Effect Of Cold Plasma Treatment On Wheat Quality

As a non-thermal processing technology,cold plasma is now mainly used in food material modification,sterilization and crop breeding.Therefore,it has a good application potential for wheat flour quality and storage characteristics.In this paper,helium gas is used as the gas source to perform cold plasma treatment(0 s,10 s,15s,20s)on wheat with different moisture content and different varieties.Combining grain chemistry and biochemical analysis methods,the physiological characteristics of wheat,flour quality and protein secondary conformation changes before and after treatment are studied;the changes in storage stability of wheat with different moisture content before and after treatment are compared,which is why this technology is used in wheat processing.And storage applications provide theoretical basis.The main findings are as follows:(1)After cold plasma treatment,the germination rate of wheat grains increased significantly,and the corresponding catalase(CAT)activity also increased significantly;both of them increased significantly with the extension of the treatment time,and the water content was The germination rates of 12.5% of Xinmai 26 and Zhongyanmai 1(50 W,20 s)were 6.7% and 8.5% higher than those of the sample control group,respectively,and the CAT activity was 1.81 and 2.17 times that of each sample control group.After treatment,the L~* and WI of wheat grains increased,and the a~* and b~* values decreased,and the related change trends were positively correlated with the treatment time.The wheat fatty acid value and polyphenol oxidase(PPO)activity decreased significantly after treatment.It shows that cold plasma treatment has the effects of enhancing wheat seed vigor,improving wheat freshness and delaying quality deterioration.(2)After cold plasma treatment,the wet gluten content of wheat increased significantly,and the gluten index increased;after treatment,the peak viscosity,minimum viscosity and attenuation value of wheat dough increased significantly,and the rebound value decreased significantly.),midline peak value(MPV),midline left peak width(MLW),midline right peak width(MRW),midline width at 8 min(MTx W)and 8 min midline integral(MTx I)significantly increased,midline peak time(MPT))Significantly increase,and the weakening slope(WS)is significantly reduced.The gluten index,flour gelatinization and kneading analysis results show that cold plasma treatment is beneficial to enhance wheat flour gluten strength,mixing tolerance,elasticity and stretch resistance,etc.,and has a positive effect on the improvement of wheat dough quality.(3)SE-HPLC analysis results showed that the content of large molecular weight polymers in wheat samples increased significantly after cold plasma treatment.FTIR results showed that the content of α-helix and β-turn in wheat samples increased significantly after treatment,and β-sheets and The content of random coils was significantly reduced.Ellman results showed that the content of disulfide bonds in each sample after treatment was significantly higher than that in the control group of each sample.It shows that the cold plasma treatment promotes more obvious polymerization between protein components by changing the protein secondary structure and intermolecular cross-linking interaction.(4)The germination rate of each wheat sample before and after cold plasma treatment decreased during storage.Root length and shoot length increased first and then decreased.The magnitude of the change was positively correlated with water content;the change of its catalase activity during storage The law is the same as that of seedlings,first increase and then decrease;its fatty acid value increases significantly.The germination rate of Zhongyanmai No.1 with a moisture content of 12.5% was stored for 6 months after 20 s of cold plasma treatment,and the germination rate was reduced to 80%,which was higher than the germination rate of the control group(71%)at the end of storage;the CAT activity was the control group 1.7 times.After cold plasma treatment,the increase in fatty acid value of the sample was significantly lower than that of the sample before treatment.Zhongyanmai No.1 with a moisture content of 12.5% was 85% of the control group after being stored for20 s with cold plasma treatment for 6 months.It shows that this treatment is beneficial to delay the decrease of seed vigor and the increase of fatty acid value during wheat storage,and improve the storage stability of wheat.(5)The peak flour viscosity,attenuation value,and α-amylase activity of each wheat sample before and after cold plasma treatment decreased during storage,and the rebound value increased,that is,the gelatinization characteristics of each wheat sample changed before and after treatment.Before and after treatment,the wet gluten content and gluten water absorption of each wheat sample decreased during the storage process,that is,the quality of flour deteriorated,and the speed of flour deterioration was positively correlated with the moisture content.The moisture content of Zhongyanmai No.1 with a moisture content of 15.5% was stored for 6 months after being treated for 20 s,and the wet gluten content and gluten water absorption decreased to 28.3% and 191%,respectively,which were higher than the corresponding control group(26.8%,185%).After 20 s of cold plasma treatment,the peak viscosity of Zhongyanmai No.1 at the end of storage was 50 cp-140 cp higher than that of the control group;the attenuation value was higher than the respective control group by 40 cp-80 cp;the rebound value was that of the respective control group87%-91%,indicating that cold plasma treatment has the effect of improving the quality of flour and improving storage stability.(6)Zhongyanmai No.1 with moisture content of 12.5%,14%,and 15.5% after being treated with cold plasma for 20 s and stored for 6 months,the α-helix decreased to 18.26%,18.14%,and 18.1%,respectively.At the end of storage in the group,the α-helix decreased to17.45%,16.83%,and 17.3%;after the cold plasma treatment,the β-turn content of the samples stored after the storage was significantly higher than that of the control group,with a moisture content of 12.5%.No.1 was stored for 6 months after being treated for 20 s,and the β-turn content was 1.08 times that of the control group;before and after treatment,theβ-sheet and random curl of the samples changed in the same manner during storage,indicating that cold plasma treatment can delay the storage of wheat The disordered secondary structure during the period improves the stability of wheat protein during storage.