Gradientes de mudanças fisiológicas na maturação, compostos bioativos e conservação pós-colheita em abacaxi ‘Perola’ parcialmente recobertos

Abstract

Pineapple is an infructescence formed by the coalescence of fruitlets with the central axis of the peduncle, which have different physiological ages along the axis, causing heterogeneity in maturation and quality, making it difficult to use postharvest technologies to prolong storage. In the Experiment I, 'Pérola' pineapple infructescences were harvested at three maturity stages (green, yellow-green and totally yellow) and evaluated in three sections (base, middle and apex) for O2 consumption, CO2 production, color , firmness, soluble solids, titratable acidity, reducing, non-reducing and total sugars, ascorbic acid, yellow flavonoids, total carotenoids, total extractable polyphenols and antioxidant activity. Each fruitlet section had different respiratory activity, which was greater at the base, declining in the apical direction of the fruit, all showing, however, a typical non-climacteric behavior. Changes in respiration and these different physiological ages of the fruitlets produced gradual changes in the physical and physicochemical attributes of the pulp. Experiment II aimed to study the effects on the quality and maintenance of the useful postharvest life by applying a biodegradable coating to different 'Perola' pineapple sections during storage under room conditions (24±3°C and 85±5°C RH) . Pineapples were coated with cassava starch (2.2%) and chitosan (0.3%), with a total of 2.5%, in 1/3, 2/3 and 3/3 of the fruit and without coating (Control), and stored for 20 days, and evaluated every 4 days, in 4 replications. Pineapples were subjected to physical, physicochemical and bioactive compounds analysis. Pineapples partially coated on 1/3 and 2/3 of the surface showed a reduction in respiratory rate, delay in the development of yellow color and maintained high firmness for a longer time. The partial coating application also maintained the soluble solids contents and the highest SS/AT ratio, providing tastier fruits, in addition to maintaining higher ascorbic acid and yellow flavonoid contents and lower levels of total extractable phenolics, indicating that pineapples maintained their quality. without conferring an increase in the oxidative stress. Together, the partial coating of 1/3 and 2/3 of the pineapple with cassava starch and chitosan was more effective in maintaining the quality and prolonging the posthavest life of 'Perola' pineapple than when it was fully coated.