CN103478739B - A kind of high-quality garlic skin dietary fiber and preparation method thereof - Google Patents

Abstract

The invention discloses a high-quality garlic skin dietary fiber and a preparation method thereof, and relates to the technical field of deep processing of agricultural products. Follow the steps below: crush and sieve the dried garlic skin to obtain garlic skin powder, use enzymatic hydrolysis, chemical method, enzyme-chemical method and other techniques to extract the dietary fiber in garlic skin, and then use enzymatic method and microbial fermentation method High-quality dietary fiber can be obtained by modifying the dietary fiber in garlic skin by chemical, compound and other methods. The content of soluble dietary fiber in the dietary fiber prepared by using garlic skin as a raw material in the present invention is as high as 30%, and has light color, good water absorption, large expansion force and strong oxidation resistance, and is a high-quality dietary fiber.

Description

A kind of high-quality garlic skin dietary fiber and its preparation method

technical field

The invention relates to the technical field of deep processing of agricultural products, in particular to high-quality dietary fiber prepared by using garlic skin as a raw material to extract and modify the dietary fiber contained in it.

Background technique

Dietary fiber (DF) is a general term for a class of edible plant components and their analogs that cannot be digested and absorbed by the human small intestine, but can be partially or fully fermented in the large intestine, including cellulose, hemicellulose, lignin , pectin and related plant matter. Dietary fiber is divided into insoluble dietary fiber (insoluble dietary fiber, IDF) and soluble dietary fiber (soluble dietary fiber, SDF). IDF mainly acts on the intestinal tract to produce mechanical peristalsis, while SDF exerts more metabolic functions, such as promoting the proliferation of lactic acid bacteria, regulating blood sugar, lowering blood fat, lowering cholesterol, lowering blood pressure and other physiological functions. Therefore, the proportion of SDF in dietary fiber is an important factor affecting the physiological function of dietary fiber. Scholars such as Leitz in the United States suggest that high-quality dietary fiber is only high-quality dietary fiber if the SDF content in the dietary fiber composition reaches more than 10%, otherwise it can only be called a filler-type dietary fiber. Dietary fiber products from different sources and with different structures have different physiological functions. Therefore, when developing dietary fiber, those dietary fiber raw materials with relatively good physiological functions should be selected in order to obtain a new generation of high-quality dietary fiber food with good taste and function.

Garlic is a perennial herb of Liliaceae. my country produces 11 million tons of garlic annually. It is an important garlic producing and trading country, accounting for more than 70% of the world's output and trade volume. Garlic is not only an indispensable condiment in people's life, but also has good health care and therapeutic effects, such as lowering blood lipids, preventing thrombosis, inhibiting cancer cell growth, and lowering blood sugar. Garlic products currently popular in the market, such as garlic flakes, garlic powder, garlic granules, garlic oil, pickled garlic, garlic polysaccharides, etc., all need to remove the garlic skin during processing. For example, the production of 1 ton of garlic essential oil and 15 tons of garlic polysaccharides can Consume 300 tons of fresh garlic, of which about 20% of the raw materials are garlic skins. Garlic skin is a by-product of garlic processing, and its soluble dietary fiber accounts for less than 10%, which is far lower than the high-quality dietary fiber requirement. Therefore, along with the rapid development of the garlic processing industry, its output is increasing, and the demand for the development of garlic skin is becoming more and more urgent.

Contents of the invention

The present invention aims to provide a high-quality dietary fiber with light color, high yield, good water absorption, large expansion force and strong oxidation resistance, so as to increase the added value of intensively processed agricultural products. In order to achieve the purpose, the present invention uses the by-product garlic skin of deep processing of garlic as raw material to prepare high-quality garlic skin dietary fiber.

A kind of preparation method of high-quality garlic peel dietary fiber is carried out according to the following steps:

(1) Dried, crushed and sieved the garlic raw material;

(2) extracting the dietary fiber from the raw materials processed in step (1);

(3) Molecular modification of dietary fiber;

(4) The modified solution is dried to obtain high-quality dietary fiber.

