POROUS WET NATURAL FOAMING GEL SOFT MATERIAL, METHOD THEREOF AND APPLICATION THEREOF IN TRANSPORTATION OF FRESH FOOD

Abstract

Disclosed is a porous wet natural foaming gel soft material, comprising the following raw materials in parts by weight: 1 part to 5 parts of foaming agent; 0.1 part to 1 part of calcium ion releasing agent; 0.2 part to 2 parts of gelling agent; 0.5 part to 1 part of polyol; 0.001 part to 1 part of bacteriostatic agent; and the balance of deionized water supplemented to 100 parts, and the above ingredients are foamed to obtain a hydrogel buffer material, which is the porous wet natural foaming gel soft material. The material has a water content of more than 90%, which can effectively maintain a high wet state of fresh food in transportation. The material is flexible, which reduces a damage caused by friction and collision between a packaging material and a surface of the fresh food during vibration.

Claims

1. A porous wet natural foaming gel soft material, comprising the following raw materials in parts by weight: 1 part to 5 parts of foaming agent; 0.1 part to 1 part of calcium ion releasing agent; 0.2 part to 2 parts of gelling agent; 0.5 part to 1 part of polyol; 0.001 part to 1 part of bacteriostatic agent; and the balance of deionized water supplemented to 100 parts, wherein the above ingredients are foamed to obtain a hydrogel buffer material, which is the porous wet natural foaming gel soft material.

2. The porous wet natural foaming gel soft material according to claim 1, wherein the foaming agent is a soybean protein isolate-sodium alginate compound, and a preparation method of the foaming agent specifically comprises: activating a soybean protein isolate in an NH.sub.3 plasma for 5 minutes to 30 minutes, adding the activated soybean protein isolate into deionized water, magnetically stirring the mixture until the mixture is fully dissolved to prepare into a soybean protein isolate solution with a mass concentration of 1% to 6%, treating the solution by an ultrasonic wave at a power of 600 W for 10 minutes, then adding a sodium alginate solution with a mass concentration of 1% to 3% in a volume ratio of 1:1, homogenizing the mixture by a 50 MPa high-pressure homogenizer for thrice, fully hydrating the homogenized mixture overnight, and then freeze-drying the hydrated product to obtain the soybean protein isolate-sodium alginate compound.

3. The porous wet natural foaming gel soft material according to claim 1, wherein the calcium ion releasing agent is insoluble calcium salt; or, the gelling agent is weak acid; or, the polyol is selected from 1,2-pentanediol, 1,2-hexanediol and glycerol; or, the bacteriostatic agent is selected from p-hydroxyacetophenone, potassium sorbate and plant essential oil.

4. The porous wet natural foaming gel soft material according to claim 3, wherein the insoluble calcium salt is selected from CaO.sub.2, CaCO.sub.3 and Ca.sub.10(PO.sub.4).sub.6(OH).sub.2, and the calcium salt is selected according to a gas atmosphere required for transporting articles; and the weak acid is selected from gluconolactone, D-Glucoheptono-1,4-lactone and lactobionic acid.

5. A preparation method of the porous wet natural foaming gel soft material according to claim 1, comprising the following steps of: (1) adding the foaming agent into the deionized water, magnetically stirring the mixture until the mixture is fully dissolved, and treating the dissolved mixture by an ultrasonic wave at a power of 600 W for 5 minutes; (2) beating the mixture by a stirrer at a high speed until wet foaming is realized to obtain prefabricated gel foam; and (3) adding the calcium ion releasing agent, the gelling agent, the polyol and the bacteriostatic agent into the prefabricated gel foam, stirring the mixture evenly, and standing to form a gel to obtain the porous wet natural foaming gel soft material.

6. An application of the porous wet natural foaming gel soft material according to claim 1 in transportation of fresh food.

7. An application of the porous wet natural foaming gel soft material according to claim 1 serving as or preparing a packaging material of fresh food.

8. An application of the porous wet natural foaming gel soft material according to claim 1 serving as a wet soft material for packaging fresh food.

