Analysis and treatment of various quality problems

2022-08-01
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Analysis and treatment of various beverage quality problems

beverage is a daily drink that people often choose, but it is also one of the drinks that are most prone to quality problems. When quality problems occur in beverages, there will be many manifestations, such as taste change, color change, airlessness, impurities, turbidity, precipitation, etc. The reason for these phenomena is that eldorodo century plastics company adopts peek to manufacture cylindrical fillers. The reasons and treatment methods are summarized as follows:

the product has a bad smell after being put into production for a period of time, which can not be imported or becomes tasteless. The taste change of commodities is generally caused by microorganisms. In fruit juice carbonated beverages, Leuconostoc mesenteroides and lactobacillus can cause bad smell. When the temperature is suitable for microbial reproduction, the finished products will produce rancidity after production due to the unclean cleaning of syrup storage tanks, pipelines and equipment

impure carbon dioxide, excessive doping of other odors, hydrogen sulfide, sulfur dioxide, etc. will also bring odor to the product. In addition, the carbon dioxide produced by fermentation is rough, which will also bring alcohol taste or other strange taste to the product

in summer, the product will be exposed to the sun after being produced, which will cause chemical changes and peculiar smell of essence. Some essence and fragrances in beverages contain a lot of terpenes. After being stored for a period of time, the components of these essence and fragrances are oxidized due to the sun, temperature, residual air in the bottle and other reasons, resulting in the change of flavor

some recycled beverage bottles contain other substances with strong odor, which are not cleaned completely during cleaning, or pollute some clean bottles, which will also cause the product to change its flavor. In some areas, due to serious water pollution, more bleach powder fungicides are added to tap water, insufficient volume of activated carbon tanks for odor removal in some factories or too long use, the amount of residual chlorine exceeds the standard. After entering the finished products, the chlorine smell is heavy, which can have a great impact on the flavor of the products

discoloration

the discoloration of beverages is mainly manifested in the beverages processed with plant materials as raw materials, especially in vegetable juice beverages, tea drinks and flower drinks. Take the discoloration of fruit and vegetable juice as an example:

enzymatic browning of fruit and vegetable juice

there are a variety of phenolic substances and polyphenol oxidase in the fruit and vegetable tissues. During the processing, the phenolic substances are oxidized by polyphenol oxidase due to the contact between the tissues and the air, The brown quinones, such as apple juice, edible mushroom juice and asparagus juice, will change from light to dark, or even dark brown

the method to prevent enzyme browning is to kill enzyme activity. The polyphenol oxidase activity was inactivated by heating at 70 ~ 80 ℃ for 3 ~ 5 minutes or 95 ~ 98 ℃ for 30 ~ 60 seconds. Edible acid was added to inhibit enzyme activity. All kinds of edible acid can effectively inhibit the activity of polyphenol oxidase, because its enzyme activity is most suitable for the environment with pH of 6 ~ 7. After adding edible acid, its medium pH can be reduced, so that the enzyme activity is inhibited in the environment with low pH. For example, when the activity of apple polyphenol oxidase is adjusted to pH2.5 ~ 2.7 with malic acid, it can be completely inactivated; After that, even if the ph3.1 ~ 3.3 was increased again, the enzyme activity could not be recovered and the enzyme Browning would not occur again. For vegetable raw materials, if treated with 0.05% ~ 0.1% citric acid, the browning effect of enzymes can be delayed, and the addition of vitamin C can also inhibit the browning of enzymes. The dosage is 0.03% ~ 0.04%, but the cost is high, so it can not be widely used. Tools or containers that do not contact iron and copper during processing and minimize heating time

non enzymatic browning of fruit and vegetable juices

fruit juices stored in cans or other containers are stored at or above room temperature for a long time, and there are often various kinds of fruit juices with deepened color. Light colored fruit juices such as grapefruit, pineapple and lemon change from milky white or light yellow to dark yellow or even brown. Sweet orange or tomato juice with high carotene content turns brown. Grape and strawberry juice with high anthocyanin content is covered by pigments, Although the color change is not obvious, it has changed color. This is because the sugars in fruit juice are mainly fructose or glucose and amino acid (lysine), which undergo non enzymatic browning reaction at high temperature to produce melanins and carbon dioxide. The non enzymatic browning of fruit juice will be accelerated with the increase of temperature during storage. Reducing pH value can inhibit non enzymatic browning

control methods include Newton N and kn (also expressed by "kg kg, ton T and kPa KP"): control the pH value below 3.3; Prevent excessive thermal sterilization; The product is stored at a lower temperature, such as 10 ℃ or lower

browning caused by pigment compounds in fruit and vegetable juices

fruit and vegetable juices contain many pigment compounds. The pigments that change color mainly during processing and product storage and transportation include chlorophyll and flavonoid pigments. Chlorophyll is replaced under acidic conditions to produce demethylated chlorophyll. The green color disappears and turns brown. Heating can accelerate the reaction; The color change of flavonoids is that a certain proportion of flavonoids and other metal ions generate dark pigments, which are not affected by pH value. These pigments are also very sensitive to light, heat and pH. Fruit juices rich in flavonoids will quickly turn brown or fade under light. Flavonoid pigments are easy to oxidize into brown precipitates in the air, which is one of the reasons for the precipitation of some plant drinks after long storage

the solutions are as follows: avoid contact with heavy metal ions in processing engineering, and remove such metal ions in water at the same time; Minimize the heating time and illumination time of the beverage; Add antioxidants, color protectants, metal ion complexing agents, etc. to the beverage

insufficient gas

insufficient gas actually means that the carbon dioxide content is too low or there is no gas at all. Such products are silent when opening the cover, and there are no bubbles. In some factories, due to poor sanitary conditions, the products are not only airless, but also have a rancid smell. Because carbon dioxide is acidic when dissolved in water, and carbon dioxide has a certain mimetic effect on microorganisms. Therefore, low carbon dioxide content or no gas is easy to cause product deterioration

the reasons for insufficient carbon dioxide include: low purity or substandard purity of carbon dioxide; The water temperature or sugar temperature (mixed syrup temperature) is too high; The mixing effect of the mixer is not good; Air is mixed; Air leakage of mixer or pipeline; The canning machine is not easy to use and the air is not discharged well; The rubber nozzle of the filling machine leaks, or the position of the bottle holder is too low, or the position of the automatic filling machine is too low, resulting in gas leakage while filling; Untimely capping and long opening time make carbon dioxide lose at high temperature; The bottle mouth and cap are unqualified and not matched; The gland is not tight

to ensure that the product is full of air and meets the standard, the air content of the finished product must be sampled and measured regularly (usually once every 1-2 hours). In case of nonconformity, the causes shall be found out in sequence. If the cause is found to be impure carbon dioxide, the carbon dioxide shall be purified. If it is a problem with the equipment, it shall be repaired or replaced in time until the finished product with high elongation of polymer materials meets the requirements

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