Effect of container smoking and incubation temperature on the microbiological and some biochemical qualities of fermenting Ergo, a traditional Ethiopian sour milk

被引:17
作者
Ashenafi, M
机构
[1] Department of Basic Sciences, Awassa College of Agriculture, Addis Ababa University, Awassa
关键词
D O I
10.1016/0958-6946(94)00037-9
中图分类号
TS2 [食品工业];
学科分类号
0832 ;
摘要
Raw milk was allowed to sour naturally at ambient temperature (25 degrees C) in smoked or unsmoked containers. Milk in smoked containers had a lower rate of pH drop and the fermented product had good flavour for a longer time after coagulation. The total count of non-lactic acid bacteria in milk in unsmoked containers reached a high count (> 10(8) cfu mL(-1)) within 12 h, whereas milk in smoked containers required more than 24 h to reach this level. Similarly, the growth of coliforms and lactic acid bacteria was slow in milk in smoked containers, thus assuring good and slow development of flavour components, safety of finished product and better keeping qualities. Lactobacilli dominated the flora of the fermented product in unsmoked containers, while lactococci were equally dominant in fermented milk in smoked containers. As the temperature of incubation increased (20 to 42 degrees C), the rate of pH drop also increased and the time of coagulation became shorter. At lower temperatures, the rate of acid formation was lower but the titratable acidity in the final products was higher. Milk incubated at lower temperatures had a better Ergo taste. The rate of growth of the various groups of bacteria increased with an increase in incubation temperature. At lower incubation temperatures, lactococci dominated the lactic flora, while lactobacilli dominated at higher incubation temperatures. Smoking of containers may help to produce a safer and tastier Ergo with better keeping qualities. In addition, lower incubation temperatures (around 20 degrees C) may favour the proliferation of lactic acid bacteria and thus guarantee a desirable fermentation.
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页码:95 / 104
页数:10
相关论文
共 14 条
[1]  
Ashenafi M., 1993, Tropical Science, V33, P368
[2]  
Ashenafi M., 1992, Ethiopian Journal of Health Development, V6, P23
[4]  
ASHENAFI M, 1993, ETHIOPIAN MED J, V31, P91
[5]  
ECKLES CH, 1951, MILK MILK PRODUCTS
[6]  
EL-SADEK M G, 1972, Milchwissenschaft, V27, P570
[7]  
FERNANDES CF, 1987, FEMS MICROBIOL LETT, V46, P343, DOI 10.1111/j.1574-6968.1987.tb02471.x
[8]   RAPID METHOD FOR DISTINCTION OF GRAM-NEGATIVE FROM GRAM-POSITIVE BACTERIA [J].
GREGERSEN, T .
EUROPEAN JOURNAL OF APPLIED MICROBIOLOGY AND BIOTECHNOLOGY, 1978, 5 (02) :123-127
[9]   THE TAXONOMIC SIGNIFICANCE OF FERMENTATIVE VERSUS OXIDATIVE METABOLISM OF CARBOHYDRATES BY VARIOUS GRAM NEGATIVE BACTERIA [J].
HUGH, R ;
LEIFSON, E .
JOURNAL OF BACTERIOLOGY, 1953, 66 (01) :24-26
[10]  
KASSAYE T, 1991, MILCHWISSENSCHAFT, V46, P649