Which preservatives can PVP be combined with for better results?

Compound ingredients

Central role

Synergy mechanism

Application case

Chitosan

Broad-spectrum antibacterial (effective to mildew and bacteria), good film-forming property, and can enhance the compactness and flexibility of the film

1. The water solubility of PVP and the film-forming property of chitosan complement each other to form a "dense + breathable" composite film;
2. The amino group (-NHNH) of chitosan and the amide group of PVP act synergistically to enhance the ability to destroy microbial cell membranes.

Peach preservation: 0.1% PVP + 1.5% chitosan, after 15 days of storage, the decay rate decreased to 5% (PVP alone group 12%, untreated group 25%), and the hardness retention rate increased by 15 percent

Plant essential oil (such as lemon essential oil, cinnamon essential oil)

Natural bacteriostasis (containing terpenes and phenols, with special effect on Penicillium and Botrytis), with natural aroma

1. The polymer chain of PVP can "wrap" the molecules of essential oil, delay its volatilization and prolong the antibacterial time;
2. The lipid solubility of essential oil can enhance the permeability of membrane to microbial cell membrane, which is superimposed with the weak bacteriostasis of PVP.

Strawberry preservation: 0.2% PVP + 0.3% lemon essential oil compound, after 7 days of storage, the mildew rate was only 8% (PVP alone group 18%), and retained the natural fruit aroma of strawberries, no odor

Organic acids (e.g. citric acid, lactic acid)

Adjust the pH value of the membrane (acidic environment inhibits microbial reproduction), protect vitamin C (reduce oxidation)

1. organic acid reduce that pH value of the film surface and inhibit neutral/alkaline-loving microorganisms (such as Erwinia, which cause soft rot);
2. Citric acid can combine with the polar groups of PVP to enhance the water adsorption capacity of the membrane.

Green pepper preservation: 0.15% PVP + 0.5% citric acid, after 10 days of storage, the retention rate of vitamin C was 75% (62% in PVP alone group), and there was no soft rot phenomenon

Compound ingredients

Central role

Synergy mechanism

Application case

Glycerol/propylene glycol

Plasticizer, improve the flexibility and ductility of the film, avoid cracking of the film

The hydroxyl group (-oh) of glycerol and the amide group of PVP form hydrogen bonds, which destroy the close packing of PVP molecular chains, increase the elasticity of the membrane, and improve the permeability of the membrane (avoid anaerobic respiration).

Navel orange preservation: 0.2% PVP + 0.3% glycerol, film thickness controlled at 3 μm, after 20 days of storage, the rate of film cracking was only 3% (PVP alone group 12%), and the fruit had no alcohol taste (anaerobic respiration index).

Polyvinyl alcohol (PVa)

Increase the balance of compactness and permeability of the film, and improve the resistance of the film to temperature fluctuation (not easy to embrittle/soften)

The polymer chains of PVP and PVA are cross-linked to form a "network structure", which not only retains the water-locking property of PVP, but also adjusts the porosity of the membrane through the hydroxyl of PVA to balance ventilation and barrier.

Cucumber preservation: 0.15% PVP + 0.5% PVA compound, after 10 days of storage, the weight loss rate was only 6% (PVP alone group 9%), and the cucumber remained crisp and tender, without skin shrinkage

Nanoparticles (such as nano SiO2, nano TiO2)

Enhance the mechanical strength and antibacterial property of the membrane, and reduce the oxygen permeability of the membrane

Nanoparticles are uniformly dispersed in the PVP membrane to fill the tiny pores of the membrane and reduce the oxygen permeability; At the same time, nano-TiO2 can produce free radicals under light to assist in inhibiting microorganisms.

Apple preservation: 0.2% PVP + 0.1% nano-SiO2 compound, after 30 days of storage, the oxygen permeability decreased by 20% (PVP alone group), and the browning area of the epidermis decreased by 10 percent

Compound ingredients

Central role

Synergy mechanism

Application case

Calcium Chloride (CaClCa)

Enhance the toughness of fruit and vegetable cell walls (reduce softening), inhibit ethylene release (delay ripening), and assist in water locking

1. Calcium ions (CaCa) combine with pectic acid in the cell wall of fruits and vegetables to form "calcium pectate" and enhance the structure of the cell wall;
2. Superimposed with the water-locking effect of PVP to reduce water loss from the cell wall

Tomato preservation: 0.2% PVP + 0.5% calcium chloride, after 12 days of storage, the retention rate of hardness was 80% (65% in the PVP group alone), and the tomatoes still maintained sweet and sour taste, without softness.

Ascorbic acid (vitamin C)

Inhibition of oxidative reactions (protection of vitamin C, carotenoids), reduction of epidermal browning

1. that ascorbic acid is use as a reducing agent and preferentially reacts with oxygen to prevent the nutrition of the fruit and vegetables from being oxidized;
2. It cooperates with the oxygen barrier effect of PVP to form "active antioxidant + passive oxygen barrier" dual protection.

Carrot preservation: After 15 days of storage, the carotenoid retention rate of 0.1% PVP + 0.2% ascorbic acid was 90% (78% in PVP group), and the skin was not browned

1-Methylcyclopropene (1-MCP, low concentration)

Inhibition of ethylene receptor activity (delaying ripening and aging), suitable for climacteric fruits and vegetables (apples, bananas)

PVP membrane could delay the volatilization of 1-MCP and prolong its action time. At the same time, the oxygen isolation of PVP reduces the production of ethylene, and both of them delay aging from the dual dimension of "inhibiting receptor + reducing production".

Banana preservation: The combination of 0. 2% PVP and 0. 1 μL/L 1-MCP could keep the green color after 20 days of storage (only PVP group turned yellow after 12 days), and the ripening process was delayed

Compound ingredients

Central role

Synergy mechanism

Application case

Tea Polyphenols

Strong antioxidant, weak antibacterial (inhibit bacteria and mold), protect fruit and vegetable nutrition from loss

The phenolic hydroxyl group of tea polyphenols combined with the amide group of PVP to enhance the antioxidant capacity of the membrane; At the same time, tea polyphenols can penetrate into the epidermis of fruits and vegetables and inhibit the oxidative browning of epidermal cells.

Pear preservation: 0.15% PVP + 0.3% tea polyphenols, after 20 days storage, the retention rate of vitamin C was 85% (70% in PVP alone group), and the flesh was not browned

Propolis Extract

Broad-spectrum antibacterial (effective against bacteria, mold and virus), antioxidant, and non-toxic

Flavonoids in propolis cooperate with PVP to destroy the cell membrane of microorganisms. At the same time, the liposolubility of propolis can enhance the adhesion of the membrane and avoid the membrane from falling off.

Blueberry preservation: 0.2% PVP + 0.2% propolis extract compound, after 10 days of storage, the decay rate was only 6% (PVP alone group 15%), and blueberries remained plump and juicy