Effects Of The Fruiting-bodies Of Auricularia Auricular-judae And Its Polysaccharide On The Properties Of Noodles

Chinese noodles,as a kinds of traditional staple food,have been deeply loved in China.With the improvement of people’s living standards,traditional noodle products processed with wheat flour have not been developed to meet the needs of consumers.More and more functional noodles have been put into the market.Auricularia auricular-judae is recognized as an edible and medicinal fungus containing many nutrients and functional constituents.Polysaccharide is the main active substance in the fruiting-body of Auricularia auricular-judae and has a variety of health and pharmacological functions.In this article,the effects of A.auricular-judae fruiting-bodies and its polysaccharide on the properties of Chinese noodles were investigated.In order to develop the quality of noodles with A.auricular-judae fruiting-bodies,the effects of three additives on noodle properties was studied.In addition,the extraction condition of the polysaccharide A.auricular-judae fruiting-bodies（APP）was optimized.Moreover,the interaction between APP and wheat and gluten was also analyzed;the relationship between interaction and the quality of noodles has been established.The raw and cooked A.auricular-judae fruit-bodies powder（1%、2%、3%、4%、5%、6%、7%）was added to prepare nutritional and functional fresh noodles.After comparing the effects of raw and cooked A.auricular-judae powder on texture characteristics,sensory and cooking quality of fresh noodles,the optimum amount of raw flour was determined to be 5%.Meanwhile,water absorption was 192.20%;dry materials loss was 10.13%;hardness was3221;elasticity was 0.88;breaking force was 16.80;and the sensory evaluation score was 87.Three kinds of food additives including gluten,xanthan gum and salt were used to improve the quality of A.auricular-judae noodles.The optimized formula by orthogonal experiments was:2%salt,0.6%xanthan gum,and 5%gluten.The three additives could improve the overall quality of A.auricular-judae noodles,including the appearance.They increased the sensory evaluation score of noodles containing A.auricular-judae fruit-bodies power up to 95points.Response surface methodology was used to optimize the extraction conditions of AAP from A.auricular-judae and the optimal extraction parameters were as follows:extraction temperature was 90°C;solid-to-liquid ratio was 1:63 g/mL;extraction time was 4 h.Under these conditions,AAP extraction rate was 22.41%.AAP was a brown-yellow flocculent solid,and poorly soluble in cold water,but has good solubility in hot water.While,its molecular weight was mainly distributed in the area lager than 5×10⁵ Da and 1².3×10⁴ Da,polysaccharide content was 78.8%,which was a protein polysaccharide without starch.Addition of 0.2%,0.4%,0.6%,0.8%,1%AAP was used added to prepare noodles,the result revealed that AAP reduced the cooking loss of noodles,while increased the texture quality of cohesiveness,breaking force and stretching distance.Combined with scanning electron microscopy,the more compact microstructure of the inner part of noodles added AAP was found,meanwhile,the encapsulation of starch was enhanced and the starch granule loss was reduced.The effect of AAP on the characteristics of starch in flour and the secondary structure of gluten protein was studied,and the correlation between AAP and AAP noodle quality was explored.RVA analysis showed that the peak viscosity,the minimum viscosity and the gelatinization temperature of starch showed an increasing tendency.The retrogradation value showed a decreasing tendency below 1.5%AAP addition.DSC analysis showed that with the increase addition of AAP,the initial temperature（T₀）,termination temperature（Tc）and the enthalpy（ΔH）of starch gelatinization were all increased,and 1.5%AAP increased by 2.165J/g compared to the blank sample.The addition of AAP increased the S-S bond content of gluten,and compared with the blank sample,10%AAP increased the S-S bond content by 1.06μmol/g.Fourier transform infrared spectroscopy results can show the effect of AAP on the secondary structure of gluten protein.Compared with the control,10%AAP increased theβ-sheet 1.32%,α-helix 0.11%,andβ-turn 1.28%,which indicating that AAP could cause the conversion of secondary structure such asβ-sheet,α-helix andβ-turn of gluten protein.Confocal laser scanning microscopy results showed that AAP makes the gluten network more intensive and compact.At the same time,the starch granules more evenly dispersed in the gluten network;the internal structure of the whole dough were more uniform and compact.Combined with the effect of AAP on starch and gluten,it showed that AAP improved the gluten network structure and increased the encapsulation of starch granules.The correlation between the effect of AAP on starch properties and secondary structure of gluten protein and the quality of noodles was been analyzed,the results showed that the peak viscosity,lowest viscosity,gelatinization temperature,peak temperature（Tm）,Tc andΔH change of the starch were positively correlated with the quality of the noodles,while the value of starch attenuation and retrogradation were negatively correlated with the noodle quality.The final viscosity of starch and the change of T₀ had no significant effect on the quality of noodles（p>0.05）;the secondary structure change of gluten was only positively correlated with the hardness of noodles（p<0.05）.