title: Survival of freeze-dried microcapsules of α-galactosidase producing probiotics in a soy bar matrix.
abstract: Soy oligosaccharides, mainly α-galactosides, are prevalently present in soy protein products, and can result in unfavorable digestive effects when consumed. The aim of this research was to investigate the efficiency of α-galactoside reduction by probiotic bacterial hydrolysis and if such bacteria could be maintained in a high number in a soy protein product in a microencapsulated and freeze-dried form. The probiotic bacterium, Lactobacillus acidophilus LA-2, when induced by raffinose, exhibited a high level of α-galactosidase activity at 5.0 U/mg. To preserve probiotics with high viability, cells were microencapsulated and freeze-dried. Optimization of microencapsulation presented that a combination of κ-carrageenan and inulin at a proportion of 1.9:0.1 (w:w) as capsule wall materials, significantly retained the viability of the probiotics through freeze-drying (P ≤ 0.05). Scanning electron microscopic images confirmed that the morphology of the microcapsules was well preserved after freeze-drying. Upon incorporation into soy protein bars, the freeze-dried microcapsules of L. acidophilus LA-2 remained in high numbers throughout 14 weeks of storage at 4 °C. Results of this work with the support of other studies on microencapsulation benefits indicate a promising use of freeze-dried α-galactosidase positive microencapsulated probiotics in a soy food.
authors.affiliation: Food Science Program, Division of Food Systems and Bioengineering, University of Missouri, Columbia, MO, USA.
authors.forename: Mo
authors.initials: M
authors.lastname: Chen
authors.forename: Azlin
authors.initials: A
authors.lastname: Mustapha
mesh_terms: D001644:Bifidobacterium / Q000254:growth & development / Q000302:isolation & purification; D002214:Capsules / Q000378:metabolism; D002351:Carrageenan; D002470:Cell Survival; D004339:Drug Compounding / Q000379:methods; D005516:Food Microbiology / Q000379:methods*; D005519:Food Preservation / Q000379:methods; D005612:Freeze Drying / Q000379:methods*; D007444:Inulin; D007778:Lactobacillus / Q000254:growth & development / Q000302:isolation & purification; D008855:Microscopy, Electron, Scanning; D009844:Oligosaccharides / Q000378:metabolism; D019936:Probiotics / Q000378:metabolism*; D045730:Soy Foods / Q000032:analysis*; D000519:alpha-Galactosidase / Q000378:metabolism*
chemical_list: D002214:Capsules; D009844:Oligosaccharides; D002351:Carrageenan; D007444:Inulin; D000519:alpha-Galactosidase