The popularity of yogurt in the world is increasing. The strained yogurt type, called Greek yogurt, has become an industry with billions of dollars today. There are many articles about how healthy yogurt is because of the beneficial bacteria it contains.
Making yoghurt at home is very easy. The number of those who share their homemade yogurt on the internet and under a microscope and examine the process of making a chemical process in yogurt production is not at all low.
The fact that yogurt production is controlled is a process of cutting milk. So you force the milk to break in a certain way. In commercial yogurt making, shake the milk in a washing machine similar tool to hold the correct consistency. This process changes the microscopic structure of the milk by dividing the large fat rolls in milk into small pieces. Each layer covers a layer of milk proteins. Thus, when the milk begins to be cut, these proteins adhere to each other to ensure that the fat is evenly distributed in the yogurt and to be in good consistency.
Heating degree and duration
Then the heat setting is increased and harmful bacteria are killed in the milk. Heating also starts the process of setting up the molecular network structure by dissolving the proteins.
The degree and duration of milk heating determines the taste of yogurt. In commercial yogurt production, milk is usually heated at 85 degrees for 30 minutes or 90-95 degrees for 5 minutes. According to a company that develops an electric appliance for homemade yogurt, the yogurt made with milk heated to less than 76 degrees carries a sloppy and slightly sour taste, while the milk that is held for 10 minutes at 90 degrees is harder and less sour.
When the heated milk is kept to the temperature of the body (37 degrees), the main part of the yogurt production is passed to fermentation process. At this temperature, two of the most common bacteria in yogurt, lactobacillus bulgaricus and Streptococcus thermophilus begin to grow. They multiply the sugar in milk, ie, take lactose and convert it to lactic acid. As the acid in the milk increases, the pH level decreases.
What happens when the acid rises?
Milk proteins recognize this change. To date, the proteins are adhered to clusters around the fat beds or in clusters stabilized by the calcium phosphate salt. However, with the decrease of pH balance, this salt dissolves and protein clumps begin to dissolve. The released proteins form a network by clinging together. Water and oil rollers are attached to this network. The milk has now turned into yogurt.
When the fermentation process is interrupted by kneading, the product is in gel form. Strained yogurt is obtained by passing an extra stage. Here yogurt is mixed, water, sugar and proteins are decomposed. Thus, a more creamy consistency is obtained. However, many things, from the heating of the milk to the amount of protein it contains and without influencing it, act on the final consistency.
Yogurt producers and food scientists have studied and tried many forms of consistency so far. Various instruments are used to make these measurements.
In the production process, it is possible to see the clusters of protein in the microscopes used to closely examine the structure of yogurt, the bacteria that are attached to the webs, the fat grains and the other elements in the sensitive chemical structure that makes yogurt with the help of fluorescence.