CN115462510A - A method of intermittent microwave combined with hot air drying to prepare low GI green banana powder - Google Patents

Abstract

The invention relates to a method for preparing low GI green banana powder by intermittent microwave combined with hot air drying. Density 4-6W/g drying for 1-3min, followed by microwave power density 2W/g drying for 2-4min, and finally hot air drying at 45°C for 120min-150min; milling according to known knowledge, passing through a 100-mesh sieve to obtain green banana powder. The low GI green banana powder prepared by intermittent microwave combined with hot air drying in the present invention has a slow digestible starch content of 55% to 65%, a resistant starch content of 20% to 30%, and a GI value of 45.7 to 52.3. Food can effectively improve intestinal health and inhibit the rapid rise of blood sugar after meals.

Description

A method of intermittent microwave combined with hot air drying to prepare low GI green banana powder

technical field

The invention relates to the technical field of food processing, in particular to a method for preparing low GI green banana whole powder by intermittent microwave combined with hot air drying.

Background technique

Banana is rich in nutrition and is deeply loved by consumers. It is designated by the Food and Agriculture Organization of the United Nations as the fourth largest food crop in the suitable area. Among them, the total starch and resistant starch content in green bananas can be as high as 80% and 60% respectively, which is a natural resistance. One of the widest sources of starch (RS). However, bananas are perishable and not resistant to storage, causing serious economic losses. If they are dried and developed into high-value banana powder, it will be of great significance to alleviate the contradiction between production and sales. Banana powder not only retains the functional properties of banana itself, but also is rich in resistant starch (Resistant starch, RS), which can effectively reduce postprandial glycemic index (GI), control body weight, and effectively prevent obesity; it is rich in calcium and magnesium , phosphorus, potassium and other minerals, polyphenols, and dietary fiber have the effect of improving intestinal health, can reduce intestinal pH, and are beneficial to the health of the large intestine or colon. During the drying process of green bananas, the structure and properties of starch may change, resulting in the transformation of resistant starch into rapidly digestible starch (Rapidly digestible starch, RDS) or slowly digestible starch (Slowly digestible starch, SDS). Studies have shown that SDS can be digested slowly and release energy continuously, and the GI value is low. Making food with SDS, RS and dietary fiber as the main raw materials can significantly reduce the digestion rate of food, reduce postprandial blood sugar, and reduce hunger. Therefore, it will be of great significance to use green bananas as raw materials to develop low-GI banana powder products, which are suitable for people with diabetes and obesity.

Processing bananas into banana powder has the advantages of good storage stability, low transportation cost, wide application, high raw material utilization rate, and broad market, and has become a new trend. Existing fruit and vegetable milling methods mainly involve wet method and dry method. Fresh bananas are dried into granules, flakes or powdered dehydrated products, which can retain the nutrients and flavors of fresh bananas to the greatest extent, such as starch, Dietary fiber, protein, sugar, fat, minerals, etc. Among them, the dry preparation process of banana powder can be divided into two categories, namely cold drying process and thermal drying process. Although vacuum freeze-drying can better maintain the original color, aroma, taste, shape and vitamins and other nutrients of food, the shortcomings of vacuum freeze-drying equipment, such as large one-time investment, large energy consumption, and long drying time, restrict it. large-scale application. Microwave drying technology and hot air drying technology have long been used in banana drying and the preparation of banana powder. Among them, microwave drying has a broad application prospect due to its advantages of short drying cycle, high efficiency, good product quality and low processing cost. However, the existing banana powder preparation technology focuses more on the physical and chemical properties of the powder itself, and there are few reports on its digestion properties and low GI properties.

Contents of the invention

technical problem

Aiming at the deficiencies of the prior art, the present invention provides a method for preparing low GI green banana powder by intermittent microwave combined with hot air drying, which has the advantages of green, pollution-free, high efficiency, etc., and the prepared green banana powder has a low GI value, It is a low glycemic index product. The invention not only solves the shortcomings of the existing traditional freeze-drying technology, such as high energy consumption, high input cost, low production efficiency of single hot-air drying technology, and high GI value of banana powder products; serious problem.

