Green Packaging New Product Development

Fruits and vegetables are highly active foods that are very sensitive to the surrounding environment and, after harvesting, life cycles continue. The complex life activities it experiences are closely related to packaging and storage, affecting and limiting the life span of fruits and vegetables.
This article intends to start from the mechanism of fruit and vegetable preservation, through experiments to determine a reasonable formula to achieve the preservation effect of green packaging.
1. Fresh-keeping mechanism of fruits and vegetables 1.1 Mechanism of decay of fruits and vegetables 1.1.1 Biological deterioration of fruits and vegetables This form is caused on the one hand by the normal aging process of the living fresh food itself. Such foods remain fresh until they are sold to customers, and they are still living organisms. They also carry out complex life activities such as dormancy, germination, and evaporation of water and respiration. These activities are closely related to the packaging and storage of fruits and vegetables, affecting and limiting the life of fruits and vegetables. The most restrictive of these effects is respiration and water loss.
Respiration, that is, fruits and vegetables constantly consume their own nutrition under the action of oxygen, and the starch in the respiratory matrix in fruits and vegetables is gradually decomposed into sugar, pyruvic acid, CO2, and water under the action of enzymes, and the heat is released. The qualitative, quality, color, flavor, and nutritional value of fruits and vegetables are constantly undergoing qualitative changes, and eventually wilting, rots, and deteriorates, thereby losing the value of food.
The factors affecting respiration include temperature, humidity, air composition, and even fruit and vegetable varieties, maturity, and mechanical operations, all of which affect the intensity of respiration of fruits and vegetables. But it is the temperature that controls it. Experiments show that the lower the temperature, the weaker the respiratory intensity, the lower the material consumption and the longer the shelf life, but it should be above the “cold damage” temperature. Since the breath absorbs O2 and releases CO2, therefore, under the premise of guaranteeing the normal life activities of fruits and vegetables, by properly increasing the CO2 content in the air and reducing the O2 content, the CO2 produced by the respiration can be reduced, thereby reducing the respiratory heat of fruits and vegetables. , To extend the storage time of fruits and vegetables.
Water may cause loss of nutritional value, appearance of wilting and shrinkage, etc. Therefore, evaporation rate should be minimized, storage temperature should be reasonably controlled, and external pressure and other damage should be avoided so that fruits and vegetables can be kept within a suitable temperature range.
On the other hand, fruits and vegetables are damaged by the destruction of microorganisms such as bacteria, mold, and yeast during storage. There are many factors that affect the reproduction of microorganisms in foods, mainly including: temperature, humidity, proper amount of oxygen, pH, chemical stability, and biological isolation materials.
1.1.2 The non-biodegradation of fruits and vegetables is caused by the inherently existing causes. There are bound to be chemical and physical changes in the chemical properties of different foods and nature. Under the influence of external factors, it may cause various changes. Chemical changes can lead to browning and rancidity, and physical changes also lead to deterioration.
1.2 Freshness mechanism of fruits and vegetables Through the preservation technology, strict control of temperature, humidity and air or moisture, minimize the evaporation rate, prevent excessive water loss; under the premise of maintaining the normal life activities of fruits and vegetables, increase the content of CO2 in the air, reduce O2 content can reduce the CO2 produced by the respiration, thereby reducing the respiration heat of fruits and vegetables, and prolong the storage time of fruits and vegetables.
2. Development of fresh-keeping film for fruits and vegetables 2.1 Principle of cling-film The reagent is made of natural sugar, protein, oil, etc. as a main raw material, coated on the surface of fruits and vegetables, egg products, and dried to form a thin film. It not only has the effect of keeping fresh, but also does not pollute the environment. When it is consumed, it only needs to be cleaned with simple water.
2.2 Test Formula and Phenomenon Analysis 2.2.2 Phenomenon Record
2.2.1 proportion of formula ingredients
2.2.3 Analysis of results From the point of view of the raw material of cling film, proteins can form a selective permeation membrane. If the concentration is too small, the formed film thickness is not enough, the degree of O2, CO2, and water vapor inside and outside the film cannot be well controlled, and the effect of reducing O2 entry cannot be achieved, so that the respiration rate and strength are not well controlled. Sugars prevent food from decaying at a certain concentration without causing the cells to lose water. In addition, adding a certain amount of gelling agent and other auxiliaries can accelerate film curing. Appropriate proportion of the film is applied on the surface of the fruit to balance the internal and external infiltration of fruit cells. The metabolism of living cells and the respiratory rate are effectively controlled. After long-term storage of the fruits, the tissues are not destroyed, and the cell membrane protein still selectively penetrates. And the osmotic pressure in the protoplasm remains normal, so as to achieve a good preservation effect.
3. Conclusions (1) The effects of temperature, humidity and mechanical damage on the strength of respiration, such as temperature, are not in the optimal range for the survival of fruits and vegetables; if the humidity is too low, the cells lose water, and if they are too high, the microorganisms will multiply; when the machine is damaged, the microorganisms will enter the cell wall. Collapse, cells lose water and gradually dark and light and so on. When they affect the respiration in different degrees, they release a lot of heat, H2O and CO2, and then they are wilted and decayed.
(2) With the prolonged storage period, due to poor preservation, the metabolic rate is accelerated and the rate of conversion of starch into sugar is accelerated. The moisture and calories are reduced due to respiration, and the starch is also reduced. It is impossible to guarantee the expansion and gelatinization of starch granules under water and heat conditions. As a result, the cells cannot swell, giving a firm and plump tissue.
(3) The viscous material found in the intermediate thin layer that promotes the connection of plant cells is a water-soluble pectin substance, which is lightly hydrolyzed into a water-soluble pectin. Water-soluble pectic substances react with calcium ions to produce calcium pectate (insoluble) that increases hardness. Due to poor preservation, ripening of fruits and vegetables is accelerated, and with the different degree of maturity, water-soluble pectin substances are reduced and the corresponding water-soluble pectin is increased, so that the tissue is softened.
(4) Organic acids in fruits can relieve bacterial deterioration and impart food storage, flavor and color. However, if aging accelerates the reduction of organic acids, it directly affects the shelf life, texture, and appearance.
(5) Microorganisms in the epidermis of fruits and vegetables invade the food ingredients, and some of them decompose sugar and hydrolyze the starch, causing fats to hydrolyze and fail, digesting proteins, and affecting the shelf life. Put it into a thick syrup, because the bacteria have a cell membrane, allowing water to enter and leave the cell, so that the water in the cell goes out and the osmotic balance. 80% of the water from the cells into the sugar solution, the local dehydration of cells, and the effect of anti-corrosion.
(6) The fruit and vegetable cling film made by the best formula, applied to the appearance of fruits and vegetables, under the condition of ensuring normal metabolism, can control the intensity of respiration to be delayed so as to consume less of their own nutrition as much as possible, and prevent excessive water from being lost. Keep fresh, and use fresh water to rinse the plastic wrap. Therefore, it is a kind of green packaging material that does not pollute food, does not pollute the environment, and has the effect of keeping fresh. References 1.[Day] Yokoyama Yoshiro/Shigu Takato, ed., Food and Packaging, Beijing; Light Industry Press, 1989. 2. Shi Zhenmu Chief, Food Packaging, Tianjin; Tianjin Science and Technology Press, 19913. [Day] Yokoyama Li Xiong, food packaging seminar, Japanese food industry will, 19834.A Handbook of food packaging Frank A. Paine, 1983. (author: Beijing Technology and Business University, Zhu Hui)