Method for extracting steviol glycosides from stevia rebaudiana leaves

Abstract

The invention discloses a method for extracting steviol glycosides from stevia rebaudiana leaves by microwave and ultrasonic combination. The method includes the following steps: rinsing stevia leaves, immersing in anhydrous ethanol, drying, crushing and sieving to obtain stevia leaf powder; uniformly mixing the stevia leaf powder, water and compound enzyme to adjust the pH value, then heating with microwaves, insulating and soaking, heating to obtain the extract and residue after ultrasonic treatment; stirring and homogenizing the residue and ether and then separating centrifugally, and combining the supernatant and the extract to obtain the mixture extract; mixing the ferric chloride solution, the calcium hydroxide solution, the polyacrylamide solution and the mixture extract to obtain the mixed solution, mixing the mixed solution with the aluminum sulfate solution uniformly, and adjusting the pH value to obtain the extract solution by supercritical fluid extraction; adsorbing the extraction solution with macroporous resin, rinsing, depressurized-distilling, concentrating and drying to obtain crude stevia glycoside; adding the crude stevia glycoside into water, and then adding attapulgite after the ultrasonic treatment; standing, centrifuging, concentrating and drying after the pH value is adjusted.

Description

technical field

[0001] The invention relates to the technical field of stevioside extraction, in particular to a microwave-ultrasonic composite method for extracting stevioside from stevia leaves. Background technique

[0002] Stevia is a small evergreen shrub native to the South American Paraguayan Plateau between 25-26 degrees south latitude, and has been introduced all over the world. Its leaves contain a class of steviol glycosides, which are derived from a class of tetracyclic diterpenes. It is mainly composed of 8 kinds of glycosides including stevioside, stevioside A, stevioside B and stevioside C, and its sweetness is about 300 times that of sucrose. Studies have shown that stevioside has the characteristics of high sweetness, low calorie, and no obvious side effects. It can inhibit high blood sugar and high blood pressure, and has anti-inflammatory, anti-tumor, antidiarrheal and diuretic effects, and assists in immune regulation. Currently, South America, Japan and...

Examples

Embodiment 1

[0025] A method for microwave-ultrasonic composite extraction of steviol glycosides in stevia leaves proposed by the present invention comprises the following steps:

[0026] S1. Rinse the stevia leaves with clean water, then soak them in absolute ethanol for 30 minutes, take them out, dry them to a moisture content of 10 wt%, crush them, and sieve them to obtain stevia leaf powder;

[0027] S2, mixing the stevia leaf powder and water evenly in a mass ratio of 1:5, then adding the compound enzyme, wherein the quality of the compound enzyme is 0.25% of the quality of the stevia leaf powder, adjusting the pH value of the system to 7, Then microwave heating to 50°C, heat preservation and soaking for 20 minutes, then heat up to 90°C, ultrasonication for 20 minutes, and filter to obtain the extract and filter residue; add the filter residue and ether into the centrifuge at a mass ratio of 1:5, stir evenly and then centrifuge Separation, wherein the speed of centrifugation is 2000r / ...

Embodiment 2

[0032] A method for microwave-ultrasonic composite extraction of steviol glycosides in stevia leaves proposed by the present invention comprises the following steps:

[0033] S1. Rinse the stevia leaves with clean water, then soak them in absolute ethanol for 100 minutes, take them out, dry them to a moisture content of 5 wt%, crush them, and sieve them to obtain stevia leaf powder;

[0034]S2, mixing stevia leaf powder and water uniformly in a mass ratio of 1:10, then adding compound enzyme, wherein the quality of the compound enzyme is 0.2% of the quality of stevia leaf powder, adjusting the pH value of the system to 8, Then microwave heating to 40°C, heat preservation and soaking for 50 minutes, heat up to 70°C, ultrasonication for 50 minutes, and filter to obtain the extract and filter residue; add the filter residue and ether into the centrifuge at a mass ratio of 1:3, stir evenly and then centrifuge Separation, wherein the speed of centrifugation is 3000r / min, the time o...

