Preparation method of soybean protein isolate / xanthan gum composite oil-in-water emulsion

Abstract

The invention discloses a preparation method of soybean protein isolate / xanthan gum composite oil-in-water emulsion, and belongs to the technical field of composite food development. The method comprises the following steps: (1) dissolving SPI in deionized water at the temperature of 4 DEG C according to different mass proportions, stirring for 30 minutes at the speed of 700 r / min, and standing for 12 hours at the temperature of 4 DEG C to obtain an SPI solution; (2) dispersing XG in the SPI solution obtained in the step (1) according to different mass proportions, stirring for 30 minutes at the speed of 700 r / min, and standing for 48 hours at 4 DEG C to obtain an SPI / XG mixed solution; (3) adding 20% by mass of soybean oil and 0.02% by mass of sodium azide into the mixed solution obtained in the step (2); and (4) homogenizing the mixed solution obtained in the step (4) by using a high-speed homogenizer (the rotating speed is 10000 rpm, and the homogenizing time is 20 minutes) to obtain the SPI / XG composite oil-in-water emulsion. The SPI / XG composite oil-in-water emulsion disclosed by the invention has more excellent emulsifying performance, and has important significance for widening the application of SPI.

Description

Technical Field

[0001] The present invention belongs to the technical field of compound food development, and specifically relates to a preparation method of a soybean protein isolate (SPI) - xanthan gum (XG) composite - stabilized oil - in - water emulsion. Background Art

[0002] Soybean protein isolate (SPI) is a protein with a protein content of more than 90% extracted from defatted soybean meal using the alkali - dissolution and acid - precipitation technique. It contains various amino acids required by the human body, has high nutritional value, and excellent functional properties such as emulsifying property, foaming property, and film - forming property. It is widely used in the food industry.

[0003] Xanthan gum (XG), an anionic natural heteropolysaccharide produced by Gram - negative bacteria during aerobic fermentation, is one of the most widely used industrial gums. XG is a non - adsorbing polysaccharide that can increase the viscosity of aqueous solutions and is widely used in the food industry as a thickener, stabilizer, and suspending agent. XG can stabilize oil - in - water emulsions by increasing the viscosity of the continuous phase and slowing down the movement of oil droplets.

[0004] An oil - in - water emulsion is a complex dispersion system formed by oil droplets dispersed in a continuous water phase, and its droplet size is usually in the micron - to - nanometer range. This unique structure endows the oil - in - water emulsion with many excellent properties, enabling various functions such as protecting active ingredients and drug delivery, and thus it is widely used in product fields such as food, medicine, and cosmetics. In the oil - in - water emulsion system, the regulation of emulsion stability is crucial, which determines the actual use of emulsion products. Currently, the most common stabilizers are biopolymers (proteins or polysaccharides). They provide long - term stability by adsorbing at the oil / water interface and changing the water - phase viscosity, or simply by the influence of non - adsorbing properties on water viscosity.

[0005] In summary, combining the advantages and disadvantages of the functional properties of SPI and XG, the present invention composites SPI and XG in an optimal compounding ratio through high - pressure homogenization technology to prepare an SPI / XG composite - stabilized oil - in - water emulsion and produce an emulsion product with desired properties. Summary of the Invention

[0006] The object of the present invention is to use the natural ingredient SPI to composite XG to stabilize the oil - in - water emulsion system, making the properties of the oil - in - water emulsion better and enabling the performance of the oil - in - water emulsion to be achieved by adjusting the raw material ratio.

[0007] To achieve the above object, the technical solution of the present invention is realized through the following technical solutions: (1) Dissolve SPI in deionized water at 4°C in different mass ratios, stir at a speed of 700 r / min for 30 min, and let it stand at 4°C for 12 h to obtain an SPI solution; (2) Disperse XG in the SPI solution obtained in step (1) according to different mass ratios, stir at a speed of 700 r / min for 30 min, and let it stand at 4°C for 48 h to obtain the SPI / XG mixture; (3) Add soybean oil with a mass ratio of 20% and sodium azide with a mass ratio of 0.02% to the mixture obtained in step (2); (4) Homogenize the mixture obtained in step (4) with a high-speed homogenizer (rotation speed: 10,000 rpm, homogenization time: 20 min) to obtain the SPI / XG composite oil-in-water emulsion; Preferably, the mass ratio of SPI to deionized water is 1% and 3%; Preferably, the addition amounts of XG are 0.02%, 0.08%, and 0.1% (W / W). Description of the Drawings

[0008] Figure 1 Flow chart of this method; Figure 2 Droplet size diagram of the SPI / XG composite oil-in-water emulsion; Figure 3 Zeta-potential diagram of the SPI / XG composite oil-in-water emulsion; Figure 4 Emulsion stability diagram of the SPI / XG composite oil-in-water emulsion; Figure 5 Creaming index diagram of the SPI / XG composite oil-in-water emulsion. Specific Embodiments

