CN109984320B - A kind of preparation method of low viscosity yam powder - Google Patents

Abstract

The invention belongs to the technical field of food processing, and particularly relates to a preparation method of low-viscosity yam powder. In the present invention, two kinds of yam with different yam mucopolysaccharide contents are firstly selected, and then the mixed yam is cleaned, sliced, pulped, etc., and the moisture content of the yam powder is reduced to 20-30% by moderate vacuum drying, and then the yam powder is heated at high temperature. Remove remaining moisture to form low viscosity yam powder. In the invention, the yam polysaccharide is completely coated on the surface of the starch granules to form a dense thin layer, so that the yam powder is difficult to absorb water during the heating and gelatinization process, and the expansion and gelatinization of the starch granules is prevented, so that the yam powder has a relatively high performance. low viscosity.

Description

A kind of preparation method of low viscosity yam powder

technical field

The invention belongs to the technical field of food processing, and particularly relates to a preparation method of low-viscosity yam powder.

Background technique

Yam is not only a common food, but it is also used as a traditional Chinese medicine to treat diabetes, diarrhea, asthma, jaundice and other diseases. Chinese yam contains active ingredients such as mucin, diosgenin, allantoin, choline, phytosterol, oligosaccharides and essential amino acids, which have strong commercial value and research value. Fresh yam has a high water content and is not easy to store. It is easy to rot and deteriorate during storage. The emergence of yam powder solves the problem of transportation and storage of fresh yam. Yam powder has been used in liquid foods such as beverages. When applied to these products, yam powder is required to have low viscosity to improve the ease of processing and product fluidity and taste. However, due to the large amount of mucopolysaccharide and starch contained in yam, yam In the process of powder dissolving, caking and sticking are prone to occur, which makes the product easy to become viscous and has poor stability. Therefore, it is necessary to develop low-viscosity yam powder for the production of yam-containing beverages and other liquid foods.

SUMMARY OF THE INVENTION

In order to make up for the deficiencies of the prior art, the present invention provides a preparation method of low-viscosity yam powder.

The present invention is achieved through the following technical solutions:

A method for preparing low-viscosity yam powder, comprising the following steps:

(1) Selection of raw materials: select yam with higher content of mucopolysaccharide and yam with lower content of mucopolysaccharide as raw materials for preparing yam powder; the mass ratio of yam with higher content of mucopolysaccharide to yam with lower content of mucopolysaccharide is: 1 :4-1:6.

(2) Pretreatment: Wash and peel the above-mentioned raw materials, and cut them into 3-4mm thin slices.

(3) Beating: After the yam flakes are protected for color, they are beaten by a colloid mill to form a yam paste.

(4) Adjust the pH value: adjust the pH value of the yam pulp to 8.0-9.0 with a concentration of 1mol/L NaOH solution.

(5) Homogenization: Homogenize the yam pulp once under the condition of 20-40Mpa.

(VI) Drying: The homogenized yam pulp is dried under the conditions of vacuum degree of 0.9Mpa and 50°C until the moisture content is 20%-30%.

(7) Heat treatment: After the dried yam is pulverized, it is heated at 110-130°C for 4-6 hours to obtain low-viscosity yam powder.

As a preferred option:

In the step (1), the yam with higher mucopolysaccharide content is any one of Japanese white yam, long taro yam, and water yam; the yam with lower mucopolysaccharide content is any one of iron yam and fine-haired yam.

In the step (6), a vacuum drying oven is used for drying.

In the step (7), a hot air drying oven is used for heating treatment.

The selection of yam varieties in the present invention is very important, which directly affects the viscosity of the final prepared yam powder, and the selection of raw materials has undergone various theoretical studies and experimental demonstrations. The reason why two kinds of yam were selected as raw materials for preparation is that the varieties of yam with high mucopolysaccharide content, such as Japanese white yam, long taro yam, and water yam, not only have high mucopolysaccharide content, but also high moisture content, and the drying energy consumption is relatively high. However, the yam with low mucopolysaccharide content, such as iron yam and fine-haired yam, has low moisture content, high starch content, and low drying energy consumption, and the obtained yam powder has a significant heating viscosity. Increase. Based on this, the present invention selects two kinds of yam with high viscosity and low viscosity as raw materials, on the one hand, the characteristics of the two kinds of yam can be integrated, and the production cost of yam powder can be effectively reduced; , to make yam polysaccharide adhere to the surface of starch granules, and form a dense polysaccharide film on the surface of starch granules. The yam varieties with high mucopolysaccharide content have high mucopolysaccharide content, but their drying speed is slow, and the processing cost is higher if used alone. The yam varieties with low mucopolysaccharide content are difficult to form a dense polysaccharide film on the surface of starch granules because of the low mucopolysaccharide content. Therefore, the present invention selects two kinds of yam with high mucopolysaccharide content and low mucopolysaccharide content as raw materials, and determines the mass ratio of the two kinds of yam: 1:4-1:6. If the ratio of the two is too high, that is, the amount of yam with high mucopolysaccharide content is large, the processing cost will be higher, and if the ratio of the two is too low, that is, the amount of yam with low mucopolysaccharide content is too much, it will be difficult to form Dense polysaccharide film. After a long time of theoretical research and experimental demonstration, the best quality ratio of the two kinds of yam was finally obtained.

