A composite additive for improving the stability of colored milk and its use and application

Abstract

The application relates to a composite additive for improving the stability of fancy milk, a preparation method and application, and belongs to the technical field of food preparation. In order to solve the problem of poor shelf life stability of the existing fancy milk product, the application provides a composite additive for improving the stability of fancy milk. Through specific compounding of emulsifiers and stabilizers, the synergistic effect of each component is fully exerted, the total amount and the number of categories of the additive are greatly reduced under the premise of guaranteeing excellent stability effect, the interfacial stability of milk protein is effectively enhanced, fat floating and protein precipitation are inhibited, the shelf life is significantly prolonged, and scientific basis and data support are provided for quality improvement and realization of a clean label of the fancy milk product in industrial production.

Description

Technical Field

[0001] This invention belongs to the field of food preparation technology, and in particular relates to a compound additive for improving the stability of flavored milk, its usage method and application. Background Technology

[0002] Due to their complex composition, flavored milk products are prone to instability during processing and storage, such as fat floating and protein flocculation, leading to nutrient loss and flavor degradation. Currently, industrial manufacturers typically regulate system stability by adding emulsifiers and stabilizers. These additives are mostly chemical substances that can effectively improve product stability by adjusting rheological properties and interfacial properties.

[0003] However, existing research largely focuses on the mechanisms of action of single additives, lacking a systematic exploration of the synergistic effects of components in compound additive formulations. Meanwhile, with consumers' increasing demand for health products, developing formulations with the fewest types and lowest dosages of additives, suitable for flavored milk systems, has become a key direction for industry development. Ensuring product shelf-life stability while reducing the types or amounts of emulsifiers and stabilizers used has become a pressing industry challenge. Summary of the Invention

[0004] To address the problem of poor shelf-life stability of flavored milk products in the prior art, this invention provides a compound additive for improving the stability of flavored milk, along with its usage and application.

[0005] One of the objectives of this invention is to provide a composite additive for improving the stability of flavored milk. The composite additive is composed of an emulsifier and a stabilizer. The emulsifier is a mono- or diglyceride fatty acid ester, and the stabilizer is carrageenan.

[0006] The second objective of this invention is to provide the application of the above-mentioned composite additive in improving the stability of flavored milk systems.

[0007] In a preferred embodiment of the present invention, the step of the composite additive improving the stability of the flavored milk system is as follows: the above-mentioned composite additive is softened, the softened composite additive is added to the preheated initial sample of flavored milk and mixed evenly, and then homogenized, sterilized, cooled, and filled into a storage tank to obtain the finished flavored milk product.

[0008] In a preferred embodiment of the present invention, the softening treatment step is as follows: the composite additive is placed in water at 40-50°C for softening and stirred until completely dissolved.

[0009] In a preferred embodiment of the present invention, the preheating temperature of the flavored milk sample is 55-65°C.

[0010] In a preferred embodiment of the present invention, the amount of the composite additive added is 0.7-1.2 g / L of the total volume of the initial sample of the flavored milk.

[0011] In a preferred embodiment of the present invention, the homogenization conditions are: homogenization temperature of 80-90°C and homogenization pressure of 18-24 MPa.

[0012] In a preferred embodiment of the present invention, the sterilization conditions are: sterilization temperature of 135-137°C and sterilization time of 4 seconds.

[0013] In a preferred embodiment of the present invention, the cooling conditions are: cooling down to a temperature of 15-20°C.

[0014] In a preferred embodiment of the present invention, the storage tank is an ultra-clean tank.

[0015] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention provides a compound additive for improving the stability of flavored milk. Through the specific combination of emulsifiers and stabilizers, the synergistic effect of each component is fully utilized, significantly reducing the total amount and variety of additives used while ensuring excellent stability. The synergistic effect of the compounded emulsifiers and stabilizers effectively enhances the stability of the milk protein interface, inhibits fat rising and protein precipitation, and significantly extends shelf life. The compound additive provided by this invention is suitable for various flavors and sterilization processes, effectively maintaining the product's color, flavor, and taste under different heat treatment conditions, significantly enhancing market competitiveness.