9. An application method of the porous wet natural foaming gel soft material according to claim 1, comprising the following steps of: injecting the natural foaming gel soft material into a packaging container, putting fresh food to be transported into the packaging container, and sealing an opening of the container to wait for gel formation, wherein the gel formation is carried out by standing, the gel formation lasts for 1 hour to 2 hours, and transportation is carried out after the gel formation.

10. An application method of the porous wet natural foaming gel soft material according to claim 1, comprising the following steps of: using the natural foaming gel soft material as a coolant, pre-cooling packaged fresh food in a low-temperature environment before transportation during application, and using the porous wet natural foaming gel soft material to maintain a low temperature during transportation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0052] FIG. 1 shows a stability kinetics curve of a foaming gel soft material prepared in Embodiment 1 of the present invention;

[0053] FIG. 2 shows a stability kinetics curve of a foaming gel soft material prepared in Embodiment 2 of the present invention;

[0054] FIG. 3 shows a stability kinetics curve of a foaming gel soft material prepared in Embodiment 3 of the present invention;

[0055] FIG. 4 is a DSC scanning chart of different materials in the present invention;

[0056] FIG. 5 shows stress-strain curves of cyclic loading in the present invention;

[0057] FIG. 6 is an image of micro-structures before and after the cyclic loading in the present invention;

[0058] FIG. 7 is an image of different packages of strawberries in the present invention;

[0059] FIG. 8 is a schematic diagram of damages of strawberries with different packages in simulated transportation and a drop experiment in the present invention; and

[0060] FIG. 9 shows damage indexes of the strawberries with different packages in the simulated transportation and the drop experiment in the present invention.

DETAILED DESCRIPTION

[0061] An embodiment of the present invention is described in detail hereinafter. It should be noted that the embodiment is descriptive and nonrestrictive, and cannot limit the scope of protection of the present invention.

[0062] Unless otherwise specified, the raw materials used in the present invention are all conventional products commercially available. Unless otherwise specified, the methods used in the present invention are all conventional methods in the art.

[0063] A porous wet natural foaming gel soft material comprises the following raw materials in parts by weight:

[0064] 1 part to 5 parts of foaming agent;

[0065] 0.1 part to 1 part of calcium ion releasing agent;

[0066] 0.2 part to 2 parts of gelling agent;

[0067] 0.5 part to 1 part of polyol;

[0068] 0.001 part to 1 part of bacteriostatic agent; and

[0069] the balance of deionized water supplemented to 100 parts, wherein the above ingredients are foamed to obtain a hydrogel buffer material, which is the porous wet natural foaming gel soft material.

[0070] Preferably, the foaming agent is a soybean protein isolate-sodium alginate compound, and a preparation method of the foaming agent specifically comprises: activating a soybean protein isolate in an NH.sub.3 plasma for 5 minutes to 30 minutes, adding the activated soybean protein isolate into deionized water, magnetically stirring the mixture until the mixture is fully dissolved to prepare into a soybean protein isolate solution with a mass concentration of 1% to 6%, treating the solution by an ultrasonic wave at a power of 600 W for 10 minutes, then adding a sodium alginate solution with a mass concentration of 1% to 3% in a volume ratio of 1:1, homogenizing the mixture by a 50 MPa high-pressure homogenizer for thrice, fully hydrating the homogenized mixture overnight, and then freeze-drying the hydrated product to obtain the soybean protein isolate-sodium alginate compound.

[0071] Preferably, the calcium ion releasing agent is insoluble calcium salt;

[0072] or, the gelling agent is weak acid;

[0073] or, the polyol is selected from 1,2-pentanediol, 1,2-hexanediol and glycerol for adjusting latent heat of phase change, and has moisturizing and bacteriostasis functions at the same time;

[0074] or, the bacteriostatic agent is selected from p-hydroxyacetophenone, potassium sorbate and plant essential oil.

[0075] Preferably, the insoluble calcium salt is selected from CaO.sub.2, CaCO.sub.3 and Ca10(PO.sub.4).sub.6(OH).sub.2, and the calcium salt is selected according to a gas atmosphere required for transporting articles; and

[0076] the weak acid is selected from gluconolactone, D-Glucoheptono-1,4-lactone and lactobionic acid.