Technical solutions

(1) Material selection: select fresh green bananas with first-grade maturity, no rot, and no mechanical damage as raw materials for processing;

(2) Peeling and removing the network: peel off the banana skin, and remove the unpeeled tendons, try not to damage the banana pulp;

(3) Slicing: Cut the banana pulp into 3mm-5mm thin slices with a slicer;

(4) Color protection: Soak the banana slices in 0.5% sodium D-isoascorbate solution for 60-80 minutes:

(5) Drain: spread the banana slices after color protection on a sieve and drain;

(6) Drying: Spread the drained banana slices in a single layer on the sample tray and place them in the microwave drying chamber. First, set the microwave power density to 4-6W/g, and dry for 1-3 minutes; then adjust the microwave power density 2W/g, dry for 2-4min; finally dry the banana chips after microwave drying with hot air, the drying temperature is 45°C, the drying time is 120min-150min, and the final moisture content of the sample is 5%-6%.

(7) The banana chips obtained in step (6) are ground according to the known methods, and the gained banana powder is passed through a 100-mesh standard sieve, and the under-sieve is the green banana powder finished product.

The slow-digestible starch content in the whole green banana powder described in the step (7) is 55%-65%, the resistant starch content is 20%-30%, and the GI value is 45.7-52.3.

Beneficial effects of the present invention

Compared with the prior art, the present invention provides a method for preparing low GI green banana powder by intermittent microwave combined with hot air drying, which has the following beneficial effects:

1. The present invention uses first-grade ripe green banana as raw material, which is an excellent raw material for preparing low GI full powder products.

2. The low GI green banana powder prepared by the present invention has a slow digestible starch content of 55% to 65%, a resistant starch content of 20% to 30%, and a GI value of 45.7 to 52.3, which can effectively improve intestinal Road health, inhibit the rapid rise of blood sugar after meals.

3. The present invention uses microwave combined with hot air drying to directly prepare low GI banana powder, which avoids the cumbersome process of obtaining banana powder through spray drying after the traditional wet process of deenzyme, color protection, beating, and homogenization, and greatly improves the production efficiency of banana powder. Production efficiency, reducing production costs.

detailed description

The invention will be further described below in conjunction with the description, but the scope of protection required by the present invention is not limited to the scope described in the embodiments.

Example 1

Select fresh green bananas with level 1 maturity, no rot, and no mechanical damage as processing raw materials, peel off the banana skin, and remove the unpeeled tendons, try not to damage the banana pulp, and cut the banana pulp with a slicer into 3mm thin slices; soak the banana slices in 0.5% D-sodium erythorbate solution to protect the color for 60 minutes, spread the banana slices on the sieve for color protection and drain; put the drained banana slices on a single Spread the layers on the sample tray and place them in the microwave drying chamber; first set the microwave power density to 4W/g, and dry for 3min; then adjust the microwave power density to 2W/g, and dry for 4min; Drying with hot air, the drying temperature is 45°C, the drying time is 150min, and the final moisture content of the sample is 5.22±0.16%. According to the known method, the banana slices are ground and passed through a 100-mesh standard sieve to obtain the finished green banana powder. After determination, the actual content of slow digestible starch in green banana powder is 59.35%, the actual content of resistant starch is 28.28%, and the GI value is 46.9.

