Deciphering the role of fruit maturity, calcium and freezing on the nutritional and textural attributes of crisps from red guava

Abstract

Guava (Psidiumguajava L.), being highly nutritious possesses commercial importance in the tropical and subtropical region of the world. The climacteric guava, however, records highest postharvest loss and needs to be processed for higher shelf life and utility. This study entails evaluation of fruit maturity stage and prior freezing for development of calcium enriched guava crisps through atmospheric frying. The sliced fruits (of three maturity stages) were subjected to vacuum impregnation to infuse maltodextrin, salt, ascorbic acid and calcium lactate. Fracturability and crispness was significantly affected by fruit maturity, freezing pre-treatment and calcium impregnation. Freezing pre-treatment enhanced the texture, decreased toughness and gave superior crisps with crunchy mouthfeel. While browning increased due to freezing pre-treatment, calcium impregnation led to decreased browning. More than 15-fold increase in the calcium content of crisps was realised upon 1% calcium lactate impregnation. The average ascorbic acid and lycopene retention in the crisps was 36.18 and 37.58%, respectively. Mature guava showed highest lycopene retention (43.07%) in crisps. Based on MANOVA analysis, all the main effects, two factor interaction and three factor interaction were statistically significant at 1% level. The first three PCs could explain 73.64% variation in data. The highest ascorbic acid retention, crispiness and sensory scores were recorded for crisps from ripe stage of guava fruits given freezing and calcium infusion pre-treatments. Thus, ripe guava fruits could be converted to shelf stable and attractive crisps, which would provide essential nutrients and potential health benefits, ensuring off-season availability of perishable guava in the form of crisps.