Studies of Different Lactic acid Bacteria on the Production of

• Main Authors: Yeh, Chin-Kuei, 葉金桂
• Other Authors: Chung-Hsung Shih
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/88812403808684524513

碩士 === 東海大學 === 畜產學研究所 === 85 === Five strains of lactic acid bacteria Lactobacillus bulgaricus (CCRC14009), Streptococcus thermophilus (CCRC 12257), L. acidophilus (CCRC 10695),B. bifidum (CCRC 11844) and B. longum (CCRC 11847) were used as startersculture on the manufacturing of goat(s yogurt. In experiment Ⅰ the grown-uptest of single or mixed starters was performed for testing of variation of thenumbers of lactic acid bacteria, TA%, carbohydrate and organic acid in theprocess of fermentation as basic condition. In exp. Ⅱ, C ange on content ofcholesterol, free fatty acid, folic acid and free amino acid by exp. Ⅰstarter used after fermentation.In exp. Ⅲ, three goat(s yogurt ( L.bulgaricus + S. thermophilus、 L. acidophilus + B. bifidum and L. acidophilus +B. longum ) was examined during processing and storaging at 4 ℃ for 4 weeks. The results were as follows： Experiment Ⅰ. 1. L. bulgaricus was the starter first reached stationary phase within sixhours. Mixed starters of S. thermophilus and L. bulgaricus (1:1), were the early reached the stationary phase within six hours. The stationary phase can keep going for about 14 hours. 2. L. bulgaricus had the strongest ability in lactose hydrolysis and lacticacid forming ( p<0.05). Mixed starters of S. thermophilus and L. bulgaricus had the strongest ability in lactose hydrolysis and lactic acid forming(p<0.05). 3. The maximum production of L(+) lactic acid is the mixture L. bulgaricus andS. thermophilus (p<0.05) at the mix ratio of 1:1, the average is 1.42 (g/dl)during the periods of fermentation. In the single starter was L. bulgaicusproducing maximum L(+) lactic acid (p<0.05). 4. The L. bulgaricus has the better perfermance of viscosity in the singlestarter treatments, and the mixed starter can improve the viscosity fermentedwith single starter. Exp. Ⅱ. 5. After fermentation, the amont of saturated short chain fatty acid (C4-C10)had decreased (p>0.05) in all starters. 6. Cholesterol content was increased after fermentation in all starters. 7. Folic acid content, except L. bulgaricus was decreased after fermentation,others were increased. 8.After fermentation, free amino acids content of S. thermophilus and B.bifidum group increased, individually, which higher than other strains. Exp.Ⅲ 9. 4 weeks of storage, the lactic acid bacteria counts of three goat(s yogurttreatments were 109 CFU/ml, there were slightly increased during storage. 10.With the increasing of storage time, the activity of β -galactosidase ofthree goat milk yogurt treatments was decreased. 11. With the increasing of storage time, the syneresis increase slightly amongthe three treatments, and the viscosity decreased slightly. 12. During storage, three goat(s yogurt were not different significantly inyogurt composition (protein, fat and ash,etc) (p>0.05). 13. In respect of organoleptic test, with the increasing of storage time, themean total acceptability decrease, but there is not different significantly intexture (p>0.05). During the storage time of goat milk yogurt, both L.acidophilus and B. bifidum had the lowest mean appearance score. In general, the lactic acid bacteria in goat yogurt decreased duringstorage. But they can still maintain above 109 CFU/ml during four weeksstorage which is reaching the Chinese National Standard about the fermentedmilk ( 107 CFU/ ml). Not only goat milk was low lactose content than cow milk, but also a great deal of lactose were hydrolyzed in the goat,s yogurt whichshould be advantagous of lactase intolerance consume it. Concering goat milkordor, which applied to developing market, many kinds of fla ored productsshould be developed to satisfy the request of the multiplicities of products.