Application of PVP in fruit preservation

Polyvinylpyrrolidone (PVP) is a high-end fine chemical downstream of acetylene, which is a polymer material with excellent performance, with excellent biocompatibility, solubility (soluble in water, but also soluble in many organic solvents), complex, dispersibility, film formation, solubilization, bonding, chemical stability, bioinert and safe and non-toxic. Widely used in cosmetics, medicine and health, food, textile printing and dyeing, paper making, adhesives, coatings,pigments, detergents, metal processing, energy, polymer polymerization, electronics, separation film, lithium battery, photovoltaic, medical polymer materials,nanomaterials, graphene, catalysts, adsorption materials and agriculture and animal husbandry and other fields. At present, the new uses of PVP are still emerging and in the ascendant. The new application of PVP in the field of lithium-ion battery and photovoltaic has attracted great attention in the industry,however, the new use of PVP in fruit preservation has not attracted enough attention.

Harvested in the hot and rainy Meiyu season, the postharvest tissue metabolism is strong, easy to lose water, brown and rot, difficult to store. Studies have shown that the use of 0.1%PVP aqueous solution to treat peach fruit can effectively inhibit the respiratory intensity of fruit, reduce its respiratory peak, reduce water loss, reduce the loss of vitamin C, reducing sugar and other nutrients in fruit, and maintain the hardness, so as to maintain the quality of peach fruit and extend the storage period. Compared with the commonly used chitosan preservative, the preservation effect of 0.1%PVP coated peach was even better than that of 1.0% chitosan. The amount of PVP is small, the effect is good, and the advantages are obvious.

Food scientists also took Gannan navel orange as the test fruit, designed a series of experiments, with the rot rate, weight loss rate and vitamin C content as evaluation indexes, to investigate the effects of different concentrations of unique extract, sodium carboxymethyl cellulose, PVP and γ-aminobutyric acid composite coating preservative on the preservation effect of Gannan navel orange. The results showed that the fresh-keeping effect was the best when the supplemental levels of monoviable extract, sodium carboxymethyl cellulose, PVP and γ-aminobutyric acid were 2.0%, 0.6%, 0.4% and 1.0%, respectively. The composite coating material can effectively reduce the water loss of fruit tissue during storage, and delay the decrease of soluble solid, vitamin C and total sugar content of fruit, and play a good fresh-keeping effect.

The preservation mechanism of fruit by PVP may be due to its good complexation and film forming ability, which inhibits the activity of enzymes related to ethylene production on fruit surface and reduces the contact with oxygen. At present, the research of PVP as fruit preservative ingredient is still in the initial stage, but due to its good film forming property, less dosage and good effect, it deserves attention and further development and application.