and micellization of carotenoids and the flavor in tomato pulp

Abstract

To find a superior peeling method and increase peeled tomato quality, this investigation aims to evaluate the composition, isomerization, micellization, and antioxidant activity of carotenoids and the flavor of tomatoes using novel catalytic infrared, hot-water, hot-lye and manual peeling. Compared to manual peeling, thermal peeling methods significantly improved carotenoid extractability, increased lutein and β-carotene contents, and enhanced their micellization during in vitro digestion. Additionally, these methods reduced micelle viscosity and size. Among the thermal methods, catalytic infrared peeling resulted in tomatoes with a redder color, the highest carotenoid extractability (716.51 μg/g), and superior antioxidant activity. This method also exhibited the highest proportion of all-trans isomers before and after digestion—54.26 % and 15.57 % for all-trans lycopene and 75.46 % and 22.79 % for all-trans β-carotene. Furthermore, catalytic infrared peeling produced the richest flavor compounds, most closely resembling manual peeling. These results suggest that catalytic infrared peeling is optimal for maintaining high tomato quality.