Option Of Harvest Time And Storage Condition As Well As Trial Production Of Smallanthus Sonchifolius In Lueyang

With field cultivated yacon tuber in year2010and2011in Lueyang base of south Shaanxias this experimental materials, the method of obtaining was been to yacon base and scoop theunderground tubers every fifteen days since the beginning of August of each year until the end ofNovember when the winter was coming and the aboveground part of yacon plants were startingto wilt. The tubers of different harvest time should be peeled and deactivated enzyme every timewhen they are brought back from the base, and then drying and crushing as the harvest samples.meanwhile, selected the tubers of the final harvest of year2010as the storage experimentalmaterial and divided into two groups at random, with one stored under room condition and theother in4℃after the tubers in each group was marked and weighed; the day of final harvest isthe first day of storage and then took out the sample in orders of both storage condition everytwenty days afterwards. This step was going on seven times and that means the whole storageperiod was145days. The processing method of storage material is the same as harvestexperiment. The harvest sample and storage sample were ready to under analysis respectively.Doing determination of the main ingredients including fructooligosaccharide (FOS), totalsugar, phenolic acids, chlorogenic acid, total flavonoids and proteins, and analysed thefluctuation and draw the curve of dynamic change of each component's content, and according tothe output and then ascertain the best harvest time. The same determination method could applyto the storage sample. Doing analytical research on the content change of each component andcompare them under two different storage conditions and times, then draw the dynamic changecurve, selecting optimal storage condition and time according to various aims and usage. Theresults of above researches can provide scientific suggestion and reference of harvest time andway of storage for yacon in Lueyang region and offer practical guidance for them. Furthermore,using the tuber of Lueyang yacon as raw material, made yacon preserved fruit and yacon juice inLab. Investigate the impact of antibrowing agent and sugar solution constitute on yaconpreserved fruit as well as antibrowning, clarifying and sterilization method on yacon juice, whichcan provide guidance for the yacon product development.1. In harvest experiment, FOS and total sugar were extracted by microwave method, and its contents were measured by Uv-vis method. The results showed that fluctuation of FOS and totalsugar contents are similar. Both of them accumulated quickly at the first harvest stage and didn'tstay stable until beginning of November. The conten of FOS and total sugar were76%(DW) and52%(DW) at that time respectively; The content of total protein, another nutritional componentin yacon tuber, was4.28%at end of November with a drop at middle of October but didn'tobvious. The phenolic acids including chlorogenic acid were extracted by ultrasonic method, andmeasured by Uv-vis and HPLC respectively. The results indicated that the phenolic acids andchlorogenic acid accumulated and ascended gradually during entire growth period and staystable at last two harvest times, namely, the beginning of November, which content were3.8mg·g^-1and0.35mg·g^-1respectively; Flavonoids, another pharmacological component inyacon tuber, was a little bit special, which reached its maximum at middle of October and had aslight descent at the last harvest, the content is9.75mg·g^-1and8.05mg·g^-1respectively. In sum,combined with the consideration of yacon tuber's fresh weight, drying rate and the contents ofvarious nutritional and pharmacological components, the best harvest time should start at themiddle of November. This conclusion is the same with the local opinion: yacon tuber should beharvested before the frost.2. Extraction and measurement methods of both nutritional and pharmacological componentfor storage experiment were the same as harvest experiment. The results argued that the dynamicchange of FOS are similar under two storage conditions while the content are dissimilar duringsame storage days. In the whole storage period, the FOS content of4℃were always higher thanits counterpart and the drop much later, that is to say, FOS in4℃group could stay for a longtime rather than decomposed into sucrose and monosaccharide. The fluctuation of total sugarcontent was tiny during the entire storage period, therefore, when the FOS is the main acquiredtarget, it is better the store in4℃for20days or between85to125days; On contrast, if yacon isfor raw food and sweetness is into consideration, it should better store in4℃after125days orin room condition for45day on condition that the weight loss was low, but the room condition iscosteffective, so it is more available. The content of phenolic acid in room condition were lowerthan4℃at every storage time and reached its highest when stored in4℃for45days andbetween105to125days, so it should be took out at this time when you want to get morephenolic acids. The fluctuation of total flavonoids was unconspicuous under two conditions, so itis better stored in4℃for45or125days when you want get more pharmacological compound.3. The result of trial production indicated that the yacon preserved fruit, after processed bythe antibrowning agent which consist of1.5%sodium chloride,0.5%citric acid,0.5%calciumchloride and0.15%ascorbic acid as well as sugar solution which consist of25%sucrose,15% glucose,0.1%CMC-Na2and0.2%citric acid, were not browning and had better mouthfeel andgood appearance. The antibrowning agent consist of0.1%ascorbic acid,0.1%citric acid,0.1%sodium sulfite and1.5%sodium chloride as well as pasteurization for processing of yacon juicehad preserved the flavor and nutrition value of yacon, what is more, yacon juice did notbrowning and appear precipitation for a long time, so all the agent and methods were proved tobe feasible.