Comparison Of6Isoflavones Isomers In Soy And Soy Processed Produce From China And Japan

The soybean isoflavone is a kind of plant estrogen with biological activity. Thesoybean isoflavons is pointed out to have Antioxidant activity and the protective effects of mostkinds of cancers. Beside these soybean isoflavones is also point out to have many otherbiological activities.Recently more and more researchers start to concentrate on it.But thesedays soybean isoflavones is also proved to have some side affects to special populations.Refereeing to this results special populations should choose the food which content highamount of isoflavones cautiously.The soy and soybean produce people daily eat are rich insoybean isoflavones.In this situation a good method which can detect the amount of isoflavonesprecisely is very important to us. The good method can provide stable and reliable data. And thedetection of the amount of isoflavones in soy and soybean produce can give people significantadvice during the choosing of food.The condition and the method of determination of soybean isoflavones in the AOACofficial method was analyzed. In this method there are there steps includingextract,saponification and HPLC detection.The effects of extraction temperature, extractiontime,extraction methanol concentration on the determination of soybean isoflavones weredeveloped in this work. We also analyzed the day to day precision of the results of this methodin5days. The results shows that as the same to the results of the AOAC method65℃is thebest extraction temperature,2h is the best extraction time and the best extraction methanolconcentration is80%. The result also shows that this method have good day to day precision in5days. And as a result this method can provide stable and reliable data to the determination ofsoybean isoflavones in soy and soybean produce. Under this method and HPLC detectionconditions the six standard isoflavones were well separated and the standard curve of the6kinds of standard soybean isoflavones shows good linear relationship. In this method only6kinds of soybean isoflavones standard samples were used but can well detect the soybeanisoflavones in soybean and soybean products. Because in the saponification period6kinds ofglucoside change to aglycone.The AOAC method possess the feature of low cost, simpleoperation,reliable and stable of data. The AOAC method was proved to have important guidingsignificant in the detect of soybean isoflavones at home.During this work we use the name ofthe6kinds of isoflavones which The national natural science noun authorized committeeuse.As a common name, it can make a unite guide to the name of soybean isoflavones.Soy and soy products content high amount of isoflavones. Using the method of AOACWe abstracted6kinds of isoflavones in18kinds,21soybeans and soy products samples fromChina and also14soybeans and soy products samples from Japan. Determined and compared the amount and distribution of the6different kinds of isoflavones from Chinese and Japanesesamples.We choose the soy and soybean products that people daily eat and all bought from thelocal chain hypermarket. The result shows that in products of Chinese samples fuzhu is thesample which contents highest amount of isoflavones which is350.19±2.22mg/100g while inJapanese samples natto content the highest amount of isoflavones which is122.73±3.70mg/100g. In Chinese samples, the amount of isoflavones is also very high infuzhu、ttofuyi、dougan and doufuhua. And the content of the soybean isoflavones in fuzhu、ttofuyi、doufuhua and dougan is350.19±2.22、218.12±0.83、89.13±1.33、79.47±0.32mg/100g.As the same to products,in dry samples the sample of China which contents the highestamount of soy isoflavones is also fuzhu. But to the Japanese samples in dry samples the onecontents the highest amount of isoflavones is soymilk.In products The sample contents the most amount of daizin and genistin is fuzhu(149.45±0.46mg/100g,189.74±1.73mg/100g), to the glycitin the sample is tofu (36.92±1.55mg/100g), to the daidzein the sample is douchi (49.06±0.22mg/100g), to the glycitein issoybean sauce (15.40±0.87mg/100g) and to the genistein is white furu(46.45±0.51mg/100g).Doujiang,doufu, dougan, fuzhu and qianzhang those un-ferment samples content moreglucoside than aglycon and some of the ratio of glucoside is higher than90%. While furudoubanjiang soybean sauce douchi those ferment samples content more aglycone thanglucoside and some of the the ratio of aglycone is higher than90%. To Chinese samples duringthe fermenting of soybean a large amount of glucoside had been hydrolyzed to aglycone. Themost important reason of this result is the impact of the microorganism during the fermenting ofthe soybean produce. But this didn’t happen to the Japanese samples，the sample contents themost amount of daizin and genistin is juantofu (145.24±0.52mg/100g,207.47±0.9mg/100g),tothe glycitin the sample is natto1(22.77±0.65mg/ml), to the daidzein the sample isdoujiang(16.92±0.24mg/100g), to the glycitein is doujiang(1.26±0.01mg/100g) and to thegenistein is doujiang(18.06±0.24mg/100g). The content of soybean isoflavones in natto is thesimilar to it in the dougan. This may because of the differences of the microorganisms. And themicroorganism in Japanese natto do not have the function of changing the glucoside toaglyconer. Both in products and dry samples the amount of isoflavones in Chinese youfang ismuch littler to it in the dougan. This may because of the high temperature during the producingperiod.The high temperature destroyed the soybean isoflavones. But this did not happened tothe Japanese samples. Both in products and dry samples Youfang of Japan have higher amountof isoflavones to dougan. This point out that during the producing period of youfang theisoflavones have not been destroyed. This is an important phenomenon to the differents of theproduct method. Although a number of studies have pointed out that isoflavones have a series ofadvantages such as antibiosis,anti-tumor and cancer prevention, too much isoflavones havesome side effects to people of certain stage and some special populations.As a result specialpopulations like adolescent in development age, breast feeding women and pregnant womanshould choose the food which content high amount of isoflavones such as fuzhu, doufuyi andnatto cautiously. Referring to the high content of aglycone which is much easier to be absorbedin ferment products the special populations should also eat these products modestly.Ignoringthese side effects eating isoflavones in moderation is definitely usefull to normal yang women.As a conclusion people should choose the products which content high amount of isoflavonesin proper quantity and referring to their own situation.