ARS | Publication request: Protection of probiotic bacteria in a synbiotic matrix following aerobic storage at 4 deg C

Submitted to: Beneficial Microbes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 29, 2012
Publication Date: September 1, 2012
Citation: Chaluvadi, S., Hotchkiss, A.T., Call, J.E., Luchansky, J.B., Phillips, J.G., Liu, L.S., Yam, K.L. 2012. Protection of probiotic bacteria in a synbiotic matrix following aerobic storage at 4 deg C. Beneficial Microbes. 3:175-187.

Interpretive Summary: Valuable bioactive food ingredients are present in agricultural byproducts such as citrus peel, yet they are primarily used as cattle feed ingredients valued under $0.05/pound, and frequently there is more supply than demand for this use. Short-chain carbohydrates in these agricultural byproducts in combination with health-promoting good bacteria can be used to stimulate the immune system and prevent chronic diseases. However, it is important to maintain high levels of good bacteria in food products and dietary supplements in order to achieve these health beneficial effects. Carbohydrate fragments from citrus pectin were able to protect the viability of good bacteria and extend their shelf life up to four months. These citrus pectin carbohydrates are new alternatives to fructose-rich carbohydrates currently on the market to stimulate the growth of health-promoting bacteria. Commercialization of these new carbohydrates will add value to U.S. specialty crops and benefit consumer health.

Technical Abstract: The survival of single strains of Bifidobacterium breve, Bifidobacterium longum, Lactobacillus acidophilus, and Lactobacillus reuteri was investigated in synbiotics that included 10 mg/mL of fructo-oligosaccharides, inulin and pectic-oligosaccharides in an alginate matrix under refrigerated (4 C) aerobic storage conditions. When the matrices were cross-linked with calcium (45 mM), 100-1000 CFU/mL of Lactobacillus acidophilus and L. reuteri, and 0-1000 CFU/mL of Bifidobacterium breve and B. longum survived refrigerated aerobic storage for 28 days. Following refrigerated storage, acetic (3-10 mM), butyric (0-3 mM), propionic (5-16 mM) and lactic acids (30-60 mM) were produced during the growth of probiotics in BHI broth at 37 C, suggesting their metabolic activity after storage was stressed. When calcium cross-linking was not used in synbiotics, the matrix had a much more gel-like appearance after inoculation when compared to the calcium cross-linked matrix. At least 10,000,000 CFU/mL of probiotic bacteria survived after 21 days of storage within these gel-like alginate matrices. Significantly higher levels of Bifidobacterium breve, Lactobacillus acidophilus and L. reuteri were obtained from the synbiotic matrices supplemented with fructo-oligosaccharides, inulin and pectic-oligosaccharides compared to alginate alone. Bifidobacterium longum survival was the same (~7 logs) in all gel-like synbiotic matrices. These results show that synbiotics protected probiotic bacteria and extended their shelf-life under refrigerated aerobic conditions. Synbiotics represent a viable delivery vehicle for health-promoting bacteria.