CN109938328B

CN109938328B - Method for preparing fat substitute by regulating and controlling oil drop aggregation in emulsion through flaxseed gum

Info

Publication number: CN109938328B
Application number: CN201910263703.6A
Authority: CN
Inventors: 刘骞; 曹传爱; 孔保华; 贾惜文; 赵神彳
Original assignee: Northeast Agricultural University
Current assignee: Northeast Agricultural University
Priority date: 2019-04-03
Filing date: 2019-04-03
Publication date: 2022-04-29
Anticipated expiration: 2039-04-03
Also published as: CN109938328A

Abstract

A method for preparing fat substitute by regulating and controlling oil drop aggregation in emulsion with flaxseed gum is provided. This study is directed to the fact that fat is an essential component of our daily diet and plays an important role in determining the physicochemical and organoleptic properties of food products (particularly some emulsion-based food products: such as mayonnaise). However, scientific studies have shown that the intake of excessive fat is dangerous to health, and therefore a method for preparing a fat substitute by controlling the aggregation of oil droplets in an emulsion using flaxseed gum is characterized in that Whey Protein Isolate (WPI) and Whey Protein Concentrate (WPC) were the subjects of the research, and the influence of heat pretreatment (90 ℃, 5min) on the physical stability of oil-in-water (O/W) emulsions during storage was investigated; then, the emulsion is used as a substrate, the influence of the linseed gum and different environmental pH values on the aggregation of oil drops in the whole mixed system is researched, and the fat substitute with the best effect is screened out.

Description

Method for preparing fat substitute by regulating and controlling oil drop aggregation in emulsion through flaxseed gum

Technical Field

The invention relates to a method for preparing a fat substitute by regulating and controlling oil drop aggregation in an emulsion by using flaxseed gum, belonging to the technical field of food.

Background

The oil and fat can endow food with unique flavor, smooth mouthfeel, certain tissue state and good stability, and simultaneously the oil and fat in the food can provide 37.3kJ/g of energy, so that the oil and fat is one of important sources for obtaining energy by a human body. However, studies have shown that high calorie food threatens human health and is prone to cause obesity and a series of cardiovascular and cerebrovascular diseases. Therefore, development and application of low-fat food are receiving wide attention. However, when fat is removed, undesirable changes in the appearance, aroma, mouthfeel and texture of the product occur, and the viewer acceptance and commercial success of low-fat foods is limited. In order to meet the market demand and improve the acceptance of consumers, the fat simulant is developed and developed, and the fat content in the food is reduced to the maximum extent on the basis of keeping the original flavor and taste of the food.

The fat simulant is prepared from protein or carbohydrate as main raw material, and is added into food after being treated by certain physical method to simulate partial characteristics of fat and replace fat substance. The fat simulant can improve the structural characteristics of the water phase, induce the gel to form a three-dimensional network structure, capture water, and increase the viscosity of the product, and produce the mouthfeel and texture similar to fat, wherein the captured water has better fluidity. Thus, maintaining high viscosity and gel-like properties in low fat emulsions can be achieved by inducing aggregation of the fat droplets to form a three-dimensional network.

In general, the aggregation state of fat droplets can be controlled by varying the relative magnitudes of the attractive and repulsive forces between the droplets. Such as electrostatic forces, steric hindrance, hydrophobic forces, depletion and bridging. This can be achieved by the nature of the droplet surface (e.g. surface hydrophobicity, thickness, or potential), the solution conditions (e.g. pH and ionic strength), the system components (e.g. type and concentration of biopolymer) and the environmental conditions (e.g. temperature). For protein-coated fat droplets, aggregation can be induced in the following manner: (i) adjusting the pH to about the isoelectric point (pI); (ii) increasing the ionic strength; (iii) heating to a temperature above the thermal denaturation temperature; (iv) adding the adsorbed biopolymer; (v) non-adsorbed biopolymer is added.

