MICROBIOLOGICAL AND CHEMICAL STUDIES ON FERMENTED MILK (ZABADY) PRODUCED BY SMALL ARTISANS IN ASSIUT CITY | ||
| Egyptian Journal of Agricultural Research | ||
| Article 16, Volume 90, Issue 1, March 2012, Pages 237-249 PDF (440.86 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/ejar.2012.159747 | ||
| Authors | ||
| MANAL M. KHODEAR1; ABEER F. ZAYAN2; NOUR EL-HODA E. HANAFY3; ALY I. HASSAN3 | ||
| 1Agricultural Research Center, Food Technology Research institute, Assiut, Egypt | ||
| 2Agricultural Research Center, Food Technology Research Institute, Giza, Egypt | ||
| 3Dairy Department, Faculty of Agriculture, Assiut unirersity, Assiut, Egypt | ||
| Abstract | ||
| The evaluation of quality and keeping quality of zabady produced at Assiut city by small artisans was the aim of the research. Zabady samples were collected from six small dairies in Assiut city and stored at 5±2ºC in their containers representing the first group of samples. As soon as samples of the first group arrived to the laboratory, one cup from each sample was used as a starter for manufacturing experimental zabady (the second group of samples) in reconstituted skim milk (NIDO, 11%W/V) in distilled water. All samples were analysed daily for: total bacterial count, count of lactic acid bacteria, coliform and yeast & mold. As well, all samples were chemically examined for: pH, acidity, total solids, fat, total nitrogen, total protein and soluble nitrogen content. Regarding samples of the group I the surface layer of one cup was asceptically removed, then the surface portion and the bottom portion were microbiologically analysed separately. On the other hand samples of the group II were analysed as one portion. The obtained results showed that at the beginning of incubation period their was minor difference between the 2 portions of the group I and group II of samples concerning the total bacterial count. However at the end of the incubation period some times the surface layer contained higher bacterial counts as compared with the bottom layer or with group II samples. On the other hand, the total lactic acid bacteria (L.A.B) counts showed that the difference between different samples was not great. Regarding yeast and mould, the minimum count reached in group I after 5 days and group II after 7 days and the maximum count reached in group I after 5 days. Only 2 samples both from the I and II group were positive for coliforms overall the storage period. Concerning chemical determinations, the pH of all samples of the group I were lower compared to samples of the group II, on the other hand the acidity was higher. Only one sample from group I contained highest T.S. when compared to all other samples, in the mean time, all samples of group II always contained higher T.S. Concerning fat content, there were great differences, between fresh samples of group I with minimum value of 2.5% and a maximum value of 4.7%. Also, percentage of total protein showed the same trend with a minimum value of 2.676% and 3.662% as a maximum. The obtained results showed great differences concerning the S.N content between samples of group I either at the beginning and at the end of storage period. The organoleptic properties examination indicated that their was big difference between the different samples of the first group, which may be due to the difference in the raw milk used by each dairies, on the other side approximately their was no big difference between the samples of the second group, as no big difference between the raw material used for manufacturing , also the samples of the second group always had higher score in comparison with the samples of the first group, normally this can be explained by the quality of the raw material used and the manufacturing process. | ||
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