| Summary: | 碩士 === 國立海洋大學 === 食品科學系 === 89 === The highest viable cell count of Lactobacillus (Lb.) plantarum CCRC 12250 could be obtained while cultured in MRS broth at 37oC for 8 hr. After 36 hr incubation in the same conditions, the cultured broth present the highest relative viscosity (RV). As compare to the extracting efficiency of EAS from strain CCRC 12250 by different heat treatment, the better extracting treatment was under 80oC for 60 min (0.622 g/L). When strain CCRC 12250 cultured in MRS broth at 20, 26, 37, or 45oC for 48 hr, the results indicated that the optimal growth temperature was under 37oC, and the highest yield of EAS was obtained while incubated at 26oC. The optimal condition of growth and production of EAS was using a medium with initial pH 7.2, after initial pH 4.2-7.2 was used for the cultivation for 48 hr. The predominant composition of EAS lyophilized powder is polysaccharide. Results from Sephacryl S-400 gel permeation chromatography indicated that this EAS could be a mixture of protein-polysaccharide complex. The relative viscosity (RV) of EAS rehydrated aqueous solution was increased when the concentration of EAS was increased in the reacting solution. However, EAS solution with increasing NaCl concentration showed lower RV. The 0.2% lyophilized EAS powder rehydrated solution showed the higher and more stable RV over a pH range from 4.0 to 6.0. The RV of 0.2% lyophilized EAS powder rehydrated solution decreased as the temperature increased from 10 to 80oC. Effect of EAS addition on emulsifying activity and emulsion stability of soy protein isolate emulsions is not obviously. 1% EAS rehydrated solution presented the capability of film formation.
Two EAS producing lactic acid bacteria (LAB), Lactococcus (Lc.) lactis subsp. lactis CCRC 12315 and Lb. plantarum CCRC 12250, were used as starters in amberfish meat paste, which purchased as frozen state from the Jia-Fu Frozen Co. Ltd, and fermentation was conducted at 37oC and RH 85%. The LAB growth rapidly and became predominant during fermentation period. The pH values declined to under 4.6 after 16 hr fermentation at 37oC. The pH of amberfish meat paste fermented by Lb. plantarum CCRC 12250 was decreased drastically, and the gel strength of this meat paste was higher than other treatments. By using the same treatment, a fresh amberfish, that purchased from Ren-Ai market in Keelung, meat paste was also fermented under 37oC and RH 85% with 1% starter culture employed. The results indicated that LAB growed rapidly, predominate the fermentation, and may inhibit the growth of certain spoilage bacteria and pathogens, especially in the amberfish meat paste with strain CCRC 12250. The pH values of amberfish meat paste were decreasing from 6.3 to 4.7 after 30 hr fermentation. The gel strength obtained from the 12 hr fermented amberfish meat paste with the addition of 1% strain CCRC 12250 was 327.0 cm · g. The results also showed that the gel strength of amberfish fermented sausage could be enhanced by addition of 10% tilapia meat paste, and then the tilapia and amberfish meat paste product could reach a gel strength of 439.2 cm · g after 18 hr fermentation under 37oC. While the same treatments were used on the round herring, that purchased from Penghu, the LAB fermentation were conducted at 37oC and RH 85% with the addition of 1% starter culture. Every combination of LAB starter showed rapid growth, and then predominate the fermentation and possibly inhibit the growth of most of other microbes. Round herring meat paste that inoculated with EAS producing strain CCRC 12250 exhibited better performance than the rest experimental combinations. The pH value of this round herring meat paste declined to 4.6 after 12 hr fermentation, and its VBN value still below 20.2 mg/100 g after 36 hr fermentation. These results suggested that EAS produced from LAB could enhance the gel strength of round herring meat paste, the gel strength achieved 220.4-236.8 cm · g after 12 hr fermentation. The results also show that the gel strength of round herring fermented sausage could be enhanced after 10% tilapia meat paste was combined, and then the gel strength of mixed meat paste could reach 532.3 cm · g, after 18 hr fermentation under 37oC.
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