Disclosure of Invention

The invention aims to provide a method for preparing a fat substitute by regulating and controlling oil drop aggregation in an emulsion by using linseed gum. The invention takes Whey Protein Isolate (WPI) and Whey Protein Concentrate (WPC) as research objects, and researches the influence of heat pretreatment (90 ℃, 5min) on the physical stability of oil-in-water (O/W) emulsion during storage; then, the emulsion is used as a substrate, the influence of the linseed gum and different environmental pH values on the aggregation of oil drops in the whole mixed system is researched, and the fat substitute with the best effect is screened out.

The purpose of the invention is realized by the following technical scheme:

a method for preparing fat substitute by regulating and controlling oil drop aggregation in emulsion with flaxseed gum is provided. The method comprises the following steps: the preparation method comprises the following steps of preparing an emulsion, preparing a flaxseed gum-emulsion mixture, preparing a flaxseed gum-cassava modified starch mixture, and preparing a flaxseed gum-cassava modified starch granule-emulsion mixture.

Detailed Description

The first embodiment is as follows: weighing a certain amount of Whey Protein Isolate (WPI) powder, dispersing in deionized water, and stirring for at least 1h at room temperature by using a magnetic stirrer to fully dissolve the WPI powder to prepare 4% (w/v) of protein dispersion liquid. The WPI protein dispersion was divided into two equal volumes, one of which was heated in a water bath at 90 ℃ for 5min and then rapidly cooled to room temperature after removal, as Pre-heated whey protein isolate (H-WPI). Whey Protein Concentrate (WPC) and Pre-heated whey protein concentrate (H-WPC) dispersions were prepared in the same manner. 90mL of each of these four protein dispersions was mixed with 10mL of rapeseed oil and homogenized for 2min at 13500rmp using an Ultra-Turrax homogenizer to obtain an emulsion. The resulting emulsion was homogenized under 40MPa, and the homogenized solution (fresh emulsion) was stored at 4 ℃ for 0, 1, 4, 7, 10, and 14 days, respectively, and measured. The four proteins were used as emulsifiers and mixed with the oil phase (rapeseed oil) in a ratio (24:1) and homogenized using a homogenizer at 15,000rpm for 2min to prepare an oil-in-water emulsion. A stock solution of polysaccharide (0.5%, w/v) was prepared by dispersing the flaxseed gum powder into deionized water and stirring overnight at room temperature to ensure complete hydration. And step two, mixing the emulsions (10%, w/v) in different proportions, the linseed gum stock solution and deionized water to prepare linseed gum-emulsion mixtures with the same oil content (2%, w/v) but different linseed gum concentrations. After mixing, the pH of the mixture was adjusted to 3.0, 5.0, 7.0 using 1M HCl or 1M NaOH, then the mixture was placed in a 90 ℃ water bath and heated with constant stirring for 5min, after which it was rapidly cooled to room temperature. And step three, preparing cassava modified starch dispersion liquid (3 percent, w/v) containing different concentrations of the flaxseed gum by mixing a certain amount of cassava modified starch powder, the flaxseed gum stock solution and deionized water. After mixing, the pH of the mixture was adjusted to 3.0, 5.0, 7.0 using 1M HCl or 1M NaOH, then the mixture was placed in a 90 ℃ water bath and heated with constant stirring for 5min, after which it was rapidly cooled to room temperature. Step four, preparing mixed systems with the same oil content (2%, w/v) but different linseed gum concentrations by mixing the emulsions (10%, w/v) and the linseed gum stock solution water-denatured tapioca starch (3%, w/v) in different proportions and deionization. After mixing, the pH of the mixture was adjusted to 3.0, 5.0, 7.0 using 1M HCl or 1M NaOH, then the mixture was placed in a 90 ℃ water bath and heated with constant stirring for 5min, after which it was rapidly cooled to room temperature.

The second embodiment is as follows: the difference between this embodiment and the first embodiment is that the concentration of the flaxseed gum in the flaxseed gum-emulsion mixture is 0, 0.005, 0.01, 0.015, 0.02%, w/v.

