Spray drying co-encapsulation of lactic acid bacteria and lipids: A review

Spray drying is an efficient, rapid and relatively low-cost method for preparing microencapsulated lactic acid bacteria (LAB) in industry, but high temperature reduces the survival rate of LAB. Oil can polymerise with LAB by hydrophobicity and reduce the thermal and oxidative damage on bacteria during spray drying. However, oil is easily oxidised during spray drying, and its insolubility makes it difficult to evenly disperse the emulsion in the oil phase. In this comprehensive review, the oils used for LAB microcapsule and its protectional mechanism were discussed. And then wall materials and modification methods, which stabilizes co-microcapsule containing lactic acid bacteria and oil, is presented. Oils were a promising material for spray-dried LAB. Liquid oils with more unsaturated fatty acids reduced oxidative stress. Solid oils with high saturated fatty acid content are often added in the form of solid small particles, reducing the bacterial thermal damage by absorbing heat during spray drying. Appropriate wall materials and pre-treatment on oil-LAB co-microcapsule can reduce lipid oxidation, stabilize the emulsion and enhance the survival rate of lactic acid bacteria after spray drying.