In the preparation process of the present invention, the purpose of adjusting the yam pulp to alkalinity is to change the charge state on the surface of the starch granules, and at the same time effectively reduce substances such as proteins, lipids and the like adsorbed on the surface of the starch granules, which is conducive to the sufficient adsorption of polysaccharides and starch. Then, through homogenization treatment, the polysaccharide and starch can be dispersed more evenly, forming a system in which the polysaccharide is the continuous phase and the starch granules are the dispersed phase, so as to prevent phase separation.

In the present invention, the drying temperature is also one of the key factors. The main purpose of drying at 50° C. is to remove the moisture of the yam pulp. On the one hand, if the temperature is too high, the starch will be gelatinized, and it is difficult to maintain the integrity of the starch granules. On the other hand, it will lead to If the drying speed is too fast, the polysaccharide is easy to form agglomeration, which makes it difficult to form a complete polysaccharide film on the surface of starch granules. The water mass percentage is further controlled at 20%-30%, mainly to make the polysaccharide have an equilibrium process in the further heating process, so that the polysaccharide distribution is more uniform. If the moisture content is too high, the starch is prone to gelatinization when heated further, and if the moisture content is too low, the polysaccharide is not easy to distribute in a balanced manner.

Finally, the purpose of heat treatment at a high temperature of 110-130 ℃ is not only to fully remove the water in the yam, but also to form hydrogen bonds between the starch surface and the polysaccharide, so that the polysaccharide film is tightly adsorbed to the surface of the starch granules.

In the invention, by matching different varieties of yam, in the drying process, the yam polysaccharide is initially adsorbed on the surface of the yam starch granules, and the surface water of the molecule is fully removed by further heating, so that the yam polysaccharide is more tightly embedded in the yam starch granules. The coating of polysaccharide inhibits the water swelling of yam starch, inhibits the gelatinization of yam starch, and reduces the viscosity of the starch significantly, and finally a low-viscosity yam powder is obtained. The prepared yam powder can be widely used in the production of beverages and other products, and solves the problems existing in the production of liquid foods such as beverages containing yam.

Detailed ways

Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent transformations made on the basis of the technical solutions of the present application fall into the protection scope of the present invention.

Example 1:

A method for preparing low-viscosity yam powder, comprising the following steps:

(1) Selection of raw materials

The Japanese white yam with high mucopolysaccharide content and the iron yam with low yam mucopolysaccharide content were selected as the raw materials for the preparation of yam powder, and the mass ratio of Japanese white yam and iron yam was 1:4.

(2) Preprocessing

Wash and peel the above two kinds of yam, and cut into 3-4mm thin slices.

(3) Beating

After protecting the color of the two yam flakes, they are pulped together through a colloid mill to form yam pulp.

(4) Adjust the pH value

The pH value of yam pulp was adjusted to 8.0 by using NaOH solution with a molar concentration of 1 mol/L.

(5) Homogenization

The yam pulp was homogenized once under the condition of 20Mpa.

(6) Drying

The homogenized yam pulp is dried in a vacuum drying oven, and the drying conditions are as follows: the degree of vacuum is 0.9 Mpa, the temperature is 50° C., and the water mass percentage of the yam pulp is dried to 20%.

(7) Heat treatment

After the dried yam is pulverized, it is put into a hot air drying box and heated at 110° C. for 4 hours to obtain low-viscosity yam powder.

Example 2:

A method for preparing low-viscosity yam powder, comprising the following steps:

(1) Selection of raw materials

The Japanese white yam with high mucopolysaccharide content and the iron yam with low yam mucopolysaccharide content were selected as the raw materials for the preparation of yam powder, and the mass ratio of Japanese white yam and iron yam was 1:5.

(2) Preprocessing

Wash and peel the above two kinds of yam, and cut into 3-4mm thin slices.

(3) Beating

After protecting the color of the two yam flakes, they are pulped together through a colloid mill to form yam pulp.

(4) Adjust the pH value

The pH value of yam pulp was adjusted to 8.5 by using NaOH solution with a molar concentration of 1 mol/L.

(5) Homogenization

The yam pulp was homogenized once under the condition of 30Mpa.

(6) Drying

The homogenized yam pulp is dried in a vacuum drying oven, and the drying conditions are as follows: the degree of vacuum is 0.9 Mpa, the temperature is 50° C., and the water mass percentage of the yam pulp is dried to 25%.

(7) Heat treatment

After the dried yam is pulverized, it is put into a hot-air drying box and heated at 120° C. for 5 hours to obtain low-viscosity yam powder.

Example 3:

A method for preparing low-viscosity yam powder, comprising the following steps:

(1) Selection of raw materials

Japanese white yam with high mucopolysaccharide content and iron yam with low yam mucopolysaccharide content were selected as raw materials for the preparation of yam powder, and the mass ratio of Japanese white yam and iron yam was 1:6.

