Study On Extraction With Supercritical Carbon Dioxide And Microencapsulation With Yeast Cell Wall Of Gingerin

Extraction with supercritical carbon dioxide and microencapsulation with yeast cell wall of gingerin were investigated.Emphasis was put on the conditions for extraction, the qualities and the components of gingerin, the conditions for yeast autolysis, and the qualities of gingerin microcapsule. Results showed that:(i) Proper conditions for extraction are : water amount in ginger powder, 10%, brokenness of powder, 50 ~ 60 mesh, extraction pressure, 28MPa, extraction temperature, 45 ℃, flow of carbon dioxide, 2.5 ml/min, time for extraction, ISOmin, separation pressure, 7.0MPa and separation temperature, 40℃. Gingerin extraction ratio reaches 4.41% under these conditions.(ii) Influence of temperature to extraction is related much to pressure. There is a turn pressure of 26.8MPa in the course of gingerin extraction. When presure is below 26.8MPa, retio of gingerin extraction decreases while temperature rises, when pressure is over 26.8MPa, ratio of gingerin extraction increases while temperature rises. Influence of temperature to extraction is of little importance when pressure is near 26.8MPa, but it becomes more and more important when pressure deviates more from 26.8MPa.(iii) Comparated with traditional extractions, ratio of gingerin extraction with supercritical carbon dioxide is far higher than that with water steam and than that with ethanol. Gingerin extracted with supercritical carbon dioxide, with relatively full components, rich aroma and strong pungency, retains peculiar flavors of ginger.(iv) Indentification of gingerin components by gas chromatography and by mass spectrojnetry following gas chromatgraphy is statifactory. Ninety-five components were identified and their hump area reaches 92.08% of the total. Quality and quantity of components were listed in table 7.(v) Conditions for yeast autolysis have indirect effects on the quality of microcapsule. On the basis of mass ratio of gingerin microencapsulated, the optimum conditions for autolysis are: changeable temperature. 40 - 60℃, inital pH, 6.0, mass ratio of yeast cell to water, 1:1, mass ratio of ethanol used to speed autolysis, 1.0%, and time for autolysis, 24h. Mass ratio of gingerin microencapsulated is over 96.17% under these conditions.(vi) Microcapsule, with even size of less than 20 μ m. retains peculiar aroma and pungency ofginger and releases gingerin slowly. Aroma-loss rate of microcapsule is notably less than that of gingerin and antioxidant effects of it are notably better than that of gingerin. Thereby, as a spice, gingerin microcapsule with yeast cell wall can be used for roast, swelled food, beverage, sweets and tobacco products. As an antioxidant preparation, it can be used for storage of oils and delicacy retaining of fried food with oil.(vii) Extraction with supercritical carbon dioxide is the best way for gingerin of high quality at present and microencapsulation with yeast cell wall which was not reported is feasible for quality retaining of gingerin, both of which are of deep significance for further processing of gingerin and comprehensive utilization of yeast resources.