[0016] This invention systematically evaluates the shelf-life stability of flavored milk products by optimizing emulsifier and stabilizer formulations at the front end. It indicates shelf-life stability at multiple scales, including molecular structure, interfacial properties, droplet characteristics, and macroscopic stability. Through the optimized low-dosage, low-variety compound additive formulations of this invention, product shelf-life stability can still be guaranteed even with reduced types and amounts of emulsifiers and stabilizers. This solves the industry problem of difficulty in guaranteeing product shelf-life stability after reducing the types or amounts of emulsifiers and stabilizers used. It achieves clean labeling while ensuring product quality, providing a scientific basis and data support for improving the quality of flavored milk products and developing clean label formulations in industrial production. Attached Figure Description

[0017] Figure 1 This is a graph showing the effect of compound additives on the particle size of flavored milk. Figure 2 The graph shows the effect of compound additives on the potential of flavored milk. Figure 3 Figure showing the effect of compound additives on the Turbiscan stability index of flavored milk; Figure 4 Figure 1 shows the effect of compound additives on the centrifugal sedimentation rate and fat flotation rate of flavored milk. Figure 5 This is a graph showing the effect of compound additives on the turbidity of flavored milk. Figure 6 The graph shows the effect of compound additives on different types of volatile odor substances in flavored milk. Detailed Implementation

[0018] Those skilled in the art can refer to the content of this document and appropriately improve the process parameters to achieve the desired results. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The methods and applications of this invention have been described through preferred embodiments, and those skilled in the art can obviously make modifications or appropriate alterations and combinations to the methods and applications described herein without departing from the content and scope of this invention to implement and apply the technology of this invention.

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.

[0020] Example 1: The compound additive (composed of mono- and diglyceride fatty acid esters and carrageenan) was softened in water and stirred until completely dissolved. The softened compound additive was added to the initial strawberry flavored milk sample preheated to 55-65℃ and mixed evenly. Homogenization was carried out at 75-85℃ and 18-22 MPa. The sample was sterilized at 135-137℃ for 4 seconds. The sterilized strawberry flavored milk sample was rapidly cooled to 15-20℃ and filled into an ultra-clean storage tank to obtain new strawberry flavored milk (referred to as new strawberry).

[0021] Example 2: The compound additive (composed of mono- and diglyceride fatty acid esters and carrageenan) was softened in water and stirred until completely dissolved. The softened compound additive was added to a cocoa flavored milk sample preheated to 55-65°C and mixed evenly. Homogenization was performed at 75-85°C and 18-22 MPa. The sample was then sterilized at 135-137°C for 4 seconds. The sterilized cocoa flavored milk sample was rapidly cooled to 15-20°C and filled into an ultra-clean storage tank to obtain new cocoa flavored milk (referred to as new cocoa).

[0022] Comparative Example 1: The conventional additives (composed of mono- and diglycerides of fatty acids, carrageenan, microcrystalline cellulose, and sodium carboxymethyl cellulose) were softened in water at 40-50°C and stirred until completely dissolved. The softened compound additives were added to the initial strawberry flavored milk sample preheated to 55-65°C and mixed evenly. Homogenization was carried out at 75-85°C and 18-22 MPa. The sample was sterilized at 135-137°C for 4 seconds. The sterilized strawberry flavored milk sample was rapidly cooled to 15-20°C and filled into an ultra-clean storage tank to obtain old strawberry flavored milk (referred to as old strawberry).

[0023] Comparative Example 1: The conventional additives (composed of mono- and diglyceride fatty acid esters, carrageenan, microcrystalline cellulose, and sodium carboxymethyl cellulose) were softened in water at 40-50°C and stirred until completely dissolved. The softened compound additives were added to a cocoa flavored milk sample preheated to 55-65°C and mixed evenly. Homogenization was performed at 75-85°C and 18-22 MPa. The sample was then sterilized at 135-137°C for 4 seconds. The sterilized cocoa flavored milk sample was rapidly cooled to 15-20°C and filled into an ultra-clean storage tank to obtain old cocoa flavored milk (referred to as old cocoa).

[0024] Effect Experiment: 1. Nutritional composition determination The nutritional components of the new strawberry and new cocoa milk prepared in Examples 1-2, and the old strawberry and old cocoa milk prepared in Comparative Examples 1-2 were determined using a milk component analyzer. The results included the following nutritional indicators: protein, fat, total solids, non-fat milk solids, and lactose in the flavored milk.

[0025] The steps are as follows: Take 45 mL of the sample to be tested and put it into a 50 mL centrifuge tube. Heat the tube in a water bath at 40℃ for 30 min. Put the tube into two layers of self-sealing bags, leaving some air. Before use, calibrate twice with zero solution (blue) and calibration solution (transparent). Centrifuge manually. There will be foam at the top of the centrifuge tube. Measure the sample and click the "green centrifuge tube" button. After the measurement is completed, rinse the tube with deionized water, calibrate with zero solution, calibrate with calibration solution, and finally rinse the tube with excess liquid from the conical flask.

[0026] The results are shown in Table 1. The comparison of milk component content between new cocoa and old cocoa, and between new strawberry and old strawberry shows that the flavored milk (new cocoa and new strawberry) prepared using the compound additives provided by this invention retains milk components better. The formula optimization effect is significant, and all indicators are better than those of old cocoa and old strawberry. In particular, the synergistic improvement of protein and fat makes it more advantageous in terms of nutritional structure and taste.

[0027] Table 1

[0028] 2. Particle size and zeta potential measurement The particle size and potential changes of whey protein and casein were measured using a nanolaser particle size analyzer on the new strawberry and new cocoa prepared in Examples 1-2, and the old strawberry and old cocoa flavored milk prepared in Comparative Examples 1-2.

[0029] Particle size: After defatting, the sample was diluted with deionized water, and the particle size of casein micelles in the sample was determined using a nanoparticle size and Zeta potential analyzer.

[0030] Potential: The sample to be tested was diluted with deionized water and its zeta potential was measured using a nanoparticle size and zeta potential analyzer.

[0031] The results are as follows Figure 1-2 As shown, there is a significant difference in particle size between the flavored milk samples (new cocoa, new strawberry) prepared using the composite additive provided by this invention and those prepared using conventional additives (old cocoa, old strawberry) (P<0.05); among them, the protein particle size of the new cocoa and new strawberry flavored milks is significantly reduced. This indicates that the composite additive provided by this invention has substantially changed the particle size of the two flavored milk samples.

[0032] There was no significant difference in potential between the flavored milk (new cocoa, new strawberry) samples prepared using the composite additive provided by this invention and the flavored milk (old cocoa, old strawberry) samples prepared using conventional additives (P>0.05). This indicates that the composite additive provided by this invention does not affect the surface charge properties of the cocoa and strawberry flavored samples, and their colloidal stability-related potential characteristics remain consistent.

[0033] Therefore, the composite additive provided by this invention significantly reduces the particle size of the emulsion system and improves its physical stability by optimizing the homogenization process and the emulsifier compounding ratio; at the same time, the zeta potential of the particles in the system remains stable; indicating that the composite additive provided by this invention does not destroy the original electrostatic stable layer while refining the particles, and retains the anti-aggregation ability of the system, providing a microstructural basis for achieving long-term shelf-life stability under reduced addition. 3. Physical stability analysis The stability kinetic index (TSI) is an important indicator for measuring the overall stability of emulsions. The Turbiscan stability index (TSI) was determined for the new strawberry and new cocoa flavored milks prepared in Examples 1-2, and the old strawberry and old cocoa flavored milks prepared in Comparative Examples 1-2, to study the particle aggregation, flocculation, or agglomeration behavior in the new cocoa and new strawberry flavored milks.

[0034] The procedure is as follows: Pipette 20 μL of the sample to be tested into a stability analysis bottle, cap it, place it in the sample slot of the instrument, set the number of scans, and set the temperature to 25℃ to determine the TSI of the flavored milk sample.

[0035] The results are as follows Figure 3 As shown, the TSI values ​​of the flavored milk samples were all at a low level, and the TSI value of the flavored milk samples prepared using the composite additives provided by this invention was lower than that of flavored milk with conventional additives. It is evident that this invention, by improving the synergistic effect of additives (emulsifiers and stabilizers), more effectively inhibits unstable processes such as fat buoyancy and protein aggregation, significantly improving the physical stability of flavored milk.

[0036] 4. Circular dichroism chromatographic determination The secondary structures of whey protein and casein in the new strawberry and new cocoa prepared in Examples 1-2, and the old strawberry and old cocoa flavored milk prepared in Comparative Examples 1-2 were detected using a circular dichroism chromatograph.

[0037] The procedure is as follows: Circular dichroism spectroscopy is used to analyze changes in the secondary structure of proteins. 0.05 mg / mL of the test solution is added to a 0.1 cm thick cuvette. The scanning wavelength is 200-260 nm. Deionized water and PBS buffer are used as blanks, respectively. The results are analyzed using CDNN software to determine the content of protein secondary structures.

[0038] The results are shown in Tables 2-3. Compared with conventional additives, the flavored milk samples (new cocoa, new strawberry) prepared using the composite additive provided by this invention showed increased α-helix content and decreased β-sheet and random coil content of whey protein and casein. Therefore, the composite additive provided by this invention optimizes protein conformation and improves the stability of flavored milk.

[0039] Table 2

[0040] Table 3

[0041] 5. Determination of centrifugal sedimentation rate and fat buoyancy rate Centrifugal sedimentation rate: This refers to the proportion of precipitated substances (such as unstable protein particles, impurities, etc.) in milk after centrifugation, reflecting the stability of the solid components in milk. It serves as a direct indicator of the stability of a mixture. Fat buoyancy rate: This refers to the proportion of fat globules that float to the surface in milk, reflecting the emulsification stability of the fat globules.

[0042] The centrifugation sedimentation rate and fat buoyancy rate of the new strawberries and new cocoa prepared in Examples 1-2, and the old strawberries and old cocoa flavored milk prepared in Comparative Examples 1-2 were respectively tested.

[0043] Centrifugal sedimentation rate determination: Record the mass of the empty centrifuge tube as m0. Weigh 10 mL of the sample to be tested into the centrifuge tube and record the total weight as m1. Centrifuge at 2760 g for 30 min, thoroughly discard the supernatant, and weigh again as m2. The centrifugal sedimentation rate is calculated using the following formula: .

[0044] Fat buoyancy determination: Take 20 mL of the ultra-high temperature sample to be tested (accurate to 0.001 g) into a 50 mL centrifuge tube and weigh it. The mass of the empty centrifuge tube is m0, and the mass of the sample and the centrifuge tube is m1. Centrifuge at 3000 rpm for 10 min at 25°C. Remove as much fat layer as possible with a clean spatula, weigh the remaining mass and record it as m2. Calculate the fat buoyancy rate according to the following formula.

[0045] .

[0046] The results are as follows Figure 4 As shown, the centrifugal sedimentation rate of flavored milk samples (new cocoa, new strawberry) prepared using the composite additive provided by this invention is significantly lower than that of flavored milk prepared using conventional additives (old cocoa, old strawberry). Specifically, the fat buoyancy of the new cocoa is significantly lower than that of the old cocoa, while the fat buoyancy of the new and old strawberries is essentially the same. Therefore, the composite additive provided by this invention improves the physical stability of both flavored milks, providing strong assurance for their shelf-life quality.

[0047] 6. Protein turbidity determination: Turbidity is an important parameter for evaluating the physical stability and particle dispersion of liquid dairy products such as flavored milk. Protein turbidity was measured in the new strawberry and new cocoa products prepared in Examples 1-2, and the old strawberry and old cocoa flavored milk products prepared in Comparative Examples 1-2.

[0048] The steps are as follows: Centrifuge the defatted sample to be tested, take 200 L of the lower supernatant, dilute it 50 times with deionized water, and measure the OD value of the sample at 600 nm using a UV spectrophotometer. Take the average value of the three parallel measurements as the turbidity value of the milk sample.

[0049] The results are as follows Figure 5As shown, the turbidity of old cocoa and old strawberry samples prepared using conventional additives increased during the 0-30 day storage period, indicating that particle aggregation or flocculation occurred in the system; while the turbidity of new cocoa and new strawberry samples prepared using the composite additives provided by this invention remained constant, proving that the new formula effectively inhibited aggregation instability and that the flavored milk samples with improved additives were stable.

[0050] 7. Measurement of electronic nose Electronic nose assays were performed on the new strawberries and new cocoa prepared in Examples 1-2, and the old strawberries and old cocoa flavored milk prepared in Comparative Examples 1-2. The electronic nose used nine specific sensors to identify different types of volatile odor substances (aromatics, organosulfur compounds, nitrogen oxides, ammonia, alcohols, aldehydes and ketones, sulfides, hydrides, methyl groups, and short-chain alkanes) in old strawberries, new strawberries, old cocoa, and new cocoa.

[0051] The steps are as follows: accurately weigh 10 g of the sample to be tested (accurate to 0.001 g) into an electronic nose test bottle, quickly seal the bottle and place it in a water bath for heating at 42℃ for 5 min, and then test it on the instrument. The purpose of heating is to allow the flavor components in the milk to volatilize and fill the bottle cavity, which is beneficial for the instrument to respond to the flavor of the sample.

[0052] The results are as follows Figure 6 As shown, compared with the old strawberry and old cocoa flavored milk prepared using conventional additives, the response values ​​of each volatile odor substance in the new strawberry and new cocoa flavored milk prepared using the composite additives provided by the present invention did not show significant fluctuations; indicating that the composite additives provided by the present invention have no substantial impact on the odor composition and overall odor characteristics of the flavored milk samples.

[0053] The specific embodiments of the present invention disclosed above are merely illustrative of the invention. These embodiments do not exhaustively describe all details, nor do they limit the invention to the specific embodiments described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A compound additive for improving the stability of flavored milk, characterized in that, The composite additive is composed of an emulsifier and a stabilizer, wherein the emulsifier is a mono- or diglyceride fatty acid ester and the stabilizer is carrageenan.

2. The application of the composite additive as described in claim 1 in improving the stability of flavored milk systems.

3. The application according to claim 2, characterized in that, The steps for improving the stability of the flavored milk system with the composite additive are as follows: softening the composite additive described in claim 1, adding the softened composite additive to the preheated initial sample of flavored milk and mixing it evenly, then homogenizing, sterilizing, cooling, and filling it into a storage tank to obtain the finished flavored milk product.

4. The application according to claim 3, characterized in that, The softening process involves placing the composite additive in water at 40-50°C for softening and stirring until completely dissolved.

5. The application according to claim 3, characterized in that, The preheating temperature of the initial sample of the flavored milk is 55-65℃.

6. The application according to claim 3, characterized in that, The amount of the compound additive added is 0.7-1.2 g / L of the total volume of the initial sample of the flavored milk.

7. The application according to claim 3, characterized in that, The homogenization conditions are: homogenization temperature of 80-90℃ and homogenization pressure of 18-24MPa.

8. The application according to claim 3, characterized in that, The sterilization conditions are: sterilization temperature of 135-137℃ and sterilization time of 4 seconds.

9. The application according to claim 3, characterized in that, The cooling conditions are as follows: the temperature is reduced to 15-20℃.

10. The application according to claim 3, characterized in that, The storage tank is an ultra-clean tank.

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