Ding W K, Shah N P
School of Molecular Sciences, Victoria Univ., Werribee Campus, PO Box 14428, Melbourne, Victoria 8001, Australia.
J Food Sci. 2007 Nov;72(9):M446-50. doi: 10.1111/j.1750-3841.2007.00565.x.
Eight strains of probiotic bacteria, including Lactobacillus rhamnosus, Bifidobacterium longum, L. salivarius, L. plantarum, L. acidophilus, L. paracasei, B. lactis type Bl-O4, and B. lactis type Bi-07, were studied for their acid, bile, and heat tolerance. Microencapsulation in alginate matrix was used to enhance survival of the bacteria in acid and bile as well as a brief exposure to heat. Free probiotic organisms were used as a control. The acid tolerance of probiotic organisms was tested using HCl in MRS broth over a 2-h incubation period. Bile tolerance was tested using 2 types of bile salts, oxgall and taurocholic acid, over an 8-h incubation period. Heat tolerance was tested by exposing the probiotic organisms to 65 degrees C for up to 1 h. Results indicated microencapsulated probiotic bacteria survived better (P < 0.05) than free probiotic bacteria in MRS containing HCl. When free probiotic bacteria were exposed to oxgall, viability was reduced by 6.51-log CFU/mL, whereas only 3.36-log CFU/mL was lost in microencapsulated strains. At 30 min of heat treatment, microencapsulated probiotic bacteria survived with an average loss of only 4.17-log CFU/mL, compared to 6.74-log CFU/mL loss with free probiotic bacteria. However, after 1 h of heating both free and microencapsulated probiotic strains showed similar losses in viability. Overall microencapsulation improved the survival of probiotic bacteria when exposed to acidic conditions, bile salts, and mild heat treatment.
对8株益生菌进行了酸、胆汁和热耐受性研究，这些益生菌包括鼠李糖乳杆菌、长双歧杆菌、唾液乳杆菌、植物乳杆菌、嗜酸乳杆菌、副干酪乳杆菌、嗜热栖热放线菌Bl - O4型和嗜热栖热放线菌Bi - 07型。采用藻酸盐基质微胶囊化技术提高细菌在酸和胆汁中的存活率以及短暂受热时的存活率。游离益生菌用作对照。在MRS肉汤中用HCl在2小时的孵育期内测试益生菌的耐酸性。在8小时的孵育期内用两种胆盐，即牛磺胆酸和牛磺胆酸钠测试胆汁耐受性。通过将益生菌暴露于65℃长达1小时来测试耐热性。结果表明，在含有HCl的MRS中，微胶囊化益生菌比游离益生菌存活得更好（P < 0.05）。当游离益生菌暴露于牛磺胆酸时，存活率降低了6.51 log CFU/mL，而微胶囊化菌株仅损失3.36 log CFU/mL。在热处理30分钟时，微胶囊化益生菌平均仅损失4.17 log CFU/mL存活，而游离益生菌损失6.74 log CFU/mL。然而，加热1小时后，游离和微胶囊化益生菌菌株的存活率损失相似。总体而言，微胶囊化提高了益生菌在酸性条件、胆盐和温和热处理下的存活率。