The third concrete implementation mode: the difference between the present embodiment and the first embodiment is that the concentrations of flaxseed gum in the mixed liquid of flaxseed gum and tapioca modified starch are 0, 0.005, 0.01, 0.015, 0.02%, w/v.

The fourth concrete implementation mode: the difference between this embodiment and the first embodiment is that the concentrations of the flaxseed gum in the emulsion (10%, w/v) and the flaxseed gum stock solution water-denatured tapioca starch (3%, w/v) mixed system are 0, 0.005, 0.01, 0.015, 0.02%, w/v.

TABLE 3-1 distribution of emulsifier in aqueous phase under different treatment conditions

Tab.3-1 Partitioning of emulsifier in the aqueous solution under different treatment conditions

Note:^A-Dindicates significant differences (p) in the same column<0.05), the following are the same

Table 3-1 shows the distribution of WPI, H-WPI, WPC, and H-WPC in the water phase and the oil-water interface after 14 days of storage. As can be seen from Table 3-1, the content of WPI in the aqueous phase was slightly higher than that of H-WPI, namely 80.90 + -1.31% and 73.96 + -1.04%, respectively, and the difference therebetween was significant (p <0.05), and the content of WPC in the aqueous phase was also higher than that of H-WPC, namely 85.59 + -2.10% and 68.40 + -1.08%, respectively, and the difference therebetween was significant (p < 0.05). The distribution coefficients of the H-WPI and the H-WPC at the oil-water interface are respectively 3.17 and 4.16, which are higher than the distribution coefficients of the WPI (2.13) and the WPC (1.52) at the oil-water interface. Peng et al tested pea protein stabilized emulsions that were pre-treated with heat (90 ℃, 30min) and showed that at the same protein concentration, the protein adsorption of the heat-treated emulsion was higher than that of the unheated emulsion, which is also consistent with Li et al that the pre-heated soy protein emulsion adsorbed a higher percentage of protein than the unheated protein emulsion.

TABLE 3-2 Effect of flaxseed gum of different concentrations on the particle size of the MCS + FG + emulsion mixing System under different pH conditions

Tab.3-2 The average particle size d_4,3 of mixed MCS+FG+emulsion dispersions containing various flaxseed gum levels at different pH(3.0,5.0 and 7.0)

Note:^A-Crepresenting significance in the same columnSexual difference (p)<0.05)，^a-cRepresenting significant differences (p) in the same line<0.05)

TABLE 3-3 Effect of flaxseed gum of different concentrations on the particle size of MCS + emulsion mixing System under different pH conditions

Tab.3-3 The average particle size d_4,3 of mixed MCS+emulsion dispersions containing various flaxseed gum levels at different pH(3.0,5.0and 7.0)

Note:^A-Cindicates significant differences (p) in the same column<0.05)，^a-cRepresenting significant differences (p) in the same line<0.05)

Adding different concentrations of flaxseed gum (0, 0.01 and 0.02%, w/v) to the average droplet diameter (d) of the mixed system at different pH values (3.0, 5.0 and 7.0)_4,3) The effects of (A) are shown in tables 3-2 and 3-3. As can be seen from tables 3-2 and 3-3, at pH 3.0, with an accompanying increase in the concentration of flaxseed gum from 0% (w/v) to 0.02% (w/v), after addition of tapioca modified starch (3%, w/v), d of a mixed system prepared with four proteins as emulsifiers_4,3Are all remarkably increased (p)<0.05); a similar trend was also observed at pH 5.0; and d of the mixed system at pH 7.0_4,3Slightly, but not significantly, with increasing flax concentration (p)>0.05) because under this pH condition, a repulsive force acts dominantly between the droplets, thereby suppressing the oil droplets from aggregating. When the concentration of the flaxseed gum and the emulsifier are constant, the mixed system has the maximum d at the pH of 5.0_4,3Value, and d at pH 7.0_4,3The values are minimal and similar changes are observed in the two-component mixing system without the addition of tapioca modified starch (3%, w/v). D of the two-component mixing system without addition of starch (3%, w/v) compared to the three-component mixing system with addition of tapioca modified starch (3%, w/v)_4,3The value is relatively small. Furthermore, d of a mixed system comprising H-WPC or H-WPI is compared to a mixed system comprising WPC or WPI_4,3And higher. And comprising H-WPI stabilizationOf the mixed system of emulsions_4,3Maximum, WPI-stable mixed system d_4,3The minimum value indicates that the particle size of the prepared mixed system is larger after the protein is subjected to preheating treatment.