[0077] A preparation method of the porous wet natural foaming gel soft material above comprises the following steps of:

[0078] (1) adding the foaming agent into the deionized water, magnetically stirring the mixture until the mixture is fully dissolved, and treating the dissolved mixture by an ultrasonic wave at a power of 600 W for 5 minutes;

[0079] (2) beating the mixture by a stirrer at a high speed until wet foaming is realized to obtain prefabricated gel foam; and

[0080] (3) adding the calcium ion releasing agent, the gelling agent, the polyol and the bacteriostatic agent into the prefabricated gel foam, stirring the mixture evenly, and standing to form a gel to obtain the porous wet natural foaming gel soft material.

[0081] An application of the porous wet natural foaming gel soft material above in transportation of fresh food is provided.

[0082] An application of the porous wet natural foaming gel soft material above serving as or preparing a packaging material of fresh food is provided.

[0083] An application of the porous wet natural foaming gel soft material above serving as a wet soft material for packaging fresh food is provided.

[0084] An application method of the porous wet natural foaming gel soft material above is provided, and steps comprise:

[0085] injecting the natural foaming gel soft material into a packaging container, putting fresh food to be transported into the packaging container, and sealing an opening of the container to wait for gel formation, wherein the gel formation is carried out by standing, the gel formation lasts for 1 hour to 2 hours, and transportation is carried out after the gel formation.

[0086] An application method of the porous wet natural foaming gel soft material above is provided, and steps comprise:

[0087] using the natural foaming gel soft material as a coolant, pre-cooling packaged fresh food in a low-temperature environment before transportation during application, and using the porous wet natural foaming gel soft material to maintain a low temperature during transportation.

[0088] Specifically, related preparation and detection embodiments are as follows.

Embodiment 1

[0089] A preparation method of a foaming gel soft material comprised the following steps.

[0090] (1) A soybean protein isolate was added into deionized water, and magnetically stirred until the mixture was fully dissolved to prepare into a soybean protein isolate solution with a mass concentration of 4%, the solution was treated by an ultrasonic wave at a power of 600 W for 10 minutes, and then a sodium alginate solution with a mass concentration of 2% in a volume ratio of 1:1 was added, homogenized by a 50 MPa high-pressure homogenizer for thrice, fully hydrated overnight, and then freeze-dried to obtain the soybean protein isolate-sodium alginate compound.

[0091] (2) 3 parts of soybean protein isolate-sodium alginate compound were added into the deionized water, magnetically stirred until the mixture was fully dissolved, and treated by an ultrasonic wave at a power of 600 W for 5 minutes.

[0092] (3) The mixture was beaten by a stirrer at a high speed until wet foaming was realized to obtain prefabricated gel foam.

[0093] (4) 0.3 part of CaCO.sub.3, 0.6 part of gluconolactone, 1 part of glycerol and 0.05 part of clove essential oil were added into the prefabricated gel foam, stirred evenly, and stood for gel formation to obtain the foaming gel soft material.

[0094] The above parts were all parts by weight, and a sum of the parts by weight of the soybean protein isolate-sodium alginate compound, the deionized water, the CaCO.sub.3, the gluconolactone, the glycerol and the clove essential oil was 100 parts.

Foaming rate=foam volume/solution volume100%.

[0095] A stability kinetics curve of the prefabricated gel foam was measured by a TURBISCAN Lab multiple light scatterometer.

[0096] A storage modulus G and a loss modulus G of the gel were measured by a rheometer, a test rotor was a flat rotor, a test speed was 1 rad/s, tan =G/G, and tan equal to 1 was taken as gel solidification time.

TABLE-US-00001 TABLE 1 Characteristics of material Foaming rate 251.7 3.5% Density 0.39 g/cm.sup.3 Gel formation time 74 minutes

[0097] It can be seen from Table 1 that the foaming rate of the soybean protein isolate-sodium alginate compound formed by pre-treating the soybean protein isolate by the ultrasonic wave at the power of 600 W for 10 minutes during foaming is 251.7%. The gel formation time is 74 minutes, and the density of the material is 0.39 g/cm.sup.3. It can be seen from FIG. 1 that a TSI index of the foam can reach 49.59 after 12 hours, and the foam is unstable.

