CN108338210A - A kind of method of microwave drying Siraitia grosvenorii - Google Patents

Abstract

For the present invention using Siraitia grosvenorii as raw material, cleaned → punching → blanching → drains → microwave drying, obtains dry Siraitia grosvenorii.New fresh fructus momordicae is cleaned, punches, is placed in 1 3min of blanching in 90 95 DEG C of aqueous solution；The tea polyphenols that mass fraction is 0.1 0.3% are added in blanching solution, citric acid regulating solution pH to 5.1 6.0 is used in combination in 0.05% sodium iso-vc；Blanching water is drained, the Siraitia grosvenorii after draining is put into microwave drying facility, is operated according to operating instruction, and control microwave power, drying time, microwave open and close three factors of ratio.These technical combinations are together, it supports mutually, collective effect, channel is provided for moisture evaporation in fruit, accelerate rate of drying, fried fruit and burned phenomenon are avoided, the Siraitia grosvenorii porosity and looseness, surface after reaching dry are in golden yellow, soaked yellowly, fragrant, the sweet taste for brewing mouthfeel reservation Siraitia grosvenorii and ginger.

Description

A kind of microwave drying method of Luo Han Guo

technical field

The invention relates to the field of biochemical technology, in particular to a method for drying Luo Han Guo.

Background technique

Luo Han Guo has high nutritional value and contains mogroside, glucose, fructose, polysaccharide, protein, amino acid, flavonoids, vitamin C, enzymes and various mineral elements. The effect of quenching thirst is suitable for lung heat or dry cough, whooping cough and thirst caused by summer heat, etc. In addition, it has the effect of moistening intestines and laxative. Due to the short preservation time of Luo Han Guo fresh fruit, the deep processing of Luo Han Guo is mainly to dry and preserve the Luo Han Guo. Common drying methods include direct drying, vacuum drying, freeze drying, and microwave drying. Due to the high temperature and long time of the drying method, after drying, the fruit is scorched black, the skin is hard-shelled, the flesh has obvious shrinkage, and the brown is uneven; the retention rate of vitamin C and other nutrients is low; the soaked water turns brown and has an obvious burnt smell and aroma. No, the taste of brewing is not good. Microwave technology is a new contemporary high-tech. The principle is to change the space in an uninterrupted direction through the space of high-frequency electric field, so that the materials in polar molecules vibrate at high frequency following the electric field. This is quite different from ordinary heat transfer. Due to the friction and extrusion between molecules, the material will be heated up rapidly, so as to achieve the purpose of drying food. The characteristics of microwave drying are short heating time, fast speed, penetration ability and heating uniformity, and easy control.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for microwave-drying Luo Han Guo. The dried Luo Han Guo fruit is natural in shape, porous and loose; the surface is golden yellow and uniform in color; it turns yellow when soaked in water; taste.

In order to solve this technical problem, the present invention adopts following technological process:

Fresh Luo Han Guo→cleaning→punching→blanching→draining→microwave drying

The main points of process operation are as follows:

(1) Cleaning: Wash the sediment and impurities on the surface of the fresh Luo Han Guo with water;

(2) Punching: Punch the outside of the fresh Luo Han Guo after cleaning, one hole can be punched, or multiple holes can be punched; the hole diameter is 1.5-2.5mm, and the depth is about 2.0-3.0cm; the hole can also be punched directly ;Punching the fresh fruit of Luo Han Guo mainly provides a channel for the water in the fruit to evaporate, speeds up the drying speed, and avoids the phenomenon of fried and scorched fruit;

(3) Blanching: Place the washed fresh fruit in an aqueous solution at 90-95°C for 1-3 minutes; add 0.1-0.3% tea polyphenols and 0.05% sodium isoVC to the blanching liquid, And adjust the pH of the solution to 5.1-6.0 with citric acid;

This kind of blanching can inhibit the enzymes in the fresh fruit of Luo Han Guo, kill bacteria, and has the effect of protecting color, protecting the color of the dried Luo Han Guo, enhancing the toughness of the peel, and maintaining the shape of the fruit; it also has a stabilizing effect for the sensory evaluation of the dried Luo Han Guo.