The raw material in the step (1) of the present invention comes from one or both of white-skinned garlic or purple-skinned garlic.

The extraction of dietary fiber in the step (2) of the present invention can be carried out by enzymatic hydrolysis, chemical method or enzyme-chemical method.

The enzyme and reaction conditions used in the enzymatic hydrolysis method are as follows: according to the mass ratio of enzyme and substrate (E/S), add amylase at 2% and react at 95°C for 35 minutes; according to the mass ratio of enzyme and substrate (E/S), Add protease at a ratio of 0.5%, react at 60°C for 30 minutes; add glucosidase at 0.01% according to the mass ratio of enzyme and substrate (E/S), and react at 60°C for 30 minutes; the chemical reagents used in the chemical method include: acid (0.1MH ₂ SO ₄ , hydrolyzed at 50°C for 2h), alkali (0.5MNaOH, hydrolyzed at 50°C for 3h), ethanol (95% ethanol, kept at 50°C for 2h); the enzyme-chemical method refers to the combination of enzymatic hydrolysis and Several chemical methods are used in combination according to the above conditions.

The modification of dietary fiber in step (3) of the present invention can be realized by enzymatic method, microbial fermentation method, chemical method and composite treatment method. The enzymes used in the enzymatic method include one or more of cellulase, xylanase, lignin oxidase, etc. (E/S3%, 50°C reaction for 3h); the reagents used in the chemical treatment method include acid (H ₂ SO ₄ , pH2.0, hydrolysis at 50°C for 1h), alkali (NaOH, pH12, hydrolysis at 50°C for 2h), carboxymethylation (at 40°C, the concentrations of NaOH and monochloroacetic acid are 0.3M each); microbial fermentation method is Utilize plant lactic acid bacteria to ferment; the composite treatment method includes chemical, enzyme and microbial fermentation methods combined successively according to the above conditions.

The drying method in step (4) of the present invention includes drying methods such as oven drying at 50°C, freeze drying at -20°C and spray drying (inlet air temperature 150°C, outlet air temperature 60°C).

The garlic skin dietary fiber product obtained by the present invention contains 18%-30% of soluble dietary fiber and 82%-70% of insoluble dietary fiber.

The present invention has the advantages of: taking the by-product garlic peel of garlic with relatively good physiological function as raw material, extracting dietary fiber, modifying the molecular composition of dietary fiber, so that the proportion of soluble dietary fiber is as high as 30%, and obtaining The product is light in color, high in yield, good in water absorption, large in swelling force and strong in oxidation resistance, and is a high-quality dietary fiber.

detailed description

The content of soluble dietary fiber in dietary fiber was determined according to the national standard GB/T5009.88-2008 of the People's Republic of China.

The present invention will be described in further detail below in conjunction with the examples, but the embodiments of the invention are not limited thereto.

Example 1

(1) Pulverization: crush and sieve the garlic skin of white-skinned garlic dried in an oven at 50°C to obtain garlic skin powder.

(2) Extraction of dietary fiber: Weigh 1.0g of garlic peel powder, add 25mL of distilled water, adjust the pH to 8.0, add 1mL of α-amylase with a concentration of 20mg/mL, react at 95°C for 35min; after reaction, cool to 60°C , adjust the pH to 7.0, add 100 μL of 50 mg/mL papain, bathe in 60°C water for 30 minutes, then add 5 mL of 3 mol/L acetic acid solution, adjust the pH to about 4.5, add 100 μL of glycosidase solution, and react at 60°C for 30 minutes; Precipitate with 4 times the volume of 95% ethanol for 1 h, centrifuge at 5000 rpm for 15 min, wash the precipitate once with 78% ethanol, 95% ethanol, and acetone, and dry in an oven at 50°C to obtain dietary fiber.

(3) Modification and drying: put 1.0g of dietary fiber in the above step (2) into 20mL of pH 6.0 phosphate buffer, then add 3% cellulase, keep warm in a constant temperature water bath at 50°C, and put it in place immediately after 3h. Put it in a water bath at 100°C to inactivate the enzyme for 15 minutes, add 4 times the volume of 95% ethanol to the enzymolysis solution to precipitate for 1 hour, centrifuge at 5000 rpm for 15 minutes, wash the precipitate once with 78% ethanol, 95% ethanol, and acetone, and freeze-dry at -20°C to obtain The modified high-quality dietary fiber is determined to be 30% soluble dietary fiber and 70% insoluble dietary fiber.