Embodiment 2

[0098] A preparation method of a foaming gel soft material comprised the following steps.

[0099] (1) A soybean protein isolate was put into a plasma treater, and treated with an NH.sub.3 plasma for 10 minutes under a base pressure of less than 3 Pa, the activated soybean protein isolate was added into deionized water, and magnetically stirred until the mixture was fully dissolved to prepare into a soybean protein isolate solution with a mass concentration of 4%, and then a sodium alginate solution with a mass concentration of 2% in a volume ratio of 1:1 was added, homogenized by a 50 MPa high-pressure homogenizer for thrice, fully hydrated overnight, and then freeze-dried to obtain the soybean protein isolate-sodium alginate compound.

[0100] (2) 3 parts of soybean protein isolate-sodium alginate compound were added into the deionized water, magnetically stirred until the mixture was fully dissolved, and treated by an ultrasonic wave at a power of 600 W for 5 minutes.

[0101] (3) The mixture was beaten by a stirrer at a high speed until wet foaming was realized to obtain prefabricated gel foam.

[0102] (4) 0.25 part of Ca.sub.10(PO.sub.4).sub.6(OH).sub.2, 0.7 part of D-Glucoheptono-1,4-lactone, 1 part of glycerol and 0.001 part of potassium sorbate were added into the prefabricated gel foam, stirred evenly, and stood for gel formation to obtain the foaming gel soft material.

[0103] The above parts were all parts by weight, and a sum of the parts by weight of the soybean protein isolate-sodium alginate compound, the deionized water, the Ca.sub.10(PO.sub.4).sub.6(OH).sub.2, the D-Glucoheptono-1,4-lactone, the glycerol and the potassium sorbate was 100 parts.

Foaming rate=foam volume/solution volume100%.

[0104] A stability kinetics curve of the prefabricated gel foam was measured by a TURBISCAN Lab multiple light scatterometer.

[0105] A storage modulus G and a loss modulus G of the gel were measured by a rheometer, a test rotor was a flat rotor, a test speed was 1 rad/s, tan =G/G, and tan equal to 1 was taken as gel solidification time.

TABLE-US-00002 TABLE 2 Characteristics of material Foaming rate 171.2 4.2% Density 0.58 g/cm.sup.3 Gel formation time 68 min

[0106] It can be seen from Table 2 that the foaming rate of the soybean protein isolate-sodium alginate compound formed by treating the soybean protein isolate with the NH.sub.3 plasma for 10 minutes during foaming is 171.2%, and the foaming rate is lower than that in Embodiment 1. The gel formation time is 68 minutes, and the density of the material is 0.58 g/cm.sup.3. It can be seen from FIG. 2 that a TSI index of the foam is 43.83 after 12 hours, which is lower than that in Embodiment 2, and the foam is relatively stable. It is indicated that the compound formed with the soybean protein isolate treated with the NH.sub.3 plasma for 10 minutes and the sodium alginate has the foaming rate lower than that of ultrasonic pretreatment during foaming, resulting in a higher density of the final material, but the formed foam is more stable.

Embodiment 3

[0107] A preparation method of a porous wet natural foaming gel soft material comprised the following steps.

[0108] (1) A soybean protein isolate was put into a plasma treater, and treated with an NH.sub.3 plasma for 10 minutes under a base pressure of less than 3 Pa, the activated soybean protein isolate was added into deionized water, and magnetically stirred until the mixture was fully dissolved to prepare into a soybean protein isolate solution with a mass concentration of 4%, the solution was treated by an ultrasonic wave at a power of 600 W for 10 minutes, and then a sodium alginate solution with a mass concentration of 2% in a volume ratio of 1:1 was added, homogenized by a 50 MPa high-pressure homogenizer for thrice, fully hydrated overnight, and then freeze-dried to obtain the soybean protein isolate-sodium alginate compound.