(4) Drain: Remove the Luo Han Guo from the blanching water and drain for easy drying;

(5) Microwave drying: put an appropriate amount of drained Luo Han Guo into the microwave drying equipment, operate according to the operating procedures, and control the three factors of microwave power, drying time, and microwave opening and closing ratio to prevent the appearance of dried Luo Han Guo from coking. After brewing, there is a burnt smell, and the brewed water is brown. The dried Luo Han Guo fruit has a natural shape, porous and loose; the surface is golden yellow, and the color is uniform; the water turns yellow; the brewing taste retains the fragrance of Luo Han Guo and tea , sweetness.

The microwave on-off ratio refers to the number of times the microwave is stopped during the microwave opening process during the drying process, that is, the microwave heating is turned on for a period of time and then the microwave heating is stopped for a certain period of time, so as to prevent overheating during the drying process, resulting in fruit frying and coking. Use a microwave oven to dry and control the opening and closing ratio to 1-4.

The present invention has following advantages and characteristics:

1. The combination technology is novel. After drying, the sensory evaluation of Luo Han Guo is high and the taste is unique. Perforate the fresh Luo Han Guo to provide a channel for water vapor to be removed during microwave drying, speed up the drying speed, and avoid the phenomenon of fruit frying; use blanching liquid to blanch the fresh fruit to kill enzymes and bacteria, enhance the toughness of the peel, maintain the shape of the fruit, and form a unique shape for the future. The brewing flavor lays the foundation; microwave drying, especially the control of the three factors of microwave power, drying time, and microwave opening and closing ratio, can form the dried Luo Han Guo fruit with natural shape, peel and pulp connected together, and no shrinkage of tissue. Porous and loose; the surface is golden yellow and uniform in color; it turns yellow when soaked in water; the taste of brewing is unique, and the fragrance and sweetness of Luo Han Guo and ginger are retained; the shelf life is long.

2. Short drying time, high retention rate of vitamin C and other nutrients. Due to the use of blanching and color protection treatment, microwave heating and drying, and reasonable control of process parameters, the drying time of Luo Han Guo is shortened, and the retention rate of nutrients such as vitamin C is increased by 5-10%. These technologies are combined together, support each other, and work together to get high-quality dried Luo Han Guo.

Detailed ways

The examples described below illustrate the present invention in detail.

Example 1

The present invention adopts following technological process:

Fresh Luo Han Guo→cleaning→punching→blanching→draining→microwave drying

(1) Cleaning: Wash the silt and impurities on the surface of Luo Han Guo with drinking water;

(2) Punching: Punch holes at the top pedicle and bottom navel of the fresh Luo Han Guo fruit, and punch through the Luo Han Guo with a hole diameter of 2.0mm to provide a channel for the water in the Luo Han Guo fruit to evaporate, speed up the drying speed, and avoid the phenomenon of fruit frying at the same time;

(3) Blanching: First configure the blanching solution, add 0.3% tea polyphenols and 0.05% sodium isoVC into the drinking water, and adjust the pH of the solution to 6.0 with citric acid; heat to 95°C, wash the The final fresh fruit is blanched in blanching solution at 95°C for 1 min;

This kind of blanching can kill enzymes and bacteria in fresh Luo Han Guo, has the effect of color protection, protects the color of Luo Han Guo after drying, enhances the toughness of the peel, maintains the shape of the fruit, and lays the foundation for the formation of the unique taste of Luo Han Guo after drying;

(4) Drain: Remove the Luo Han Guo from the blanching solution and drain to facilitate drying;

(5) Microwave drying:

Using a microwave oven model EG823LC8-NS, put 2 dried Luo Han Guo fresh fruits into the microwave oven, operate according to the operating procedures, and control the drying process parameters as follows: the microwave power is 80W, the drying time is 100min, and the microwave opening and closing ratio is 3. Stop the microwave for 5 minutes when the drying time is 30, 60, and 90 minutes. Discharge, place and cool, and vacuum pack to prevent the dry Luo Han Guo from absorbing moisture.

