High-thermal-stability beet red pigment hard candy and preparation method thereof

Abstract

The invention belongs to the technical field of food processing, and particularly relates to a beet red pigment hard candy with high thermal stability and a preparation method thereof. The preparation method comprises the following steps: mixing white granulated sugar, malt syrup and a buffer solution to obtain a syrup solution; heating and boiling the syrup solution to 90-125 DEG C, then reducing the heating power, maintaining the temperature but not boiling, adding a polysaccharide stabilizer and beet red pigment in a state that the syrup is not boiling, and continuously carrying out heat preservation and stirring for 5-15 minutes for uniform mixing; and finally, adding an antioxidant, stirring for 1-3 minutes, uniformly mixing, pouring into a mold, and cooling and molding to obtain the beet red pigment hard candy. The polysaccharide and the antioxidant are directly added in the hard candy processing technology to improve the thermal stability of the beet red pigment in the hard candy, the technological conditions for improving the thermal stability of the beet red pigment in the hard candy by the polysaccharide type, the antioxidant type and the adding sequence thereof are defined for the first time, and the replacement of artificial pigment by natural pigment in the hard candy product is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of food processing, and particularly relates to a hard candy with high thermal stability of betalain and a preparation method thereof. Background Art

[0002] Betalain is a water-soluble natural red pigment with bright color, good coloring power, and many physiological functions such as antioxidant and anti-cancer effects. Therefore, it is highly favored by food practitioners. Compared with synthetic red pigments, due to its natural properties, bright color, and many beneficial physiological functions, betalain can be used to completely replace artificial synthetic pigments and is widely used in various foods such as beverages, candies, jellies, and ice creams for food coloring. However, due to the defects in its own structure, betalain has poor stability and is extremely susceptible to degradation and fading under the influence of environmental factors such as heat and pH during extraction and processing, which greatly affects its application in the food field.

[0003] Hard candy is a type of candy made by high-temperature boiling. The candy body is hard and brittle, so it is called hard candy and belongs to an amorphous non-crystalline structure. Hard candy melts slowly in the mouth, is chewable, and the candy body has three types: transparent, semi-transparent, and opaque. Since the processing of hard candy often requires high-temperature heating and synthetic pigments have better thermal stability, etc., currently, the pigments in hard candy production mainly rely on synthetic pigments. However, long-term consumption of synthetic pigments has certain potential health risks, and there is an urgent need to find new pigments for replacement. Betalain is a good choice. However, due to the thermal processing technology of hard candy and the thermal instability of betalain, the application of betalain in hard candy processing is limited.

[0004] Patent CN 111067009 A discloses a method for improving the thermal stability of betalain, which is completed by mixing a compound composition of a hydrocolloid, an antioxidant, and cyclodextrin with betalain. Patent CN 118415292 A discloses a preparation method of a high-stability betacyanin complex, in which betacyanin is compounded with a polyphenol co-colorant and a protein. The polyphenol co-colorant can undergo a co-coloring reaction with betacyanin to enhance the color of the pigment and improve the stability of the pigment against adverse environmental factors such as heat, light, and hydrogen peroxide. In our previous patents CN 117694492 A and CN 117859860 A, it is also respectively disclosed that the heat resistance of betalain is improved by physical embedding of sodium alginate combined with antioxidant protection of ascorbic acid; and the heat resistance of betalain is improved by adsorbing the pigment and ascorbic acid on starch granules and combining with sodium alginate coating.

[0005] All of the above methods involve pre - compounding stabilizers with betacyanin. Although they can all improve the heat resistance of betacyanin, none of them are combined with the hot - processing technology of hard candy. During the high - temperature heating process of hard candy, the choice of different stabilizers and the timing of addition often show obvious differences in effects. At the same time, there are also obvious differences in the thermal stability of betacyanin in the hard - candy system and that in the conventional complex. Developing a processing method that uses natural betacyanin to replace artificial pigments during the hard - candy processing and achieves good coloring effects has broad application prospects and market demand. Summary of the Invention

[0006] Aiming at the shortcomings and deficiencies of the above - mentioned existing technologies, the primary object of the present invention is to provide a method for preparing hard candy with betacyanin having high thermal stability. The preparation method of the present invention does not require chemical modification of betacyanin, nor does it require pre - physical embedding. Instead, by directly adding different stabilizers and regulating their addition sequences in the production process of hard candy, betacyanin becomes more heat - resistant, and hard candy with bright colors and high retention rate of betacyanin is obtained.

