CN113861153B

CN113861153B - Method for preparing black rice anthocyanin particles through dry separation

Info

Publication number: CN113861153B
Application number: CN202111043474.0A
Authority: CN
Inventors: 马勤; 张名位; 张瑞芬; 池建伟; 刘磊; 黄菲; 贾栩超; 赵东; 董丽红; 黄志坚; 余谦
Original assignee: Guangdong Jiang Mao Yuan Grains And Oils Co ltd; Life No 1 Pharmaceutical Co ltd; Sericulture and Agri Food Research Institute GAAS
Current assignee: Guangdong Jiang Mao Yuan Grains And Oils Co ltd; Life No 1 Pharmaceutical Co ltd; Sericulture and Agri Food Research Institute GAAS
Priority date: 2021-09-07
Filing date: 2021-09-07
Publication date: 2023-04-25
Anticipated expiration: 2041-09-07
Also published as: CN113861153A

Abstract

The invention discloses a method for preparing black rice anthocyanin particles by dry separation. 2% -6% of the outermost layer of the black rice is selected as a raw material, the low-temperature continuous phase-change degreasing is adopted, the treatment time is short, the degreasing efficiency is high, the oxidation rancidity of black rice skin is reduced to the greatest extent, and the anthocyanin is not damaged; the microwave adopts a pulse type, so that long-time microwave heat generation is avoided; and further reduces degradation of anthocyanin by adopting a way of embedding granulation; the series of process flows are all carried out at low temperature, and degradation of anthocyanin is reduced to the greatest extent while stabilizing. The black rice anthocyanin particles prepared by the method have the characteristics of good dispersibility, high anthocyanin content, strong stability, rich phenolic acid, soluble dietary fibers, insoluble dietary fibers and the like; the black rice can be widely applied to the fields of food, cosmetics, medical rehabilitation and the like, realizes diversified production of high added value products, and further provides technical support.

Description

Method for preparing black rice anthocyanin particles through dry separation

Technical Field

The invention relates to the technical field of food processing. In particular to a method for preparing black rice anthocyanin particles by dry separation.

Background

Anthocyanin is a flavonoid compound and has various biological activities of resisting oxidation, resisting inflammation, reducing blood sugar, reducing blood fat and the like. At present, organic solvent extraction modes, such as ethanol, acetone and the like, are mostly adopted for preparing anthocyanin. However, anthocyanin has the characteristic of poor stability, and is processed by various processes in the extraction process, so that the extraction yield is low. And the extraction process uses a large amount of organic solvent, so that the raw material utilization rate is not high.

Black rice (Oryza sativa l.) is an excellent specialty rice resource, is rich in active ingredients such as anthocyanin, dietary fiber, etc., and is mainly enriched in black rice husks. The high-value utilization of the black rice can be promoted by efficiently preparing rich anthocyanin active substances in the black rice. Only extracting anthocyanin substances simply can cause loss of active ingredients such as black rice dietary fiber and the like. The anthocyanin content in the mature black rice husks can reach 1.5% -3.5%, the dietary fiber content can reach 30%, but the fat content in the black rice husks is high, and the black rice husks are extremely easy to oxidize, rancid and deteriorate under the action of lipase, so that the black rice husks cannot be stored for a long time. Although there are a number of ways to prevent or retard oxidative rancidity of fat in rice husks, these include: superheated steam, microwaves, ultrahigh pressure and the like, and have certain inhibition effects, but the treatment can directly or indirectly cause the loss of active ingredients in the black rice husks, especially anthocyanin. In addition, anthocyanin is easy to degrade in the storage process, so that the product quality is not ensured. How to reduce the oxidation rancidity of the black rice skin and reduce the degradation of anthocyanin is a key for realizing the efficient preparation of the black rice anthocyanin.

Disclosure of Invention

In order to overcome the defects and shortcomings of the prior art, the invention aims to provide a method for preparing black rice anthocyanin particles through dry separation.

It is another object of the present invention to provide black rice anthocyanin particles prepared by the above method.

