Indução de maturação pós-colheita de frutos de morango (Fragaria × ananassa)

Abstract

Strawberry (Fragaria x ananassa) is a pseudo-fruit that has sensory characteristics much appreciated by the consumer, besides being rich in antioxidant compounds, mainly anthocyanins, phenolic compounds and vitamin C. It is a fruit of great commercial importance. However, a limiting factor is the low mechanical strength, leading to significant postharvest losses. In the current production system, strawberries are harvested at the final stage of ripeness. A practice performed on climatic fruits is harvesting before full ripeness. In this sense, the objective of this study was to evaluate the effect of abscisic acid (ABA) or sucrose postharvest application on the accumulation of compounds related to the ripening process of strawberries. The study was divided into three studies, the first consisted of the application of three doses of sucrose and mannitol (osmotic control) in the induction of maturation, the second study evaluated the application of ABA and nordihydroguaiaretic acid (NDGA), and the third study evaluated accumulation of compounds related to postharvest ripening compared to in vivo ripening. Postharvest induced ripening resulted in fruits with anthocyanin profile and color distinct from in vivo ripening, higher content of total and individual phenolic compounds (catechin, hydroxybenzoic acid and epicatechin) antioxidant activity, vitamin C content in the treatments with the lowest sucrose dose and control, reduced sugar content, especially sucrose, higher flesh firmness, and increased stress marker compounds (ABA-glycosyl ester, phaseic acid and dehidrophaseic acid and proline). Fruits that were submitted to sucrose application showed higher content of soluble solids content, anthocyanins, phenolic compounds, vitamin C, and antioxidant activity when compared to mannitol. Moreover, they presented higher sugar content (glucose, fructose and sucrose) and higher percentage of red fruits after three days of storage, compared to both controls (with water or with mannitol). ABA application resulted in increased ABA and ABA-GE content in fruits and induced an increase in epicatechin content. Its inhibitor has resulted in a reduction in sugar content, soluble solids content, anthocyanin content and vitamin C, thus slowing the maturation process. Results indicate an acceleration of the postharvest ripening process of strawberry fruits using sucrose and delay due to the application of mannitol and NDGA.