Spray-drying microencapsulation and oxidative stability of conjugated linoleic acid

Conjugated linoleic acid (CLA) as the free acid was microencapsulated using whey protein concentrate (WPC) as a wall material. An emulsion of CLA was prepared using an emulsifier formulated with a 1:4 (w/w) ratio of a 30% WPC solution and was spray-dried with a laboratory unit. Microcapsules were stored at 35 and 45degreesC at different water activities. Oxidation was monitored by measuring the CLA concentration, and peroxide, anisidine and total oxidation values. The encapsulation efficiency was 89.60% with a surface oil concentration of 1.77 g/100 g of sample. Microcapsules stored at a(w)=0.743-0.898 had very good stability against oxidation for at least 60 days; therefore WPC is considered as an effective microencapsulating agent.