Method for improving emulsifying property of soybean protein isolate emulsion by compounding locust bean gum

Abstract

The invention relates to a method for improving the emulsification characteristic of a soybean protein isolate emulsion by compounding locust bean gum. The method comprises the following steps: (1) preparing a soybean protein isolate (SPI) solution; (2) preparing a locust bean gum (LBP) solution; (3) preparing an LBP-SPI solution; and (4) preparing the LBP-SPI emulsion. According to the method, the LBP with different mass concentrations is added into the SPI solution to prepare the emulsion, so that the emulsification characteristic of the SPI is greatly improved, and the method has very important significance in widening the application field of the SPI.

Description

Technical Field

[0001] The invention belongs to food processing technology and relates to a method for improving the emulsification properties of soybean protein isolate emulsion by utilizing locust bean gum. Background Art

[0002] Soybeans are an important source of plant protein. Soy protein isolate (SPI) is a high-purity protein extracted from soybeans, with a protein content of usually over 90%. SPI has a variety of functional properties, including gelling, emulsifying, foaming, solubility, etc. These properties make it widely used in the food industry, such as in meat products, pasta products, aquatic products and vegetarian products. However, due to the structure and composition of the protein, some of its properties are disadvantageous. For example, SPI has a compact tertiary structure, which leads to poor solubility and insufficient surface hydrophobicity, which in turn affects its functional properties such as emulsification and foaming. The addition of polysaccharides can increase the surface hydrophobicity of SPI, unfold its structure, and expose the hydrophobic groups, thereby improving its solubility and emulsification ability.

[0003] Locust bean gum (LBG) is a natural polysaccharide extracted from locust bean seeds. It is mainly composed of galactomannan, which is composed of mannose and galactose. It has excellent thickening, emulsification and stabilization properties. LBG is mainly used as a thickener, emulsifier and stabilizer in the food industry. Due to the good synergistic effect between LBG and other hydrophilic colloids, this property makes it have a wide range of application prospects in the food industry, and it can achieve more efficient and economical product development by optimizing the compounding ratio and processing conditions.

[0004] At present, there are few studies on improving the emulsification properties of soy protein isolate emulsion by compounding locust bean gum. The present invention uses locust bean gum to improve the emulsification properties of soy protein isolate emulsion and determines the optimal LBG mass concentration. This is expected to obtain SPI emulsion with better emulsification properties and broaden its application in the food field. Summary of the invention

[0005] The present invention provides a method for improving the emulsification property of soybean protein isolate emulsion by utilizing locust bean gum, aiming at further improving the emulsification property of soybean protein isolate and broadening its application in the field of food.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows: A method for improving the emulsifying properties of a soy protein isolate emulsion by using locust bean gum as a compound, the method comprising the following steps: Preparation of soy protein isolate (SPI) solution: SPI powder was dispersed in deionized water to prepare a solution with a protein concentration of 2% (w / v), and stirred at room temperature to completely dissolve the solution, which is the SPI solution; Preparation of locust bean gum (LBG) solution: Locust bean gum powder was dispersed in deionized water to prepare a 0.2-0.8% (w / v) LBG solution; (3) Preparation of LBG-SPI solution: add an equal volume of 0.2-0.8% (w / v) LBG prepared in step (2) to the SPI solution prepared in step (1), and stir for 1-3 h to obtain the LBG-SPI solution; (4) Preparation of LBG-SPI emulsion: The LBG-SPI solution prepared in step (3) was added with soybean oil at an oil-water ratio of 1:4 / 1:9 (volume ratio), and homogenized at 10,000 r / min for 2 min using a homogenizer to obtain a crude emulsion, which was then subjected to three cycles of high-pressure homogenization at a pressure of 40-60 MPa to obtain the LBG-SPI emulsion. The SPI-stabilized emulsion was used as the control group.

[0007] The preferred condition is that the optimal concentration of LBG is 0.6% (w / v); The preferred condition is that the optimal stirring time is 2 h; The preferred condition is that the optimal oil-water ratio is 1:4; The preferred condition is that the optimal high-pressure homogenization pressure is 50 MPa.