Embodiment 3

[0039] A method for microwave-ultrasonic composite extraction of steviol glycosides in stevia leaves proposed by the present invention comprises the following steps:

[0040] S1. Rinse the stevia leaves with clean water, then soak them in absolute ethanol for 80 minutes, take them out and dry them at 60° C. until the moisture content is 6 wt%, and pass through a 50-mesh sieve after crushing to obtain stevia leaf powder;

[0041] S2, Stevia rebaudiana leaf powder and water are mixed evenly in the ratio of 1:6 by mass ratio, then add compound enzyme, wherein, the compound enzyme is the mixture of cellulase and pectinase by weight ratio of 5:3, The quality of the compound enzyme is 0.24% of the mass of the stevia leaf powder. Adjust the pH value of the system to 7.2, and then heat it to 48°C with microwave. Ultrasonic for 30min, the ultrasonic power is 250W, after filtration, the extract and filter residue are obtained; the filter residue and ether are added to the centrifuge at ...

technical field

[0001] The invention relates to the technical field of stevioside extraction, in particular to a microwave-ultrasonic composite method for extracting stevioside from stevia leaves. Background technique

[0002] Stevia is a small evergreen shrub native to the South American Paraguayan Plateau between 25-26 degrees south latitude, and has been introduced all over the world. Its leaves contain a class of steviol glycosides, which are derived from a class of tetracyclic diterpenes. It is mainly composed of 8 kinds of glycosides including stevioside, stevioside A, stevioside B and stevioside C, and its sweetness is about 300 times that of sucrose. Studies have shown that stevioside has the characteristics of high sweetness, low calorie, and no obvious side effects. It can inhibit high blood sugar and high blood pressure, and has anti-inflammatory, anti-tumor, antidiarrheal and diuretic effects, and assists in immune regulation. Currently, South America, Japan and...

Examples

Embodiment 1

[0025] A method for microwave-ultrasonic composite extraction of steviol glycosides in stevia leaves proposed by the present invention comprises the following steps:

[0026] S1. Rinse the stevia leaves with clean water, then soak them in absolute ethanol for 30 minutes, take them out, dry them to a moisture content of 10 wt%, crush them, and sieve them to obtain stevia leaf powder;

[0027] S2, mixing the stevia leaf powder and water evenly in a mass ratio of 1:5, then adding the compound enzyme, wherein the quality of the compound enzyme is 0.25% of the quality of the stevia leaf powder, adjusting the pH value of the system to 7, Then microwave heating to 50°C, heat preservation and soaking for 20 minutes, then heat up to 90°C, ultrasonication for 20 minutes, and filter to obtain the extract and filter residue; add the filter residue and ether into the centrifuge at a mass ratio of 1:5, stir evenly and then centrifuge Separation, wherein the speed of centrifugation is 2000r / ...

Embodiment 2

[0032] A method for microwave-ultrasonic composite extraction of steviol glycosides in stevia leaves proposed by the present invention comprises the following steps:

[0033] S1. Rinse the stevia leaves with clean water, then soak them in absolute ethanol for 100 minutes, take them out, dry them to a moisture content of 5 wt%, crush them, and sieve them to obtain stevia leaf powder;

[0034]S2, mixing stevia leaf powder and water uniformly in a mass ratio of 1:10, then adding compound enzyme, wherein the quality of the compound enzyme is 0.2% of the quality of stevia leaf powder, adjusting the pH value of the system to 8, Then microwave heating to 40°C, heat preservation and soaking for 50 minutes, heat up to 70°C, ultrasonication for 50 minutes, and filter to obtain the extract and filter residue; add the filter residue and ether into the centrifuge at a mass ratio of 1:3, stir evenly and then centrifuge Separation, wherein the speed of centrifugation is 3000r / min, the time o...

Embodiment 3

[0039] A method for microwave-ultrasonic composite extraction of steviol glycosides in stevia leaves proposed by the present invention comprises the following steps:

[0040] S1. Rinse the stevia leaves with clean water, then soak them in absolute ethanol for 80 minutes, take them out and dry them at 60° C. until the moisture content is 6 wt%, and pass through a 50-mesh sieve after crushing to obtain stevia leaf powder;

[0041] S2, Stevia rebaudiana leaf powder and water are mixed evenly in the ratio of 1:6 by mass ratio, then add compound enzyme, wherein, the compound enzyme is the mixture of cellulase and pectinase by weight ratio of 5:3, The quality of the compound enzyme is 0.24% of the mass of the stevia leaf powder. Adjust the pH value of the system to 7.2, and then heat it to 48°C with microwave. Ultrasonic for 30min, the ultrasonic power is 250W, after filtration, the extract and filter residue are obtained; the filter residue and ether are added to the centrifuge at ...