Changes in the shelf life stability of riboflavin, vitamin C and antioxidant properties of milk after (ultra) high pressure homogenization: Direct and indirect effects

摘要

Changes in the stability during shelf life of riboflavin, vitamin C and the antioxidant capacity of (ultra) high pressure homogenized ((U)HPH) milk were explored. With increasing pressures, a decrease of up to 50% in the degradation rate of riboflavin was observed, likely due to an indirect effect induced by (U)HPH leading to increased scattering and absorbance of the wavelengths related to riboflavin's photosensitized oxidation. Such mechanism was also confirmed in a model system. Vitamin C presented minimal decrease in concentration immediately after (U)HPH treatment, yet it quickly degraded during shelf life. The antioxidant capacity of (U)HPH treated milk measured by ORAC showed a higher value when compared to pasteurized milk, yet no effect was observed by the ABTS method. The observed changes during shelf life, that can be related to direct and indirect processing effects suggest that (U)HPH can assist in possible improvement of milk nutritional quality.Industrial relevanceMilk is a highly consumed product worldwide due to its high nutrient content. Novel innovative methods are constantly researched to improve the nutritional qualities of foods including milk. High or Ultra high pressure homogenization ((U)HPH, depending on the maximal pressure) is a novel technology that can possibly provide microbial inactivation in addition to numerous physicochemical changes in the product. The aim of this project was to evaluate the direct and indirect effect of (ultra) high homogenization pressures on nutritional qualities of milk exposed to fluorescent light during shelf life, conditions encountered in retail stores. A better fundamental understanding of the outcomes of novel processing technologies such as (U)HPH on quality parameters such as vitamin content and antioxidant properties can promote further development and acceptance of those technologies by the industry and by the consumers.