Stirred yogurt refers to a yogurt product that is obtained by uniformly stirring and mixing jam auxiliary materials and yogurt gel obtained after fermentation, then putting it into a cup or other container, and then cooling and ripening. Compared with ordinary yogurt, stirred yogurt has the characteristics of diversified tastes and richer nutrition.
stirred yogurt-processing technology
production process of stirred yogurt (I)
Lactobacillus bulgaricus and Streptococcus thermophilus.
(II) Raw materials and formula
Full-fat fresh milk: 85%;
skimmed milk powder: 1%;
mango sauce: 4.2%;
white sugar: 4%;
aspartame: .3%;
compound stabilizer: 2.15%;
mango essence: .2%;
starter: 3.6%.
(III) Process flow
Fresh milk, skimmed milk powder (dissolved and left standing), sweetener and compound stabilizer (fully dissolved) → mixing → preheating → homogenization → sterilization (at 125℃ for 5 seconds) → cooling → fermentation → continuous cooling and stirring (fruit and essence) → filling → cold storage and ripening → finished product.
(IV) Key points of operation
① Preparation of mango sauce: After peeling and coring fresh mango, cut up the pulp and immediately add water (5ml/1g pulp) to cook it to 65℃ to inactivate the enzyme activity, then beat it with a beater for 4 minutes (3,5rpm), add appropriate amount of sucrose (4g/1g pulp), and then.
② cooling: after fermentation, it is quickly cooled to 38℃ to inhibit the proliferation of lactic acid bacteria, and then it is continuously cooled to about 18℃. At this time, it begins to stir under the condition of continuous cooling, and at the same time, it is added with cooled fruit and other auxiliary materials, canned at about 1℃, and then it is continuously cooled to about 6℃ and stored in a refrigerator (6℃) for ripening. After 12-24 hours, the finished product is obtained.
③ stirring: the purpose is to mix the auxiliary materials such as fruit and yogurt gel evenly, which belongs to the physical treatment process, but it will also cause some chemical changes. Because yogurt gel belongs to pseudoplastic gel, severe mechanical force or long-term stirring will reduce the hardness and viscosity of yogurt and precipitate whey. If a large amount of air is mixed, it will also cause phase separation. Therefore, for stirred yogurt, it is most important to complete the best mechanical treatment of stirring. At the beginning of mixing, use a slower speed, and then use a faster speed. The whole process should not exceed 3 minutes. The mixing effect is affected not only by the type of mixing equipment, but also by the mixing time, acidity of gel and temperature. It is best to use a wide-blade agitator, and if it is produced on a small scale, manual agitation can also be used, which can minimize the damage of the tissue state of yogurt.
④ ripening after refrigeration: canned yogurt can be eaten after being refrigerated at 2 ~ 6℃ for 12 ~ 24 hours. This process is mainly to promote the production of aromatic components in yogurt, improve the viscosity of the product, and form a good taste, smell and organizational state of the product.
(5) Quality standard
1. Sensory index
It is yellowish, and its state is similar to condensed milk, with a small amount of whey on the surface, uniform texture, no sandy, flaky or mushy feeling, delicate taste, moderate sweetness and sourness, and pure lactic acid fermentation flavor and mango flavor.
2. Physical and chemical standard
Lactic acid bacteria content >: 1 ~ 7/g, acidity (T): 7 ~ 11 < P > Solidified yogurt < P > Lactic acid bacteria grow and multiply in milk, and ferment and decompose lactose to produce organic acids such as lactic acid, which leads to the decrease of the PH value of milk and the agglutination of cheese protein near its isoelectric point < P > Solidified yogurt < P >. Solidified yogurt has a strong natural fermentation aroma, delicate and smooth, thick texture, sweet and sour, and endless aftertaste. Can effectively relieve lactose intolerance. Coagulated yogurt is a good natural source of calcium, and every 1 grams of coagulated yogurt contains about 12 mg of calcium. At the same time, it is rich in B vitamins and choline. So it has a strong competitive advantage.
The solidified yogurt tastes more delicate because it is homogenized, while the stirred yogurt tastes better.
Acidic substances in yogurt also help to soften the sticky surface of the skin, remove dead old cells, and eliminate wrinkles on the skin.
Because yogurt itself has therapeutic and health-care effects on the stomach and intestines, in general, yogurt can be drunk almost anytime and anywhere, and it will not affect the human body. However, in order to give full play to the nutritional value of yogurt, drinking it is still a little particular. For example, some people think that yogurt is nutritious, so they use a cup of yogurt as a breakfast, which is a bit unscientific.
The optimal temperature for drinking yogurt is 1-12 degrees. At this temperature, the taste and texture of yogurt are good. In the hot summer, the drinking temperature of yogurt should be reduced appropriately. When drinking yogurt in cups or bottles for a long time, there will be a layer of coagulum at the mouth of the cup or bottle, which is the fat in yogurt and has high nutritional value.
Yogurt should be refrigerated at -4 degrees. Because yogurt does not contain preservatives, the shelf life of yogurt is generally only 7-14 days. In summer, if the preservation environment is not good, the acidity of yogurt will continue to increase, which will make yogurt more sour, and in severe cases, yogurt will deteriorate. Therefore, the purchase of yogurt in summer should pay attention to the preservation environment of yogurt, and it is best not to drink yogurt placed in a high temperature place for a long time.