Packaging of the hottest fruit juice and jam

Packaging of fruit juice and jam

1 Characteristics of fruit juice and jam

different fruit juices can be made from different fruits, and their components and characteristics are different. In general, the main factors related to the compatibility and protective function of packaging are acidity, enzyme, vitamin C, color and flavor

(L) acidity

all fruits and fruit juices contain organic acids to varying degrees, which are acidic. Acidity is usually regarded as a sign of fruit maturity. The more mature the fruit is, the less acidic it is. Fruit acidity can also be controlled through variety improvement. For example, oranges of early maturing varieties are very acidic. They can be crossed with late maturing oranges with low acidity to obtain oranges of medium maturing varieties, and their acidity will be reduced. The organic acids in fruit juice show the characteristics of fruit flavor and give people a taste. Some organic acids are beneficial to human health. Protecting organic acids in fruit juice and preventing the corrosion of acid value on packaging is one of the important topics of fruit juice packaging

(2) enzymes

almost all juices contain enzymes. Enzymes have a direct impact on the quality and processing of fruit juice. The main one is pectinase. The turbidity of orange juice is caused by pectin. The heating experiment can be completed. Therefore, the pectin in the juice must be destroyed to make the juice clear. Some turbid citrus juice must be pasteurized at a sufficiently high temperature (generally at 95 ℃ for 3O seconds, depending on the pH value) to inactivate pectinase. In the processing of apple and black tea fruit juice, human pectinase needs to be added to destroy the pectin in it

(3) vitamin c

is also known as ascorbic acid. Fresh fruits and vegetables are rich in vitamin C. During the growth of fruits, the content of vitamin C increases gradually. After fruit ripens, the content of vitamin C begins to decline, which is due to the action of enzymes and ascorbic acid oxidase. When the fruit is cooked, most of the ascorbic acid in the fruit dissolves in the water and is destroyed by oxidation. Especially in iron, steel and other metal containers, the painting process is improper, there are metal ions, and ascorbic acid is easier to be oxidized. If the cooking speed is fast, ascorbic acid oxidase is inactivated, and the tendency of oxidation will be reduced. Vitamin C is also lost during storage. Low storage, airtightness and shading will also reduce the loss of vitamin C. When canning, a certain amount of sulfite is added to protect vitamin C

(4) color and flavor

for fruit juice and fruit juice drinks, color and flavor become important. Most fruit juice drinks contain the legally permitted amount of pigments to make up for the bleaching effect of preservative sulfite on fruit juice and beautify the color of fruit juice at the same time. In the manufacturing process of fruit juice drinks, some spices are sometimes added to increase their aroma

the deterioration of fruit juice is mainly caused by yeast. Under room temperature, raw fruit juice will deteriorate due to alcohol intoxication. Yeast and mold play a major role in the deterioration of fruit juice. Therefore, the deterioration of fruit juice and the inactivation of mold must be pasteurized, and then filtered or added with preservatives to eliminate the destructive effect of yeast

2 packaging of fruit juice drinks

concentrated drinks or fruit juices with a storage period of more than a few weeks generally need to add preservatives. According to the provisions of health laws and regulations, the preservatives of fruit juice drinks mainly include sulfur dioxide and benzoic acid. Sulfur dioxide can inhibit the exposure reaction, but even in sealed containers, sulfur dioxide will slowly dissipate. It is not a long-term preservative. In addition, sulfur dioxide will also combine with aldehydes and groups, and aldehydes and ketones are harmful to human body. This is also a disadvantage of sulfur dioxide preservative. Therefore, the total amount of sulfur dioxide added (there are legal provisions) is actually more than required. Benzoic acid has no effect on inhibiting browning reaction, but its bleaching effect on natural pigments and synthetic pigments is not as serious as that of sulfur dioxide. Sulfur dioxide is usually used in the form of sodium sulfite or sodium bisulfite (or potassium), which is generally used as a preservative of fruit products; Benzoic acid is directly added to fruit juice with sodium benzoate

pure fruit juice or fruit juice and jam without preservatives generally adopt the methods of hot filling and pasteurization in bottles. The juice passes through the heat exchanger and then has sufficient mechanical strength at 70 ℃

in China, fruit juice drinks and jam are mostly packaged in glass bottles. In recent years, plastic coated cartons (paper aluminum box rotation organization, special polyethylene composites for green manufacturing) have been used for packaging on the forming filling sealing packaging machine. These two kinds of packaging are basically imported equipment and packaging materials from abroad. Low density polyethylene blow molding bottles are widely used for fruit juice drinks sold in the market in summer, which are disposable packaging and low cost. However, due to the high oxygen permeability of polyethylene, fruit juice drinks are prone to oxidation and deterioration, and the shelf life is very short, which is only suitable for packaging sold in a short time

in foreign countries, except for glass bottle packaging, polyethylene plastic coated cartons and flexible packaging of aluminum foil and plastic film composites have been widely used for fruit juice drinks. Orange juice is packed in polyvinylidene oxide/aluminum foil/polyethylene composite soft bags, and its protective effect is better than that of polyester/polyethylene and cellophane/polyethylene materials. In addition, plastic bottles, aluminum two piece cans and bags in boxes (plastic bags in cartons) are also widely used. Among them, plastic coated cartons and paper aluminum foil plastic composite packaging bags are developing rapidly. This kind of packaging is also applied to alcohol and other liquid foods

beverage containers are mainly metal cans in the United States, Japan and other countries, that is, iron cans and aluminum cans. Tin plated iron sheet and Wuxi iron sheet are mostly used for iron cans. Wuxi tin can making cost is low and does not contain tin, so it will have a better development prospect. In recent years, the manufacturing process of three piece cans has developed, and the high-frequency welding technology is widely used instead of the conventional welding technology. Due to the use of lead-free electrode, the pollution of lead ions to beverages is avoided. The internal coating of beverage cans generally adopts epoxy phenolic paint. For drinks with high acidity, a layer of vinyl coating is also coated on the epoxy phenol coating to improve its corrosion resistance

the selection of canning materials depends on the variety of beverages and processing technology. Fruit juice and coffee drinks are hot filled, causing a vacuum of 46662.7 - 53328.8pa (350 - 40ommhg) in the tank. Therefore, a ring rib structure should be designed on the tank body to enhance its pressure resistance

beer and mineral water are generally made of two pieces of cans made of iron and aluminum. For beer, the pressure resistance is required to be 58.8-63.7n/cm2; For mineral water, the pressure resistance is required to be 74.8n/cm2

3 jam packaging

the packaging container of jam, tomato, mayonnaise and other foods can adopt soft plastic bottles that are easy to extrude food, such as polyethylene bottles. However, this kind of sauce food should avoid oxidation. Jam and tomato will change color after oxidation, the fat in egg yolk sauce will be rancid after oxidation, and the oxygen permeability of polyethylene plastic bottle is high. In recent years, due to the development of plastic molding technology, multi-layer plastic bottles can be manufactured. Multilayer plastic bottles of polyethylene and polyvinylidene chloride or ethylene vinyl alcohol copolymer can be used to package oxygen sensitive food. Table 9-4 lists the performance data of several plastic bottles

let you know about the device of the testing machine

source: Food Forum