Synthesis of Galactooligosaccharides in the Cheese Whey-based Medium by a Lactase from Lactobacillus paracasei YSM0308

• 발행기관: 한국축산식품학회
• 저자명: Tae Suk Song Kyung Sang Lee Seung Bum Kang Seong Ho Yoo Jong Ik Lee Sung Sik Yoon
• 간행물 정보: 『Food Science of Animal Resources』Korean Journal for Food Science of Animal Resources 제33권 제5호, 565~571쪽, 전체 7쪽
• 주제분류: 농수해양 > 식품과학
• 파일형태: PDF
• 발행일자: 2013.10.31

영문 초록

An enzyme β-galactosidase or β-galactohydrolase [EC3.2.1.23], commonly called lactase, mediates galacto-oligosaccharide (GOS) synthesis under conditions of high substrate concentrations. Also, lactase hydrolyzes β(1→4) lactose into glucose and galactose, the latter is successively transferred to free lactose to make various oligosaccharides via transgalactosylation. GOS is non-digestible to human digestive enzymes and has been used as a functional prebiotics. Among the 24 lactic acid bacteria (LAB) strains used, Lactobacillus paracasei YSM0308 was selected based on its exhibition of the highest β-galactoside hydrolysis activity, and the crude lactase was prepared for examination of reaction conditions to affect the GOS synthesis. Lactase activity was measured with a spectrophotometer using ONPG (o-nitropheyl β-D-galactopyranoside) method. Lactase activity was not detected in the culture supernatant and was mostly present in the cell pellet after centrifugation. Activity of the crude lactase preparation ranges from102 to 1,053 units/mL, with the highest activity determined for L. paracasei YSM0308. Optimal conditions for GOS synthesis are as follows: concentration of whey powder, pH, temperature, and time were 30%, pH 6.5-7.0, 30oC, and 4 h, respectively. The final GOS concentration was 19.41% (w/v) by the crude YSM0308 lactase, which was obtained from strain YSM0308 grown in the 10% (w/v) reconstituted whey-based medium.

키워드

cheese whey-based medium galacto-oligosaccharides GOS lactase Lactobacillus paracasei transgalactosylation activity