In the last few years, modern microbiology has helped to establish that more than 99% of probiotic bacteria are anaerobic, a fact that may have been of significance for the therapeutic use of probiotics. In general, aerobic, mostly gram-positive, spore formers and gram-negative cocci dominate the human colonic microbiota. In contrast, obligate anaerobes account for only a small percentage of the total colonic bacterial population. Strains of lactic acid bacteria are the most commonly used probiotics despite many controversial issues about their efficacy as health promoters. The use of selected probiotic organisms that are resistant to gastrointestinal contamination far the most challenging. An important area of research is the capacity of probiotic strains to survive in the low pH environment of the stomach or the high-pressure colonic environment. There are a large number of probiotic products on the market but the products usually are not amenable to scientific evaluation. Most of them are simply blends of isolates and do not conform to the AUA/FDA requirements. Furthermore, these isolates may be pathogenic or may be present in the normal gut flora.
Although maize starch does not affect tolerance to oxidant stress, it does have a definite effect on antioxidant defense systems followed by a reduction in tissue proline content, which is a major cellular osmolyte that contributes to cellular volume. In the light of these findings, the potential effects of starch on antioxidant systems, and physical parameters, are believed to contribute to the well-known health effects of maize consumption.
On the other hand, the complete replacement of group B sugars with group F sugars causes consistent changes in physical properties of the starch substrate. These changes were viewed as being due to the increased proportion of glucose-1,4-beta-D-galactopyranose which weakens the amylose helical structure and alters the mechanical properties of starch. d2c66b5586