[0008] The SPI prepared by the method of the present invention has better emulsification properties. The emulsification activity of the SPI treated with LBG mass concentration of 0.6% (w / v) is increased by 1.59 times, the emulsification stability is increased by 1.13 times, the particle size is increased by 4.62 times, and the absolute value of Zeta potential is increased by 1.21 times.

[0009] The above preparation method can obtain SPI emulsion with good emulsification properties, further expanding the application value of SPI. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Attached Figure 1 Flow chart of this method; Attached Figure 2 Particle size and potential of soy protein isolate solution after adding LBG; Attached Figure 3 Emulsifying activity and emulsifying stability of soy protein isolate emulsion after adding LBG. DETAILED DESCRIPTION

[0011] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0012] A method for improving the emulsifying properties of a soy protein isolate emulsion by using locust bean gum as a compound. The method comprises the following steps: (1) preparing a soy protein isolate (SPI) solution: dispersing SPI powder in deionized water to prepare a solution with a protein concentration of 2%, and stirring at room temperature to dissolve the solution completely, thereby obtaining a SPI solution; (2) preparing a locust bean gum (LBG) solution: dispersing locust bean gum powder in deionized water to prepare a LBG solution with a concentration of 0.2-0.8% (w / v); (3) preparing an LBG-SPI solution: adding LBG with a mass concentration of 0.2-0.8% (w / v) prepared in step (2) to the SPI solution prepared in step (1), respectively, and stirring for 2 h, thereby obtaining a LBG-SPI solution; (3) preparing an LBG-SPI emulsion: adding soybean oil to the LBG-SPI solution prepared in step (2) at an oil-water ratio of 1:4 (volume ratio), and homogenizing the solution using a homogenizer at 10,000 r / min for 2 h. min to obtain a crude emulsion, which was then subjected to three cycles of high-pressure homogenization at a pressure of 50 MPa to obtain the LBG-SPI emulsion. The SPI-stabilized emulsion was used as the control group. Experimental Case 1

[0013] 8 g of SPI powder was dispersed in 400 mL of deionized water to prepare a solution with a protein concentration of 2% (w / v), and stirred at room temperature to dissolve it completely, which was the SPI solution. No LBG was added. The SPI solution was added with soybean oil at an oil-water ratio of 1:4 (volume ratio), and homogenized at 10,000 r / min for 2 min using a homogenizer to obtain a crude emulsion, which was then subjected to 3 cycles of high-pressure homogenization at a pressure of 50 MPa to obtain the SPI emulsion, which served as the control group. The emulsifying activity obtained at this time was 13.59 m 2 / g, the emulsification stability is 85.40%, the particle size is 152.8 nm, and the Zeta potential value is -36.10 mv. Experimental Case 2

[0014] 8 g of SPI powder was dispersed in 400 mL of deionized water to prepare a solution with a protein concentration of 2% (w / v), and stirred at room temperature to dissolve it completely, which is the SPI solution. LBG with a mass concentration of 0.2% (w / v) was added to the SPI solution and stirred for 2 h to obtain the LBG-SPI solution; soybean oil was added to the LBG-SPI solution at an oil-water ratio of 1:4 (volume ratio), and a homogenizer was used to homogenize at 10,000 r / min for 2 min to obtain a crude emulsion, which was then subjected to 3 cycles of high-pressure homogenization at a pressure of 50 MPa to obtain the LBG-SPI emulsion. The emulsification activity obtained by the treatment was increased by 1.02 times, the emulsification stability was increased by 1.04 times, the particle size was increased by 2.24 times, and the absolute value of the Zeta potential was increased by 1.04 times. Experimental case 3

[0015] 8 g of SPI powder was dispersed in 400 mL of deionized water to prepare a solution with a protein concentration of 2% (w / v), and stirred at room temperature to dissolve it completely, which was the SPI solution. LBG with a mass concentration of 0.4% (w / v) was added to the SPI solution and stirred for 2 h to obtain the LBG-SPI solution. Soybean oil was added to the LBG-SPI solution at an oil-water ratio of 1:4 (volume ratio), and a homogenizer was used to homogenize at 10,000 r / min for 2 min to obtain a crude emulsion, which was then subjected to three cycles of high-pressure homogenization at a pressure of 50 MPa to obtain the LBG-SPI emulsion. At this time, the emulsification activity increased by 1.36 times, the emulsification stability increased by 1.36 times, the particle size increased by 1.05 times, and the absolute value of the Zeta potential increased by 1.15 times. Experimental Case 4