The aim of the invention is achieved by the following technical scheme:

a method for preparing black rice anthocyanin particles by dry separation, which comprises the following steps:

(1) Grinding a certain amount of black rice brown rice into black rice peel, sieving to obtain black rice peel, and degreasing by adopting low-temperature continuous phase change extraction to obtain degreased black rice peel;

(2) Regulating the moisture content of defatted black rice husks, performing microwave treatment, drying the black rice husks subjected to the microwave treatment to obtain black rice husks subjected to microwave enzyme deactivation and curing, crushing and sieving to obtain Pi Chao micro powder of black rice;

(3) Mixing fructus Zizaniae Caduciflorae Pi Chao micropowder with starch, beta-cyclodextrin/pectin, citric acid and ascorbic acid, sieving, and oven drying to obtain fructus Zizaniae Caduciflorae anthocyanin granule.

The black rice selected in the step (1) is preferably high in maturity, rich in anthocyanin accumulation and other qualities meeting the first-grade rice requirements of the national rice standard (GB/T1354-2018).

In the step (1), the ground black rice husk accounts for 2-6% of the mass of the black rice. After the accuracy of the polished black rice husks exceeds 6%, the anthocyanin content can be obviously reduced, and the quality of raw materials is affected.

The screening in the step (1) is preferably carried out by a 10-20-mesh screen, and further by a 20-mesh screen. Can effectively remove broken rice particles in the black rice husk and reduce the impurity content.

In the step (1), the degreasing extraction solvent is normal hexane, the extraction temperature is 40-60 ℃ (further 45-50 ℃), and the water content of the material is preferably below 5%. The degreasing efficiency of low-temperature continuous phase-change extraction is high, and the rice bran oil obtained by extraction can be further utilized.

In the step (1), the extraction time is preferably 1 to 4 hours; further 1.5 to 3 hours.

In the step (2), the moisture content of the defatted black rice skin is preferably 24% -28%, and the thickness of the defatted black rice skin layer in the sample tray is 0.5-2 cm during microwave treatment, and more preferably 1cm.

In the step (2), in order to avoid the influence of long-time microwave heat generation on the active substance content of the black rice husk, the microwave is preferably in a pulse form: the power is 600-800 w, each time the work is 15-30 s, the interval is 30-50 s, and the work treatment time is 90-180 s; the method further comprises the following steps: the power is 700w, the interval is 40s, and the working treatment time is 120s every 20s of working.

In the step (2), the temperature of the drying is 45-55 ℃; further 50 ℃.

In the step (2), the moisture content of the dried black rice husk after the microwave treatment is preferably below 5%.

In the step (2), the crushing is performed by an ultrafine crusher, and the crushing is performed by sieving through a 80-120 mesh sieve, and further by sieving through a 100 mesh sieve;

in the step (3), the mass ratio of the black Mi Pichao micro powder, the starch, the beta-cyclodextrin/pectin, the citric acid and the ascorbic acid is preferably as follows: 100 parts of black rice Pi Chao micropowder, 3.4 to 3.6 parts of starch, 1.5 to 2.6 parts of beta-cyclodextrin/pectin, 0.1 to 0.2 part of citric acid and 0.025 to 0.045 part of ascorbic acid.

Further, in the step (3), the mass ratio of the black Mi Pichao micro powder, the starch, the beta-cyclodextrin/pectin, the citric acid and the ascorbic acid is preferably as follows: 100 parts of black rice Pi Chao micropowder, 3.4 to 3.6 parts of starch, 1.5 to 2 parts of beta-cyclodextrin/pectin, 0.1 to 0.2 part of citric acid and 0.025 to 0.045 part of ascorbic acid.

Still further, in the step (3), the mass ratio of the black Mi Pichao micro powder, the starch, the beta-cyclodextrin/pectin, the citric acid and the ascorbic acid is preferably as follows: 100 parts of black rice Pi Chao micropowder, 3.4 to 3.6 parts of starch, 1.5 to 2 parts of beta-cyclodextrin/pectin, 0.1 to 0.15 part of citric acid and 0.040 to 0.045 part of ascorbic acid.

In the step (3), sieving is preferably carried out by a 35-55 mesh sieve; further sieving with 40-50 mesh sieve;

in the step (3), the temperature of drying is preferably 40-55 ℃; further, the temperature is 45 to 50 ℃.

In the step (3), the mixture is dried until the moisture content is below 5%.

The black rice anthocyanin particles are prepared by the method.

