EFFECT OF SODIUM BENZOATE AND POTASSIUM METABISULPHITE COMBINATIONS ON THE QUALITY AND SHELF STABILITY OF APPLE-PEAR JUICE BLENDS

Abstract

Fruit juices deteriorate gradually during storage because of chemical reactions, oxidative losses and shifts in acidity. These changes are often more pronounced in blended beverages, where the mixture of fruit components can accelerate instability. In this study, the influence of sodium benzoate (SB) and potassium metabisulphite (KMS) on the quality of an apple–pear juice blend was examined over 90 days of ambient storage. Seven preservative treatments were prepared, including a control without additives and several combinations of SB and KMS. Periodic analyses were carried out for pH, total soluble solids (TSS), titratable acidity, sugar–acid ratio, ascorbic acid and reducing sugar fractions. All samples showed progressive changes during storage, but the extent varied with preservative level. Blends containing both SB and KMS resisted quality losses more effectively than single-preservative treatments. In particular, the formulation with 0.04% SB and 0.06% KMS maintained pH, vitamin C and sugar balance better than the other treatments. Although the study relied on single measurements at each interval, the overall pattern supports the use of combined preservatives for stabilizing apple–pear juice blends during unrefrigerated storage.