Production of microencapsulated casein hydrolysate as a bioactive food additive using the double emulsion/spray drying technique

Casein is an important precursor of bioactive peptides, which can be produced through the hydrolysis of casein. However, there are several challenges associated with using hydrolyzate as a food additive. It is crucial to maintain the high bioactivity of peptides during food processing, storage, and digestion. Moreover, the peptides formed after hydrolysis can have an unpleasant taste and exhibit high hygroscopicity. Encapsulation technology offers an effective solution to overcome these limitations. In this thesis, a food additive encapsulated with casein hydrolyzate using the double- emulsion/spray drying technique was developed. Initially, an emulsion formulation suitable for producing a two-layer emulsion was determined, and the conditions for emulsification were optimized. Subsequently, the wall materials for microencapsulation and their usage rates were identified, and the potential bioactive properties of the resulting powders were examined after in vitro digestion. Within the scope of this thesis, the most suitable primary emulsions were produced using a rotor-stator type homogenizer. The optimal formulation for creating a double emulsion involved dispersing the primary emulsion in an 80% outer water phase using an ultrasound homogenizer. The powders obtained from the spray dryer drying process of this double-layered emulsion exhibited free radical scavenging activity (214.1±1.4 umol Trolox/g sample) and angiotensin-converting enzyme inhibitory effects (34.7±0.1%) after in-vitro digestion.