Yogurt Research Paper

Yogurt is a fermented milk product that contains the bacterial cultures such as Lactobacillus bulgaricus and Streptococcus thermophilus. All yogurt must contain at least 8.25% solids not fat. Full fat yogurt must contain not less than 3.25% milk fat, low fat yogurt not more than 2% milk fat, and non fat yogurt less than 0.5% milk. Milk is the main ingredient in yogurt. The type of milk used depends on the type of yogurt – whole milk for full fat yogurt, low fat milk for low fat yogurt, and skim milk for non fat yogurt. To adjust the composition, other dairy ingredients are allowed in yogurt such as cream to adjust the fat content, and non fat dry milk to adjust the solids content. Probiotics like Lactobacillus bulgaricus and Streptococcus

Streptococcus thermophiles, as the name convey, looks like a chain of spheres. It is a gram-positive microbe. The cell wall is composed of N-acetylglucosamine (NAG) and N-acetylmuranic acid (NAM), which is bond by ether bonds. This particular structure allows S. thermophilus to cope with raised temperatures, which is beneficial for many industrial dairy fermentations be in need of the process of milk at higher temperatures. S. thermophilus is a facultative anaerobe, which is an organism that is having the ability of generating ATP through both aerobic respiration and fermentation. This capability is depending on the presence or absence of oxygen. Besides, S. thermophilus is shortage of genes or contain pseudogenes expressing surface protein (excluding lipoproteins); pathogenic streptococci use these surface proteins to attached to mucosal surfaces and avoid host defense mechanisms. S. thermophilus does not form spores and does not move on its own. As the species name gives away, the microbe likes warmer temperatures. Its optimum growth rate take place at the bottom of the thermophile spectrum, around 45°C. It is also capable of create energy, in the form of adenosine triphosphate (ATP), by aerobic respiration with the existence of oxygen; however, without the presence of oxygen, it still can produce ATP through fermentation. S. thermophilus lacks cytochrome, oxidase, and catalase enzymes. Although S. thermophilus is nearly linked to other pathogenic streptococci such as S. pneumoniae and S. pyogenes. S. thermophilus is classified as a non-pathogenic, alpha-hemolytic species that is part of the viridians