Example 2

(1) Pulverization: crush and sieve the garlic skin of the purple-skinned garlic after freeze-drying to obtain garlic skin powder.

(2) Extraction of dietary fiber: Weigh 1.0g of garlic skin powder, add water according to the ratio of material to liquid 1:10, and add 1M H ₂ SO ₄ solution to make the final concentration 0.1M, put it in a constant temperature water bath at 50°C for 2 hours for hydrolysis, Filter and wash with hot water 2 to 3 times until the filter residue is neutral. Then add 10mL NaOH with a concentration of 1.0M to extract at room temperature for 2 hours, add 4 times the volume of 95% ethanol to the hydrolyzate to precipitate for 1 hour, centrifuge at 5000rpm for 15 minutes, wash the precipitate with 78% ethanol, 95% ethanol, and acetone once respectively, at 50°C Oven drying to obtain dietary fiber.

(3) Modification and drying: put 1.0g of dietary fiber in the above step (2) into 20mL of pH6.0 phosphate buffer, then add 3% xylanase, cover with tinfoil, and place in a constant temperature water bath at 50°C After 3 hours, put it into a 100°C water bath to inactivate the enzyme for 15 minutes, add 4 times the volume of 95% ethanol to the enzymolysis solution for precipitation for 1 hour, centrifuge at 5000 rpm for 15 minutes, and wash the precipitate with 78% ethanol, 95% ethanol, and acetone once respectively. After drying in an oven at 50°C, high-quality dietary fiber was obtained. It was determined that 25% of the soluble dietary fiber and 75% of the insoluble dietary fiber contained in the product.

Example 3

(1) Pulverization: crush and sieve the garlic skin of white-skinned garlic after infrared drying to obtain garlic skin powder.

(2) Extraction of dietary fiber: Weigh 10.0g of garlic skin powder, add 0.5M NaOH 100mL, hydrolyze in a constant temperature water bath at 60°C for 3h, add 4 times the volume of 95% ethanol to the hydrolyzate for precipitation for 1h, centrifuge at 5000rpm for 15min, and use for precipitation Wash once with 78% ethanol, 95% ethanol, and acetone, and dry in an oven at 50°C to obtain dietary fiber.

(3) Modification and drying: put 1.0g of dietary fiber in the above step (2) into 20mL of pH6.0 phosphate buffer, then add 3% lignin oxidase, cover with tinfoil, and place in a constant temperature water bath at 50°C After 3 hours, put it into a 100°C water bath to inactivate the enzyme for 15 minutes, add 4 times the volume of 95% ethanol to the enzymolysis solution for precipitation for 1 hour, centrifuge at 5000 rpm for 15 minutes, and wash the precipitate with 78% ethanol, 95% ethanol, and acetone once respectively. After drying in an oven at 50°C, high-quality dietary fiber was obtained. It was determined that the soluble dietary fiber in the product was 18%, and the insoluble dietary fiber was 82%.

Example 4

(1) Pulverization: crush and sieve the garlic skin of white-skinned garlic after infrared drying to obtain garlic skin powder.

(2) Extraction of dietary fiber: Weigh 10.0g of garlic skin powder, add 100mL of 95% ethanol, incubate at 50°C for 2h, centrifuge at 5000rpm for 15min, wash the precipitate once with 78% ethanol, 95% ethanol, and acetone, respectively, 50 ℃ oven drying to obtain dietary fiber.