Compared with the prior art, the invention has the following advantages and effects:

(1) In the invention, except black rice with high anthocyanin content is selected, 2% -6% of the outermost layer of rice bran is selected as the raw material, so that the initial high anthocyanin content of the raw material is ensured; in addition, the outermost layer of the rice bran is rich in phenolic acid active substances such as ferulic acid, p-coumaric acid and the like, has a certain auxiliary color effect, and can promote anthocyanin to be metabolized and utilized by an organism.

(2) The invention adopts a low-temperature continuous phase change method for degreasing, has short treatment time and high degreasing efficiency, reduces the oxidation rancidity of the black rice skin to the greatest extent, and has no damage to anthocyanin; the microwave adopts a pulse type, so that long-time microwave heat generation is avoided; the series of process flows are carried out at low temperature, and the thermal degradation of anthocyanin in the black rice husk is reduced to the maximum extent while the black rice husk is stabilized. And granulating the black rice husk ultrafine powder by adopting starch and beta-cyclodextrin/pectin to reduce anthocyanin degradation, and finally obtaining black rice anthocyanin particles.

(3) The black rice anthocyanin particles prepared by the invention have the characteristics of good dispersibility, high anthocyanin content, strong stability, low fat, low heat, superfine grinding wall breaking, fine taste, storage resistance and the like, and are rich in phenolic acid, soluble dietary fibers and insoluble dietary fibers. Solves the key problem of high added value utilization of the black rice skin, can be widely applied to the fields of food, cosmetics, medical rehabilitation and the like, realizes diversified production of high added value products, and further provides technical support.

Drawings

FIG. 1 is the anthocyanin and total phenol content of black rice husks obtained in example 1 at different milling accuracies.

FIG. 2 is the anthocyanin content of the black rice hulls after various treatments in example 2.

FIG. 3 shows the change in acid value of the black Mi Pichao micropowder after various treatments in example 2.

Fig. 4 is black rice anthocyanin granules prepared in example 4.

Detailed Description

The present invention will be described in further detail with reference to examples and drawings, but embodiments of the present invention are not limited thereto.

Method for measuring relevant parameters

Anthocyanin content determination

Accurately weighing 1.00g of black rice husk, placing into a 100mL centrifuge tube, adding precooled 30mL of acidified methanol solution (methanol and 1M HCl 85:15, v/v), mixing, homogenizing with a homogenizer ice bath (10000 rpm) for leaching for 5min, centrifuging (8000 Xg) for 10min, collecting supernatant, precipitating, repeating the above operation for 2 times, and mixing the supernatants to 100mL. Taking 1mL of anthocyanin extract, adding potassium chloride buffer (0.025M KCl,pH 1.0) and sodium acetate solution (0.4M CH) ₃ COONa·3H ₂ O, pH 4.5), diluting to a proper concentration, mixing uniformly, keeping away from light, standing for reaction for 20min, measuring absorbance values at 515nm and 700nm respectively by using a spectrophotometer, and calculating anthocyanin content according to a formula;

absorbance calculation: a= (a ₅₁₅ -A ₇₀₀ )pH 1.0-(A ₅₁₅ -A ₇₀₀ )pH 4.5

The total anthocyanin content was calculated using the following equation:

C＝(A/eL)×M×D×(V/W)

wherein C is total anthocyanin content (mg/g), A is measured absorbance, e is molar absorptivity of cyanidin-3-glucoside (26900L/cm/mol), L is optical path (1 cm), M is molecular weight of cyanidin-3-glucoside (449.2 g/mol), D is dilution factor, V is final volume (mL), and W is sample weight (g).

Black rice husk acid value determination

Weighing the sample about4-5 g of the mixture is placed in a conical flask with a sieve, 50mL of ethanol is added by a pipette, the mixture is plugged and shaken for a few seconds, the plug is opened for air release, the bottle stopper is closed again, the mixture is placed on a shaking table at 180rpm, the mixture is oscillated for 30 minutes, the mixture is taken out and then is transferred into a 100mL centrifuge tube, 8000 Xg of the mixture is centrifuged for 10 minutes, and the supernatant is transferred into the 50mL centrifuge tube. Accurately transferring 30mL of supernatant into a potentiometric titration cup, titrating with 0.05mol/L potassium hydroxide solution, and recording the consumed potassium hydroxide volume V when the final pH is 8.20 ₁ . Directly titrating 30mL of ethanol, and recording the volume V of the consumed potassium hydroxide ₀ . The acid value X is calculated as follows:

X＝((V ₁ -V ₀ )×C×56.1×50)/(m×(100-M)×30)

wherein X is the acid value (mg KOH/g), V ₁ Volume of KOH consumed by sample (mL), V ₀ Is the volume of KOH (mL) consumed by the blank, C is the actual concentration of KOH (mol/L), M is the sample mass (g), and M is the moisture content.

