Changes In Nutrient Composition During Soybean Germination And Its Isoflavone Bacteriostatic And Inhibition Of Myeloma Cell Proliferation Activity

Soybean,an important traditional crop in China,could become edible sprouts after germination.The contents or types of nutrients,biological active substances and anti-nutritional factors of soybean were changed at different degree when dealt with germination processing.To study the dynamic changes of nutrients and biological active ingredient contents of soybeans after germination processing,ultrasound-microwave assisted extraction technology of isoflavones from sprouts,the antibacterial activities of isoflavone extract and inhibiting activity of proliferation on myeloma cells would be very important to the development of soybean source.The dynamic changes of major nutrients and biological active ingredient contents of two soybeans(Wandou 6,Kennong 4)during germination were studied in this paper.Ultrasound-microwave assisted extraction technology of isoflavones from sprouts was optimized.The antibacterial activities of isoflavone extract and inhibiting activity of proliferation on myeloma cells were analyzed.The results showed that the content of nutrients in two kinds of soybean after germination processing(0-6 days)changed in varying degrees.The fat contents of Wandou 6 and Kennong 4 were decreased by almost 28.28%and 40.75%,respectively,on the fifth and sixth days of germination.In addition,moisture content and reducing sugar content of sprouts in Wandou 6 and Kennong 4 had greatly increased after germination processing;reducing sugar content of Kennong 4 increased by about 4.2 times compared to soybean;crude protein content of two kinds of sprouts also increased significantly and the crude protein content was the highest(46.51%,47.67%)on the fifth and sixth day of germination.With the increase of germination time,soluble protein content in two sprouts also increased,while,insoluble protein content decreased.Changes of globulin,gliadin,gluten and albumin content of two sprouts were not obvious after germination processing(0-6 days).Two kinds of soybeans after germination had a high level of content of amino acids(especially essential amino acids).Variety of amino acids was relatively complete and the proportion was more appropriate,very close to the patterns of essential amino acids.Overall,soybean handled a higher nutritional value and more easily absorbed by the body after germination appropriately.Sprouts had more good taste and good flavor than soybean.In this paper,Kennong 4 sprouts germinated two days were collected as experiment material.Ultrasound-microwave assisted extraction technology of isoflavones from sprouts was obtained:liquid ratio 1:25(g/mL)(w/v),50%ethanol concentration,extraction temperature 65 ?,extraction time 250s.Under the extraction conditions,the rate of isoflavones from sprouts was 0.387%,significantly higher than conventional hot water bath extraction(0.244%).The particle size analysis showed that frequency distribution of the sample powders particle size processed by hot water bath was significantly higher than those treated by the ultrasound-microwave assisted extraction technology at the range particle size of 2.00-200.00?m.The morphology results of scanning electron microscope showed that the surface of sample was uneven and organizations became loose after dealing with ultrasound-microwave assisted extraction.The more isoflavones dissolved from the sprouts powders,the higher extraction rate of isoflavones was.The reason might be the sprouts powders became swollen and loose after treated with ultrasound-microwave assisted extraction.Four components contents of isoflavones from two kinds of soybean sprouts were determinated in different stages of germination.Studies have shown that the total isoflavone content of Wandou 6 was the highest on 5th day(705.39?g/g).And the genistin,daidzin,daidzein contents of Wandou 6 were reached the highest level at 385.40,120.23,316.13 ?g/g on 4th,4th,5th day,respectively.The total isoflavone content of Kennong 4 soybean germinated 4 days was 787.7 ?g/g,much higher about 3.18 times that of raw soybean.The isoflavone content of two kinds of sprouts was higher than that of soybean,and at the same germination period,isoflavone content of two soybeans showed little difference.Antioxidant activity of isoflavones from two kinds of soybean with germinated in different days were studied by DPPH and ABTS test methods.Tests showed that with the increase of germination time,the antioxidant activities of isoflavones from two kinds of sprouts were increased,and at the same concentration,isoflavones extract of Kennong 4 displayed better antioxidant activity than that of Wandou 6.The isoflavone extract from two kinds of soybean sprouts at different germination time had inhibitory effect against Staphylococcus aureus(gram-positive bacteria),but not against Escherichia coli(gram-negative bacteria).Compared to Kennong 4,isoflavone extract of Wandou 6 had better inhibitory effect against Staphylococcus aureus at the same germination time.Both isoflavone extract of two kinds of sprouts showed better antibacterial ability against Staphylococcus aureus than that of soybean.The isoflavone extract from Wandou 6 sprouts germinated 5 days had best inhibitory effect on Staphylococcus aureus.And further exploration of this bacteriostatic mechanism showed Staphylococcus aureus of treated group began to enter the decline phase after incubation 15h.Relative volume of soluble protein(extracellular and intracellular)and extracellular nucleic acid in Staphylococcus aureus were significantly higher(p<0.05)than the negative control group.The morphology results of scanning electron microscope showed that form of staphylococcus aureus were considerable changed after dealing with the soybean isoflavone.The bacteria became deformed and into squares.The inhibitory effect of isoflavone on proliferation of multiple myeloma cells was studied by CCK-8 kit method.The isoflavone extract of two kinds of soybean germinated 0-6 days had good inhibition on the proliferation of myeloma cells.This effect had a significant dose-response relationship.The isoflavone extract of sprouts with appropriate germination processing had stronger effect on the proliferation of myeloma cells than that untreated with germination processing.