Improvement of Lactobacillus acidophilus La‐5 microencapsulation viability by spray‐drying with rice bran protein and maltodextrin

Abstract

Lactobacillus acidophilus La-5 microencapsulation using rice bran protein (RBP) and maltodextrin (MD) by spray-drying was studied. The effects of process variables—drying inlet air temperature (x1), inlet flow (x2), and MD:RBP ratio (x3)—on encapsulation efficiency (EE) and viability reduction (VR) during 45 storage days were investigated using a 23 Central Composite Rotatable Design. EE (%) and viable cells number increased when lower drying temperature, higher input flow, and high RBP proportion were applied. The optimum microencapsulation variables were x1 = 78°C, x2 = 0.58 L/hr, and x3 = 10:2.5 w w−1 (EE = 90.26%; VR = 2.64 log cycles). L. acidophilus showed viability during storage, which remained higher than 8 log CFU/g after 45 days at 4 ± 1°C. Microencapsulated L. acidophilus presented thermal stability up to 240°C and its survival in a simulated gastric and intestinal fluids solution was greater than its free-form. The results suggested that MD and RBP provided the microencapsulated microorganism with increased viability. Practical applications Potential health benefits related to probiotic intake have been recognized and confirmed. However, to achieve such benefits, the probiotic must survive in food matrices used as vehicles for its intake and passage through the digestive system. Thus, microencapsulation is a promising alternative to ensure probiotic viability, mainly when coating materials may resist adverse extrinsic conditions. For industrial food application, biocompatible and biodegradable materials are needed to provide the bioactive compounds microencapsulation. Rice bran protein and maltodextrin blend as encapsulating agents for probiotics encapsulation has not yet been reported on the literature. The results showed that microencapsulated Lactobacillus acidophilus LA-5 had its viability increase during storage and in simulated gastrointestinal conditions, as well as in thermal stability, compared to free probiotic cells. The technique was deemed robust to probiotic protection, allowing for the use of microcapsules in functional foods production in different food matrices.