Study on Emulsification Process Parameters of Forage Soybean Powder Oil

The powdered fat is added to a common liquid oil, a hardened oil or a semi-hardened fat to form a film-like component protein, a carbohydrate, a saccharide or the like, and after being emulsified, it is spray-dried in a high-temperature air stream to expand Evaporation surface area, a powdered fat product obtained by a transient drying method (Zhao Guozhi et al., 2005). Compared with liquid oil, powdered fat has the following advantages: 1 can exert the functional properties of oil; 2 can greatly increase the content of feed oil, increase the energy concentration of animal diet, and provide the best fatty acid composition for various animals; The external environment (heat, light, water, etc.) damages the active ingredients, prevents deterioration and loss, even in the summer high temperature season, it will not cause the rancidity of the feed, greatly extending the shelf life; 4 the active ingredients are evenly dispersed in the formula feed, digestion and absorption The rate is increased. In particular, oils, vitamins, trace elements, and bioactive substances and feed active ingredients are processed by high pressure homogenization to become micron fine particles, which are uniformly dispersed in the feed, easy to digest and absorb, and improve the bioavailability and utilization rate of the feed (Xiong Hua Zheng Wei, 2003).

The microencapsulated powdered fat is a new type of solid fat product prepared by encapsulating a core material in a wall material by using a grease as a core material, selecting a suitable wall material, and microcapsule technology (Huang Xiujuan, 2006). The emulsification process is an important process for the formation of microcapsules. In order to obtain an emulsion with good emulsion stability, this experiment uses soybean oil as the core material, chitosan and maltodextrin as wall materials, emulsifier ratio and emulsifier dosage. The emulsification process parameters were studied and laid the foundation for the production of feed soybean powder by spray drying.

1 Materials and methods

1.1 Test materials and instruments

1.1.2 Test materials

Soybean oil GB1535, Hubei Zhongchang Vegetable Oil Co., Ltd.; Chitosan, Hubei Yufeng Bio-engineering Co., Ltd.; Maltodextrin, Mengzhou Xinyuan Co., Ltd.; Sucrose fatty acid ester S-13, Hangzhou Ruisen Chemical Co., Ltd. Molecular distillation of glyceryl monostearate, Dongguan Xinshi Essence Co., Ltd., all food grade.

1.1.2 Test equipment

Analytical balance; JJ-2 organization mashing homogenizer; electric thermostatic water bath.

1.2 Preparation of feed soybean powder grease emulsion

Weigh 3g of chitosan in a beaker, add 100ml of 5% acetic acid solution, weigh 30g of maltodextrin and a certain amount of sucrose ester in a beaker, add 200ml of deionized water, and mix the two solutions into a wall material solution; In a 70 ° C water bath, a certain amount of monoglyceride dissolved in 30 ml of soybean oil into a core solution; under stirring, the core solution was added dropwise to the wall material solution, placed in the tissue mashing and homogenizing machine The emulsion was emulsified for 10 min to form an O/W emulsion, and the emulsion stability was measured.

1.3 Evaluation of emulsion stability

The stratified volume method was used: the emulsion was poured into a test tube with a scale, and allowed to stand at room temperature for 6 hours to observe the stratification and calculate the emulsion stability (Xue Wentong, 2004; Yilmaz G, 1999)

Stratified volume (ml)

Emulsification stability (%) = —————————————— × 100%

Total emulsion volume (ml)

