| In this study,porous rice starch was used as raw material,and octenyl succinic anhydride(Octenyl Succinic Anhydride,OSA)modifier was used to prepare modified porous rice starch,which was then compounded with Xanthan gum(XG)and embedded separately Cinnamon essential oil(CEO),cinnamon essential oil and sodium metabisulfite(Na2S2O5)with antibacterial and fresh-keeping effects,and the physical and chemical properties of the two microcapsules prepared above were characterized,and finally applied to Xinjiang The fresh-keeping effect of seed grape and cherry tomato was studied.The main research content and results of this paper are as follows:(1)Preparation of modified porous starch(Modified porous starch,MPS):optimize the modified porous starch with oil absorption and substitution degree as indicators,and prepare modified porous starch with octenyl succinic anhydride as a modifier The porous starch process was optimized by response surface experiments.The experimental results showed that the best process conditions for preparing modified rice porous starch by esterification modification are:OSA addition amount is 5%,reaction time is 3 hours,and porous starch milk solution pH is 8.5,The oil absorption rate under this condition is 246.12%,and the degree of substitution is 0.0342;the porous starch after modified esterification has no major difference in appearance with porous starch.Esterification modification will not change the original porous starch.Morphology;XRD results show that:porous starch and modified porous starch are both typical A-type crystal structure,indicating that esterification modification does not change the crystal type of porous starch;at the same time,the FTIR spectrum shows that the modified porous starch is at 1722 cm-1 New absorption peaks were added at 1 and 1568 cm-1,but their structure was not changed.(2)Modified porous starch compound xanthan gum embeds cinnamon essential oil,cinnamon essential oil and sodium metabisulfite respectively,and the optimal conditions for preparing cinnamon essential oil microcapsules(MPS/XG-CEO)are MPS/XG=20:1,CEO/MPS=0.6:1,CEO embedding rate is 69.75%;the optimal conditions for preparing cinnamon essential oil and sodium metabisulfite microcapsules(MPS/XG-CEO/Na2S2O5)are MPS/XG=20:1,CEO/MPS=0.6:1,Na2S2O5/MPS=1:100,the embedding rate of CEO is 68.73%,and the embedding rate of Na2S2O5 is 72.42%;the particle size of the two groups of microcapsules is equivalent to the particle size of the modified porous starch.There is no significant difference between them.(3)The freeze-dried microcapsules are similar in appearance to those of modified porous starch granules;through XRD and Fourier infrared spectroscopy analysis,two substances,cinnamon essential oil and sodium metabisulfite,have been successfully embedded;The TGA results showed that the thermal stability of the microcapsules of sodium metabisulfite was improved after being embedded.In a normal temperature environment,the cumulative release rate of cinnamaldehyde and the cumulative release rate of sulfur dioxide in the microcapsules are gradually increased;the filter paper method test is used to determine the antibacterial effect on Escherichia coli.Bacillus subtilis,yeast and mold.The results showed that cinnamon essential oil and its two groups of microcapsules have obvious antibacterial effects on the four bacteria,and their sensitivity index to the four bacteria is in the order of mold>yeast>Bacillus subtilis>E.coli.(4)Evaluate the effects of sodium metabisulfite microcapsules on cherry tomatoes,Xinjiang through changes in hardness,weight loss rate,soluble solids,decay rate,titratable acid content,vitamin C content,pH value,total number of colonies and sensory quality scores.The fresh-keeping effect of seedless grapes shows that the microcapsules can effectively inhibit the spoilage of two kinds of fruits and vegetables and maintain the better quality of fruits and vegetables,and the fresh-keeping effect of seedless grapes in Xinjiang is greater than that of cherry tomatoes. |
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