Browning in Relation to Enzymatic Activities and Phytochemical Content in Terap Peel (<i>Artocarpus odoratissimus</i> Blanco) during Postharvest Ripening

Enzymatic browning is a common limiting factor in the fruit industry because it causes significant losses through fresh product deterioration, affecting taste, flavor, and nutrition. <i>Artocarpus odoratissimus</i>, locally known as terap, is an exotic indigenous fruit to Borneo. This fruit remains underutilized due to its perishability, short shelf-life, and peel browning. Currently, no information has apparently been published on the browning mechanisms of <i>A. odoratissimus</i>. Thus, the present study aims to evaluate the degree of browning and enzymatic activities in relation to the phytochemical contents in <i>A. odoratissimus</i> during postharvest ripening. The experimental design consists of packaging (without packaging and with packaging) and storage temperatures (ambient at 25 °C, and cold storage at 10 °C), which were arranged in a randomized complete block design. Findings showed significantly higher weight loss in fruit stored at 25 °C on days 4 (T1) at 12.20 ± 0.19% and 8 (T5) at 11.09 ± 0.24%. The degree of browning was higher in the fruits stored with packaging at 25 °C, collected on day 4 at 0.48 ± 0.01 and day 8 at 0.51 ± 0.02, and consequently, the phenylalanine ammonia-lyase (671.00 ± 5.25 UE g⁻¹ min⁻¹) and polyphenol oxidase (670.00 ± 2.56 UE g⁻¹ min⁻¹) enzymatic activities were also higher. The lower enzymatic activities were recorded in the fruit stored at 10 °C without packaging, resulting in the least degree of browning. The fruit with the lowest enzymatic activities was stored at 10 °C without packaging, resulting in the least amount of browning. This trend is supported by lower total phenolic content (TPC) and is explained by a strong positive correlation between TPC and PAL (r = 0.927). Low-temperature storage was effective in reducing the effect of browning and deterioration on <i>A. odoratissimus</i> for up to 16 days. The results not only provided insights into the peel browning in <i>A. odoratissimus</i> but also guidance on controlling postharvest fruit browning.