2 results and discussion

2.1 Single factor test

2.1.1 Effect of different emulsifier ratios on emulsion stability

An emulsifier is a substance which can uniformly disperse two or more mutually incompatible liquids into an emulsion. The difference in emulsifying ability of emulsifiers is generally expressed by HLB. An emulsifier with a lipophilicity of 100% is specified, and its HLB value is 0, and the hydrophilicity is 100%, which is 20, which is divided into 20 equal parts, thereby indicating its hydrophilicity, lipophilic performance and application characteristics (Zhang Jiacheng, 1997). ). In China, sucrose fatty acid esters (sucrose esters) and molecularly distilled monoglycerides (monoglycerides) are generally used as emulsifiers for the production of powdered fats and oils (Zhu Xuntao, 1998). In this experiment, monoglyceride and sucrose ester were used as emulsifiers, and the mass ratios of monoglyceride and sucrose ester were selected to be 0:10, 1:9, 2:8, 3:7, 4:6, 5:5, respectively. As a composite emulsifier, the emulsion ratio is determined as the measurement index, and the optimum ratio of emulsifier is determined. At the same time, the optimal hydrophilic-lipophilic balance (HLB) of the emulsion can be obtained. The effects of different emulsifier ratios on HLB value and emulsion stability are shown in Table 1.

Table 1 Effect of different emulsifier ratios on HLB value and emulsion stability

mA × HLBA+mB ×HLBB

Note: HLB = ————————————— (Li Yanhui, 2005)

mA+mB

Where: HLB - Hydrophilic lipophilic balance

mA, mB - the mass of A and B in the composite emulsifier;
HLBA, HLBB - HLB value when A and B are used alone in the composite emulsifier.

It can be seen from Table 1 that when the mass ratio of monoglyceride to sucrose ester is 1:9, that is, the HLB value is 12.1, the emulsion stability of the emulsion with chitosan and maltodextrin as the wall material is the best. Thus, the optimum mass ratio of monoglyceride to sucrose ester is 1:9 and the HLB value is 12.1.

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2.1.2 Effect of emulsifier addition on emulsion stability

Using 1:9 monoglyceride and sucrose ester as emulsifier, the stability of the emulsion was determined when the amount of emulsifier added was 0.25%, 0.5%, 1%, 1.5%, 2%, 3%, 4%, respectively. The optimum amount of emulsifier added. The test results show that when the emulsifier content is less than 1%, the emulsion stability is less than 100%, and the emulsion stability of the emulsion is 100% when it is more than 1%, so the emulsion for emulsifying the wall material and the core material in the test. The amount of the agent added was 1%.

2.1.3 Effect of emulsification temperature on emulsion stability

The wall material contains chitosan, one of its characteristics is that the viscosity decreases with increasing temperature. According to the Stokes formula, the sedimentation speed of the particles is inversely proportional to the viscosity. The smaller the viscosity, the higher the sedimentation speed, that is, the more the emulsion It is easy to produce delamination, so appropriately lowering the emulsification temperature can improve the emulsion stability. If the temperature is too low, the viscosity will be too large, the interparticle resistance will be too large, and it is difficult to mix and emulsify. The emulsification temperatures were selected to be 30, 40, 50, 60, 70, and 80 ° C, respectively, and the emulsion stability was measured. The results are shown in Fig. 2 .

It can be seen from Fig. 2 that the emulsion stability is best when the emulsification temperature is 70 °C.

2.1.4 Effect of emulsification time on emulsion stability

As the emulsification time is prolonged, the viscosity of the emulsion is lowered, and the emulsion stability is deteriorated. In the emulsification process, the particle size of the oil droplets is also continuously reduced, the sedimentation speed is also reduced, and the emulsion stability is increased. The emulsification time should not be too short, otherwise the wall material that is not sufficiently hydrated will not be evenly dispersed. In this experiment, the emulsification time was 1, 3, 5, 10, 15 min, and the emulsion stability was determined. The emulsion stability was better when the emulsification time was 10 min.

2.1.5 Effect of wall material content on emulsion stability

As the content of the wall material increases, the viscosity of the continuous phase increases, the stability of the emulsion is better, and the microcapsule product is easy to form a shell during the drying process, thereby improving the quality and embedding effect of the product, and the microencapsulation efficiency is also Rise. However, as the content is further increased, the viscosity is increased and the difficulty of spray drying is increased. High-viscosity emulsions do not easily form uniform, spherical particles during spraying, and can also cause sticking. The viscosity is too high, which can lead to an increase in the moisture content of the product, which is so fast in film formation that moisture cannot be removed from the inside. Discharges and creates an internal pressure that affects the formation of the film. In the test, when the wall material content reaches 20%, the sticking wall phenomenon occurs, and when the wall material content reaches 25%, due to the large viscosity of the solution and poor fluidity, there is a blockage phenomenon when the spray drying atomizer occurs, which seriously affects The quality and effectiveness of microcapsule products. Therefore, the test selected wall material content was 15%.
2.1.6 Effect of wall material ratio on emulsion stability

