At present, there are dozens of high-temperature instantaneous bactericidal juices produced in China. Among them, orange juice and orange juice are rich in nutrition and people are very fond of beverages, and the processing method is simple and easy. 1 Selection of raw materials The raw materials for producing orange juice are mainly sweet oranges, which are divided into golden yellow ordinary orange, navel orange and bright red blood orange according to the color of pulp. The raw materials for producing orange juice are Wenzhou dense orange, banana orange, Fuzhou red orange and so on. According to the mature period of precooked, medium and late ripening three. The raw material requirements of the juice making process are as follows: 1.1 The raw materials must be fresh and complete, such as long picking time, resulting in loss of fruit moisture evaporation, reduced freshness, reduced acidity, elevated sugar, and vitamin loss. 1.2 Maturity of the fruit The maturity of the fruit has an influence on its sap content, soluble solids content and aroma composition content. Generally, about 90% of the raw material is required to be ripe, bright color, and pure and fruity aroma is preferred. 1.3 The sugar and acid content of the raw materials are high, the aroma is rich, and the juice is abundant. The indicators are as follows: 25%ï½ž50% of the whole fruit juice, 9.2%ï½ž10% of the outer fruit peel, 12%ï½ž20% of the inner fruit peel; , 25% to 30%; juice density, 1.036% to 1.063g/m3; soluble solids, 9% to 15%; total acid, 0.6% to 2.0%. Do not use rot, fruit drop, or the damage of pests, and do not use bitter-tasting varieties. 2 Processing methods The processing flow of fresh orange juice and orange juice is as follows: washing and sorting of raw materials â†’ extraction of juice â†’ filtration â†’ mixing and sugar addition â†’ degassing and degreasing â†’ pasteurization â†’ homogenization â†’ canning and cooling. 2.1 Cleaning and sorting In order to prevent impurities from entering the juice during juicing, the fruit must be fully washed before juicing, usually by flushing with water or running water. Fruits with more pesticide residues can be immersed in detergent-containing water. Then spray with water, wash and test the fruit once again, and then remove the pest, unripe fruit, dried fruit, and wounded fruit. 2.2 The surface of the pressed citrus fruit contains essential oils, glycosides, and terpenoids to produce offensive odors. There are a large number of flavonoids represented by naringin and limonene represented by lemon alkali in the pericarp, endocarp and seeds. After heating, these compounds turn from insolubility to solubility, which makes the juice bitter. When squeezing juice must try to avoid these substances into the juice. Therefore, it is not appropriate to use crushing and juice extraction method, but to adopt a cone-cone method. 2.3 The filtered juice contains some suspended matter, which not only affects the appearance and flavor of the juice, but also makes the juice deteriorated. So, filter it. For the cloudy juice, the coarse particles and the suspended particles dispersed in the juice are removed on the premise of preserving the colored particles to obtain the color, flavor and aroma characteristics. For the transparent juice, the fine filtration is required after the coarse filtration, not only to remove all the suspended matters. Also need to remove the colloidal particles that are prone to precipitation. There are two methods of filtration: pressure filtration and vacuum filtration. 2.4 Mixing and Adding Sugar Some juices are not necessarily suitable for consumers' tastes. To make the juices meet product specifications and require improved flavors, the proportion of sugars and acids must be properly adjusted, but the adjustment range should not be too large to avoid losing the original flavor of the juice. The ratio of sugar to acid in finished fruit juice is preferably 13:1 to 15:1. The methods for adjusting sugar acid include: adding appropriate amount of sugar and edible acid in fresh fruit juice; using different types of raw material juice mix to mix. All kinds of fruits have different sugar content, acidity, color and flavor, and two or more kinds of fruit juices are mixed in proportions, so that a beverage having a different flavor from a single juice can be obtained, and a reinforcing effect can be obtained. 2.5 Degassing, degreasing Gases such as oxygen and nitrogen present in the intercellular spaces of fruits and the products of respiration such as carbon dioxide can enter the juice in a dissolved state during processing, or they can be adsorbed on the surfaces of fruit particles and colloids. As a result of the contact of fruit juice with air, the gas content is increased, so that a large amount of oxygen and other gases will certainly be present in the resulting juice. The presence of oxygen not only destroys Vc in the juice, but also reacts with various components in the juice to deteriorate the aroma and color. These adverse effects are even more pronounced when heated, so the degassing must be removed before the juice is heated and sterilized. Excess oxygen makes the oxygen content as low as possible. Deoxygenation and degreasing are accomplished during the same operation. Citrus skin essential oil is essential to ensure the best flavor of fruit juice. However, excess skin oil mixed with fruit juice often produces odor, so control the essential oil content. Deoxygenation methods include: vacuum, nitrogen exchange, enzymatic degassing, and antioxidants. 2.6 pasteurization pasteurized orange juice not only eliminate spoilage bacteria, but also can cause chemical changes in the enzyme (pectin, etc.) passivation. However, since the quality of the juice is significantly reduced due to heating, it is necessary to select a reasonable heating temperature and time in order to achieve the purpose of sterilizing and to minimize the influence on the quality of the juice. Generally used: 93 Â°C 2 Â°C to maintain 15 ~ 30s; special circumstances can be more than 120 Â°C 3 ~ 10s instant sterilization method. 2.7 Homogeneous homogenization is a special operation on the preparation of cloudy fruit juices. It is mostly used in glass packaging products. The homogenization is that the juice passes through the homogenizing device, so that the particles contained in the juice are further broken and uniform in size, which promotes the exudation of the pectin and enables the pectin and the juice to be uniformly and stably dispersed in the juice, thereby obtaining a certain degree of turbidity. But juice that does not separate and precipitate. Homogeneous commonly used high-pressure homogenizer or colloid mill and other equipment. When a high-pressure homogenizer is used, after the citrus juice is introduced, the suspended particles are broken in a high-pressure state and forced through a 0.002 to 0.003 mm pore size hole of the homogenizer to split into finer particles, uniformly and stably. Scattered in citrus juice. 2.8 Canned, cooled sterilized fruit juice (temperature about 85Â°C) is pumped to the drum and poured directly into the can. The residence time of the juice in the bucket must not exceed 1 to 2 minutes to reduce the change in flavor. After the canning seal is inverted, it is left for 20 minutes to sterilize the sealing cap with the temperature of the juice. Then, spray cold water, cooled to 38 Â°C or less, it is important that the cans after cooling retain residual heat, which will help the can body dry and prevent rust. 3 Quality Control The off-taste of orange juice and orange juice is an important issue affecting quality, especially orange juice is more likely to become bad. Excessive sterilisation often results in boiled odors. Fruits that are not fresh produce undesirable flavors. When degassed and deoiled, too much essential oil can be added to produce terpene. Therefore, reasonable and strict operations must be performed during the processing to ensure the quality of the juice.