The Properties Of Auricularia Auricular-Judae And Effect Of It Supplemented With Kappa-Carrageenan On The Gel Properties Of Black Rice

As people pay more attention to healthy functional foods,auricularia auricular-judae(AAJ)and black rice(BR)are recognized health foods for both food and medicine in my country,but there are few related deep-processed products on the market.Because k-carrageenan(k C)can achieve good gel properties when it is compounded with other additives in the field of food processing,this thesis is based on studying the effects of different factors on the properties of AAJ.Choosing k C to deeply analyze its influence on the freeze-thaw stability of AAJ gel,and adding a mixture of AAJ and k C to BR to explore the effect.The compound and the freeze-thaw cycle affect the gel characteristics of BR.Finally,the compound of AAJ and k C was used to make BR sponge cake,and its quality was studied.The specific research results are as follows:1.The results showed that with the increase of mass fraction of the powder or sucrose,the dynamic viscoelasticity and shear viscosity of AAJ in water gradually increased.Within the tested range,the dynamic viscoelasticity and shear viscosity of the powder decreased as the incubation time at 95?increased.Compared with the control group,the tested salts decreased the dynamic viscoelasticity and shear viscosity of the powder in water,and their effects in descending order were as follows:Ca Cl₂>KCl>Na Cl.As the p H of water increased from p H3 to p H9,the dynamic viscoelasticity and shear viscosity initially increased from p H 3 to p H5,and then plateaued from p H5 to p H7,and eventually decreased from p H7 to p H9.Compared with the control group,addition of hydrocolloids resulted in increased dynamic viscoelasticity and shear viscosity.2.The results showed that a greater amount of k C significantly increased the storage modulus to a greater extent for cycling 1 to 7 times,indicating k C enhanced the gel-like properties of AAJ supported by TPA during FTC.Moreover,reducing the amount of freezable water and enhancing the water holding capacity of AAJ gel demonstrated by the shorter relaxation times and strengthened hydrogen bonding after the addition of k C were determined by LF-NMR and FT-IR.In addition,more crystallites and higher peak intensity based on DSC and XRD,as well as more uniform and ordered honeycomb-like holes in AAJ gel observed by SEM formed by the addition of k C helped for reducing damages from FTC.The findings suggested that 20%k C was significant for developing and improving novel AAJ-based foods.3.The measurement results of gelatinization and dynamic viscoelastic properties show that AAJ and k C can significantly increase the gelatinization viscosity of BR gel and promote the gelation of BRduring cooling.In addition,through low-field nuclear magnetic resonance and texture properties measurement,it was found that AAJ and k C inhibited the water flow of the BR gel,and significantly increased the hardness and elasticity of the BR gel.Furthermore,by analyzing the measurement results of DSC,XRD and FT-IR,the gelatinization enthalpy of BR gel with AAJ increased from 3.01J/g to5.94J/g.The peak of the hydroxyl stretching vibration of BR is reduced from3390 cm^-1to 3374 cm^-1,forming a stable structure,indicating that the AAJ and k C can improve the stability of the BR gel structure.In addition,combined with the results of scanning electron microscopy,the mechanism of the interaction between the two to improve the structure of BR gel is further explained.Adding AAJ and k C can form a more ordered BR gel network structure.4.The measurement results of dynamic viscoelastic properties show that,compared with BR gel,the storage modulus of BRe gel added with AAJ/k C is significantly improved under 1 to 7 cycles of FTC.The combined texture results also proved that AAJ/k C enhanced the stability of BR gel during the freeze-thaw cycle.Through the results of XRD and FT-IR,it was found that the crystallization area of AAJ/k C-BR increased significantly.Combined with the LF-NMR index,the NMR relaxation time T₂was significantly reduced,indicating that AAJ/k C inhibited and hindered the fluidity of water in BR gel,indicating that AAJ/k C can improve the freeze-thaw stability of BR gel.At the same time,AAJ/k C-BR can obtain a smaller,denser,porous and structurally stable BR gel network structure,that is,to improve the freeze-thaw stability of the BR gel.5.The effect of AAJ,k C,AAJ/k C on the quality of BR sponge cake was determined by texture characteristics,and the results showed AAJ,k C,AAJ/k C can increase the elasticity and cohesion of the BR sponge cake to a certain extent.Among them,the BR sponge cake made by adding AAJ/k C has the best effect.It shows that AAJ and k C have a certain improvement effect on the texture characteristics of BR sponge cake,and the combination of the two has a better effect on improving the texture characteristics of BR sponge cake.Furthermore,the specific volume and internal texture are used to characterize the effect of AAJ/k C on the quality of BR sponge cake.The results show that AAJ/k C significantly increases the specific volume of BR sponge cake.Porosity and stomata density reduced the average area of stomata of BR sponge cake,indicating that AAJ/k C can improve the quality of BR sponge cake.Through low-field NMR measurement,we can see the mechanism of AAJ/k C to improve the low temperature stability of BR sponge cake.The results show that AAJ/k C reduces the free water of BR sponge cake.The content inhibits the flow of moisture and is more resistant to storage.It shows that AAJ/k C can improve the quality of BR sponge cake to a certain extent.