Encapsulation of mixtures of tuna oil, tributyrin and resveratrol in a spray dried powder formulation

Abstract

Spray dried emulsions are effective for carrying and stabilising combinations of fish oil and tributyrin, fish oil and resveratrol, or fish oil, tributyrin and resveratrol in one formulation. The encapsulation efficiencies were >99% for all three bioactives when a heated mixture of sodium caseinate: glucose: dried glucose syrup matrix (Encapsulant matrix 1) was used. When a heated sodium caseinate: glucose: processed starch matrix (Encapsulant matrix 2) was used, the encapsulation efficiencies were 90–92% for tributyrin and ∼98% for resveratrol for all formulations but 79–91% for tuna oil where the efficiency was more formulation dependent. There was 84–86% remaining EPA, 85–87% remaining DHA, 85% remaining tributyrin and 94–96% remaining resveratrol after 18 months at 25 °C storage of the spray dried emulsions using Encapsulant matrix 1 across all formulations. In comparison, there was 83–87% remaining EPA and 84–89% remaining DHA, 80–82% remaining tributyrin, and 81–100% remaining resveratrol across all formulations with Encapsulant matrix 2. In vitro studies showed that on sequential exposure to simulated gastric and intestinal fluids, <5% tuna oil was found as triglycerides, but all the tributyrin had been lipolysed. The presence of diglycerides, monoglycerides and free fatty acids in the in vitro digests suggested that lipolysis of tuna oil had occurred. The type of matrix used for encapsulating the bioactives had little effect on the lipolysis of the oils but affected the amount of solvent extractable resveratrol. The ability of delivering mixtures of bioactives within one formulation was demonstrated.