Example 1 different milling precision of the anthocyanin and phenolic acid content of black rice husk

Taking a certain amount of black rice brown rice, respectively grinding black rice husks accounting for 2%, 4%, 6%, 8% and 10% of the mass of the black rice by using a rice polisher, sieving with a 20-mesh sieve to obtain black rice husks with different grinding precision, measuring anthocyanin and phenolic acid contents, and measuring the phenolic acid monomer contents by using an HPLC method.

As a result, as shown in fig. 1, the anthocyanin and total phenol contents per gram of black rice husk gradually decreased as the milling accuracy increased, and the content decreasing rate was greater particularly when the milling accuracy increased from 6% to 8%.

The monomeric phenol content is shown in Table 1, ferulic acid, p-coumaric acid and protocatechuic acid are main phenolic acids in black rice husk, and the content also decreases with increasing milling precision.

TABLE 1

Example 2 Effect of different treatments on acid value and anthocyanin content of Black Rice husk

Grinding a certain amount of black rice brown rice into black rice husk accounting for 6% of the mass of black rice by a rice polisher, sieving with a 20-mesh sieve, wherein the reference group is untreated black rice husk, and the black rice husk of the low-temperature continuous phase change degreasing group is defatted black rice husk obtained by extracting with n-hexane at 50 ℃ for 1.5h by adopting low-temperature continuous phase change extraction equipment; the superheated steam treated black rice husk is obtained by treating black rice husk in autoclave at 121deg.C for 15min, and oven drying at 50deg.C until water content is below 5%. The black rice husks in the low-temperature continuous phase-change degreasing combined microwave treatment group are black rice husks in the low-temperature continuous phase-change degreasing group, the black rice husks are placed into a microwave oven for treatment, and a sample after microwave treatment is dried at 50 ℃ until the moisture content is below 5% to obtain the black rice husks. And (3) respectively treating the black rice husks of the different treatment groups by adopting an ultrafine grinder for 10 minutes, and sieving the black rice husks by a 100-mesh sieve to obtain Pi Chao micro powder of black rice. And (3) vacuumizing and packaging the black Mi Pichao micro powder of different treatment groups by using an aluminum foil self-sealing bag, and detecting the acid value and anthocyanin content of the black rice husks of different groups after strengthening and storing for 90 days in a 37 ℃ incubator.

As a result, as shown in fig. 2 and 3, the control group black rice husks contained a large amount of anthocyanin, but their acid values were rapidly increased with the increase of the storage time, and were severely rancid, and the superheated steam treatment group had only a slight increase in the acid value during the storage time, but the anthocyanin content was mostly destroyed by high temperature and high pressure, and only a small amount of anthocyanin was present. The low-temperature continuous phase-change degreasing group and the low-temperature continuous phase-change degreasing combined with microwave treatment group of the black rice husk anthocyanin retain a large amount of anthocyanin, and the acid value of the anthocyanin is stable and unchanged in the storage period.

Example 3 Effect of different granulation entrapment on storage stability of black rice husk anthocyanin

Mixing the black Mi Pichao micropowder subjected to the low-temperature continuous phase change degreasing combined with microwave treatment with starch, beta-cyclodextrin, citric acid and ascorbic acid, uniformly mixing, sieving, drying to obtain black rice anthocyanin particles, taking non-granulated black Mi Pichao micropowder as a control group, storing at room temperature for 6 months, and measuring anthocyanin retention rate in the particles.

As shown in Table 2, the non-granulated black rice husk anthocyanin retention rate was the lowest, but the anthocyanin retention rate was less improved than that of the control group when any one of the beta-cyclodextrin, citric acid and ascorbic acid was absent, and the anthocyanin retention rate was the highest up to 92.07% when the amounts of black Mi Pichao micropowder, starch, beta-cyclodextrin, citric acid and ascorbic acid added were 350g, 12g, 6g, 0.4g and 0.15g, respectively.