[0007] Another object of the present invention is to provide a hard candy with betacyanin prepared by the above - mentioned method.

[0008] The object of the present invention is achieved by the following technical solutions:

[0009] A method for preparing hard candy with betacyanin having high thermal stability, comprising the following preparation steps:

[0010] (1) Mix white granulated sugar, malt syrup and buffer solution to obtain a syrup solution;

[0011] (2) Heat the syrup solution to boiling between 90 - 125 °C, then reduce the heating power to maintain the temperature without boiling. Add a polysaccharide stabilizer and betacyanin to the non - boiling syrup, and continuously stir and keep warm for 5 - 15 min to mix evenly;

[0012] (3) Add an antioxidant to the syrup in step (2) and stir for 1 - 3 min to mix evenly, then pour it into a mold and cool it to form, obtaining hard candy with betacyanin.

[0013] Further, the buffer solution in step (1) is an acetic acid - sodium acetate buffer solution with pH = 3 - 7.

[0014] Further, the mass ratio of white granulated sugar: malt syrup: buffer solution in step (1) is 5:1 - 3:1 - 5.

[0015] Further, the addition amount of betacyanin in step (2) is 0.01 - 0.06% of the mass of the syrup solution.

[0016] Furthermore, the polysaccharide stabilizer described in step (2) includes at least one of dextrin, maltodextrin, xanthan gum, sodium alginate, β-cyclodextrin, gum arabic, pectin, carrageenan, and D(+)-galactose.

[0017] Further preferably, the weight ratio of the addition amount of the polysaccharide stabilizer to the betacyanin is 0.1-2:1.

[0018] Furthermore, the antioxidant described in step (3) includes at least one of ascorbic acid, D-isoascorbic acid, gallic acid, anhydrous citric acid, citric acid, DL-malic acid, and DL-tartaric acid.

[0019] Further preferably, the weight ratio of the addition amount of the antioxidant to the betacyanin is 0.1-2:1.

[0020] A betacyanin hard candy is prepared by the above method.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] (1) The present invention does not chemically modify the betacyanin nor pre-physically embed it, but directly adds polysaccharides and antioxidants in the hard candy processing technology to improve the thermal stability of the betacyanin in the hard candy. This method is simple to operate, green and safe, and effectively reduces the thermal degradation of the betacyanin caused by high temperature during the processing of the hard candy.

[0023] (2) The present invention first clarifies the process conditions for improving the thermal stability of betacyanin in hard candy by the types of polysaccharides, the types of antioxidants, and their addition sequences. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a process flow chart for preparing betacyanin hard candies in Examples 1-2 and Comparative Examples 1-2 of the present invention.

[0025] Figure 2 is the retention rate of betacyanin in the hard candies of Examples 1-2 and Comparative Examples 1-2 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The present invention will be described in further detail below in conjunction with the embodiments and the drawings, but the embodiments of the present invention are not limited thereto.

[0027] Example 1

[0028] A method for preparing a betacyanin hard candy with high thermal stability, the process flow chart of which is as Figure 1 shown, and includes the following preparation steps:

[0029] (1) Mix white granulated sugar, malt syrup, and an acetic acid-sodium acetate buffer solution with a pH of 4 in a weight ratio of 5:2:2 to obtain a syrup solution.

[0030] (2) Heat the syrup solution on an induction cooker at a power of 1000 W until it boils at 100 °C, then turn the power of the induction cooker to 500 W and continue boiling until it reaches 120 - 125 °C. Then turn the power of the induction cooker to 300 W to maintain the temperature without boiling. Add dextrin and beet red pigment to the syrup when it is not boiling. The addition amounts of both dextrin and beet red pigment are 0.05% of the mass of the syrup solution, and continuously stir while keeping warm for 10 min.

