SPRAY DRY-MICROENCAPSULATION OF FERULOYL ESTERASE-PRODUCING LACTOBACILLUS STRAINS

ABEIJÓN MUKDSI MC ; SANTACRUZ A ; ROSS R ; JIMÉNEZ-MUNGÍA MT ; MEDINA RB; PALOU E ; GAUFFIN CANO P; LOPEZ MALO A

San Miguel de Tucumán

Simposio; V INTERNATIONAL SYMPOSIUM OF LACTIC ACID BACTERIA; 2016

CERELA-CONICET

Feruloyl esterases (FE) are enzymes responsible for the release of ferulic acid (FA), naturally present in vegetable foods as non-digestible ester-linked forms. FA has antioxidant properties and its consumption has shown to exert beneficial effects in pathologies related to oxidative stress, such as metabolic syndrome and obesity. In this context, probiotic FE-producing bacteria can be used as dietary supplements or incorporated into functional foods.Spray-dry microencapsulation is an efficient method for protecting probiotic strains during food processing and storage, as well as gastrointestinal tract (GIT) transit. High temperatures during spray-drying are detrimental to probiotics, thus encapsulating agents and operation conditions should be carefully selected. The aim of this study was to optimize the spray-dry encapsulation of FE-producing Lactobacillus strains, evaluate their viability and FE activity after drying, during refrigerated storage and their resistance to GIT conditions. Three strains were used: L. fermentum (Lf) CRL1446, L. johnsonii (Lj) CRL1231 and L. acidophilus (La) CRL1014. Cells at late-log phase (~9 log cfu/ml) were incorporated in a sodium alginate/maltodextrin/inulin mixture and dried in a pilot spray-dryer, adjusting operation parameters to reach outlet air temperatures below 80-85°C. Strain viability and FE activity were determined before and after spray-drying process and during storage at 4°C up to 9 months. Reconstituted powders were incubated in PBS pH7 containing methyl ferulate as substrate, and released FA was quantified by HPLC.Resistance of microencapsulated and free cells to GIT conditions was assessed by sequential incubation in simulated gastric and intestinal juices. Physical properties of powders (density, moisture, porosity) were determined. At optimized process conditions, powder recovery was ~65%. All strains survived to drying, yielding ~9 log cfu/g powder, and maintained their FE activity. Lf and Lj were stable during storage at 4°C for 1 month (8.2 and 8.7 log cfu/g,respectively), while viability of La decreased considerably (6.1 log cfu/g). After 9 months, cell counts were 8.3, 7.2 and 5.6 log cfu/g for Lf, Lj and La, respectively. FE activities were similar in La and Lj powders (39-44 U/log cfu), higher than in Lf powder (17 U/log cfu), and increased slightly during storage. Microencapsulated cells showed higher survivability to GIT conditions compared to free cells. Powders presented adequate physical properties. Our results indicate that spray-dried microcapsules containing FE-producing Lf CRL1446 or Lj CRL1231 could be used as suitable ingredients to develop novel dietary supplements or functional foods.