Chitosan has the function of surfactant, can adsorb to the oil-water interface, and its interfacial tension is slightly reduced, so it is easy to form an emulsion. The emulsified oil droplets are stabilized by the protein adsorbed on the surface of the oil droplets, forming a viscoelastic interface. The membrane prevents the accumulation of oil droplets and the emulsion breaking of the emulsion (Chen Tian, ​​2000). Maltodextrin (MD) is a white powder or granule, slightly absorbent, non-sweet or slightly sweet, has nutritional value, is easy to dissolve, does not have emulsifying ability, and has poor film forming ability, but has low viscosity at high concentration. The combination with chitosan can increase the solids concentration of the system, help reduce drying energy consumption and reduce production costs. It can also be used as a filler to increase the strength and compactness of the microcapsules. The permeability of the interfacial film in the emulsion is related to the viscosity of the film and the tightness of the arrangement of the adsorbed molecules. The greater the viscosity, the smaller the permeability ( Hao Liping, 2004). In order to obtain a stable emulsion and a high microencapsulation efficiency, the mass ratio of chitosan to maltodextrin in the wall material should be suitable, and too high and too low is not conducive to the stability of the emulsion. The mass ratio of chitosan to maltodextrin was 1:5, 1:10, 1:15, 1:20, 1:25, and the emulsion stability was determined. The mass ratio of chitosan to maltodextrin was 1 : 5 when the emulsion stability is the best.

2.2 Study on the emulsification process parameters of chitosan and maltodextrin as wall materials

In order to study the effect of different factors on the emulsion stability, the emulsion temperature, emulsification time, wall material content and wall were compared under the condition that the mass ratio of monoglyceride to sucrose ester was 1:9 and the amount of emulsifier added was 1%. Four factors and three levels of orthogonal test were carried out for factors such as material ratio. The test design is shown in Table 2. The test results and analysis are shown in Tables 3 and 4, respectively.

Table 2 Emulsification Process Orthogonal Experiment L9 (34) Factor Level Table

Note: The ratio of wall material in the table is the mass ratio of chitosan to maltodextrin.

Table 3 Orthogonal test results of emulsification process

Table 4 emulsification process orthogonal test analysis results

It can be seen from Table 4 that according to the range of the range R, the order of the factors affecting the index is: C > A > B > D, ie wall material content > emulsification temperature > emulsification time > wall material ratio. The optimum emulsification process parameters are A2B3C2D1, ie the emulsification temperature is 60 ° C, the emulsification time is 10 min, the wall material content is 10%, and the wall material ratio (chitosan: maltodextrin) is 1:10. Under this condition, the most Good emulsification effect.

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3 conclusions

3.1 Using chitosan and maltodextrin as wall materials, the monoglyceride and sucrose ester were compounded to determine the mass ratio of monoglyceride to sucrose was 1:9, and the HLB value was 12.1.

3.2 When chitosan and maltodextrin are used as wall materials, when the 1:9 monoglyceride and sucrose ester are used as emulsifiers, the amount of emulsifier added is 1%.

3.3 Chitosan and maltodextrin are used as wall materials, 1:9 monoglyceride and sucrose ester are used as emulsifiers, and the amount of emulsifier added is 1%. Using the emulsification temperature, emulsification time, wall material content and wall material ratio as the influencing factors, the optimal emulsification condition was A2B3C2D1, ie the emulsification temperature was 60 °C, using the L9(34) orthogonal table. For 10 min, the wall material content is 10%, and the wall material ratio (chitosan: maltodextrin) is 1:10, and the best emulsification effect is obtained under these conditions.