Method for ultrasonic extraction of steviosides

Abstract

The invention discloses a method for the ultrasonic extraction of steviosides. Smashed dry leaves of stevia rebaudiana serve as raw material; based on the characteristic that an ultrasonic cavitation can reinforce the extraction of active ingredients in plants, the solvent and the smashed raw materials flow in opposite directions, and the extract of the stevia rebaudiana is prepared by immersed extraction and ultrasonic extraction; white powder of the stevia rebaudiana is prepared by flocculating, filtering, absorbing, decolorizing, exchanging, concentrating, spray drying and the like; the stevioside content of the products is 85 to 98 percent. In the invention, the extraction time is only 10 to 60 minutes; the extraction rate can reach 95 to 99.9 percent; the temperature of the extraction solvent is only 10 to 40 DEG C; and the mass-to-volume ratio of the dry leaves to the solvent is only 1: 10-40 (kg: L). The method has the advantages of short extraction time, high extraction rate, low consumption of solvent, clean and sanitary production process and large scale and industrial continuous production; and the produced stevioside products have high purity and good quality.

Description

technical field [0001] The invention relates to a method for extracting effective plant components, in particular to a method for ultrasonically extracting steviol glycosides. technical background [0002] Stevioside, also known as steviol glycoside, commonly known as stevioside, is a kind of pure natural, high sweetness, low calorie value, edible safety food additive extracted from the leaves of stevia rebaudiana. The third natural sugar source after beet sugar, its sweetness is 200-300 times that of sucrose, but its calories are only 1 / 300 of sucrose. Stevioside is resistant to acid and alkali, good thermal stability, non-fermentative, can be kept in the solution of pH 3-9 for a long time, and does not decompose at up to 200°C, and can be widely used in food, beverage, wine making, medicine, flavor Spices, etc. are used in almost all sugar fields. Stevioside has low calorific value and is safe to eat. It has a certain auxiliary therapeutic effect on hypertension, hypergl...

AI Technical Summary

Problems solved by technology

[0004] The disadvantages of the above-mentioned conventional production techniques for extracting steviosides are: the extraction temperature is high, reaching 40-80° C., and energy consumption (such as steam) is large; operation method; the extraction time is longer, and it takes 4-8 hours; because the stevia rebaudiana slag after the extraction liquid is not squeezed out in time, the loss of glycosides is large, and the extraction rate of glycosides is low, generally only 80-90%; Large consumption, dry leaves and solvent ratio (mass) solvent ratio up to 1:40-50

This method is theoretically sound, but in fact there are the following deficiencies: (1) the stevia leaf is difficult to be smoothly stirred in a spiral mode in the extraction solvent without pulverization, so it is difficult for the solution and the stevia leaf to maintain a high concentration gradient; (2) Although the countercurrent method can maintain a relatively high concentration gradient, the dissolution rate of glycoside components is relatively slow because there is no other auxiliary extraction means such as ultrasonic waves, so the extraction time is still relatively long; (3) In order to maintain The higher the glycoside extraction rate, the length of the extraction equipment will become very long, so the floor area and equipment investment will be larger; (4) This method is not equipped with ultrasonic and other auxiliary extraction means in the extraction process, and the extraction efficiency is low , the extraction rate of steviol glycosides is about 90%. Although it is improved compared with the traditional conventional process, about 10% of the glycosides are still not extracted and enter the extraction solution, resulting in waste