[0016] 8 g of SPI powder was dispersed in 400 mL of deionized water to prepare a solution with a protein concentration of 2% (w / v), and stirred at room temperature to dissolve it completely, which was the SPI solution. LBG with a mass concentration of 0.6% (w / v) was added to the SPI solution and stirred for 2 h to obtain the LBG-SPI solution. Soybean oil was added to the LBG-SPI solution at an oil-water ratio of 1:4 (volume ratio), and a homogenizer was used to homogenize at 10,000 r / min for 2 min to obtain a crude emulsion, which was then subjected to three cycles of high-pressure homogenization at a pressure of 50 MPa to obtain the LBG-SPI emulsion. At this time, the emulsification activity increased by 1.60 times, the emulsification stability increased by 1.13 times, the particle size increased by 4.62 times, and the absolute value of the Zeta potential increased by 1.21 times. Experimental Case 5

[0017] 8 g of SPI powder was dispersed in 400 mL of deionized water to prepare a solution with a protein concentration of 2% (w / v), and stirred at room temperature to dissolve it completely, which was the SPI solution. LBG with a mass concentration of 0.8% (w / v) was added to the SPI solution and stirred for 2 h to obtain the LBG-SPI solution. Soybean oil was added to the LBG-SPI solution at an oil-water ratio of 1:4 (volume ratio), and a homogenizer was used to homogenize at 10,000 r / min for 2 min to obtain a crude emulsion, which was then subjected to three cycles of high-pressure homogenization at a pressure of 50 MPa to obtain the LBG-SPI emulsion. At this time, the emulsification activity increased by 1.50 times, the emulsification stability increased by 1.12 times, the particle size increased by 1.31 times, and the absolute value of the Zeta potential increased by 1.02 times.

Claims

1. A method for improving the emulsifying properties of soy protein isolate emulsion by using locust bean gum, the method comprising the following steps: (1) Preparation of soy protein isolate (SPI) solution: SPI powder was dispersed in deionized water to prepare a solution with a protein concentration of 2% (w / v), and stirred at room temperature to completely dissolve the solution, thereby obtaining the SPI solution. (2) Preparation of locust bean gum (LBG) solution: Locust bean gum powder was dispersed in deionized water to prepare a 0.2-0.8% (w / v) LBG solution; (3) Preparation of LBG-SPI solution: add an equal volume of 0.2-0.8% (w / v) LBG solution prepared in step (2) to the SPI solution prepared in step (1), and stir for 1-3 h to allow the two to fully recombine to obtain the LBG-SPI solution; (4) Preparation of LBG-SPI emulsion: The LBG-SPI solution prepared in step (3) was added with soybean oil at an oil-water ratio of 1:4 / 1:9 (volume ratio), and homogenized at 10,000 r / min for 2 min using a homogenizer to obtain a crude emulsion, which was then subjected to three cycles of high-pressure homogenization at a pressure of 40-60 MPa to obtain the LBG-SPI emulsion. The SPI-stabilized emulsion was used as the control group.

2. The method for improving the emulsifying properties of soy protein isolate emulsion by using locust bean gum as a composite according to claim 1, characterized in that: The optimal concentration of LBG was 0.6% (w / v).

3. The method for improving the emulsifying properties of soy protein isolate emulsion by using locust bean gum as a composite according to claim 1, characterized in that: The optimal stirring time is 2 h.

4. The method for improving the emulsifying properties of soy protein isolate emulsion by using locust bean gum as claimed in claim 1, characterized in that: The best oil-water ratio is 1:

4.

5. The method for improving the emulsifying properties of soy protein isolate emulsion by using locust bean gum as claimed in claim 1, characterized in that: The optimal high-pressure homogenization pressure is 50 MPa.

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