Effects of Processing and Storage Conditions on Functional Properties of Powdered Blueberry Pomace

Promoting a circular economy through valorisation of food processing waste into functional ingredients is a challenge today. The combination of hot air drying with milling is a cheap and highly available option for obtaining powdered products from blueberry pomace, a residue with a large amount of fibre and a high proportion of polyphenols from the fruit. The objective of this work was to analyse the effect of drying temperature (60 degrees C and 70 degrees C) and granulometry (coarse and fine) on physicochemical properties, including antioxidant properties and monomeric anthocyanins content. The potential prebiotic effect of blueberry pomace powders, as well as their water and oil interaction properties, were also assessed. Stability of physicochemical properties over 20 weeks of storage was also evaluated. Powders obtained showed a total fibre content higher than 30% with a good proportion between insoluble and soluble fractions and a high retention of monomeric anthocyanins from fresh pomace (75% at 60 degrees C and 66% at 70 degrees C). The powders showed good water interaction properties and interesting technological properties, such as solubility and hygroscopicity, which were not affected by differences in particle size. Stability of powders' physicochemical properties was evidenced throughout the storage period.