Summary The effects of osmotic (OP), ultrasound‐assisted osmotic pretreatment (UAOP) and frying conditions on quality and storage stability of vacuum fried pumpkin chips were investigated. The pumpkin samples were pretreated in maltodextrin solution and subsequently fried at different temperatures (90–110 °C) and time periods (10–30 min). The results demonstrated that the moisture content, water activity, lightness, yellowness and carotenoid content of the fried chips decreased, while oil content, hardness and a* (dark brown colour) value increased with increasing frying temperature and time. UAOP reduced about 16.0% of oil absorption and enhanced approximately 70% of carotenoid retention in the fried chips. UAOP samples were also more stable during storage than the untreated ones, indicated by lower degradation kinetics constants of key quality parameters. The proposed pretreatment could be an effective method for food industries to develop vacuum fried pumpkin chips with improved quality and stability.

Sugarcane bagasse is a low-cost and abundant of bio-resources in sugar mill industry. The cellulose of bagasse can be converted into reducing sugar that has been applied in food and biological process. Statistically based Box-Behken Design (BBD) was selected for the optimization of reducing sugar production from acid hydrolysis of sugarcane bagasse. Concentration of H 2 SO 4 , hydrolysis time, and the ratio of raw material to solvent were identified for significant effects on reducing sugar production. Response surface method by BBD was employed to develop a mathematical model for predicting the optimal condition of acid hydrolysis process. The value of R 2 (0.981) for the presented mathematical model indicates the high correlation between experimental and predicted values. The optimization of concentration of H 2 SO 4 , hydrolysis time, and ratio of raw material to solvent are 27.697 %w/v, 160 min, and 1:29.827 g/ml respectively, which under this condition, it could produced 14.808% of reducing sugar from sugarcane bagasse.  Index Terms-sugarcane bagasse, reducing sugar, acid hydrolysis, Box-Behnken design.