The dried Luo Han Guo fruit has a natural shape, the peel and flesh are connected together, and the tissue is not wrinkled, porous and loose; the surface is yellow-green and uniform in color; it turns yellow when soaked in water; the taste of brewing is unique, and the fragrance and sweetness of Luo Han Guo are retained. Point with the taste of ginger. After testing, the water content of Luo Han Guo is 12.7%, and the content of vitamin C is 26.4mg/g. The same batch of fresh Luo Han Guo is dried by direct drying method, and the content of vitamin C is 23.6 mg/g. The retention of vitamin C rate increased by 10.6%.

Example 2

The present invention adopts following technological process:

Fresh Luo Han Guo→cleaning→punching→blanching→draining→microwave drying

(1) Cleaning: Wash the silt and impurities on the surface of Luo Han Guo with drinking water;

(2) Punching: Punch holes at the top pedicle and bottom navel of Luo Han Guo fresh fruit, with a hole diameter of 2.5 mm and a depth of 2.0 cm; to provide channels for the evaporation of moisture in the Luo Han Guo fruit, speed up the drying speed, and avoid fruit frying and coking at the same time ;

(3) Blanching: First configure the blanching solution, add 0.1% tea polyphenols and 0.05% sodium isoVC into the drinking water, and adjust the pH of the solution to 5.1 with citric acid; heat to 90°C, wash The final fresh fruit is blanched in blanching solution at 90°C for 3 minutes;

This kind of blanching can kill enzymes and bacteria in fresh Luo Han Guo, has the effect of color protection, protects the color of Luo Han Guo after drying, enhances the toughness of the peel, maintains the shape of the fruit, and lays the foundation for the formation of the unique taste of Luo Han Guo after drying;

(4) Drain: Remove the Luo Han Guo from the blanching solution and drain to facilitate drying;

(5) Microwave drying:

Using a microwave oven model EG823LC8-NS, put 4 dried Luo Han Guo fresh fruits into the microwave oven, operate according to the operating procedures, and control the drying process parameters as follows: microwave power is 80W, drying time is 120min, microwave opening and closing ratio is 1. Stop the microwave for 5 minutes when the drying time is 60 minutes. Discharge, place and cool, and vacuum pack to prevent the dry Luo Han Guo from absorbing moisture.

The dried Luo Han Guo fruit has a natural shape, the peel and flesh are connected together, and the tissue is not wrinkled, porous and loose; the surface is yellow-green and uniform in color; it turns yellow when soaked in water; the taste of brewing is unique, and the fragrance and sweetness of Luo Han Guo are retained. Point with the taste of ginger. After testing, the water content of Luo Han Guo is 13.2%, and the content of vitamin C is 25.5mg/g. The same batch of fresh Luo Han Guo is dried by direct drying method, and the content of vitamin C is 22.7 mg/g. The retention of vitamin C rate increased by 12.1%.

Claims (2)

1. a kind of method of microwave drying Siraitia grosvenorii, using following technique：

Fresh fructus momordicae → cleaning → punching → blanching → drains → microwave drying

Operating procedure is as follows：

（1）Cleaning：The silt impurity on Siraitia grosvenorii fresh fruit surface is cleaned with water；

（2）Punching：Siraitia grosvenorii fresh fruit is punched；

The punching can make a call to 1 hole, can also beat multiple holes；The aperture of the punching is 1.5-2.5mm, depth about 2.0- 3.0cm；Directly hole can also be punched；

（3）Blanching：Siraitia grosvenorii fresh fruit after cleaning is placed in blanching 1-3min in 90-95 DEG C of blanching solution；

The tea polyphenols that mass fraction is 0.1-0.3% are added in the blanching solution, 0.05% sodium iso-vc uses citric acid regulating solution PH to 5.1-6.0；

（4）It drains：Siraitia grosvenorii is pulled out from blanching solution and is drained；

（5）Microwave drying：Siraitia grosvenorii after draining is put into microwave dryer, is operated according to operating instruction, microwave is controlled Power, drying time, microwave open and close three factors of ratio.

2. according to the method described in claim 1, it is characterized in that：Step（5）Described in microwave drying, using model EG823LC8-NS micro-wave ovens, 2, Siraitia grosvenorii fresh fruit after draining are put into micro-wave oven, are operated according to operating instruction, and control is dry Dry process parameter control is as follows：Microwave power is 80W, drying time 100min, drying time 30min, 60min, Stop microwave operational 5 minutes when 90min.