Physicochemical Properties Of Adlay Flour And Its Effect On Properties Of Mixed Dough And Quality Of Chinese Steamed Bread

Adlay(Coixlacrryma-jobi L.var.ma-yuan Stapf)seed has been used in Traditional Chinese Medicine for a long time.The nutrient value of adaly is high,which is rich in a variety of active ingredients,such as coix polysaccharide,coix phenols,polyunsaturated fatty acids,with antioxidant,anti-allergy,anti-obesity,anti-tumor and other effects.At present,there are few studies on the physical and chemical properties of adaly,which limits the application of adaly in the food industry.Chinese steam bread(CSB),known as Mantou,is a widely consumed staple food in China.Adaly flour was added into CSB making which might improve the health benefit of CSB.Firstly,effects of particle size on the physical and chemical propertiesof adaly flours were evaluated.Then the effects of adaly flour as partial wheat flour replacer or with particle size on the pasting properties and the rheological properties of dough,and textural and sensory characteristics of Chinese steamed bread were aassessed.In addition,the effect of adaly flour on the release of polyphenols,flavonoids and antioxidant activity in vitro during the digestion of CSB was studied.The results are as follows:(1)After prepared by selecting,shredding and sieving(60 mesh,100 mesh and 200 mesh),the adlay was classed into four kinds of adlay flour,which are ?(444.836um)??(250.582um)??(105.927um)??(34.317um).With the adaly powder particle size decreases,the moisture,protein,amylase,dietary fiber,polyphenol content of adaly were declined.The Water holding capacity and oil holding capacity do it in the opposite way.In the determination of gelatinization of gelatinization properties,the peak viscosity,the measured viscosity and the final viscosity all were increased as the decrease of the particle size,but the formation time of the adlay flour paste was decreased.(2)Adaly flour paste is a typical non-Newton,shear thinning fluid,and elastic deformation is better than viscous deformation.With the adaly powder particle size decreases,K,n,apparent viscosity and the capacity of resistance to shear were increased,but the phenomenon of shear thinning were reduced.During the heating process,G' and G" increased quickly before gelatinization temperature,the G' and G"slow down.During the cooling process,G' and G" are on the rise.The G' and G" of adaly flour are increased with the frequency.And G'>G",which is weak gel.Steady-state rheological properties showed that the adaly flour showed a shear thinning condition,and the dynamic rheology test showed that the adaly flour was a typical weak gel dynamic rheological.(3)The addition of adaly flour reduces the gluten content of the dough and affects the rheological properties of the dough.With the increase of adaly flour,the peak viscosity,bottom viscosity,breaking viscosity and gelatinization temperature of mixed flour dough decreased.At the same time,the greater the amount of adaly powder substitution,the lower the water absorption rate of the mixed dough,the longer the dough formation time and the stabilization time,the more obvious the shear thinning phenomenon.With the decrease of the grain size of the adaly flour,the dough gluten content decreased,the peak viscosity,the bottom viscosity,the final viscosity and the gelatinization temperature of the mixed flour dough were significantly improved.The grain size of adaly powder had a significant effect on the water absorption,dough formation time and settling time of the mixed flour dough,but had no significant effect on the weaving degree and the stabilization time.Steady-state rheological results show that the mixed powder dough exhibits shear thinning,and the dynamic rheological results show that the mixed powder dough exhibits elastic fluid properties.(4)Add adaly powder into CSB,which will improve the content of fat,dietary fiber and polyphenols in CSB.The hardness,chewiness,recovery,elasticity and specific capacity of the CSB will increased with the amount of adaly powder.The grain size of the adaly flour will also affect the basic composition,texture characteristics and sensory evaluation of the CSB.When the addition of adaly powder were 5%and 15%,which will be accepted by people.(5)Adaly powder particle size of ?,the amount of substitution were 0%and 15%of the proportion of wheat flour into the made of CSB.In vitro,we can see that the release of polyphenols and flavonoids from the CSB is significant,which can improve the capacity of AB TS+ clearance rate and reduction properties of Fe3+.By the way,the released of polyphenol and flavonoid and the antioxidant capacity of CSB with mixed dough is higher than the CSB with wheat dough.The growth rates were 5.00%and 10.06%,17.57%and 32.79%,6.90%and 12.34%,3.14%and 11.13%respectively.