Monitoring and modelling of physicochemical properties of papaya chips during vacuum frying to control their sensory attributes and nutritional value

Abstract Vacuum frying is an alternative technology to obtain fruit snacks with higher sensory and nutritional quality compared to traditional fried snacks. Vacuum frying of a carotenoid-rich fruit (red-fleshed papaya) was performed at 25 kPa, using soybean oil at 100, 120, and 140°C from 0 to 14 min. The study aimed to monitor and model physicochemical changes that chips undergo during vacuum frying, which are related to their sensory and nutritional attributes. Moisture content, aw, oil uptake, sugar content, browning index (BI) and carotenoid contents were monitored. Water loss and oil uptake followed first-order kinetics while the decrease in aw followed a logistic trend. Glucose and fructose followed the same degradation pattern while BI and sucrose content increased as a function of frying time and oil temperature. β-cryptoxanthin (BCX) loss followed second-order kinetics and retention was 60 and 40% after 14 min at 120 and 140 °C, respectively. Contents of lycopene and β-carotene were increased suggesting an improvement in availability of these compounds to extraction. Optimal vacuum frying conditions for processing papaya fruit comprise a combination of temperatures (107-120 °C) and frying times (9-14 min) to produce quality papaya chips with aw ranging from 0.1 to 0.3, low color degradation and BCX loss ≤30 %.