(3) Modification and drying: put 1.0g of the dietary fiber in the above step (2) into 20mL of water, add NaOH and monochloroacetic acid to a final concentration of 0.3M, alkalinize in a constant temperature water bath at 40°C for 1h, etherify for 2h, Add 4 times the volume of 95% ethanol to the reaction solution to precipitate for 1 hour, centrifuge at 5000 rpm for 15 minutes, wash the precipitate once with 78% ethanol, 95% ethanol, and acetone, and then spray dry it with a spray dryer (inlet air temperature 150°C, outlet air temperature 60°C), collect the dry powder, and obtain high-quality dietary fiber. It is determined that the soluble dietary fiber in the product is 21%, and the insoluble dietary fiber is 79%.

Example 5

(1) Pulverization: crush and sieve the garlic skin of purple-skinned garlic dried at 50°C to obtain garlic skin powder.

(2) Extraction of dietary fiber: Weigh 1.0g of garlic peel powder, add 25mL of distilled water, adjust the pH to 8.0, add 1mL of α-amylase with a concentration of 20mg/mL, react at 95°C for 35min; after reaction, cool to 60°C , adjust the pH to 7.0, add 100 μL of 50 mg/mL papain, bathe in 60°C water for 30 minutes, then add 5 mL of 3 mol/L acetic acid solution, adjust the pH to about 4.5, add 100 μL of glycosidase solution, and react at 60°C for 30 minutes; Precipitate with 4 times the volume of 95% ethanol for 1 h, centrifuge at 5000 rpm for 15 min, wash the precipitate once with 78% ethanol, 95% ethanol, and acetone, and dry in an oven at 50°C to obtain dietary fiber.

(3) Modification and drying: put 10.0g of dietary fiber in the above step (2) into 200mL pH6.0 phosphate buffer, then add 3% cellulase, keep warm in a constant temperature water bath at 50°C, and put it away immediately after 3 hours. Inactivate the enzyme in a 100°C water bath for 15 minutes. Adjust the concentration of dietary fiber to 2%, then add skimmed milk powder and sucrose to make the concentration 12% and 8%, pack them in triangular flasks, put them in an autoclave, sterilize at 121°C for 30 minutes, and inoculate into plants Lactic acid bacteria, at 37°C for 24 hours, the fermentation product was homogeneously pulverized and spray-dried to obtain high-quality dietary fiber. It was determined that the soluble dietary fiber in the product was 23%, and the insoluble dietary fiber was 77%.

Claims (1)

1. a preparation method of high-quality garlic peel dietary fiber is characterized in that it is carried out according to the following steps: (1) Dried, crushed and sieved the garlic raw material; (2) extracting the dietary fiber from the raw materials processed in step (1); (3) Molecular modification of dietary fiber; (4) The modified solution is dried to obtain high-quality dietary fiber; The raw material in the step (1) comes from one or both of the garlic skins of white-skinned garlic or purple-skinned garlic; In the step (2), the dietary fiber is extracted by enzymatic hydrolysis, chemical method or enzyme-chemical method; The enzyme and reaction conditions used in the enzymatic hydrolysis method described therein are as follows: add amylase at 2% according to the mass ratio of enzyme to substrate, and react at 95°C for 35 minutes; then add protease at 0.5% according to the mass ratio of enzyme to substrate, and React for 30 minutes; add 0.01% glucosidase according to the mass ratio of enzyme and substrate, and react for 30 minutes at 60°C; The chemical reagents used in the chemical method are: 0.1MH ₂ SO ₄ , hydrolyzed at 50°C for 2h; 0.5MNaOH, hydrolyzed at 50°C for 3h; 95% ethanol, one or more of them at 50°C for 2h; The modification of dietary fiber in the step (3) is realized by enzymatic method, microbial fermentation method, chemical method or composite treatment method; The enzyme used in the enzymatic method is one or more of cellulase, xylanase, and lignin oxidase, and the enzyme is added at 3% according to the mass ratio of the enzyme to the substrate, and the reaction is carried out at 50°C for 3 hours; The chemical treatment reagent is H ₂ SO ₄ , pH 2.0, hydrolysis at 50°C for 1 hour or NaOH, pH 12, hydrolysis at 50°C for 2 hours; The drying method in the step (4) is one or more of 50°C oven drying, -20°C freeze-drying or spray drying, wherein the inlet air temperature in spray drying is 150°C, and the outlet air temperature is 60°C.