Bifidobacterium longum BB536 is one of the bifidobacteria species mainly found in the human gut and is considered as the main common species of bifidobacteria,which existing in both infant and adult. The potential benefits from consumption of B. longum including the antagonistic action toward intestinal pathogens, improved the utilization of lactose, and control the serum cholesterol levels. Several scientific studies have shown the benefits offered by Bifidobacterium longum BB536 (Kojima et al., 1996; Namba et al., 2003 ; Asahara et al., 2004).Thus there is considerable interest in incorporating these health promoting bifidobacteria into food. Growth and survival of probiotic bacteria had been found to be affected by the chemical and microbiological composition of milk, milk solids content, and availability of nutrients (Shah, 2000). The use of prebiotics with probiotic in milk was found to improve the growth and survival of probiotic bacteria in fermented dairy products (Desai et al., 2004).
The variances in survival were interpreted by the metabolic activity of Bifidobacterium in different fermented products, which may affected by the activity and availability of nitrogen and carbon source in growth media as stated by Chou and Hou, (2000).
L. acidophilus and bifidobacteria survival can also be affected by the fat composition of fermentation medium , also it has been found that complete fat yogurt reduced the properties for Bifidobacterium.bifidum as compered with the low-fat yogurt (Vinderola et al., 2000). The growth and survival of probiotic in dairy products affected by the fermentation time, incubation temperature, storage temperature, and the addition of casein. while bifidobacteria is basically anaerobic, so the level of dissolved oxygen in the product have also been an important factors influence the survival of probiotic bacteria in dairy products (Klaver et al., 1993). The survivability of Probiotics in fermented products should be stable during the shelf life of the product (Dinakar and Mistry, 1994),while a rapid reduced in the number of the growth of the probiotic bacteria during the shelf life of others fermented products (Stanton et al., 2003)
Thus, Bifidobacterium maintains production of lactic and acetic acid, the hydrogen peroxide, and the bactericides which are identified as an inhibitor factor of the development of pathogenic bacteria. It was also reported that lactic acid and acetic acid in fermented dairy product have an antibacterial effect (Bullen et al, .1976),. Therefore, pH is a major factor that restricts growth and stability of probiotic bacteria.
Lankaputhra et al. (1996) stated that the survival of just three of nine bifidobacteria strains in the pH range of 4•3–3•7. Within this investigation, the decrease of B. longum BB 536 in cold storage of the fermented madida was less than that justified for bifidobacteria. Followed by 2 weeks refrigerated storage the count of B. longum BB 536 in the fermented madida reduced by 0•9 log CFU ml?1. Thus, the shelf life of the strain on the fermented peanut milk supplemented with gum Arabic is better.
Desjardins et al. 1990 stated that the short shelf life of numerous fermented milk during referagration and frozen storage was correlated to increased the acidity. adding to low tolerance of bifidobacteria strain to lactate and acetate acids (Rasic and Kurman 1983). Increased the acidity, could caused the reduction of bifidobacteria growth by 1–2 log CFU ml?1 in the fermented milk after cooling storage at 4°C for 15 days (Hughes and Hoover 1995). Rasic and Kurman (1983) clarify that increased the acidity affects the growth of bifidobacteria and can mostly like reduce 2 log in milks medium (pH 4•7–4•3) through 1–2 weeks refrigerated storage. The reduction in B. longum counts attained 3•3 log CFU ml?1 of fermented soy milk beverage in 2weeks storage at 5°C was reported (Chou and Hou.(2000).
The Changes of total soluble solids (TSS) during refrigerated storage period of different fermented beverages beverages*
The presented results in table 4 showed the TSS of different fermented beverages. There was significant (p