Optimisation of the Encapsulation of Grape Pomace Extract by Spray Drying Using Goat Whey Protein as a Coating Material

Abstract

The aim of this research was to determine the optimal conditions for the process of the microencapsulation of phenol-rich grape pomace extract (GPE) using spray drying and goat whey protein (GW) as a coating. The encapsulation was carried out with the aim of protecting the original bioactive components extracted from grape pomace to ensure their stability and protection from external agents, as well as antioxidant activity, during the conversion of the liquid extract into powder and during storage. Using the response surface methodology, an inlet air temperature of 173.5 °C, a GW ratio of 2.5 and a flow rate of 7 mL/min were determined as optimum process parameters. Under these conditions, a high yield (85.2%) and encapsulation efficiency (95.5%) were achieved with a satisfactorily low moisture content in the product (<5%). The amount of coating had the greatest influence on the MC properties. GW showed a more pronounced stabilising effect on the phenolic compounds in GPE during a longer storage period compared to anthocyanins. The results obtained indicate the potential of GW as a coating and are an example of the possible upcycling of GPE and GW, which can lead to a high-quality product that can be a functional ingredient.