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Keywords:

  • human milk fat analog;
  • microencapsulation;
  • oxidative stability;
  • spray-drying;
  • structured lipid

Abstract

Human milk fat (HMF) analogs are structured lipids (SLs) modified to have palmitic acid content at the sn-2 position of the triacylglycerol (TAG) and fatty acid composition comparable to HMF. Some of these SLs are also designed to incorporate long-chain polyunsaturated fatty acids (LCPUFAs) because of their important role in infant development. In this study, Maillard reaction products (MRPs), obtained from heated whey protein isolates and corn syrup solids (CSS) solution, were used as encapsulants for microencapsulation of 2 enzymatically synthesized SLs for infant formula applications. The encapsulated SL powders were obtained through spray-drying and evaluated in terms of their microencapsulation efficiency, chemical and physical properties, oxidative stability, and dispersibility. The microencapsulation efficiency of the SLs was 90%. Dispersibility test using particle size measurement demonstrated that these powders dispersed quickly into a homogeneous suspension. The encapsulated SL powders had low peroxide and thiobarbituric acid-reactive substances values. Lower oxidative stability was obtained in the powder containing SL with a higher degree of unsaturation and a lower concentration of tocopherols. The results demonstrated that the degree of fatty acid unsaturation and concentration of endogenous antioxidant in starting oils influenced the oxidative stability of the encapsulated SLs.

Practical Application

Structured lipids (SLs) containing long-chain polyunsatured fatty acids (LCPUFAs) were successfully microencapsulated in Maillard reaction products (MRPs) obtained from heated whey protein isolates and corn syrup solids solution with high microencapsulation efficiency. These SLs were produced by enzymatic interesterification to have similar fatty acid profile and positional distribution to human milk fat (HMF) for infant formula application. In addition, these SLs contained LCPUFAs, which are physiologically important to infant development. The results in this study demonstrated suitability of MRPs for microencapsulation of SLs designed for infant formula application.