[0009] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. The described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention. Example 1:

[0010] 1. A preparation method of a soy protein isolate / xanthan gum composite oil-in-water emulsion, the soy protein isolate / xanthan gum composite oil-in-water emulsion is prepared by the following steps: (1) Dissolve SPI in deionized water at 4°C according to different mass ratios, stir at a speed of 700 r / min for 30 min, and let it stand at 4°C for 12 h to obtain the SPI solution; (2) Disperse XG in the SPI solution obtained in step (1) according to different mass ratios, stir at a speed of 700 r / min for 30 min, and let it stand at 4°C for 48 h to obtain the SPI / XG mixture; (3) Add soybean oil with a mass ratio of 20% and sodium azide with a mass ratio of 0.02% to the mixture obtained in Step 2; (4) Homogenize the mixture obtained in Step 4 with a high-speed homogenizer (rotation speed: 10,000 rpm, homogenization time: 20 min) to obtain an SPI / XG composite oil-in-water emulsion; Preferably, the mass ratio of SPI to deionized water is 1%; Preferably, the addition amount of XG is 0.08% (W / W). Example 2:

[0011] 1. A preparation method of a soy protein isolate / xanthan gum composite oil-in-water emulsion, and the soy protein isolate / xanthan gum composite oil-in-water emulsion is prepared through the following steps: (1) Dissolve SPI in deionized water at 4°C according to different mass ratios, stir at a speed of 700 r / min for 30 min, and let it stand at 4°C for 12 h to obtain an SPI solution; (2) Disperse XG in the SPI solution obtained in Step 1 according to different mass ratios, stir at a speed of 700 r / min for 30 min, and let it stand at 4°C for 48 h to obtain an SPI / XG mixture; (3) Add soybean oil with a mass ratio of 20% and sodium azide with a mass ratio of 0.02% to the mixture obtained in Step 2; (4) Homogenize the mixture obtained in Step 4 with a high-speed homogenizer (rotation speed: 10,000 rpm, homogenization time: 20 min) to obtain an SPI / XG composite oil-in-water emulsion; Preferably, the mass ratio of SPI to deionized water is 1%; Preferably, the addition amount of XG is 0.1% (W / W). Example 3:

[0012] 1. A preparation method of a soy protein isolate / xanthan gum composite oil-in-water emulsion, and the soy protein isolate / xanthan gum composite oil-in-water emulsion is prepared through the following steps: (1) Dissolve SPI in deionized water at 4°C according to different mass ratios, stir at a speed of 700 r / min for 30 min, and let it stand at 4°C for 12 h to obtain an SPI solution; (2) Disperse XG in the SPI solution obtained in Step 1 according to different mass ratios, stir at a speed of 700 r / min for 30 min, and let it stand at 4°C for 48 h to obtain an SPI / XG mixture; (3) Add soybean oil with a mass ratio of 20% and sodium azide with a mass ratio of 0.02% to the mixture obtained in Step 2; (4) Homogenize the mixture obtained in Step 4 with a high-speed homogenizer (rotation speed: 10,000 rpm, homogenization time: 20 min) to obtain an SPI / XG composite oil-in-water emulsion; Preferably, the mass ratio of SPI to deionized water is 3%; Preferably, the addition amount of XG is 0.02% (W / W).

[0013] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a soy protein isolate / xanthan gum composite oil-in-water emulsion, characterized in that Follow these steps: (1) SPI was dissolved in deionized water at 4°C in different mass proportions, stirred at 700 r / min for 30 min, and allowed to stand at 4°C for 12 h to obtain SPI solution; (2) Disperse XG in different mass proportions in the SPI solution obtained in step 1, stir at 700 r / min for 30 min, and stand at 4 °C for 48 h to obtain a SPI / XG mixed solution; (3) adding 20% ​​by weight of soybean oil and 0.02% by weight of sodium azide to the mixed solution obtained in step 2; (4) The mixed solution obtained in step 4 was homogenized using a high-speed homogenizer (rotation speed of 10,000 rpm, homogenization time of 20 min) to obtain a SPI / XG composite water-in-oil emulsion.

2. The method for preparing a soy protein isolate / xanthan gum composite oil-in-water emulsion according to claim 1, characterized in that: The mass ratio of SPI to deionized water in step (1) is 1% and 3%.

3. The method for preparing a soy protein isolate / xanthan gum composite oil-in-water emulsion according to claim 1, characterized in that: The addition amounts of XG in step (2) are 0.02%, 0.08% and 0.1% (W / W).

4. The method for preparing a soy protein isolate / xanthan gum composite oil-in-water emulsion according to claim 1, characterized in that: The added amounts of soybean oil and sodium azide in step (3) are 20% and 0.02% (W / W), respectively.

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