Inulin, hi-maize, and trehalose as thermal protectants for increasing viability of Lactobacillus acidophilus encapsulated by spray drying

Microparticles containing inulin, hi-maize, and trehalose were produced through spray drying to encapsulate Lactobacillus acidophilus La-5. Afterwards, the encapsulation efficiency, thermal resistance, gastrointestinal simulation, storage stability, and the microparticles' size and morphology were analyzed to evaluate the protective effect against the thermal conditions of the spray dryer of the different encapsulating matrices. Inulin and hi-maize encapsulating matrices showed the greatest encapsulation efficiency of 93.12% and 94.26%, respectively. Concerning thermal resistance, the trehalose encapsulating matrix provided the greatest protection for this microorganism. The microparticles produced with hi-maize showed the greatest viability in simulated gastrointestinal conditions thus providing higher protection for Lactobacillus acidophilus La-5. Regarding storage stability, microparticles containing trehalose showed the fewest viability losses during 120 days of storage. However, notably, at the end of 120 days of storage at room temperature (25 °C), microparticles containing inulin, hi-maize, and trehalose all kept their counts above the recommended level (>6 log CFU/g−1). Concerning the physical characteristics of the microparticles, particle sizes were as expected for products obtained by spray drying. Scanning electron microscopy showed no ruptures or cracks on the surfaces of the microparticles, a desirable characteristic for high protection.