Physiological Activities In Vitro And Processing Stability Of Polyphenols In Blue Wheat

Blue wheat,a characteristic wheat bred by hybridization,has blue grains because it is rich in natural anthocyanins.Blue wheat has the characteristics of high protein content,perfect amino acid and abundant trace elements.It also contains a large number of polyphenols in its grains,which has the functions of physiological regulation and health care,so it has broad prospects for development.In this paper,the difference of basic nutrient components between blue wheat and common wheat was analyzed.In order to study the vitro physiological activity of blue wheat polyphenols,the extraction process of free polyphenols and bound polyphenols from blue wheat was optimized by central combination test,and the structure of polyphenols was analyzed by fourier transform infrared spectroscopy.In vitro physiological activity,the antioxidant,hypoglycemic and bacteriostatic effects of free polyphenols and bound polyphenols in blue wheat were analyzed and compared.In addition,the stability of polyphenols in blue wheat under different conditions was studied.The main results are as follows:1.The basic nutritional components of blue wheat grains are:crude protein（16.5±0.6）%,crude fat（2.3±0.2）%,starch（58.7±1.6）%,crude fiber（3.3±0.02）%,ash（2.6±0.03）%,and water（12.3±0.2）%.2.The optimum extraction conditions of free polyphenols from blue wheat were as follows:ethanol concentration 60%,ratio of material to liquid 1:20g/mL,ultrasonic power240W,extraction temperature 50℃,extraction time 15minutes,extraction times 2 times.Under these conditions,the extraction amount of free polyphenols from blue wheat was（1066.0±2.7）μg/g;the optimum extraction conditions of bound polyphenols from blue wheat were as follows:mass fraction of H₂SO₄ 10%,ratio of material to liquid 1:15g/mL,water bath.The content of bound polyphenols in blue wheat was（1134.0±5.6）ug/g under the conditions of temperature 75℃,water bath time 60 minutes and extraction times 4 times.Fourier transform infrared spectroscopy（FTIR）analysis showed that the phenolic hydroxyl groups of free polyphenols and bound polyphenols in blue wheat were obvious,and the spectra showed that there were phenolic substances.3.The results of antioxidation in vitro showed that,the free polyphenols and bound polyphenols in blue wheat had certain scavenging effect on the five antioxidant systems,and the free radical scavenging effects of free polyphenols and bound polyphenols were different,that is,free polyphenols showed better scavenging effects on ABTS radical,while bound polyphenols showed better scavenging effects on DPPH radical,superoxide radical and hydroxyl radical.The antioxidation ability of blue wheat is better than that of common wheat in vitro.The hypoglycemic ability in vitro indicated that the free polyphenols and bound polyphenols in blue wheat of the inhibited the activities of a-amylase and a-glucosidase,while the inhibitory effects of free polyphenols and bound polyphenols on the a-amylase and a-glucosidase were different,by comparison,the inhibition of free polyphenols to the two enzymes was stronger than that of bound polyphenols.The hypoglycemic ability in vitro is that blue wheat is superior to common wheat.The antibacterial activity in vitro showed that the free polyphenols and bound polyphenols in blue wheat had certain inhibitory effect on the four pathogenic bacteria,and the antibacterial activity of free polyphenols and bound polyphenols were different.The antibacterial activity of free polyphenols was as follows:Staphylococcus aureus>Bacillussu btilis>Escherichia coli>Salmonellenteriditisa;the antibacterial activity of bound polyphe nols was as follows:Salmonellaenteriditis>Bacillus subtilis>Escherichia coli>Staphylo coccus aureus.4.Different processing methods have certain effects on polyphenols in blue wheat.The loss rate of polyphenols in microwave treatment group is higher than that in traditional heating treatment group.The loss rate of polyphenols in ultraviolet treatment group is higher than that in natural light treatment group.The higher the concentration of additives is,the higher the loss rate of polyphenols is.The effect of Na₂CO₃ and NaCl on polyphenols in blue wheat is greater than that of Vc.Through the study of blue wheat polyphenols,the processing and utilization of blue wheat polyphenols can be broadened,and the theoretical basis for its comprehensive utilization can be provided.