[0031] (3) Add different antioxidants (ascorbic acid, D-isoascorbic acid, gallic acid, anhydrous citric acid, citric acid, DL-malic acid, DL-tartaric acid) to the syrup in step (2) and stir for 90 s to mix evenly. The mass ratio of the added antioxidant to the beet red pigment is 1:1. Then pour it into a mold and cool it to form a hard candy containing beet red pigment.

[0032] The results of the retention rate of beet red pigment in the hard candies containing beet red pigment obtained by using different antioxidants in this example are as Figure 2 shown. The specific measurement method is as follows (the same below): Dissolve the hard candy sample in deionized water and make up the volume to 1 L. Then measure the absorbance value of the solution at 527 nm with a UV-visible spectrophotometer. Substitute it into the standard curve of beet red pigment to obtain the concentration of the pigment. By comparing the content of beet red pigment before and after processing, the retention rate of the pigment after processing (the average value of three measurements) can be obtained. At the same time, taking the sample without adding antioxidant as a blank control group, the measurement results show that the pigment retention rate of the blank control group is 28.5%.

[0033] Example 2

[0034] A preparation method of a hard candy containing beet red pigment with high thermal stability, the process flow chart of which is as Figure 1 shown, including the following preparation steps:

[0035] (1) Mix white granulated sugar, malt syrup, and an acetic acid-sodium acetate buffer solution with a pH of 4 in a mass ratio of 5:2:2 to obtain a syrup solution.

[0036] (2) Heat the syrup solution on an induction cooker at a power of 1000 W until it boils at 100 °C. Then turn the power of the induction cooker to 500 W and continue boiling until it reaches between 120 and 125 °C. Next, turn the power of the induction cooker to 300 W to maintain the temperature without boiling. Add beet red pigment and different polysaccharide stabilizers (dextrin, maltodextrin, xanthan gum, sodium alginate, β-cyclodextrin, gum arabic, pectin, carrageenan, D(+)-galactose) while the syrup is not boiling. The addition amounts of both the beet red pigment and the polysaccharide stabilizers are 0.05% of the weight of the syrup solution, and keep stirring while maintaining the temperature for 10 min.

[0037] (3) Add anhydrous citric acid as an antioxidant to the syrup in step (2) and stir for 90 s to mix evenly. The weight ratio of the added anhydrous citric acid to the beet red pigment is 1:1. Then pour it into a mold and let it cool and solidify to obtain beet red pigment hard candies.

[0038] The results of the retention rate of beet red pigment in the beet red pigment hard candies obtained in this example using different polysaccharide stabilizers are as Figure 2 shown. At the same time, taking the case without adding polysaccharide stabilizers as a blank control group, the measurement results show that the pigment retention rate of the blank control group is 35.2%.

[0039] Comparative Example 1

[0040] A preparation method of beet red pigment hard candies, adjusting the addition time of the antioxidant to be added simultaneously with the beet red pigment. Its technological process is as Figure 1 shown, including the following preparation steps:

[0041] (1) Mix white granulated sugar, malt syrup, and acetic acid-sodium acetate buffer solution with pH = 4 evenly in a weight ratio of 5:2:2 to obtain a syrup solution.

[0042] (2) Heat the syrup solution on an induction cooker at a power of 1000 W until it boils at 100 °C. Then turn the power of the induction cooker to 500 W and continue boiling until it reaches between 120 and 125 °C. Next, turn the power of the induction cooker to 300 W to maintain the temperature without boiling. Add beet red pigment, dextrin, and different antioxidants (ascorbic acid, D-isoascorbic acid, gallic acid, anhydrous citric acid, citric acid, DL-malic acid, DL-tartaric acid) while the syrup is not boiling. The addition amounts of the beet red pigment, dextrin, and the antioxidant are all 0.05% of the weight of the syrup solution, and keep stirring while maintaining the temperature for 10 min. Then pour it into a mold and let it cool and solidify to obtain beet red pigment hard candies.

