Azarkhavarani Parisa Rajaie, Ziaee Esmaeil, Hosseini Seyed Mohammad Hashem
1 Department of Food Science and Technology, Kherad Institute of Higher Education, Bushehr, Iran.
2 Department of Food Science and Technology, Shiraz University, Shiraz, Iran.
Food Sci Technol Int. 2019 Apr;25(3):233-242. doi: 10.1177/1082013218813823. Epub 2018 Dec 5.
The main objectives of this work were to study the survivability of five probiotic lactobacilli strains in sour cherry juice and citrate buffer with similar pH values (pH 3.5) during storage at 4 ℃ as well as to encapsulate the strain with the least survival in calcium alginate beads. Enterococcus faecium from probiotic strains in sour cherry juice exhibited the least survival; therefore, this strain was selected for studying the protective effect of microencapsulation in calcium alginate beads. Microencapsulated probiotic cells were incorporated into sour cherry juice and then exposed to harsh conditions (e.g. heat treatment, low pH, and simulated gastrointestinal fluids). Changes in the probiotic survivability, pH and titratable acidity of sour cherry juice were monitored during 60 d. D-values of free cells, calculated at 60, 70 and 80 ℃, were 4.87, 1.48 and 0.43 min, respectively; while, those of microencapsulated cells were 9.41, 3.73 and 1.26 min, respectively. The decrease in the number of free E. faecium after exposure to low pH values (e.g. 2.5, 2 and 1.5) was 2.81, 3.74 and 4.18 log CFU/mL, respectively. Freshly prepared and 30-d old microencapsulated cells, maintained at 4 ℃ in sour cherry juice, showed 1.31, 2.13, 2.37 and 2.19, 2.46, 3.26 log CFU/mL reduction after exposure to similar pH conditions, respectively. The number of free and encapsulated probiotic cells after incubation in simulated gastric and gastrointestinal fluids was 5.86 and 4.81 and 8.05 and 6.61 log CFU/mL, respectively. The sensory attributes of probiotic sour cherry juice samples containing encapsulated cells were better than those fortified with free probiotics.
本研究的主要目的是研究5株益生菌乳酸杆菌在pH值相似（pH 3.5）的酸樱桃汁和柠檬酸盐缓冲液中于4℃储存期间的存活率，并将存活率最低的菌株包封在海藻酸钙珠中。酸樱桃汁中益生菌菌株的屎肠球菌存活率最低；因此，选择该菌株研究海藻酸钙珠微胶囊化的保护作用。将微胶囊化的益生菌细胞加入酸樱桃汁中，然后使其暴露于恶劣条件下（如热处理、低pH值和模拟胃肠液）。在60天内监测酸樱桃汁中益生菌存活率、pH值和可滴定酸度的变化。游离细胞在60、70和80℃时的D值分别为4.87、1.48和0.43分钟；而微胶囊化细胞的D值分别为9.41、3.73和1.26分钟。暴露于低pH值（如2.5、2和1.5）后，游离屎肠球菌数量的减少分别为2.81、3.74和4.18 log CFU/mL。在酸樱桃汁中于4℃保存的新鲜制备的和保存30天的微胶囊化细胞，在暴露于相似pH条件后，数量分别减少1.31、2.13、2.37 log CFU/mL和2.19、2.46和3.26 log CFU/mL。在模拟胃液和胃肠液中孵育后，游离和包封的益生菌细胞数量分别为5.86和4.81 log CFU/mL以及8.05和6.61 log CFU/mL。含有包封细胞的益生菌酸樱桃汁样品的感官特性优于添加游离益生菌的样品。