TABLE 2

Example 4: preparation of black rice anthocyanin particles

(1) Taking 20kg of black rice brown rice, grinding black rice husks accounting for 6% of the mass of black rice by a rice polisher, sieving with a 20-mesh sieve, and extracting with n-hexane at 45 ℃ for 3h for degreasing by adopting low-temperature continuous phase change extraction equipment to obtain defatted black rice husks.

(2) Regulating the moisture content of the defatted black rice husks to 24% -28%, wherein the thickness of the defatted black rice husks in a sample tray is about 1cm; and placing the mixture into a microwave oven for treatment. The microwaves are in a pulse form: the power is 700w, the interval is 40s, and the working treatment time is 120s every 20s of working. Drying the black rice husk subjected to microwave treatment at 50 ℃ until the moisture content is below 5%.

(3) Treating the black rice husk after microwave treatment with an ultra-micro pulverizer for 10 minutes, and sieving with a 100-mesh sieve to obtain Pi Chao black rice micropowder.

(4) Taking black rice Pi Chao micro powder, and taking the black rice Pi Chao micro powder according to the mass ratio: 12g of starch, 6g of beta-cyclodextrin, 0.6g of citric acid and 200mL of distilled water, heating by an electromagnetic oven, stirring and pregelatinizing, adding 0.1g of ascorbic acid and 350g of black Mi Pichao micro powder, uniformly mixing, sieving by a 40-mesh sieve, and drying at 50 ℃ until the moisture content is below 5%, thus obtaining the black rice anthocyanin particles.

(5) Vacuum packaging the aluminum foil self-sealing bag, and storing in a 37 ℃ incubator for 90d. The acid value was determined to be 0.56mg KOH/g according to GB 5009.229-2016 and the anthocyanin content was determined to be 25.3mg/g by pH differential.

The black rice anthocyanin granules prepared in the embodiment are shown in fig. 4, are rich in anthocyanin, have the dietary fiber content as high as 34g/100g and are good dietary supplements.

Example 5: preparation of black rice anthocyanin particles

(1) Taking 50kg of black rice brown rice, grinding black rice husks accounting for 2% of the mass of black rice by a rice polisher, sieving with a 20-mesh sieve, and extracting with n-hexane at 45 ℃ for 3h for degreasing by adopting low-temperature continuous phase change extraction equipment to obtain defatted black rice husks.

(4) Taking black rice Pi Chao micro powder, and taking the black rice Pi Chao micro powder according to the mass ratio: 12g of starch, 6g of beta-cyclodextrin, 0.6g of citric acid and 200mL of distilled water, heating by an electromagnetic oven, stirring and pregelatinizing, adding 0.1g of ascorbic acid and 350g of black Mi Pichao micro powder, uniformly mixing, sieving by a 40-mesh sieve, and drying at 45 ℃ until the moisture content is below 5%, thus obtaining the black rice anthocyanin particles.

(5) And (3) vacuumizing and packaging the aluminum foil self-sealing bag, storing the aluminum foil self-sealing bag in a 37 ℃ incubator for 90 days, measuring the acid value to be 0.53mg KOH/g according to GB 5009.229-2016, and measuring the anthocyanin content to be 28.5mg/g according to a pH differential method.

Example 6: preparation of black rice anthocyanin particles

(1) Taking 20kg of black rice brown rice, grinding black rice husks accounting for 4% of the mass of black rice by a rice polisher, sieving with a 20-mesh sieve, and extracting with n-hexane at 45 ℃ for 3h for degreasing by adopting low-temperature continuous phase change extraction equipment to obtain defatted black rice husks.

(4) Taking black rice Pi Chao micro powder, and taking the black rice Pi Chao micro powder according to the mass ratio: 12g of starch, 6g of pectin, 0.6g of citric acid and 200mL of distilled water, heating by an electromagnetic oven, stirring and pregelatinizing, adding 0.15g of ascorbic acid and 350g of black Mi Pichao micro powder, uniformly mixing, sieving by a 50-mesh sieve, and drying at 50 ℃ until the moisture content is below 5%, thus obtaining the black rice anthocyanin particles.

