How to increase the expansion rate of ice cream?
The excellent expansion rate makes the ice cream soft, smooth and delicate, with a mellow and lasting flavor. In the production of ice cream, increasing its expansion rate is a very important process. Attention must be paid to the quality of raw materials, the equipment must be sophisticated, and the operators must be experienced. The expansion rate of ice cream refers to the swelling rate of the ice cream when the aging mixture is frozen.
The air bubbles are mixed in the mixture to expand the volume. The percentage increase in volume is the expansion rate of the ice cream.Ice cream mixture is frozen and expanded to greatly improve the quality of ice cream. Because ice cream contains many tiny bubbles, it makes the taste soft and smooth, and the product stability is also improved. Air is a poor conductor of heat. Because many tiny bubbles are evenly dispersed in the ice cream, the heat conduction effect is greatly reduced, the melting resistance is enhanced, and the stability of the product is improved after
The calculation method of expansion rate:
Volume calculation method
In the formula: B ――Expansion rate%
IV ――the volume of ice cream
MV ――The volume of the mixture
Weight calculation method
In the formula: B ――Expansion rate%
Iw ――The weight of ice cream in the same volume of the mixture
Mw ――weight of the mixture
Many factors affecting the expansion of ice cream
Expansion rate is a very important indicator of the quality of ice cream. Each batch of products must be tested by laboratory personnel. The expansion rate is not as high as possible. If the expansion rate is too high, the product structure will be soft, the melting resistance will be reduced, and the product shape will be easy. Deformed. If it is too low, the ice cream tastes bad, the tissue is firm, and the product is unpopular. Therefore, there must be a proper expansion rate, which is generally 2-2.5 times of the total solids.
The factors affecting the expansion rate of ice cream are as follows:
The influence of raw materials:
1.The non-fat milk solid content in the mixture is high, which can increase the expansion rate. 10% content is better, but the production of lactic acid, protein coagulation, and lactose crystallization all affect the expansion rate.
2. The higher the milk fat content in the mixture, the higher the viscosity of the mixture, but the viscosity is too high and it is not easy to mix in air, so the expansion rate is generally best when the milk fat content is 6%-12%.
3. When the sugar content is high, the freezing point will decrease, which will lengthen the freezing and stirring time. Too much sugar will affect the expansion rate, generally 13%-15% is appropriate.
4. The appropriate amount of stabilizer can increase the expansion rate, but if the amount of stabilizer is too much, the viscosity of the material liquid is too high, and it is difficult for air to enter during freezing, which causes the expansion rate to decrease. Generally, the dosage is not more than 0.5%.
5. Different auxiliary materials affect the expansion rate, and egg yolk powder, protein powder, eggs,emulsifiers, etc. help increase the expansion rate. Fruit juice, pulp, fruit pieces, chocolate, cocoa powder, will reduce the expansion rate.
6. Adding appropriate sodium salt to the mixture will increase the expansion rate, and adding calcium salt will reduce the expansion rate.
The speed of the freezing machine is not fast, and the air cannot be mixed into the mixture as quickly as possible, resulting in a decrease in the expansion rate.The scraper of the freezing machine is not sharp, and the frozen ice cream cannot be scraped off in time.
The scraper should be sharpened regularly to keep it sharp. The excessive distance between the scraper and the cylinder wall also reduces the expansion rate.
The air mixing pump is faulty and cannot pump air into the freezing machine cylinder, which reduces the expansion rate.
Incorrect operation process will also affect
Proper homogenization makes the mixture have good viscosity and allows air to enter easily, thereby increasing the expansion rate, but the homogenization is too strong, making the viscosity of the material liquid too high, and it is difficult for air to enter, reducing the expansion rate and the homogenizing pressure At 15-20Mpa, the temperature should be 65-70℃.
The aging of the mixture can increase the viscosity, hydrate the fat, protein and stabilizer, reduce the moisture in the mixture, prevent the formation of large ice crystals during freezing, thereby increasing the expansion rate. When the aging temperature of the mixture is 2-3°C, a good expansion rate can be obtained.
3. When the freezing machine is turned on, air must be properly sucked in to get a good expansion rate. Pay attention to the control valve.
4. If the mixture enters the freezing machine, if the temperature is too high, it will be difficult for air to enter stably, which will affect the expansion rate.
5. The freezing temperature is too low and the hardness of the mixture is high, making it difficult to mix inair and reducing the expansion rate. The freezing temperature is generally -2 to 4 ℃.