Heat Processing of Blueberries and Its Effect on Their Physicochemical and Bioactive Properties

Abstract

The current study aimed to evaluate the dehydration process of blueberry fruits at temperatures of 70, 80 and 90C and its effect on their physicochemical and bioactive properties. The values for moisture content and water activity (aw) were still high for dehydrated fruits, although at temperatures of 80 and 90C, the dried fruits showed a aw below the limit for contamination by pathogenic microorganisms. The antioxidant activity increased during the first half of dehydration at 80C, but after 3 h suffered a significant reduction (P < 0.05), which continued up to the end of the process. The anthocyanins showed mean half‐lives of 7.7 and 6.8 h for dehydration at 70 and 80C, respectively. These results indicated that the stability of the anthocyanins and the antioxidant capacity of the fruits could be related to both the intensity and the duration of the dehydration. Practical Applications The present work consists of a study of the dehydration of blueberry fruits at different temperatures in order to extend their shelf life and provide their consumption at any time of the year in the form of dried blueberries. Thus, mathematical modeling of the process was carried out to evaluate the behavior of water activity and moisture, and to determine the degradation of its antioxidant compounds. The optimization of the drying time and temperature of these products is essential to avoid losses in the bioactive properties of blueberries.

Recent Research on the Health Benefits of Blueberries and Their Anthocyanins

“…Dried blueberries can be stored at room temperature. Whereas conventional thermal dehydration can cause significant losses to anthocyanins ( 182 ), freeze-drying is an excellent means to remove water while preserving blueberry phytochemical quality ( 183 ). Freeze-dried blueberry powder loses anthocyanins in a temperature-dependent manner with a half-life of 139, 39, and 12 d when stored at 25, 42, and 60°C, respectively ( 184 ).…”

Minimally processed beetroot waste as an alternative source to obtain functional ingredients

“…Required moisture values were reached after drying for 11 h at 60°C, 9 h at 70°C, and 7 h at 80°C, and no difference was found between chlorinated and nonchlorinated samples. Reque et al (2015) demonstrated that the dehydration of blueberry fruit at 80 or 90°C led to moisture values below the limit for pathogenic microorganism contamination. On the other hand, they found that longer heat processing times caused a decrease in the bioactive and antioxidant properties of dried blueberry fruit.…”

Changes in Cuticular Wax Composition of Two Blueberry Cultivars during Fruit Ripening and Postharvest Cold Storage

“…Blueberry fruits contain high concentrations of bioactive components, such as procyanidins, anthocyanins, flavonols, and chlorogenic acid. − These components have antimicrobial, antioxidant, anticancer, antidiabetic, and cardioprotective activities. Blueberry is a popular fruit worldwide for its high nutritional value and health benefits.…”