[0043] The results of the retention rate of beet red pigment in the beet red pigment hard candies obtained in this comparative example using different antioxidants are as Figure 2 shown.

[0044] Comparative Example 2

[0045] A preparation method of a betacyanin hard candy, adjusting the addition timing of the polysaccharide stabilizer to before adding the betacyanin, and its process flow chart is as Figure 1 shown, including the following preparation steps:

[0046] (1) Mix white granulated sugar, malt syrup and an acetic acid-sodium acetate buffer solution with pH = 4 evenly in a weight ratio of 5:2:2 to obtain a syrup solution.

[0047] (2) Heat the syrup solution to boiling at 100 °C under the condition of an induction cooker power of 1000 W, and add different polysaccharide stabilizers (dextrin, maltodextrin, xanthan gum, sodium alginate, β-cyclodextrin, gum arabic, pectin, carrageenan, D(+)-galactose) and mix evenly. The addition amount of the polysaccharide stabilizer is 0.05% of the weight of the syrup solution. Turn the induction cooker power to 500 W and continue boiling until it reaches between 120 and 125 °C, then turn the induction cooker power to 300 W to maintain the temperature but not boil. Add the betacyanin under the condition that the syrup does not boil. The addition amount of the betacyanin is 0.05% of the weight of the syrup solution, and keep stirring and insulating for 10 min.

[0048] (3) Add anhydrous citric acid, an antioxidant, to the syrup in step (2) and stir for 90 s to mix evenly. The weight ratio of the added amount of anhydrous citric acid to the betacyanin is 1:1, and then pour it into a mold to cool and form, obtaining the betacyanin hard candy.

[0049] The results of the betacyanin retention rate of the betacyanin hard candies obtained by this comparative example using different polysaccharide stabilizers are as Figure 2 shown.

[0050] It can be seen from the above results that the betacyanin retention rates in the hard candies obtained in Examples 1 and 2 are higher than those in Comparative Examples 1 and 2, and are both higher than the corresponding blank control groups. The higher the betacyanin retention rate, the lower the pigment degradation rate, and the brighter the color of the hard candy, indicating that adding different polysaccharide stabilizers, antioxidants and different addition sequences effectively protect the betacyanin and effectively inhibit the degradation of betacyanin during the heating process of the hard candy.

[0051] It can be seen from both Example 1 and Comparative Example 1 that when the same polysaccharide (dextrin) is added, adding different antioxidants at different addition times will result in different retention rates of betanin in hard candies. The retention rate of betanin in the hard candies obtained by adding the antioxidant and the pigment simultaneously (Comparative Example 1) is lower than that of adding the antioxidant at the end of the process flow (Example 1). Among them, the antioxidant with the largest difference in retention rate is anhydrous citric acid, and the difference in the retention rate of betanin in the hard candies between the two addition times is as high as 20.33%. Followed by DL-tartaric acid, DL-malic acid, citric acid, D-isoascorbic acid, gallic acid, ascorbic acid, and the retention rate differences are 17.33%, 16.33%, 16.33%, 15.34%, 11.00%, and 10.33% respectively. The effect of adding the antioxidant and the pigment simultaneously (Comparative Example 1) is not as good as adding the antioxidant at the end of the entire process flow (Example 1): This is because the thermal degradation of betanin is a reversible reaction. Premature addition of the antioxidant will accelerate the forward reaction process of this reaction, that is, promote the thermal degradation of betanin. When the antioxidant is added at the end, the hard candy will quickly enter the molding and cooling stage, and the added antioxidant will promote the reversible reaction to proceed in the reverse direction, that is, promote the synthesis of betanin. Therefore, the retention rate of the pigment in the hard candy in Example 1 is higher than that in Comparative Example 1.