[0109] (2) 3 parts of soybean protein isolate-sodium alginate compound were added into the deionized water, magnetically stirred until the mixture was fully dissolved, and treated by an ultrasonic wave at a power of 600 W for 5 minutes.

[0110] (3) The mixture was beaten by a stirrer at a high speed until wet foaming was realized to obtain prefabricated gel foam.

[0111] (4) 0.3 part of CaCO.sub.3, 0.7 part of gluconolactone, 1 part of glycerol and 0.05 part of clove essential oil were added into the prefabricated gel foam, stirred evenly, and stood for gel formation to obtain the porous wet natural foaming gel soft material.

[0112] The above parts were all parts by weight, and a sum of the parts by weight of the soybean protein isolate-sodium alginate compound, the deionized water, the CaCO.sub.3, the gluconolactone, the glycerol and the clove essential oil was 100 parts.

Foaming rate=foam volume/solution volume100%.

[0113] A stability kinetics curve of the prefabricated gel foam was measured by a TURBISCAN Lab multiple light scatterometer.

[0114] A storage modulus G and a loss modulus G of the gel were measured by a rheometer, a test rotor was a conical rotor, a test speed was 1 rad/s, tan =G/G, and tan equal to 1 was taken as gel solidification time.

[0115] A surface friction coefficient was measured by a rheometer, a test rotor was a flat rotor, a test speed was 0.5 rad/s, and the friction coefficient was calculated according to =4T/3F.sub.NR, wherein T was a torque, F.sub.N was a normal force, and R was a contact radius.

[0116] A specific heat capacity was measured by a Mettler differential scanning calorimeter, and a scanning temperature was 10 C. to 40 C., with air as the control.

[0117] Latent heat of phase change was measured by a Mettler differential scanning calorimeter, a scanning temperature was 40 C. to 40 C., and a heating rate was 10 C./min, with polyurethane foam and polyethylene foam as the comparisons.

[0118] The obtained material was subjected to 200 cyclic loading experiments by a stretcher at a speed of 5 mm/s under a strain of 0.5. Stress-strain curves of cyclic loading of the material were measured.

[0119] Loaded and unloaded hydrogel materials were frozen in liquid nitrogen, and then freeze-dried by a vacuum freeze-dryer, and then micro-structures of the materials were observed by a scanning electron microscope.

TABLE-US-00003 TABLE 3 Characteristics of material Foaming rate 343.5 5.6%.sup. Density 0.29 g/cm.sup.3 Gel formation time 61 min Friction coefficient 0.084 0.003 Modulus 2.3 0.02 kPa Specific heat capacity 3956 49 J kg.sup.1 K.sup.1 Latent heat of phase change 201 54 J g.sup.1

[0120] It can be seen from Table 3 that the foaming rate of the soybean protein isolate-sodium alginate compound formed by pre-treating the soybean protein isolate through the NH.sub.3 plasma and the ultrasonic wave at the power of 600 W during foaming may reach 343.5%, and the foaming rate is significantly higher than those in Embodiment 1 and Embodiment 2. The density of the material is 0.29 g/cm.sup.3, which is lower than those of the materials prepared in Embodiment 1 and Embodiment 2. It can be seen from FIG. 3 that a TSI index of the foam may be 33.23 after 12 hours, which is significantly lower than those in Embodiment 1 and Embodiment 2, and the foam is relatively stable. It is indicated that the collaborated treatment of the soybean protein isolate through the NH.sub.3 plasma and the ultrasonic wave is beneficial for improving the foaming rate of the soybean protein isolate-sodium alginate compound, thus reducing the density of the packaging material, and improving the stability of the foam at the same time.

[0121] In addition, it can be seen from Table 3 that the gel formation time is 61 minutes, which is shorter than that in Embodiment 1. This is because an addition amount of the gluconolactone is increased in Embodiment 3, thus it can be seen that the gel formation time may be controlled by adjusting a proportion of a gelling agent.

[0122] It can be seen from FIG. 4 that the prepared foaming hydrogel soft material has a larger phase-change endothermic peak compared with commonly used polyurethane foam and polyethylene foam. Meanwhile, the material has larger latent heat of phase change (395649 J kg.sup.1 K.sup.1), which indicates that the material may be used as a coolant.

