A Study Of Glucosinolate Extraction From Rapeseed Meal Detoxified Solution

While detoxified rapeseed meal is good pig vegetable protein feed, glucosinolates contained in its detoxifying solution is a kind of medicine that can prevent cancer. In attempt to improve the effectiveness of the use of this natural resource, this thesis studies systematically the extracting process of glucosinolates from rapeseed meal detoxifying solution on the basis of analyzing its molecular structure and nature, in accordance with the 6 steps of concentration, dissolution, extraction, reverse-extraction, desalination and purification, and finally comes to find a brand new approach to accomplish the extraction.In the first step of concentration, the author examines the concentration effects on glucosinolates of different reagent, the volume ratio of concentration reagent to mother liguid and concentration time and finally come to the optimum condition: at the agitating speed of 1000rpm, the reagent is isooctane, the ratio is 2:1, the concentration time is 40min. Following the concentration, its dissolution with distilled water of equal volume produces flavescent glucosinolates solution. Meanwhile, the author, in an effort to decrease producing cost, determined the condition for the recycling of the isooctane: the degree of vacuum should be 0.95, the temperature should be 55℃, the recycled isooctane should be 98.2ml/100ml, with a recycling rate of 98.2%.Considering the high viscosity of the selected reagent (Cosmacol ELI), the author studies first the composition of the reagent and finds that the optimum ratio of Cosmacol ELI to n-hexane should be 3: 2. In addition, this paper optimize the all the factors that can influence extracting rate and obtained the optimum condition that the ratio of organic to aqueous phase should be 2:1; extracting time 50min; and the extraction rate could reach 84.7% in that condition. After a second-time extraction geared to improve production effectiveness, the extraction rate could reach 92.2%.Considering that the reverse-extraction reagent must be salt, which is determined by the nature of glucosinolates, the author settle down on K2SO4 as the reagent after comparing the different reverse-extraction effect of various kinds of salt reagent. Following concrete examination of some main factors possibly affecting the reverse-extraction, the optimum condition for reverse-extraction is concluded as: the concentration of K2SO4 should be 0.1mol/L; the volume ratio of extracting reagent to reverse-extracting reagent should be 1:1; reverse-extracting time should be 30min; the time of complete demixing should be 40min. 30 minutes of reverse-extraction enables the rate to reach 93.1%.The reagent, which is then scrubbed by double-volumed chlorhydric acid with the concentration of 15% for 50min and kept still for 2h afterwards, can be recycled into use with the recycling rate of 94.7%. The great deal of K2SO4 which remains in the powder obtained from concentration can be removed by the means of dissolution with a small amount of methanol and filtration.After that, the author makes crude product into glucosinolates solution with the concentration of 1μmol/ml and purifies it with resin, which is examined and selected by its adsorption rate. Following the optimization of the main factor influencing adsorption rate and elution rate, the optimum condition is determined as: optimum adsorption resin should be D201; the capacity 23.54μmol/g; optimum adsorption time 15min; and the adsorption rate could reach 96.79%; the best eluant should be NaCl of 1mol/L; the minimum elution consumption 20mL/g; elution time 30min.and the elution rate reaches 99.07%.In the optimum condition, adsorption rate and elution rate reach 96.79% and 99.07% respectively.Steps of desalination and concentration produce glucosinolates with the production rate of 65.3%.