(5) Vacuum packaging the aluminum foil self-sealing bag, and storing in a 37 ℃ incubator for 90d. The acid value was measured according to GB 5009.229-2016 to be 0.55mg KOH/g and the anthocyanin content was measured by pH differential method to be 27.5mg/g.

The above examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above examples, and any other changes, modifications, substitutions, combinations, and simplifications that do not depart from the spirit and principle of the present invention should be made in the equivalent manner, and the embodiments are included in the protection scope of the present invention.

Claims

1. A method for preparing black rice anthocyanin particles by dry separation is characterized in that: the method comprises the following steps:

(1) Grinding a certain amount of black rice brown rice into black rice peel, sieving to obtain black rice peel, and degreasing by adopting low-temperature continuous phase change extraction to obtain degreased black rice peel; wherein, the ground black rice husk accounts for 2 to 6 percent of the mass of the black rice; the degreasing extraction solvent is n-hexane;

(3) Mixing fructus Zizaniae Caduciflorae Pi Chao micropowder with starch, beta-cyclodextrin, citric acid and ascorbic acid by wet method, sieving, and oven drying to obtain fructus Zizaniae Caduciflorae anthocyanin granule; wherein, the mass ratio of the black Mi Pichao micro powder, the starch, the beta-cyclodextrin, the citric acid and the ascorbic acid is as follows: 100 parts of black rice Pi Chao micro powder, 3.4 to 3.6 parts of starch, 1.5 to 2.6 parts of beta-cyclodextrin, 0.1 to 0.2 part of citric acid and 0.025 to 0.045 part of ascorbic acid.

2. The method according to claim 1, characterized in that:

in the step (3), the mass ratio of the black Mi Pichao micro powder, the starch, the beta-cyclodextrin, the citric acid and the ascorbic acid is as follows: 100 parts of black rice Pi Chao micro powder, 3.4 to 3.6 parts of starch, 1.5 to 2 parts of beta-cyclodextrin, 0.1 to 0.2 part of citric acid and 0.025 to 0.045 part of ascorbic acid.

3. The method according to claim 2, characterized in that:

in the step (3), the mass ratio of the black Mi Pichao micro powder, the starch, the beta-cyclodextrin, the citric acid and the ascorbic acid is as follows: 100 parts of black rice Pi Chao micro powder, 3.4 to 3.6 parts of starch, 1.5 to 2 parts of beta-cyclodextrin, 0.1 to 0.15 part of citric acid and 0.040 to 0.045 part of ascorbic acid.

4. A method according to any one of claims 1 to 3, characterized in that:

sieving in the step (1) to obtain a sieve with 10-20 meshes;

in the step (1), the extraction temperature is 40-60 ℃, and the moisture content of the materials is below 5%;

in the step (1), the extraction time is 1-4 h.

5. A method according to any one of claims 1 to 3, characterized in that:

in the step (2), the moisture content of the defatted black rice skin is 24% -28%, and the thickness of the defatted black rice skin layer in the sample tray is 0.5-2 cm during microwave treatment;

in the step (2), the microwave adopts a pulse type form as follows: the power is 600-800 w, each time the work is 15-30 s, the interval is 30-50 s, and the work treatment time is 90-180 s;

in the step (2), the temperature of the drying is 45-55 ℃;

in the step (2), the moisture content of the dried black rice husks after the microwave treatment is below 5%;

in the step (2), the crushing is performed by an ultrafine crusher, and the crushed materials are sieved to pass through a sieve of 80-120 meshes.

6. The method according to claim 5, wherein:

in the step (2), the thickness of the defatted black rice cortex in the sample tray is 1cm during microwave treatment;

in the step (2), the microwave adopts a pulse type form as follows: the power is 700w, the interval is 40s, and the working processing time is 120s every 20s of working;

in the step (2), the temperature of the drying is 50 ℃;

in the step (2), sieving is 100 mesh sieving.

7. A method according to any one of claims 1 to 3, characterized in that:

in the step (3), sieving is carried out by a sieve with 35 to 55 meshes;

in the step (3), the temperature of drying is 40-55 ℃;

in the step (3), the mixture is dried until the moisture content is below 5%.

8. The method according to claim 7, wherein:

in the step (3), sieving is carried out by a 40-50 mesh sieve;

in the step (3), the temperature of drying is 45-50 ℃.