CN100562543C - A method for extracting natural melanin from black rice leaves - Google Patents

Abstract

A kind of from myrtillin leave the method for extraction of natural melanin, be main raw material with the natural phant myrtillin leave, adopt zymin in conjunction with the solvent extraction natural black pigment.The preparation method may further comprise the steps: get the raw materials ready, prepare buffered soln, preparation enzyme liquid, feed intake, enzymolysis, extraction and finished product.Utilize the natural black pigment of method preparation of the present invention, Product Safety is good, quality is good, and enzyme preparation amount is few, and the melanochrome extraction yield is followed the example of high by 30～40% than alcohol extracting, and technology is simple, and is easy to operate, and the efficient height is fit to suitability for industrialized production.

Description

A method for extracting natural melanin from black rice leaves

Technical field

The invention relates to a method for extracting natural pigment, in particular to a method for extracting natural melanin from the leaves of black rice plant.

Background technique

Melanin in plants has various pharmacological activities such as promoting resynthesis of retinoid, Vp-like function, improving blood microcirculation, anti-ulcer, anti-inflammation, and anti-aging. It includes various pigment components such as anthocyanins and flavonoid pigments, and the extraction of melanin is mainly by solvent extraction.

"Food and Fermentation Industry" published the article "Extraction and Separation and Purification of Flavonoid Pigments in the Leaves of Wufan" by Wang Li and Yao Yuanhui in Volume 30, Issue 9, 2004, and established the best extraction conditions for flavonoid pigments: extraction times 2 times , ethanol volume fraction 60%, temperature 60°C, solid-liquid ratio 1g: 35ml.

"Chinese Wild Plant Resources" published the article "Extraction Process and Pigment Properties of Black Rice Leaf Pigment" by Hu Zhijie and Jiang Ping in the 4th issue of volume 22 in 1997. The optimum condition is that the total extraction time does not exceed 6.5 hours.

The invention patent "Method of Extracting Melanin from Black Sesame" (Application No.: 91104469.8) introduces a method of extracting melanin from black sesame with alkaline solution.

"A Comparative Study on the Properties of Natural Pigments in Black Rice, Black Soybeans, and Black Sesame" published by Zhang Mingwei and Sun Ling in the 1998 Volume 13 Issue 2 of "Journal of China Cereals and Oils", which introduced hydrochloric acid ethanol solvent combined column layer Analysis of the method of extracting melanin.

The extraction methods of the above-mentioned melanin all do not use enzyme preparations, which affect the extraction rate of melanin.

Contents of the invention

The object of the present invention is to utilize enzyme preparation combined with solvent to extract melanin in the leaves of black rice plant, and improve the extraction rate of melanin.

A kind of method of extracting natural melanin from black rice leaf of the present invention, raw material is black rice leaf, reagent has pectinase (30000IU), cellulase (15000IU), 95% ethanol (food grade), citric acid (foodstuff) grade), disodium hydrogen phosphate (food grade).

A kind of method of extracting natural melanin from black rice leaf of the present invention, is made up of following steps:

(1) Material preparation: dry and pulverize the fresh black rice leaves, and sieve with 40 meshes to obtain dried black rice leaves powder for later use.

(2) Preparation of buffer solution: Mix 0.1 mol/L citric acid solution and 0.2 mol/L disodium hydrogen phosphate solution at a volume ratio of 1:1.5~2, then dilute with water twice to prepare a buffer solution.

(3) Enzyme liquid preparation: mixed buffer solution, pectinase and cellulase, and fully stirred to make it dissolve completely, thereby forming a uniform enzyme liquid; the consumption of buffer solution is by the weight of black rice leaf dry powder (kg): buffer solution Volume (L) = 1:15-30 ratio calculation; the dosage of pectinase and cellulase is 0.1-0.3g pectinase and 0.1-0.3g cellulase per L of buffer solution.

(4) Feeding: according to the ratio of the dry powder of black rice leaves powder (kg): buffer solution volume (L) = 1: 15-30, the dry powder of black rice leaves is added to the enzyme solution.

(5) Enzymolysis: Stir the dry powder of black rice leaves and enzyme solution evenly, keep it in a constant temperature water bath at 50-55°C in the dark, keep it warm, stir once every 30 minutes, and enzymolysis for 3-4 hours to generate enzymolysis solution and residue mixture.

(6) Extraction: According to the method of adding 15-30L of 75-97% ethanol per kg of black rice leaf dry powder, 75-97% ethanol is added to the above-mentioned enzymolysis solution and residue mixture, and extracted at 60-65°C for 2 ~3h, after filtration, a black extract was obtained.

(7) Finished product: put the black extract in an oven at 60-70°C and dry until constant weight to obtain natural melanin.

A kind of method of extracting natural melanin from the leaf of black rice plant of the present invention, take the leaf of natural plant black rice plant as main raw material, adopt enzyme preparation combined with solvent to extract natural melanin, its advantage is that natural melanin product safety is good, good quality (see table 1), the extraction rate of melanin is 30-40% higher than that of the alcohol extraction method, the dosage of enzyme preparation is less, the process is simple, the operation is convenient, the efficiency is high, and it is suitable for industrial production. The use of pectinase and cellulase can destroy the cell wall structure mainly composed of cellulose in plant materials and the pectin substances connected between cells, reduce the resistance of extraction and mass transfer, and make the melanin component of the content easy to dissolve. Ethanol solution is used as the extraction solvent of alcohol-soluble melanin. The citric acid-phosphate buffer solution plays the role of adjusting the pH value of the solution. The pH of the buffer solution prepared by the method of the present invention is 6, which can ensure the best effect of the enzyme preparation.

