46E-12 |
Survival of Bifidobacterium bifidum during the elaboration of a low-fat spreadable fresh cheese |
M. E. JARAMILLO-FLORES1, M. Flores-Hernández, and H. Hernández-Sánchez. (1) Depto. Ingeniería Bioquímica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Carpio y Plan de Ayala, Col. P.E. Calles, México, DF, CP. 11340, Mexico Probiotic microorganisms often die during the food process or during their transit to the intestine and so their shelf life is difficult to predict. There are several techniques for improving probiotic survival rates such as immobilization which has already been used in some cheeses with good results. The application of immobilized probiotics in the elaboration of low-fat cheeses could be a good way to produce a new series of nutritious and healthy dairy foods. The purpose of this work was to use immobilized bifidobacteria in the milk used to elaborate a low-fat fresh spreadable cheese. A commercial strain of Bifidobacterium bifidum was characterized in its ability to grow in the presence of nisin and later immobilized in calcium alginate gel spheres which were stored in saline solution at 4°C and the survival of the bacteria evaluated after a week. The immobilized organisms (2%) were added to skim milk and made into a cottage cheese which was turned into a spreadable paste by carefully mixing. Survival of the bacteria was evaluated in the final cheese and after storing the cheese at 4°C for four days. The strain was resistant to nisin concentrations of up to 0.5 mg/g and therefore compatible with nisin-producing lactic acid bacteria used in cheesemaking. A 100% survival of the bifidobacteria was obtained in the spheres stored in refrigerated saline solution after seven days. The concentration of microorganisms in the spheres was 1 X 107 CFU/g. After cheesemaking, a concentration of 1.8 X 106 CFU/g in the spheres was obtained which remained constant after a four-day cold storage period. A highly accepted spreadable cheese with 80% moisture and 4% fat was obtained. These results indicate that the immobilization is a good technique to maintain a good survival of probiotic organisms during cheesemaking.
Session 46E, International
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