Evaluation of chilling injury and internal browning condition on quality attributes, phenolic content, and antioxidant capacity during sub-optimal cold storage of Malaysian cultivar pineapples

Pineapple cold storage at sub-optimal temperature (4 ± 2 °C) and duration of storage (0, 7, 14, 21, and 28 days) was periodically tracked to investigate its effect on physical injuries known as chilling injury (CI) and internal browning (IB), which contribute to degradation of pineapple’s quality attributes (i.e., pH, total soluble solids (TSS) concentration, ascorbic acid (AA) content, ion leakage (EL), antioxidant capacity, and total phenolic content (TPC). In this study, three main Malaysian pineapple cultivars were evaluated based on the hypothesis that pineapple’s physical injuries (CI and IB) affect the quality attributes, phenolic content, and antioxidant capacity. Towards day 28 of sub-optimal cold storage treatment, cv. Morris (Queen) showed higher CI and IB incidences. However, the incidences were not statistically significant at a significance level of 0.05 in two other pineapple varieties cv. Josephine(hybrid, between ‘Johor’ Spanish and Smooth Cayenne) and cv. MD-2 or gold (the hybrid of Smooth Cayenne)), which exhibited resistance to CI and IB. Meanwhile, it was found that sub-optimal cold storage up to 28 days affects CI and IB of three main Malaysian pineapple cultivars regardless of their genetic capability towards these injuries. Further, the study revealed that CI and IB symptoms were correlated with a decrease in TSS and pH, and an increase in the percentage of EL, TPC, antioxidant capacity, and antioxidant activities measured by FRAP and DPPH, respectively. Meanwhile, in terms of overall quality attributes result with focus interaction of TPC and antioxidant capacity, cv. MD-2 was observed to be impacted the most during sub-optimal cold storage. The study concluded that CI and IB conditions were positively correlated with the degradation of quality attributes as reflected in TSS content, pH, EL, TPC content, and total antioxidant capacity