[0123] It can be seen from FIG. 5 that the prepared foaming hydrogel soft material still has certain energy dissipation after cyclic loading for 200 times, thus having a buffering effect on an external force.

[0124] It can be seen from FIG. 6 that the prepared foaming hydrogel soft material shows a porous structure before loading the external force, and the porous structure is collapsed after cyclic loading for 200 times, thus dissipating the external force.

Embodiment 4

[0125] A preparation method of a porous wet natural foaming gel soft material comprised the following steps.

[0126] (1) A soybean protein isolate was put into a plasma treater, and treated with an NH.sub.3 plasma for 10 minutes under a base pressure of less than 3 Pa, the activated soybean protein isolate was added into deionized water, and magnetically stirred until the mixture was fully dissolved to prepare into a soybean protein isolate solution with a mass concentration of 4%, the solution was treated by an ultrasonic wave at a power of 600 W for 10 minutes, and then a sodium alginate solution with a mass concentration of 2% in a volume ratio of 1:1 was added, homogenized by a 50 MPa high-pressure homogenizer for thrice, fully hydrated overnight, and then freeze-dried to obtain the soybean protein isolate-sodium alginate compound.

[0127] (2) 3 parts of soybean protein isolate-sodium alginate compound were added into the deionized water, magnetically stirred until the mixture was fully dissolved, and treated by an ultrasonic wave at a power of 600 W for 5 minutes.

[0128] (3) The mixture was beaten by a stirrer at a high speed until wet foaming was realized to obtain prefabricated gel foam.

[0129] (4) 0.3 part of CaCO.sub.3, 0.7 part of gluconolactone, 1 part of glycerol and 0.05 part of clove essential oil were added into the prefabricated gel foam, stirred evenly, and injected into a packaging container, freshly picked strawberries were put into the container, an opening of the container was sealed, and the mixture was stood for gel formation to obtain the strawberries packaged by the porous wet natural foaming gel soft material.

[0130] The above parts were all parts by weight, and a sum of the parts by weight of the soybean protein isolate-sodium alginate compound, the deionized water, the CaCO.sub.3, the gluconolactone, the glycerol and the clove essential oil was 100 parts.

[0131] (5) The packaged strawberries were divided into two groups, wherein one group was vibrated for 1 hour by a simulated transportation machine as a simulated transportation experiment, and the other group was dropped at a height of 1 m for 10 times as a drop experiment, and unpackaged strawberries were used as a control group during the experiments. The polyurethane foam and a commercial vibration reduction package were used as comparison groups.

[0132] Measurement of damage indexes of strawberries: the strawberries were divided into five grades according to damage degrees. In Grade 0, the strawberries had no damage;

[0133] in Grade 1, a damaged area of the strawberries was less than of a total area; in Grade 2, the damaged area of the strawberries was to 2 of the total area; in Grade 3, the damaged area of the strawberries was to of the total area; and in Grade 4, the damaged area of the strawberries was more than of the total area. Damage rate=.sub.i=0.sup.4L.sub.iN.sub.i/L.sub.hN.sub.t, wherein L.sub.i represented a grade i, L.sub.h represented a highest grade, N.sub.i represented a number of strawberries in the grade i, and N.sub.t represented a total number of strawberries.

[0134] It can be seen from FIG. 7 that, compared with other packages, the porous wet natural foaming gel can cover all angles of the strawberries, reduce vibration in all directions, and adapt to various sizes and shapes of fruits.

[0135] The prepared porous wet natural foaming gel soft material is compared with the two commonly used packaging materials, which are namely the polyurethane foam and the polyethylene foam to carry out the simulated transportation and the drop experiment. It can be seen from FIG. 8 to FIG. 9 that the package by the porous wet natural foaming gel soft material can significantly reduce the damages of the strawberries produced during simulated transportation and dropping, so that the effect of the material is obviously better than those of the packaging materials commonly used at present.

[0136] Although the embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art may understand that various alternatives, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments.