阅读说明：本技术 一种提高桑葚红色素稳定性的方法 (Method for improving stability of mulberry haematochrome ) 是由 何志勇 陈曦 陈洁 曾茂茂 王召君 秦昉 于 2021-10-09 设计创作，主要内容包括：本发明公开了一种提高桑葚红色素稳定性的方法,属于天然色素技术领域。本发明方法为：通过将乳清分离蛋白溶液与桑葚红色素溶液混合,加入辅色素溶液,调节pH值至3-4,以提高桑葚色素稳定性。本发明利用生物大分子、多酚类辅色素与花青素的协同相互作用来提高桑葚花色苷稳定性的处理方法简单便捷,无毒无害,不添加任何非食用的化学添加剂,对花色苷色素因热处理而导致的降解和褪色均能起到较好的抑制效果,在液体食品及固态食品加工中均具有较好的应用前景。(The invention discloses a method for improving the stability of mulberry haematochrome, and belongs to the technical field of natural pigments. The method comprises the following steps: the stability of the mulberry pigment is improved by mixing the whey protein isolate solution with the mulberry red pigment solution, adding the auxiliary pigment solution and adjusting the pH value to 3-4. The processing method for improving the stability of the mulberry anthocyanin by utilizing the synergistic interaction of the biomacromolecules, the polyphenol auxiliary pigment and the anthocyanin is simple, convenient, non-toxic and harmless, does not add any non-edible chemical additive, can play a good role in inhibiting degradation and fading of the anthocyanin pigment caused by heat treatment, and has a good application prospect in liquid food and solid food processing.)

1. A method for improving the stability of mulberry haematochrome is characterized by comprising the following steps: the stability of the mulberry pigment is improved by mixing the whey protein isolate solution with the mulberry red pigment solution, adding the auxiliary pigment solution and adjusting the pH value to 3-4.

2. The method according to claim 1, wherein the concentration of the whey protein isolate solution is 0.08-0.8 mg/mL.

3. The method according to claim 2, wherein the solvent of the whey protein isolate solution is a phosphate buffer having a pH of 6-8.

4. The method according to claim 1, wherein the concentration of the mulberry red pigment solution is 0.17-0.54 mg/mL.

5. The method according to claim 4, wherein the solvent of the mulberry red pigment solution is a citric acid buffer solution with a pH value of 3-4.

6. The method according to claim 1, wherein the mass concentration ratio of the whey protein isolate solution to the mulberry haematochrome solution is 1: 1-20: 1.

7. the method of claim 1, wherein the co-pigment comprises a polyphenol.

8. The method of claim 7, wherein the co-pigment comprises one or more of rosmarinic acid, caffeic acid, catechin, quercetin, naringin, and phlorizin.

9. The method according to claim 1, wherein the mass concentration of the co-pigment solution is 0.08-0.48 mg/mL.

10. The method of claim 9, wherein the solvent of the co-pigment solution is a citric acid buffer having a pH of 3-4.

Technical Field

The invention belongs to the technical field of natural pigments, and particularly relates to a method for improving stability of mulberry red pigment.

Background

The mulberry resource is abundant in China, the planting area of fruit mulberry reaches 15 ten thousand mu, the annual output of fresh mulberry is more than 6 ten thousand tons, however, the mulberry belongs to seasonal berries, the eating period is short, the mulberry is easy to mildew and is not easy to transport, and the economic loss caused by the transport and storage problems accounts for one third of the total value every year, so that the deep processing of the mulberry and the development of high-added-value products are very important. The mulberry contains rich anthocyanin substances, and can be applied to the natural edible pigment industry after separation, purification and extraction. The mulberry haematochrome can be used in fruit and vegetable juice (pulp) beverages, fruit wine, jelly, fruit cakes and other foods, and has a wide application range in food coloring.

The mulberry haematochrome belongs to anthocyanin natural pigments, the main anthocyanin types of the mulberry haematochrome are cyanidin-3-O-glucoside and cyanidin-3-O-rutinoside, the mulberry haematochrome has stronger antioxidation, anti-inflammatory and antithrombotic effects, and the incidence rate of coronary heart disease and diabetic complications can be reduced. However, anthocyanins are sensitive to environmental factors such as temperature, pH, light, oxygen, enzymes, metal ions and the like in an aqueous solution state, and cause food discoloration, thereby limiting the wide application thereof in the food industry.

Several anthocyanin stabilization methods and technologies mainly researched at present comprise the addition of macromolecular food components, micromolecular auxiliary color effect, metal ion chelation effect, embedding technology and the like, but the methods generally have the problems of no long-acting stability, weakening of natural color, high cost, low safety and limited application, and specifically comprise the following steps: the use of chemical reagents is not suitable for food, and the embedding method is not suitable for liquid food and masks the original color of anthocyanin. Therefore, how to improve the stability of anthocyanin and expand the application range of natural anthocyanin while ensuring the edible safety is an urgent problem to be solved.

Disclosure of Invention

In order to solve the technical problems, the invention provides a method for improving the stability of mulberry haematochrome.

A method for improving the stability of mulberry red pigment comprises the following steps: the stability of the mulberry pigment is improved by mixing the whey protein isolate solution with the mulberry red pigment solution, adding the auxiliary pigment solution and adjusting the pH value to 3-4.

In one embodiment of the invention, the concentration of the whey protein isolate solution is 0.08-0.8 mg/mL.

In one embodiment of the invention, the solvent of the whey protein isolate solution is a phosphate buffer having a pH of 6-8.

In one embodiment of the invention, the concentration of the mulberry red pigment solution is 0.17-0.54 mg/mL.

In one embodiment of the invention, the solvent of the mulberry red pigment solution is a citric acid buffer solution with a pH value of 3-4.

In one embodiment of the invention, the mass concentration ratio of the whey protein isolate solution to the mulberry red pigment solution is 1: 1-20: 1.

in one embodiment of the invention, the mass concentration ratio of the whey protein isolate solution to the mulberry red pigment solution is 2:1-4:1

In one embodiment of the invention, the co-pigment comprises a polyphenol.

In one embodiment of the present invention, the co-pigment comprises one of rosmarinic acid, caffeic acid, catechin, quercetin, naringin, phlorizin.

In one embodiment of the invention, the mass concentration of the co-pigment solution is 0.08-0.48 mg/mL.

In one embodiment of the present invention, the solvent of the co-pigment solution is a citric acid buffer solution with a pH value of 3-4.

Compared with the prior art, the technical scheme of the invention has the following advantages:

the invention provides a method for improving stability of mulberry haematochrome, which aims at solving the problems that anthocyanin natural pigments in food are poor in stability and easy to degrade and fade due to heating, mainly utilizes protein and auxiliary pigments to interact with anthocyanin to protect anthocyanidin and improve the stability of anthocyanidin, selects whey protein isolate as a biological macromolecule protective agent, adds rosmarinic acid, caffeic acid, catechin, quercetin, naringin or phlorizin as a polyphenol auxiliary agent, and reduces the thermal degradation rate of total anthocyanin in mulberry haematochrome at 80 ℃ (2h) by 10.0-41.7% after protection treatment. The processing method for improving the stability of the mulberry anthocyanin by utilizing the synergistic interaction of the biomacromolecules, the polyphenol auxiliary pigment and the anthocyanin is simple, convenient, non-toxic and harmless, does not add any non-edible chemical additive, can play a good role in inhibiting degradation and fading of the anthocyanin pigment caused by heat treatment, and has a good application prospect in liquid food and solid food processing. The method is only suitable for the stability of the anthocyanin in an acidic environment, the structure of the anthocyanin is changed in a neutral environment, and the auxiliary color effect between the anthocyanin and polyphenol is weak.

Wherein, the whey protein isolate has a plurality of binding sites and can play a role in carrying and protecting small molecules. The protein and the anthocyanin can be mutually combined through the interaction of hydrophobic interaction, van der waals force and hydrogen bond, so that the damage of external environments such as water, temperature and the like to the molecular structure of the anthocyanin is prevented to a certain extent. Meanwhile, the polyphenol compound and the anthocyanin can form a pi-pi conjugated structure, and the hydrophobic force generated by the compound prevents the attack of the nucleophilic reagent.

Therefore, when the protein and the polyphenol compound act on the anthocyanin simultaneously, a protein-polyphenol-anthocyanin ternary complex can be formed, the protein can be combined with the polyphenol and the anthocyanin simultaneously, a sandwich structure can be formed between the polyphenol and the anthocyanin, and the protein and the polyphenol have synergistic effect to enhance the stabilizing effect on the anthocyanin.

Detailed Description

The present invention is further described below in conjunction with specific examples to enable those skilled in the art to better understand the present invention and to practice it, but the examples are not intended to limit the present invention.

Example 1:

selecting whey protein isolate as a raw material, dissolving the whey protein isolate and a phosphate buffer solution with the pH value of 7.4 to prepare a 0.32mg/mL whey protein isolate solution, stirring for 2 hours at the rotation speed of 300r/min, fully dissolving, preparing mulberry red pigment into a 0.34mg/mL pigment solution, mixing the whey protein isolate solution according to the equal volume of protein and pigment, adjusting the pH value to 3.6, and stirring for 30 minutes at the rotation speed of 300r/min to prepare a liquid pigment product. Detection shows that the degradation rate of the processed mulberry red pigment solution is reduced by 26.9 percent after the processed mulberry red pigment solution is heated for 2 hours at the temperature of 80 ℃.

Example 2:

selecting whey protein isolate as a raw material, dissolving the whey protein isolate and a phosphate buffer solution with the pH value of 7.4 to prepare a 0.64mg/mL whey protein isolate solution, stirring for 2 hours at the rotation speed of 300r/min, fully dissolving, preparing mulberry red pigment into a 0.34mg/mL pigment solution, mixing the whey protein isolate solution according to the equal volume of protein and pigment, adjusting the pH value to 3.6, and stirring for 30 minutes at the rotation speed of 300r/min to prepare a liquid pigment product. Detection shows that the degradation rate of the processed mulberry haematochrome solution is reduced by 10.0 percent after the processed mulberry haematochrome solution is heated for 2 hours at the temperature of 80 ℃.

From examples 1-2, it is known that the optimal mass concentration ratio of the protein to the anthocyanin is 2:1-4:1, and that too high or too low of the protein to the anthocyanin would reduce the stability effect.

Example 3:

preparing 0.34mg/mL pigment solution from mulberry red pigment, stirring for 30min at the rotating speed of 300r/min, adding 0.32mg/mL, 0.64mg/mL and 0.96mg/mL quercetin solutions in equal volume, stirring for 1h at the rotating speed of 300r/min, and adjusting the pH value to 3.6 to obtain the liquid pigment product. Detection shows that the thermal degradation rate of the total anthocyanin in the processed mulberry anthocyanin pigment solution is reduced by 29.6%, 33.6% and 34.0% after the processed mulberry anthocyanin pigment solution is heated for 2 hours at 80 ℃.

Due to the insufficient number of electrons in the flavone ring of unstable anthocyanin, the interaction of the pi electron-rich quercetin and other co-pigments with the electron-poor flavone cation may show the best co-pigment effect. From a steric conformation, quercetin is one of the major perfect planar polyphenols, exhibiting perfect overlapping pi-pi stacking. Due to the large volume, rotation is inhibited and the degree of freedom is reduced when approaching the existing co-pigment complexes. Thus, it stabilizes the positive charge on the flavone ion, resulting in a better stabilizing effect than other phenolic co-pigments.

Example 4:

whey protein isolate powder is selected as a raw material and dissolved in a pH 7.4 buffer solution to prepare a 0.48mg/mL whey protein isolate solution. Stirring for 2 hours at the rotating speed of 300r/min, fully dissolving, preparing mulberry red pigment into 0.54mg/mL pigment solution, mixing the whey protein isolate solution and the pigment solution in equal volume, stirring for 1 hour at the rotating speed of 300r/min, adding 0.48mg/mL, 0.96mg/mL and 1.36mg/mL quercetin solutions in equal volume, stirring for 1 hour at the rotating speed of 300r/min, and adjusting the pH value to 3.6 to prepare the liquid pigment product. Detection shows that the thermal degradation rate of the total anthocyanin in the processed mulberry red pigment solution is reduced by 37.1%, 38.6% and 41.7% after the processed mulberry red pigment solution is heated for 2 hours at 80 ℃.

Example 5:

whey protein isolate powder is selected as a raw material and dissolved in a pH 7.4 buffer solution to prepare a 0.48mg/mL whey protein isolate solution. Stirring for 2 hours at the rotating speed of 300r/min, fully dissolving, preparing mulberry red pigment into 0.54mg/mL pigment solution, mixing the whey protein isolate solution and the pigment solution in an equal volume, stirring for 1 hour at the rotating speed of 300r/min, adding 0.48mg/mL rosmarinic acid solution in the equal volume, stirring for 1 hour at the rotating speed of 300r/min, and adjusting the pH value to 3.6 to obtain the liquid pigment product. Detection shows that the thermal degradation rate of the total anthocyanin in the processed mulberry red pigment solution is reduced by 18.7 percent after the solution is heated for 2 hours at the temperature of 80 ℃.

Example 6:

whey protein isolate powder is selected as a raw material and dissolved in a pH 7.4 buffer solution to prepare a 0.48mg/mL whey protein isolate solution. Stirring for 2 hours at the rotating speed of 300r/min, fully dissolving, preparing the mulberry red pigment into a 0.54mg/mL pigment solution, mixing the whey protein isolate solution and the pigment solution in an equal volume, stirring for 1 hour at the rotating speed of 300r/min, adding 0.48mg/mL caffeic acid solution in the equal volume, stirring for 1 hour at the rotating speed of 300r/min, and adjusting the pH value to 3.6 to prepare the liquid pigment product. Detection shows that the thermal degradation rate of the total anthocyanin in the processed mulberry red pigment solution is reduced by 20.5 percent after the solution is heated for 2 hours at the temperature of 80 ℃.

Example 7:

preparing 0.34mg/mL pigment solution from mulberry red pigment, stirring for 30min at the rotation speed of 300r/min, adding 0.48mg/mL catechin solution in an equal volume, stirring for 1h at the rotation speed of 300r/min, and adjusting the pH value to 3.6 to obtain a liquid pigment product. Through detection, the thermal degradation rate of the total anthocyanin in the processed mulberry anthocyanin pigment solution is reduced by 28.0 percent after the mulberry anthocyanin pigment solution is heated for 2 hours at 80 ℃.

Example 8:

whey protein isolate powder is selected as a raw material and dissolved in a pH 7.4 buffer solution to prepare a 0.48mg/mL whey protein isolate solution. Stirring for 2 hours at the rotating speed of 300r/min, fully dissolving, preparing the mulberry red pigment into 0.54mg/mL pigment solution, mixing the whey protein isolate solution and the pigment solution in equal volume, stirring for 1 hour at the rotating speed of 300r/min, adding 0.96mg/mL catechin solution in equal volume, stirring for 1 hour at the rotating speed of 300r/min, and adjusting the pH value to 3.6 to prepare the liquid pigment product. Detection shows that the thermal degradation rate of the total anthocyanin in the processed mulberry red pigment solution is reduced by 35.2 percent after the solution is heated for 2 hours at the temperature of 80 ℃.

Example 9:

whey protein isolate powder is selected as a raw material and dissolved in a pH 7.4 buffer solution to prepare a 0.48mg/mL whey protein isolate solution. Stirring for 2 hours at the rotating speed of 300r/min, fully dissolving, preparing the mulberry red pigment into a 0.54mg/mL pigment solution, mixing the whey protein isolate solution and the pigment solution in an equal volume, stirring for 1 hour at the rotating speed of 300r/min, adding the 0.96mg/mL naringin solution in the equal volume, stirring for 1 hour at the rotating speed of 300r/min, and adjusting the pH value to 3.6 to obtain the liquid pigment product. Detection shows that the thermal degradation rate of the total anthocyanin in the processed mulberry red pigment solution is reduced by 28.4 percent after the solution is heated for 2 hours at the temperature of 80 ℃.

Example 10:

whey protein isolate powder is selected as a raw material and dissolved in a pH 7.4 buffer solution to prepare a 0.48mg/mL whey protein isolate solution. Stirring for 2 hours at the rotating speed of 300r/min, fully dissolving, preparing the mulberry red pigment into a 0.54mg/mL pigment solution, mixing the whey protein isolate solution and the pigment solution in an equal volume, stirring for 1 hour at the rotating speed of 300r/min, adding the 0.96mg/mL phlorizin solution in an equal volume, stirring for 1 hour at the rotating speed of 300r/min, and adjusting the pH value to 3.6 to obtain the liquid pigment product. Detection shows that the thermal degradation rate of the total anthocyanin in the processed mulberry red pigment solution is reduced by 34.7 percent after the solution is heated for 2 hours at the temperature of 80 ℃.

Therefore, the invention provides a method for improving the stability of mulberry red pigment, which aims at the problems that natural pigments of anthocyanins in food are poor in stability and easy to degrade and fade under the influence of heat treatment, and mainly utilizes interaction between biomacromolecules and auxiliary pigments and anthocyanidins to protect anthocyanidins and improve the color stability of anthocyanidins, whey isolate protein is selected as a biomacromolecule protective agent, meanwhile, rosmarinic acid, caffeic acid, catechin, quercetin, naringin or phlorizin is added as an auxiliary pigment, and after protection treatment, the thermal degradation rate of cyanidin 3-O-glucoside at 80 ℃ (2h) can be reduced by 10.0-41.7%. The treatment method for improving the stability of the mulberry haematochrome by utilizing the interaction of the biomacromolecules and the anthocyanidins is simple and convenient to operate, is non-toxic and harmless, can play a good role in inhibiting fading and browning of the anthocyanidins caused by heat treatment, and has a good application prospect in processing of liquid foods and solid foods.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications of the invention may be made without departing from the spirit or scope of the invention.