Hekmat S, McMahon D J
Department of Nutrition and Food Science, Utah State University, Logan 84322-8700.
J Dairy Sci. 1992 Jun;75(6):1415-22. doi: 10.3168/jds.S0022-0302(92)77895-3.
Probiotic ice cream was made by fermenting a standard ice cream mix with Lactobacillus acidophilus and Bifidobacterium bifidum cultures and then freezing the mix in a batch freezer. Survival of the L. acidophilus and B. bifidum, as well as beta-galactosidase activity, was monitored during 17 wk of frozen storage at -29 degrees C. After freezing of the fermented mix, bacterial counts were 1.5 x 10(8) cfu/ml for L. acidophilus and 2.5 x 10(8) cfu/ml for B. bifidum. Seventeen weeks after freezing, these counts had decreased to 4 x 10(6) and 1 x 10(7) cfu/ml, respectively. During the same period, beta-galactosidase activity decreased from 1800 to 1300 units/ml. Probiotic ice cream was prepared at pH 5.0, 5.5, and 6.0 to determine consumer preferences and was compared with standard Utah State University "Aggie" ice cream. All samples were strawberry-flavored and were evaluated by 88 judges. The preferred pH of probiotic ice cream, based on overall acceptance, was pH 5.5. We demonstrated that probiotic ice cream is a suitable vehicle for delivering beneficial microorganisms such as L. acidophilus and B. bifidum to consumers. The bacteria can be grown to high numbers in ice cream mix and remain viable during frozen storage.
益生菌冰淇淋是通过用嗜酸乳杆菌和双歧杆菌培养物发酵标准冰淇淋混合料，然后在间歇式冷冻机中冷冻该混合料制成的。在-29℃冷冻储存17周期间，监测嗜酸乳杆菌和双歧杆菌的存活情况以及β-半乳糖苷酶活性。发酵混合料冷冻后，嗜酸乳杆菌的细菌计数为1.5×10⁸ cfu/ml，双歧杆菌为2.5×10⁸ cfu/ml。冷冻17周后，这些计数分别降至4×10⁶和1×10⁷ cfu/ml。在同一时期，β-半乳糖苷酶活性从1800单位/ml降至1300单位/ml。制备了pH值为5.0、5.5和6.0的益生菌冰淇淋以确定消费者偏好，并与犹他州立大学标准的“阿吉”冰淇淋进行比较。所有样品均为草莓味，由88名评委进行评价。基于总体接受度，益生菌冰淇淋的最佳pH值为5.5。我们证明了益生菌冰淇淋是一种向消费者传递嗜酸乳杆菌和双歧杆菌等有益微生物的合适载体。这些细菌可以在冰淇淋混合料中大量生长，并在冷冻储存期间保持活力。
