Quality Evaluation and Shelf-Life Prediction of a Mixed Mango and Passion Fruit Smoothie Under Dimethyl Dicarbonate Treatment and Packaging Interventions

This study investigated shelf-life prediction of a cold-stored mixed mango–passion fruit smoothie (60:40) using kinetic modeling to compare the effects of dimethyl dicarbonate (DMDC, 250 ppm), pasteurization (90 °C for 100 s), and packaging type (glass vs. polyethylene terephthalate (PET)) during six weeks at 4 °C. Physicochemical parameters, functional properties (total phenolic content, total flavonoid content, and antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and Ferric Reducing Antioxidant Power assay (FRAP), and microbial stability were monitored weekly. Zero- and first-order kinetic models were applied to describe quality changes, with the first-order model showing superior fit (average R2 = 0.936). pH remained relatively stable (p > 0.05), while total soluble solids (TSS) gradually declined in all treatments from approximately 16–17 °Brix to 13–14 °Brix by week 6. PET packaging resulted in a significantly higher total color difference (ΔE) than glass by the end of storage (p ≤ 0.05), particularly in DMDC-treated samples. Pasteurization reduced initial polyphenol oxidase (PPO) activity by 44–56% compared with untreated and DMDC-treated samples (p ≤ 0.05), whereas PET generally exhibited higher residual PPO activity than glass. DMDC treatment better preserved antioxidant capacity, phenolics, and flavonoids, with significantly higher DPPH and FRAP values than controls at week 6 (p ≤ 0.05). Microbiologically, DMDC effectively suppressed total viable counts (