Gamma irradiated date syrup for sucrose substitution in yogurt: effect on physicochemical properties, antioxidant capacity and sensory evaluation.

In the search for domestic natural additives favored by consumers for food flavor and antioxidant enhancement, this work aimed to estimate the influence of the substitution of sucrose by date syrup treated with gamma rays on the physico-chemical properties, antioxidant capacity and organoleptic quality of yogurt. Date syrup was irradiated by two different doses: 1 kGy and 2 kGy and incorporated into yogurt with different sucrose substitution percentages. The obtained results showed that gamma irradiation improved the microbiological quality of the date syrup while retaining its physicochemical quality. In fact, a significant reduction of the microbial charge was observed. The two-irradiation doses were proven not affected the total sugars, proteins, phenols or the syrup antioxidant activity. Besides, water content and color indices were found to decrease. The substitution of sucrose at the rate of 75 and 100% with date syrup irradiated by the dose of 1 kGy enhances the antioxidant activity, phenol, protein and sugar content of the prepared yogurt. Furthermore, yogurt with irradiated date syrup gave good sensory scores. The treated syrup, especially by the dose of 1 kGy, could be a promising technological path. This gamma irradiation guarantees a biological method for preserving the syrup for its use in the engineering of processes applied to the dairy industry. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13197-021-05000-z. © Association of Food Scientists & Technologists (India) 2021.