Hot pressing refers to heating the pulp of the raw mate […]
Hot pressing refers to heating the pulp of the raw material after crushing, and then pressing the pulp for juice extraction. Hot pressing is determined by the biochemical properties of the broken raw material and the processing technology of the fruit and vegetable juice. Before the raw material is broken, the biochemical reaction rate is quite slow in the complete cell tissue; but when the raw material is broken, the various chemicals, enzymes and microorganisms in the raw material body suddenly accelerate and interact and cause a series of chain reactions. The most important of these are various oxidation reactions catalyzed by enzymes that escape from the raw tissue cells. Oxidation reactions are often the main cause of drastic decline in the quality of fruit and vegetable juices (color, aroma, taste, and chemical composition). For example, polyphenol oxidase catalyzes the browning reaction of polyphenols, resulting in color changes in pulp and juice. Therefore, in the processing of fruit and vegetable juices, it is necessary to take effective measures to prevent or inhibit the adverse reactions such as enzymatic browning reactions. Therefore, after the raw material is crushed, sometimes the fruit will be heat treated and then hot-pressed to passivate the activity of the enzyme, and at the same time, the reproduction of microorganisms may also be suppressed, and the quality of the fruit and vegetable juice may be ensured.
Cold pressing is relative to hot pressing. Cold pressing refers to crushing of the raw material, and no heat treatment is performed. The cold pressing is performed at or below room temperature.
The reason why the secondary pressing is used is that the nature of the juice extraction is to extract the soluble solids in the fruit, and the fruit residue after the first pressing also contains a certain amount of soluble solids. In order to extract as much soluble solids from the fruit slag as possible and reduce the sugar content of the fruit slag, use normal-temperature water or recycled condensate (generally no more than 80°C) as slag: water=1: (1～2) The ratio (mass ratio) is leached with or without enzyme for 20 to 40 minutes, followed by secondary pressing. The use of secondary pressing process can increase the juice yield by 5% to 10%.
Leaching is the process of transferring the juice in the cells of fruits and vegetables into the liquid extraction medium (hot water). It is mainly used for the extraction of sap of fruit and vegetable raw materials (such as hawthorn) which has low water content, such as dried jujube, ebony, red dates, etc., and has a high content of pectin in the fruit. Extraction method is divided into static extraction, countercurrent extraction, one-time extraction, multiple extraction methods. The factors influencing the juice yield of the extraction method mainly include the extraction temperature, time, the degree of fragmentation of the raw materials, the concentration difference, and the flow rate.
The beating is achieved by scraping and crushing the broken fruit and vegetable raw materials by a beater and separating the core, fruit seeds, thin skin and the like to obtain fruit (vegetable) puree. The fineness of the puree can be achieved by selecting different apertures of the beater screen. In the processing of fruit and vegetable juices, this method is suitable for the production of fruit and vegetable pulp and pulp drinks, such as strawberry juice, mango juice, peach juice and hawthorn juice. After crushing, the raw materials of fruits and vegetables need to be precooked in the pre-cooker immediately to passivate the enzyme activity in the fruits and vegetables to prevent browning, and then beating. Three beatings are generally performed during production. The size of the sieve aperture is 1.2, 0.8, and 0.5 mm in order. After the beating, the smaller meat particles are conducive to homogenization. If single-channel beating is used, the screen aperture should not be too small, otherwise it will easily clog the mesh.
Centrifugation needs to be accomplished by a horizontal spiral centrifuge, which uses the principle of centrifugal force to separate fruit and vegetable juice from pulp. The slurry enters the centrifuge chamber of the drum through the center feed tube. Under the action of high-speed centrifugal force, the fruit slag is thrown onto the wall of the drum. The screw conveyor conveys the fruit residue continuously to the tapered end of the drum for discharge. Out of the front of the drum through the thread gap.
The coarse filtration is a process of removing the larger particles or suspended particles dispersed in the juice. In addition to the pulping method, fruits and vegetables juices obtained by other methods contain a large amount of suspended particles. If the meat fibers, peels, and fruit cores, their presence will affect the appearance quality and flavor of the products, they need to be removed in time, and the coarse filtration can be squeezed. The process of juice is performed or clicked. Shaker is usually used in production to conduct coarse filtration. Fruit and vegetable juices generally pass the 0.5 mm pore size filter to achieve coarse filtration requirements. After the coarse filtration of the fruit and vegetable juice, clarification and filtration are required, and homogenization and degassing are required for the turbid juice and the meat drink.
The breakthrough in the filling technology of Zhoushan Jinqi Beverage Production Line is a requirement for market development, and it is also a requirement for the beverage production line to strictly meet its own development. The technological innovation of beverage machinery on the road in the future will be more and more, all the way. High-end direction is walking!
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