IMPACT OF THERMAL TREATMENTS ON QUALITY ATTRIBUTES OF PINEAPPLE JUICE

Abstract

Pineapple (Ananas comosus) fruit juice is a popular beverage known for its alluring flavor, aroma, and nutrients, including organic acids, minerals, fibers, and proteins, which may help reduce the risk of chronic diseases. However, its highly perishable nature is a cause for great concern. This study compared the effects of thermal processing, specifically microwave and autoclave treatments, on physicochemical parameters, bioactive components, antidiabetic activity, vitamin C and antioxidant capacity of pineapple juice. Additionally, the study evaluated changes in endogenous enzymes such as polyphenol oxidase (PPO) and peroxidase (POD), microbial counts, and sensory qualities of juice during 28 days of storage at room temperature. The study indicated that the pH, total soluble solids (TSS), titratable acidity (TA), and antidiabetic activity of both microwave- and autoclave-treated juice exhibited no significant change. However, there were noticeable changes in the overall color difference (ΔE), bioactive components, vitamin C, and antioxidant capacity compared to fresh juice. It was found that microwave treatment resulted in higher retention of overall color difference (ΔE), total phenolic content (TPC), total flavonoid content (TFC), vitamin C, and antioxidant capacity compared to autoclave treatment. Furthermore, polyphenol oxidase, and total microbial count of juice were inactivated below the detection limits after microwave treatment, but peroxidase had some residual activity. However, the total microbial count and PPO activity showed an increasing trend during storage, while the POD activity remained constant. Overall, these results demonstrated that microwave could be an effective replacement to other conventional thermal processing for production of high-quality pineapple juice.