(2) Preprocessing

Wash and peel the above two kinds of yam, and cut into 3-4mm thin slices.

(3) Beating

After protecting the color of the two yam flakes, they are pulped together through a colloid mill to form yam pulp.

(4) Adjust the pH value

The pH value of yam pulp was adjusted to 9.0 by using NaOH solution with a molar concentration of 1 mol/L.

(5) Homogenization

The yam pulp was homogenized once under the condition of 40Mpa.

(6) Drying

The homogenized yam pulp is dried in a vacuum drying oven, and the drying conditions are as follows: the degree of vacuum is 0.9 Mpa, the temperature is 50° C., and the water mass percentage of the yam pulp is dried to 30%.

(7) Heat treatment

After the dried yam is pulverized, it is put into a hot-air drying box and heated at 130° C. for 6 hours to obtain low-viscosity yam powder.

In order to further illustrate the characteristics of the preparation method of the low-viscosity yam powder provided by the present invention, three samples are provided for comparison with the yam powder prepared in the embodiment of the present invention, and their RVA viscosity is detected respectively. The provided three kinds of comparative samples are all prepared by existing conventional methods, and the three samples are comparative examples 1-3, comparative example 1 is yam powder, comparative example 2 is yam starch, and comparative example 3 is heat-treated yam starch.

in,

The yam powder of Comparative Example 1 is prepared from fresh yam through existing conventional steps such as washing, peeling, slicing, color protection, beating, homogenizing, vacuum drying at 50° C., and pulverizing.

The yam starch of Comparative Example 2 was prepared from fresh yam through existing conventional steps such as washing, peeling, slicing, color protection, beating, homogenizing, precipitation, washing three times, and vacuum drying at 50°C.

The heat-treated yam starch of Comparative Example 3 is made from fresh yam through existing conventional steps such as washing, peeling, slicing, color protection, beating, homogenizing, precipitation, washing three times, vacuum drying at 50°C, and hot air drying at 120°C.

The RVA viscosity determination method is as follows: transfer 2.5 g of the test yam powder sample into an RVA aluminum can, and add 25 mL of distilled water. The sample was held at 50°C for 1 min, heated to 95°C at a rate of 10°C/min, held at 95°C for 2.5min, then cooled from 95°C to 50°C at a rate of 10°C/min and held at 50°C for 2min, The rotational speed was kept at 160rpm. Viscosity is expressed as Rapid Viscosity Units (RVU). Parameters such as gelatinization temperature, peak viscosity, valley viscosity, final viscosity, disintegration value and reduction value were recorded. The relevant gelatinization parameters are shown in Table 1.

Table 1 Gelatinization characteristics of yam powder prepared by different methods

The above data shows that Examples 1-3 of the present invention show extremely low peak viscosity, valley viscosity, disintegration value, final viscosity and reduction value. The examples of the present invention have lower viscosity than the comparative examples, and can be widely applied in the production of liquid food.

The above-mentioned embodiment is only one of the preferred embodiments of the present invention, and the usual changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims (3)

1. A preparation method of low-viscosity yam powder is characterized by comprising the following steps: the method comprises the following steps:

selecting raw materials: selecting Chinese yam with high mucopolysaccharide content and Chinese yam with low mucopolysaccharide content as raw materials for preparing Chinese yam powder; the mass ratio of the Chinese yam with higher mucopolysaccharide content to the Chinese yam with lower mucopolysaccharide content is as follows: 1: 4-1: 6; the rhizoma Dioscoreae with high mucopolysaccharide content is one of Japanese white rhizoma Dioscoreae, and rhizoma Dioscoreae; the rhizoma Dioscoreae with low mucopolysaccharide content is one of rhizoma Dioscoreae with ferrum pole and rhizoma Dioscoreae with capillary hair;

(II) pretreatment: cleaning above materials, peeling, and cutting into 3-4mm slices;

(III) pulping: protecting color of rhizoma Dioscoreae slice, pulping with colloid mill to obtain rhizoma Dioscoreae pulp;

(IV) adjusting the pH value: regulating the pH value of the Chinese yam pulp to 8.0-9.0 by using NaOH solution with the concentration of 1 mol/L;

(V) homogenizing: homogenizing the slurry at 20-40Mpa for 1 time;

and (VI) drying: drying the homogenized Chinese yam pulp under the conditions of 0.9Mpa of vacuum degree and 50 ℃ until the water content is 20-30% by mass percent;

(VII) heating treatment: the yam powder with low viscosity can be obtained by crushing the dried yam and heating the yam for 4 to 6 hours at the temperature of 110-130 ℃.

2. The method for preparing low-viscosity yam flour as claimed in claim 1, wherein the method comprises the following steps: and (sixthly), drying by using a vacuum drying oven.

3. The method for preparing the low-viscosity yam flour as claimed in claim 1, wherein the method comprises the steps of: and (seventhly), performing heating treatment by using a hot air drying oven.