Spray-drying of casein/pectin bioconjugate microcapsules containing grape (Vitis labrusca) by-product extract

Novel microcapsules containing grape peel by-product extract were obtained. In this pursuit, complex coacervation of casein/pectin bioconjugate and spray-drying were combined. We have investigated the role of the dispersion feed rate (F_R), drying air inlet temperature (I_T) and drying air flow rate (A_R) in the drying yield, microencapsulation efficiency, total polyphenols and anthocyanins contents, antioxidant activity, and morphology of the products. Also, the first-order degradation kinetics of the phytochemicals for both the extract and dried microcapsules was assessed and compared. The loss on the phytochemicals during spray-drying was attenuated in up to 88%, and the I_T was the main factor affecting the particle properties. The polyphenols on the extract interacted with the polymers, influencing the assemble of the bioconjugate and the particle's features. Such microencapsulation strategy enhanced the thermal stability of the phytochemicals and rendered biocompatible and biodegradable products of which the nutraceutical and cosmeceutical application may have potential.