Microencapsulation upholds biological activities of sheep whey hydrolysates and protects against in vitro gastrointestinal digestion

Recycling of dairy by-products as sources of bioactive compounds is an interesting approach for improving sustainable food production. This study aimed to encapsulate a sheep whey hydrolysate (SWH) with antioxidant and antihypertensive properties, produced by a novel proteinase P7. SWH encapsulation was achieved by spray-drying and freeze-drying methods using prebiotic gum Arabic as the encapsulating material. The morphology, colour, moisture, water activity, hygroscopicity, antioxidant and antihypertensive properties, and in vitro digestion of the microcapsules were evaluated. Spray-drying process produced powders with better characteristics as compared with freeze-drying, showing 3.9% moisture, 18.9% hygroscopicity, highest ABTS radical scavenging (65.7%) and iron chelating (78.4%) activities and 70.1% inhibition of the angiotensin I-converting enzyme. Additionally, these biological properties were not affected during simulated gastrointestinal conditions. SWH encapsulation may be an interesting strategy for valorisation of dairy industry by-products, as an ingredient for development of functional foods and potentially increasing nutritional value and shelf life.