Yoghurt has been increasingly popular in many parts of the world, especially in Europe, North America and the Middle East. The great volume of consumption and popularity of yoghurt especially among women, children and teenagers stems from its nutritional and health benefits.
Although the origin of yoghurt is not definitely known, historical records indicate that the origin of yoghurt was in the Middle East and it was first made by Turks when they were in Middle Asia and it was named as ‘‘yoghurt’’. Today, the product has gained international recognition with this word, and many other countries use ‘‘yoghurt’’ or “yogurt”.
In the Turkish commercial markets, set-style yoghurts account for almost 100% of consumption. In set-style yoghurts, fermentation takes place in the final pots, so they are subjected to less industrial handling, and the possibility of contamination become low. In Turkey, yoghurt is one of the highest volumesproduced among all dairy products, which is 1,010,000 tons/per year (FAO, 2006). The consumers look fordifferent brands of yoghurts for a variety of different flavor and texture. However, few studies have been conducted on characterization of nutritional and chemical specifications of different commercial yoghurt products sold in Turkey.
Thestudy wasconducted to: (1) determine basic nutrient composition and some physicochemical characteristics of commercially marketed Turkish yoghurts, (2) quantify volatile compound and free fatty acid compositions of the products, and (3) evaluate the relationships among the tested parameters.
In general, overall quality and properties of yoghurt are affected by acidity level, free fatty acid content, production of aroma compounds (acetaldehyde, diacetly, acetoin), sensory characteristics, and nutritional values.
Streptococcus thermophilus and Lactobacillus delbrueckii subsp.bulgaricus are the two typical strains used for yoghurt production. The two main roles of these starter bacteria in yoghurt manufacture are milk acidification and synthesis of aromatic compounds. Flavor compounds that contribute to the final aroma of yoghurt may be divided into four categories: non-volatile acids (lactic or pyruvic), volatile acids (butyric or acetic), carbonyl compounds (acetaldehyde or diacetyl) and miscellaneous compounds (amino acids or products formed by thermal degradation). These flavor compounds of yoghurt are influenced by the chemical composition of milk base, processing conditions (e.g. heat treatment, homogenization), the ratio, activity and strains of starter culture used, and incubation period for the yogurt manufacture.
Author(s) : Zehra Güler, Young W. Park
7,969 total views, 10 views today