Example 2

Select fresh green bananas with level 1 maturity, no rot, and no mechanical damage as processing raw materials, peel off the banana skin, and remove the unpeeled tendons, try not to damage the banana pulp, and cut the banana pulp with a slicer into 4mm thin slices; soak the banana slices in 0.5% D-sodium erythorbate solution to protect the color for 70 minutes, spread the banana slices on the sieve for color protection and drain; put the drained banana slices in a single layer Spread it flat on the sample tray and place it in the microwave drying chamber; first set the microwave power density to 5W/g, and dry for 1min; then adjust the microwave power density to 2W/g, and dry for 5min; Drying, the drying temperature is 45°C, the drying time is 140min, and the final moisture content of the sample is 5.89±0.14%. According to the known method, the banana slices are ground and passed through a 100-mesh standard sieve to obtain the finished green banana powder. After determination, the actual content of slow digestible starch in green banana powder is 64.35%, the actual content of resistant starch is 26.77%, and the GI value is 45.9.

Example 3

Select fresh green bananas with level 1 maturity, no rot, and no mechanical damage as processing raw materials, peel off the banana skin, and remove the unpeeled tendons, try not to damage the banana pulp, and cut the banana pulp with a slicer into 5mm thin slices; soak the banana slices in 0.5% D-sodium erythorbate solution to protect the color for 80 minutes, spread the banana slices on the sieve for color protection and drain; put the drained banana slices in a single layer Spread it flat on the sample tray and place it in a microwave drying chamber; first set the microwave power density to 6W/g, and dry for 1min; then adjust the microwave power density to 2W/g, and dry for 6min; Drying, the drying temperature is 45°C, the drying time is 130min, and the final moisture content of the sample is 5.94±0.13%. According to the known method, the banana slices are ground and passed through a 100-mesh standard sieve to obtain the finished green banana powder. After determination, the actual content of slow digestible starch in green banana powder is 55.78%, the actual content of resistant starch is 23.61%, and the GI value is 51.9.

Claims (4)

1. A method for preparing low GI (glycemic index) green banana whole flour by combining intermittent microwave with hot air drying is characterized by comprising the following steps of:

(1) Selecting materials: selecting fresh green bananas with grade I maturity, no rot and no mechanical damage as processing raw materials;

(2) Peeling and removing collaterals: peeling off banana peel, removing the un-peeled ribs and avoiding damaging banana pulp as much as possible;

(3) Slicing: cutting the banana pulp into slices of 3-5 mm by a slicer;

(4) Color protection: soaking the banana slices in 0.5 percent D-sodium erythorbate solution for color protection for 60-80 min;

(5) Draining: spreading the color-protected banana slices on a sieve for draining;

(6) And (3) drying: flatly paving the drained banana slices in a sample tray in a single layer mode, and placing the banana slices in a microwave drying cavity; firstly, setting the microwave power density to be 4-6W/g, and drying for 1-3 min; then, adjusting the microwave power density to 2W/g, and drying for 2-4 min; and finally, carrying out hot air drying on the banana slices subjected to microwave drying at the drying temperature of 45 ℃ for 120-150 min, wherein the final water content of the sample is 5-6%.

(7) And (4) grinding the banana slices obtained in the step (6) according to the known method, sieving the obtained banana powder by a 100-mesh standard sieve, and obtaining the screened substance which is the green banana whole powder finished product.

The content of slowly digestible starch in the green banana whole powder in the step (7) is 55-65%, the content of resistant starch is 20-30%, and the GI value is 45.7-52.3.

2. The method for preparing low GI banana puree by using intermittent microwave and hot air drying in combination according to claim 1, wherein the thickness of the banana slices in the step (3) is 3 mm-5 mm.

3. The method for preparing low GI banana flour by using intermittent microwave and hot air combined drying as claimed in claim 1, wherein in the step (6), the microwave power density is 4-6W/g, and the drying is performed for 1-3 min: then adjusting the microwave power density to 2W/g, and drying for 2-4 min.

4. The method for preparing low GI green banana whole flour by combining intermittent microwave and hot air drying according to claim 1, wherein the content of slowly digestible starch in the green banana whole flour in the step (7) is 55-65%, the content of resistant starch is 20-30%, and the GI value is 45.7-52.3.