TABLE 3-4 Effect of flaxseed gum of different concentrations on the optical Properties of the MCS + FG + emulsion mixing System at different pH conditions

Tab.3-4 The optical properties of mixed MCS+FG+emulsion dispersions containing various flaxseed gum levels at different pH(3.0,5.0and 7.0)

Note: same letter indicates that the difference is not significant (p >0.05)

TABLE 3-5 Effect of flaxseed gum of different concentrations on the optical Properties of MCS + emulsion mixing System under different pH conditions

Tab.3-5 The optical properties of mixed MCS+emulsion dispersions containing various flaxseed gum levels at different pH(3.0,5.0and7.0)

Note: same letter indicates that the difference is not significant (p >0.05)

In this series of experiments we investigated the effect of flaxseed gum concentration (0, 0.005, 0.010, 0.015 and 0.020%, w/v) on the optical properties of the mixed system at different pH conditions (tables 3-4 and 3-5). The L-value is a measure of brightness. As can be seen from tables 3-4 and 3-5, the L-value of the mixed system is slightly decreased with the increase of the flaxseed gum concentration at a certain pH value and emulsifier, and the difference is not significant (p > 0.05). For the same emulsifier, at a constant linseed gum concentration, the mixed systems had the smallest L-values (L > 23%) at pH 5.0, similar and relatively larger L-values (L > 26%) at pH 3.0 and pH 7.0. The corresponding two-component mixed system had a larger value of L-than the three-component mixed system, and Wu et al gave similar experimental results. Furthermore, we have found that at certain pH values and flaxseed gum concentrations, the L-values of the three-component and two-component mixed systems containing WPI are very similar to the L-values of the corresponding three-component and two-component mixed systems containing H-WPI, and that similar phenomena are observed in the three-component and two-component mixed systems containing WPC or H-WPC and are slightly greater than the L-values of the mixed systems containing WPI or H-WPI (p > 0.05).

Claims

1. A method for preparing a fat substitute by regulating and controlling oil drop aggregation in emulsion by using flaxseed gum is characterized by comprising the following steps:

weighing a certain amount of whey protein isolate WPI powder, dispersing the whey protein isolate WPI powder in deionized water, and stirring the mixture for at least 1 hour at room temperature to fully dissolve the whey protein isolate WPI powder to prepare 4% w/v protein dispersion liquid; dividing the WPI protein dispersion into two parts with equal volume, heating one part in water bath at 90 deg.C for 5min, taking out, and rapidly cooling to room temperature to obtain preheated whey protein isolate H-WPI; preparing WPC and pre-heated WPC dispersion by the same method; respectively mixing 90mL of the four protein dispersions with 10mL of rapeseed oil, and homogenizing for 2min at 13500rpm by using an Ultra-Turrax homogenizer to prepare an emulsion; homogenizing the resulting emulsion at 40MPa to prepare a 10% w/v emulsion; preparing a 0.5% w/v stock solution of flaxseed gum by dispersing flaxseed gum powder in deionized water and stirring overnight at room temperature to ensure complete hydration;

step two, preparing a linseed gum-emulsion mixture with the same oil content of 2% w/v by mixing 10% w/v of the emulsion, 0.5% w/v of a linseed gum stock solution and deionized water; after mixing, the pH of the mixture was adjusted to 3.0 using 1M HCl, then the mixture was placed in a 90 ℃ water bath and heated with constant stirring for 5min, then rapidly cooled to room temperature;

the concentration of the flaxseed gum in the flaxseed gum-emulsion mixture is 0.01%, w/v.