Research and development of the hottest fruit and

Research and development of fruit and vegetable preservation paper

at this stage, the main methods of fruit and vegetable preservation are to maintain low temperature, control water evaporation, adjust the gas environment, remove ethylene gas, sterilization and antibacterial, etc. At present, the main materials used for the preservation of fruits and vegetables are functional fresh-keeping film, fresh-keeping paper, fresh-keeping agent, new corrugated boxes, etc. Among them, fresh-keeping paper bags made of functional fresh-keeping paper can not only play a good role in preserving fruits and vegetables, but also have simple production methods, relatively low costs and long-distance transportation

the following is a brief introduction of these functional fresh-keeping paper:

SO2 fresh-keeping paper

this fresh-keeping paper is composed of substrate and SO2 fresh-keeping agent. The base material is 80/GM2 filter paper. The preservative is composed of SO2 releasing agent (sodium pyrosulfite), slow-release agent, adhesive, stabilizer and waterproof agent. According to a certain proportion, it is evenly coated on the base material with a coating amount of about 150g/m2. In addition, sorbic acid can also be used as preservative to mix with SO2 to play a synergistic or synergistic effect. However, because sorbic acid is easy to volatilize, the storage time of the fresh-keeping paper should not be too long

Chinese herbal medicine quick acting grape preservation paper

this kind of quick acting grape preservation paper is composed of preservative and double-layer substrate. The preservative is composed of pyrosulfite or bisulfite mixed with Chinese herbal antibacterial agents and adhesives. The prepared preservative is painted on a single layer of substrate, then pasted with another layer of substrate, and dried. The refrigeration switch of the fresh-keeping paper in the packaging container for transporting or storing grapes should be turned on again at an interval of 10-20 minutes (depending on the ambient temperature). Under the action of temperature and humidity, it can continuously release sulfur dioxide gas, Chinese herbal medicine sterilization volatile oil, and achieve the purpose of anti-corrosion and fresh-keeping agent for grapes. According to the test, the fresh-keeping paper can keep grapes fresh for 6-9 days in long-term temperature transportation in summer, and 11 days under 32 ℃ laboratory conditions, and the intact rate of grapes is 97%; Refrigerated grapes can keep fresh for 2-3 months

the distribution ratio of the preservative group is: pyrosulfite or bisulfite 95% - 98%, Chinese herbal antibacterial agent 1% - 2%, adhesive 1% - 3%. Pyrosulfite is sodium pyrosulfite or potassium pyrosulfite, and bisulfite is sodium bisulfite or potassium bisulfite; The antibacterial agent of Chinese herbal medicine is ferula or chamomile; The adhesive is starch, gelatin or Arabic gum. The production method: first add water to the adhesive to make a paste mucus, add the broken preservative powder of more than 80 mesh and the antibacterial agent of Chinese herbal medicine into the mucus, stir it evenly to form a thick slurry, then coat the slurry on a single layer of paper, and then paste it with another layer of paper, and then dry it

Chinese herbal medicines such as clove, cinnamon, Zanthoxylum bungeanum, Stemona officinalis, ginger and Polygonum cuspidatum can also be used as preservatives alone. Mix according to the proportion of the mass of Chinese herbal medicine powder (g) and the volume of oxidized starch solution (ML) of 1:2, and then evenly coat it on ordinary packaging paper to form a continuous and uniform coating layer of Chinese herbal medicine powder. Below are some symbols and their meanings that appear in the use process of Jinan assay metal fatigue tester. Dry it on the paper dryer at 60 ℃ - 80 ℃, that is, make fresh-keeping paper

DH-1 citrus fresh-keeping paper

the decay of citrus is mainly caused by Penicillium, dichotomous Pythium and discospora spinosa. Inhibiting the reproduction of these bacteria can prevent citrus decay. Long ago, biphenyl (DP) was used as an antitoxic to prevent the corruption of various citrus fruits, which played a key role in the development of citrus industry. It is also reported that NHA and ha also have a good effect on preventing fruit ripening. DH-1 citrus preservative paper made from DP, HA and paraffin is proved to be simple in manufacturing process, convenient in use and good in fresh-keeping effect by storage tests

the citrus preservative is a kind of thin special paper. It is composed of fibers, soft in texture, and has a certain elasticity. It is a good protective film for the wrapped fruits. Antiseptic fresh-keeping paper is to add chemical drugs to the paper fiber or coat the chemical drugs on the paper surface, and then wrap it. Because the drugs on the paper surface are in direct contact with the fruits, a large number of bacteria on the fruit surface are killed. In the later stage, it mainly depends on the slow volatilization and dissolution of drugs in the paper fiber and between the paper fibers according to drugs to eliminate bacteria and control foot rot and black rot

wrapping fruits with preservative paper has a good effect on changing the concentration ratio of 02 and CO2 in the storage environment. In addition to applying chemical drugs, most of the holes between the paper fibers are filled with appropriate proportion of fillers and adhesives, which greatly reduces the air permeability of the paper compared with oil seal paper. After waxing, the light transmittance of the paper will be very low due to the coverage of the wax film. Therefore, using preservative paper for single fruit packaging and storage can gradually change the concentration ratio of O2 and CO2 in the small space where the fruit lives in the process of fruit respiration, that is, O2 concentration gradually decreases and CO2 concentration gradually increases, thus inhibiting the respiration of the fruit and enhancing the storage resistance of the fruit. Due to its low permeability, the anti-corrosion fresh-keeping paper can not be directly blown out of the fruit surface by the wind, so that the water vapor film will not be damaged, which plays a role in inhibiting the evaporation of water, thus maintaining the weight and freshness of the fruit

the results showed that the average rotten fruit rate of DH-1 fresh-keeping paper was 4.6%, and the average water loss rate was 11.8%

self adhesive fresh-keeping wet paper

Japan Ajinomoto koji introduced a non-toxic, tough, disposable self-adhesive packaging paper with heat preservation and moisture retention properties. The outer layer of this self-adhesive packaging paper is kraft paper, which can be used for writing or printing, and the inner layer is a special PP foaming material, which can prevent the smell and juice of the packaged fruits from leaking out. Using it to package food can not only prolong the fresh-keeping period, but also lose self adhesion once unpacked, so it also has the function of preventing being unpacked

biological preservative paper

Tokai pulp company of Japan added a layer of polyethylene film on the liner of corrugated boxes, and then coated with a waterproof wax coating containing trace fruit disinfectant to make biological preservative liner paper. The corrugated box packed with this kind of liner can prevent the fruit from evaporating on the operation station where you can learn a lot, and control the breath of the fruit to achieve the purpose of fresh preservation. The freshness of the packaged fruit can remain unchanged within 1 month