摘要：The objectives of the study were to screen the ability of two of dates (hilwa and sukary) extracts to stimulate the growth of two selected strains of Bifdobacteria ( B. infantis , B. angulatum ) inoculated in three milk types (cow, goats and camel), to investigate their effects on the stability of the bacteria during cooled storage and to study the feasibility of production of acceptable healthy drinks based on milk. Dates extract were prepared by hot soaking of dried fruits at 70oC, then sterilized at 120oC and finally mixed with milk types at three concentration levels (10, 15, 20% v/v). The growth study was conducted by inoculation of milk types and their pasteurized products (90oC / 20 min) with Bifidobacterium infantis or B. angulatum to contain 106 cfu/ml and incubated at 37oC for 16 h. The bacterial counts were conducted at the beginning and every four hours for a period of 16 hr. The inoculated milk products were also stored at 4oC for 15 days during which the viability of the bacteria, hydrogen ion concentration was measured and the coagulation was monitored every three days for the same periods. No significant differences were found in the growth of the two starter cultures in most treatments, regardless of the type of milk and dates extract as well as concentration and incubation time. The pH of the control milk samples as well as that of the different milk preparations decreased gradually during incubation and refrigerated storage at 4oC for 15 days. This indicated activity of the bacteria and/or their enzyme systems. The sensory evaluation of six selected bifidus milk prepared from cow`s, goat`s and camel`s milk and hilwa dates extracts at 10% (v/v) level, revealed a moderate acceptability with no significant differences from cow`s milk with hilwa dates extract and camel`s milk with hilwa dates extract preparations, the least significant acceptance at (P< 0.05) was observed for goat`s milk preparations.