Get the melanin extract of the present invention and the melanin extract that alcohol extraction obtains, all dilute 100 times, with ultraviolet spectrophotometer, under the maximum absorption wavelength 243nm of pigment, measure its absorbance (see Table 1). The light absorption value of the melanin extracted by the enzymatic method combined with the solvent of the present invention is 0.538, which is obviously higher than the light absorption value of 0.417 extracted by the alcohol extraction method; the calculated extraction rate is 30% higher than that of the alcohol extraction method.

Table 1 Comparison of absorbance values between enzymatic combined solvent extraction and alcohol extraction

Specific examples:

In order to fully disclose a method of extracting natural melanin from the leaves of black rice plant of the present invention, it will be described below in conjunction with the examples.

Embodiment: A kind of method of extracting natural melanin from black rice leaf

The natural black rice leaves with a harvest period of 5-6 months are taken as raw materials, and the extraction method includes the following steps:

(1) Dry the fresh leaves of the black rice tree in an oven at 65°C, pulverize them with a high-speed tissue grinder, and sieve them through a 40-mesh sieve to obtain dry powder of the black rice tree leaves for use.

(2) Take 180ml of 0.1mol/L citric acid solution and 320ml of 0.2mol/L disodium hydrogen phosphate solution, mix and dilute to 1000ml to prepare a buffer solution.

(3) Take 250ml of buffer solution, add 0.05g of pectinase and 0.075g of cellulase, stir to dissolve completely, and form a uniform enzyme solution.

(4) Add 10 g of dry powder of black rice leaves to the above-mentioned enzyme liquid.

(5) After stirring evenly, keep it in a constant temperature water bath at 50°C in the dark and keep it warm, stir once every 30 minutes, and perform enzymatic hydrolysis for 3 hours to generate a mixture of enzymatic hydrolysis solution and residue.

(6) Add 250ml of 95% ethanol to the mixture of enzymolysis solution and residue, extract at 60°C for 2 hours, and filter to obtain a black extract.

(7) Dry the black extract in an oven at 65° C. to constant weight to obtain natural melanin.

Claims (2)

1. A method for extracting natural melanin from black rice leaves, characterized in that it consists of the following steps: (1) Prepare materials: dry and pulverize the fresh black rice leaves, and sieve through 40 meshes to obtain the dried black rice leaves powder for subsequent use; (2) Preparation of buffer solution: mix 0.1mol/L citric acid solution and 0.2mol/L disodium hydrogen phosphate solution at a volume ratio of 1:1.5-2, then dilute with water twice to prepare a buffer solution; (3) Enzyme liquid preparation: mix buffer solution, pectinase and cellulase, and fully stir to make it dissolve completely, thereby form uniform enzyme liquid; The consumption of buffer solution is by the dry powder weight (kg) of black rice leaf: buffer solution Volume (L)=1:15～30 ratio calculation; the dosage of pectinase and cellulase is to add 0.1～0.3g pectinase and 0.1～0.3g cellulase per L of buffer solution; (4) Feed intake: add the dry powder of leaves of black rice into the enzyme liquid according to the ratio of the dry powder weight of black rice leaves (kg): buffer solution volume (L)=1: 15～30; (5) Enzymolysis: Stir the dry powder of black rice leaves and enzyme solution evenly, keep it in a constant temperature water bath at 50-55°C in the dark, keep it warm, stir once every 30 minutes, and enzymolysis for 3-4 hours to generate enzymolysis solution and residue mixture; (6) Extraction: According to the method of adding 15-30L of 75-97% ethanol per kg of black rice leaf dry powder, 75-97% ethanol is added to the above-mentioned enzymolysis solution and residue mixture, and extracted at 60-65°C for 2 ~3h, after filtering, a black extract was obtained; (7) Finished product: put the black extract in an oven at 60-70°C and dry until constant weight. 2. A method for extracting natural melanin from black rice leaves according to claim 1, characterized in that it consists of the following steps: (1) Place fresh black rice leaves and dry them in an oven at 65°C, pulverize them with a high-speed tissue grinder, and sieve them through a 40-mesh sieve to obtain dried black rice leaves powder for subsequent use; (2) Take 180ml of 0.1mol/L citric acid solution and 320ml of 0.2mol/L disodium hydrogen phosphate solution, mix and dilute to 1000ml, and prepare a buffer solution; (3) Take 250ml of buffer solution, add 0.05g of pectinase and 0.075g of cellulase, stir to make it dissolve completely, and form a uniform enzyme solution; (4) add 10g of black rice leaf dry powder in above-mentioned enzyme liquid; (5) After stirring evenly, keep it in a constant temperature water bath at 50°C in a dark place, stir once every 30 minutes, and enzymatically hydrolyze for 3 hours to generate a mixture of enzymatic hydrolyzate and residue; (6) Add 250ml of 95% ethanol to the mixture of enzymolysis solution and residue, extract at 60°C for 2 hours, and filter to obtain a black extract; (7) Place the black extract in an oven at 65°C and dry until constant weight.