Application of polyvinylpyrrolidone (PVP) in fruit preservation

　　Polyvinylpyrrolidone (PVP) is a high-end fine chemical downstream of acetylene, is a polymer material with excellent performance, has excellent biocompatibility, solubility (soluble in water and many organic solvents), complexation, dispersion, film-forming, solubility, adhesion, chemical stability, biological inertia, and safety and non-toxicity, and is widely used in cosmetics, pharmaceuticals, hygiene, food, textile printing and dyeing, papermaking, adhesives, coatings, pigments, detergents, metal processing, energy, polymer polymerization, electronics, separation membranes, lithium batteries, polymer polymerization, electronics, separation of membranes, and so forth. PVP is widely used in cosmetics, medicine and health, food, textile printing and dyeing, papermaking, adhesives, coatings, pigments, detergents, metal processing, energy, polymer polymerization, electronics, separation membranes, lithium batteries, photovoltaic, medical polymers, nano-materials, graphene, catalysts, adsorbent materials, as well as agriculture and animal husbandry and other fields. At present, the new use of PVP is still emerging, in the ascendant. the new application of PVP in the field of lithium-ion batteries and photovoltaic has attracted great attention in the industry, however, the new use of PVP in the preservation of fruit has not yet attracted enough attention.

　　Peach is harvested in the hot and rainy rainy season, after harvesting, the tissue metabolism is vigorous, very easy to lose water, browning and rotting and deterioration, difficult to store. Research shows that by using 0.1% PVP water solution to treat peach, it can effectively inhibit the respiratory intensity of the fruit, reduce its respiratory peak, reduce water loss, reduce the loss of vitamin C, reducing sugar and other nutrients in the fruit, and maintain the hardness, so as to achieve the purpose of maintaining the quality of the peach fruit and prolonging the storage period. Compared with the commonly used chitosan preservative, 0.1% PVP coating peach preservation effect is even better than 1.0% chitosan. PVP dosage is less, the effect is good, the advantage is obvious.

　　Food science and technology workers also Gannan navel orange as the test fruit, design a series of experiments to decay rate, weight loss rate and the content of vitamin C as the evaluation index, to examine the different concentrations of the sole living extract, sodium carboxymethyl cellulose, PVP and γ-aminobutyric acid composite coating preservative on the preservation of Gannan navel orange effect. The results showed that the best preservation effect was achieved when the additive amounts of Dioscorea extract, sodium carboxymethyl cellulose, PVP and γ-aminobutyric acid were 2.0%, 0.6%, 0.4% and 1.0%, respectively. The composite coating material was able to effectively reduce the water loss of fruit tissues during storage, and delayed the decline of soluble solids, vitamin C and total fruit sugar content, and played a good preservation effect.

　　The preservation mechanism of polyvinylpyrrolidone (PVP) on fruits may be the use of its good complexing ability and film-forming properties, inhibiting the activity of enzymes related to ethylene production on the surface of the fruit, while reducing the contact with oxygen. At present, the study of PVP as a component of fruit preservative is still in its infancy, but due to its characteristics of good film-forming properties, low dosage, and good effect, it deserves attention and further development and application.