Yogurt flavoring from

Lactic Acid B cteri. The lactic acid bacteria are ubiquitous in nature from plant surfaces to gastrointestinal tracts of many animals. These gram-positive facultative anaerobes convert carbohydrates (qv) to lactic acid and are used extensively in the food industry, for example, for the production of yogurt, cheese, sour dough bread, etc. The sour aromatic flavor imparted upon fermentation appears to be a desirable food trait. In addition, certain species produce a variety of antibiotics. 

Organic acids may exhibit other sensory properties. For example, citric acid possesses sweet-and-sour sensory notes, and succinic acid has a salty-bitter taste. On the other hand, the typical taste and flavor of Emmental cheese can be ascribed to the propionic acid and a few other compounds, such as proline. In fact, taste and flavor result from the combination of different food constituents in definite proportions. Raw meat smells much like lactic acid, which arises from postmortem anaerobic glucolysis and determines the pH of meat, its final properties, and microbial stability. This same organic acid has been related to the inhibition of certain pathogenic bacteria in yogurt (3). Table 1 lists the reported threshold concentrations for various organic acids in different media (4-6). 

So when Ross and Jenny came home from school, looking for a snack, I devised some tempting treats. Instead of a whole apple, I sliced that apple and used raisins to make faces. Pretty simple. Other times I sliced a variety of fruits and offered them on a plate with some fruit-flavored yogurt as a dip. When I had the time and wanted to be creative, I cut bell peppers to use as palm fronds on trunks of longitudinally sliced carrots, perhaps with a bush of broccoli, and a pond of low-fat salad dressing on a platter. Mothers in the neighborhood began to wonder why their kids wanted to come to our house after school Yup, I was Mr. Mom, and I loved it. 

Modified whey protein concentrate (Dairy-Lo), a GRAS substance, is manufactured from high-quality whey protein concentrate. This product contributes only 4 kcal/g. Modified whey protein helps improve texture, flavor, and stability of low-fat foods. It is typically used in sour cream, frozen dairy desserts, cheese, baked goods, yogurts, dips, and sauces. Its ability to prevent shrinkage and iciness in frozen foods makes it especially desirable as a fat replacement ingredient in those products. 

Milk of UF-standardized protein and total solids content enables the production of fermented dairy products of improved quality and characteristics compared with those produced from milk fortified with milk powder or evaporated milk [11]. Due to the similarity of the protein fractions in HMPP and those of skim milk and the virtual absence of lactose, Mistry and Hassan [134] suggested its utilization for the development of new dairy products and the improvement of existing ones. When these authors used HMPP to produce nonfat yogurt, they found that fortification level up to 5.6% protein can produce acceptable yogurt with smooth texture and firm body that did not exhibit whey separation even without the addition of stabilizers. They noted, however, that >5.6% protein concentration, the yogurt becomes excessively firm and has a grainy texture and flat flavor. 

Use of added ascorbic acid delayed flavor development in packaged milk concentrates (649), in milk fat (650), in goat milk curd (651), in butter from buffalo milk (652), in y-irradiated skim-milk powder (653), in low-fat dairy spreads (654), and in khoa products (655). Experience in yogurt, cheese, and ice cream has been previously reviewed (311,312). 

The freeze-dried powder, expensive for most consumers at about 27 per pound, is nevertheless popular for manufacturing uses in smoothies, granola bars, cereals, and chocolate and as a flavor-color additive for beverages. Some American processors retain the pasteurized berry pulp as a frozen puree, which is useful in manufacturing sorbet, ice cream, gelato, jam, and yogurt products. Juice and oils are extracted from the puree raw material for manufacturing needs. 

The primary use for lactic acid in the United States is as a food additive, where it acts as an acidulant and a flavor additive. An acidulant is a compound that provides an acidic environment for foods, as is the case with yogurt, buttermilk, sauerkraut, green olives, pickles, and other acidic foods. As a flavor additive, it adds a tart or tangy flavor to foods and beverages, as well as acting as a preservative to keep them from spoiling. Lactic acid also has a number of important industrial uses, the most important of which is the... 

Industrial Fermentation. The primary and largest industry revolves around food products. Milk from cows, sheep, goats, and horses have traditionally been used for the production of fermented dairy products. These products include cheese, sour cream, kefir, and yogurt. More recently so-called probiotics appeared and have been marketed as health-food drinks. Dairy products are produced via fermentation using lactic bacteria such as Lactobacillus acidophilus and Bifidobacterium. Fungi are also involved in making some cheeses. Fermentation produces lactic acid and other flavors and aroma compounds that make dairy products taste good. 

Vanillin used in the model flavor was recovered with methanol from yogurt and analyzed using high-performance liquid chromatography (HPLC, Nakazawa et al., 1982). 

Fermentation is a process that provides us with a variety of unique flavors to enjoy. We daily come in contact with a variety of food products produced via fermentation. Some examples include soy sauce, cheese, yogurt, bread, beer, wine, fermented fish products, and sausages. The flavor of these products may be developed from the primary metabolism of the fermentation microorganisms or from residual enzymatic activity once the microbial cell has lysed. Primary metabolism is responsible for much of the flavor of alcoholic beverages while residual enzymatic activity is essential for the development of aged cheese flavor. 

A fermented milk product prepared from lowfat milk, skim milk, or whole milk. After fermentation, the yogurt may be mixed with other ingredients such ers nonfat dry milk solids, vegetable gums, flavoring, or fruit preserves. 

Citrate is present in milk, fruit, and vegetables. It can be co-metabolized with sugars by citrateutilizing LAB. Citrate utilization results in an excess of pyruvate, which is thus converted to diacetyl (2,3-butanedione), acetoin (2-hydroxy-3-butanone), and 2,3-butanediol to equilibrate the redox balance of cellular metabolism (Collins 1972 Bartowsky and Henschke 2004). Some LAB can also synthesize 2,3-pentanedione from pyruvate and threonine (Ott et al. 2000). Diacetyl and 2,3-pentanedione are associated with a buttery aroma, which positively contributes to the flavor of a range of fermented dairy products such as butter (MalUa et al. 2008), yogurt (Routray and Mishra 2011), and cheese (Curioni and Bosset 2002). Diacetyl also contributes to wine style, while it is responsible for flavor defects in beer. Diacetyl is widely produced by LAB, including species of the Lactococcus, Streptococcus, Leuconostoc, Lactobacillus, Pediococcus, and Oenococcus genera. 

With a few exceptions, many of the known important flavors in dairy products do not provide characterizing roles. This is especially true for milk, cheddar cheese, and cultured products, such as sour cream and yogurt. Delta-lactones are important flavors in butter, buttermilk, and cheeses that are derived from triglycerides containing hydroxyl fatty acids. Although not directly contributing as dairy character impact compounds, lactones play key supporting roles. The subject of key odor-active compounds in milk dairy flavors has been recently reviewed (76,77). A summary of character impact compounds for cheese and dairy flavors is presented in Table 7. 

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