Stability study of fortified low-fat spreads with preservatives

Abstract

Abstract Physicochemical variations in products are known to occur depending on storage conditions. This study examined the effects of storage time on the physicochemical, sensory, rheological, and microbiological properties of fortified low-fat spreads. Fortified spreads containing potassium sorbate (PS; 0.05% and 0.1%) or MicroGard 100 (MG; 0.5% and 1%) as preservatives and a control spread (CS) were packed in presterilized airtight polyethylene jars and their shelf lives were investigated by storage at (5±1) °C for 91 d. Based on the physicochemical properties, the addition of preservatives inhibited the formation of free fatty acids and thiobarbituric acid and influenced the pH and acidity. The emulsion stability of the preserved samples was greater than that of the CS after 14 d. As storage progressed, the sensory and rheological properties of the CS deteriorated continuously, whereas significantly smaller changes were observed for the samples containing 0.1% PS and 1% MG. The surface growth of yeasts and molds was the main cause of spoilage, particularly in the CS. For all the samples, the standard plate counts and the yeast and mold counts increased during storage. In contrast, the coliform counts were zero, indicating that the samples were manufactured and stored under hygienic conditions. The samples containing lower levels of preservatives (0.05% PS and 0.5% MG) were acceptable for 70 d and 77 d as compared to 49 d for the CS. Notably, the addition of 0.1% PS and 1% MG extended the shelf life to 91 d.