[0052] It can be seen from Example 2 and Comparative Example 2 that when anhydrous citric acid is added at the end of the fixed entire process flow, adding different polysaccharide stabilizers and the addition time of the polysaccharide stabilizer will affect the retention rate of betanin in hard candies; among them, the protective effect of adding the polysaccharide stabilizer and the pigment simultaneously (Example 2) is better than adding it after the syrup materials are mixed and dissolved (Comparative Example 2). This is because polysaccharides have a thickening effect; in addition, the negative charge of polysaccharides helps the stability of N + in the structure of betanin; dextrin also has a physical embedding effect; therefore, the addition of polysaccharide stabilizers will greatly promote the thermal stability of betanin in hard candies. Due to the difference in the addition time, the retention rate of the pigment in the hard candy also varies. It can be Figure 2 seen that the retention rate of the pigment of the same polysaccharide stabilizer at different addition times in Example 2 and Comparative Example 2 is different. The retention rate of the pigment in the hard candies obtained by adding the polysaccharide stabilizer and betanin simultaneously is almost higher than that of adding the polysaccharide stabilizer after the syrup solution is mixed. This is mainly because adding polysaccharides prematurely will damage the structure of the polysaccharides at the previous high temperature, resulting in a poor protective effect on the pigment in the later stage. Therefore, the effect of adding betanin and polysaccharides simultaneously is better.

[0053] Through Figure 2The results can be intuitively found that the present invention can effectively inhibit the thermal degradation of betacyanin in betacyanin hard candies by adding various polysaccharide stabilizers, antioxidants and different addition sequences; through the selection of polysaccharide stabilizers, antioxidants and their addition sequences, betacyanin hard candies with thermal stability can be prepared.

[0054] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A preparation method of a hard candy containing betacyanin with high thermal stability, characterized in that, It includes the following preparation steps: (1) Mix granulated sugar, malt syrup and buffer solution to obtain a syrup solution; (2) Heat the syrup solution to boil between 90 - 125 °C, then reduce the heating power to maintain the temperature without boiling. Add a polysaccharide stabilizer and beet red pigment while the syrup is not boiling, and continuously stir and keep warm for 5 - 15 min to mix evenly; (3) Add an antioxidant to the syrup in step (2) and stir for 1 - 3 min to mix evenly, then pour it into a mold and cool to form, obtaining beet red hard candy.

2. The preparation method of a hard candy containing betacyanin with high thermal stability according to claim 1, characterized in that, The buffer solution described in step (1) is an acetic acid - sodium acetate buffer solution with pH = 3 - 7.

3. The preparation method of a high heat stability betacyanin hard candy according to claim 1, characterized in that, The weight ratio of granulated sugar : malt syrup : buffer solution in step (1) is 5 : 1 - 3 : 1 - 5.

4. The preparation method of a high heat stability betacyanin hard candy according to claim 1, characterized in that, The addition amount of the beet red pigment described in step (2) is 0.01 - 0.06% of the weight of the syrup solution.

5. The preparation method of a hard candy containing betacyanin with high thermal stability according to claim 1, characterized in that, The polysaccharide stabilizer described in step (2) includes at least one of dextrin, maltodextrin, xanthan gum, sodium alginate, β - cyclodextrin, gum arabic, pectin, carrageenan, D(+)-galactose.

6. The preparation method of a high heat stability betacyanin hard candy according to claim 5, characterized in that, The weight ratio of the addition amount of the polysaccharide stabilizer to the weight of the beet red pigment is 0.1 - 2 :

1.

7. The preparation method of a high heat stability betacyanin hard candy according to claim 1, characterized in that, The antioxidant described in step (3) includes at least one of ascorbic acid, D - isoascorbic acid, gallic acid, anhydrous citric acid, citric acid, DL - malic acid, DL - tartaric acid.

8. The preparation method of a high heat stability betalain hard candy according to claim 7, characterized in that, The weight ratio of the addition amount of the antioxidant to the weight of the beet red pigment is 0.1 - 2 :

1.

9. A betacyanin hard candy, characterized in that, Prepared by the method according to any one of claims 1 to 8.

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