Effects of Non-Thermal Processing Methods on Physicochemical, Bioactive, and Microbiological Properties of Fresh Pineapple (Ananas comosus L. Merr.) Juice

Abstract

Background: Pineapple juice processing is an art of preservation, and the processing technologies play important role in pineapple juice quality. Therefore, this study aimed to explore the potential impacts of non-thermal processing methods on the physicochemical, bioactive, and microbiological properties of fresh pineapple juice.
 Methods: Extracted juices were subjected to several non-thermal processes including microwave processing, vacuum evaporation, mild pasteurization, pulsed electric field, and ultra-sonication. Physicochemical properties including Total Soluble Solids (TSS), pH, titratable acidity, and color; Total Phenolic Content (TPC); Total Anthocyanin Content (TAC); antioxidant capacity; and microbiological properties were evaluated. Data were statistically analyzed by Minitab statistical software (version: 18.1).
 Results: TSS, pH, acidity (%) of processed juices ranged from 11.03-12.03, 4.07-4.27, and 0.42-0.49, respectively. In terms of color properties both ultra-sonication and microwave processing showed the highest values of L (luminosity), a* (redness), and b* (yellow). The highest TPC was reported in ultra-sonication treatment 11.996±0.002 mg Gallic Acid Equivalents (GAE)/100 ml. The TAC varied from 0.179-0.235 mg Total Anthocyanin (TA)/100 ml, where ultra-sonication and mild pasteurization treatment yielded the highest and lowest contents, respectively.
 Conclusion: Perfect phenolic content, antioxidant capacity, retention of anthocyanin content, and attractive color in pineapple juices when treated with non-thermal techniques.