Probiotic characterization of potential hydrolases producing Lactococcus lactis subsp. lactis isolated from pickled yam.

The aim of this study was to characterize potential probiotic strain co-producing α-amylase and ß-galactosidase. Sixty-three strains, isolated from pickle samples were screened for their hydrolase producing capacity by utilizing different starches as carbon source. One out of 63 strains, isolated from traditionally fermented pickled yam showing maximum hydrolase activity (α-amylase (36.9 U/ml) and ß-galactosidase (42.6 U/ml)) within a period of 48 hours was identified as Lactococcus lactis subsp. lactis. Further, it was assessed for the probiotic characteristics under gastrointestinal conditions like acidic, alkaline, proteolytic enzymes, bile stress and found to exhibit tolerance to these stresses. The therapeutic potential of the isolate is implicated because of its antagonistic effect against enteric foodborne pathogens (Salmonella typhimurium, Escherichia coli 0157:H7, Staphylococcus aureus, Yersinia enterocolitica and Aeromonas hydrophila). The results of this study entail a potential applicability of the isolate in developing future probiotic foods besides the production of industrially significant hydrolases.

The consumer cost of calcium from food and supplements.

Nutritional authorities encourage consumers to include calcium-rich foods in their daily diets. However, consumer purchases are driven not only by health considerations and dietary preferences, but also by cost. This study assessed the cost of calcium from a wide variety of food sources, as well as supplements, based on retail prices in Seattle, San Francisco, Raleigh, NewYork City, and Washington, D.C., while controlling for seasonal variation. Costs were adjusted based on calcium absorption fractions. Calcium carbonate supplements emerged as the least expensive source of calcium, at roughly one-third the cost of the least expensive food source of calcium. The least expensive food sources of calcium were Total cereal, skim milk, and calcium-fortified orange juice from frozen concentrate. This information is useful for dietitians, health professionals, and consumers in meeting calcium requirements on a budget.

Heterologous Kluyveromyces lactis beta-galactosidase production and release by Saccharomyces cerevisiae osmotic-remedial thermosensitive autolytic mutants.

The beta-galactosidase from Kluyveromyces lactis is a high molecular weight protein with commercial interest. A major drawback of its industrial production is the high cost associated with extraction and downstream processing due to its intracellular nature. In this work, the effectiveness of the utilization of Saccharomyces cerevisiae LD1 and LHDP1 strains, osmotic-remedial mutants which lyse at 37 degrees C, for the heterologous production and release into the extracellular medium of this protein has been proved. The highest absolute values of released beta-galactosidase have been obtained with the protease-deficient strain LHDP1 by osmotic shock.