培養溫度對於乳酸菌胞外多醣產量、單醣成分與分子量之影響

Effects of Incubation Temperature on Yield, Monomer Composition, and Molecular Weight of Exopolysaccharides Produced by Lactic Acid Bacteria

林棟雍(T. Y. Lin) ； 張簡玫芳(M. F. Chang Chien) ； 楊政儒(C. J. Yang)

《華岡農科學報》 15期 (2005/06) Pp. 21-30

https://doi.org/10.29985/HKJA.200506.0002

摘要

使用能生產胞外多醣(exopolysaccharides，EPS)之乳酸菌酛進行發酵製成高濃稠度製品，以取代安定劑之添加，為目前歐美國家發酵乳之生產趨勢。EPS能提升產品黏度、穩定凝乳結構、防止製程中之機械性傷害、提高產品保水性和延展性、並具抗腫瘤功能。本研究之主要目的在探討4種乳酸菌酛：Lactobacillus acidophilus (CCRC14079)、L. delbrueckii ssp. bulgaricus (CCRC14009)、Streptococcus salivarius ssp. thermophlius (CCRC12257）與一含L. delbrueckii ssp. bulgaricus與配thermophlius商用酸酪乳菌酛在3種培養溫度下對EPS產量、單醣成分與分子量之影響。分別取上述菌酛接種於脫脂乳培養液，在25、37、與46℃培養24hr後，進行EPS之分離、純化、乾燥、與產量測定，經純化後之EPS並以HPLC分析其單醣成分，最大EPS產量之濡度處理組，亦進而分析其最大分子量。研究結果發現商用酸酪乳菌酛於三種溫度下培養24hr之EPS產量比其它3株菌酛為高，且以37℃之產量最大(2.40g/L)，L. delbrueckii spp. bulgaricus與S. salivarius ssp. thermophlius在三種溫度下，EPS產量皆低(0.12-0.30g/L);4種菌酛生成之EPS，皆含1種或多種下列4種單醣：鼠李糖、N-乙醯葡萄糖肢葡萄糖、葡萄糖與半乳糖；商用酸酪乳菌酛所生成EPS之最大分子量在4種乳酸菌酊中最高(5,842 kDa)。

關鍵字

胞外多醣 ； 乳酸菌 ； 產量 ； 單醣 ； 分子量

並列摘要

The use of exopolysaccharides (EPS) produced by lactic acid bacteria to make high viscous products, as the natural alternatives to commercial thickening agents, is the current trend on fermented milk processing in European countries. EPS could improve viscosity, stabilize curd structure, prevent mechanical damage, and increase water holding capacity and extensibility of the product. Furthermore, these polymers have also been claimed to have antitumoral activity. The objective of the study, therefore, was to investigate the effects of 4 strains of lactic acid bacteria: Lactobacillus acidophilus (CCRC14079), L. delbrueckii ssp. bulgaricus (CCRC14009), Streptococcus salivarius ssp. thermophlius (CCRC12257), and a commercial yogurt bacteria containing L. delbrueckii ssp. bulgaricus and S. thermophlius, and incubation temperature on yield, monosaccharide composition, and molecular weight of EPS. Each of the 4 culture strains was inoculated in skim milk medium, incubated at 25, 37, and 46 for 24 hr, followed by separation, purification, freeze-drying by lyophilisation, and EPS yield determination. Monomer composition of purified EPS was analyzed by HPLC. The molecular weights of EPS samples with highest yield among 3 temperature treatments were also determined. Highest EPS yield (2.40g/L) was observed in the treatment with the commercial yogurt bacteria at 37, whereas the lowest yield was found with L. delbrueckii ssp. bulgaricus and S. salivarius ssp. thermophlius. One or more of the monosaccharides: rhamnose, N-acetylglucosamine, glucose, and galactose was detected in EPS produced by those 4 strains. Additionally, The commercial yogurt bacteria yielded EPS with highest molecular weight (5,842kDa) among 4 lactic acid bacteria tested.

並列關鍵字

Exopolysaccharide ； Lactic acid bacteria ； Production ； Monosaccharide ； Molecular weight