Effect Of Whey Protein Concentrate On Noodle Quality

Noodle is one of the most important staple foods in China,but the protein content of wheat flour is generally less than 15%,and the content of lysine is insufficient,which cannot fully meet the demand of human body.Whey protein concentrate?WPC?is a precious protein isolated from milk with good nutritional quality and functional properties.Adding whey protein concentrate to wheat flour can effectively increase the protein content of noodles and make up for the problem of insufficient amino acid composition.Therefore,whey protein concentrate80 was added to wheat flour at different ratios as raw materials for making noodles in this study.The effect of whey protein concentrate on noodle quality was investigated and its mechanism was initially explored,in order to support the development of whey protein concentrate fortified noodles.The main research contents and results are as follows:Firstly,WPC in different proportions?0%,4%,8%,12%,16%and 20%?were blended with wheat flour,and the farinograph properties,gelatinization characteristics and wet gluten content of the mixed flour were measured.The results showed that with the increase of the amount of WPC,the water absorption of the dough decreased,the dough formation time increased,the peak viscosity,minimum viscosity,attenuation value,final viscosity,and rebirth value of the flour reduced,and the wet gluten content decreased;when adding 4%WPC,dough stabilization time was significantly higher than other addition amounts,the flour quality index was the highest,and the addition exceeding 4%will weaken the dough strength.Secondly,the corresponding mixed powder was made into noodles,and the color,cooking characteristics,texture characteristics and sensory quality of the noodles were measured to investigate the effect of WPC on the noodle quality.The results show that,increasing the amount of WPC addition made the raw noodle yellow,dark and rough,but white after cooking.At the same time,the optimal cooking time,cooking loss and water absorption increased.The texture results show that the addition of WPC increased the extension,hardness,chewiness and tensile strength of the noodles,and reduced the elasticity and adhesiveness.The palatability,toughness,stickiness,smoothness,and taste indexes obviously deteriorated with the addition more than 8%,reducing the sensory quality,while 4%WPC will not reduce the sensory quality of the noodles.In addition,adding WPC effectively reduced the stickiness of noodles after long-term storage,improved the cookability and storage stability of noodles to a certain extent,and promote the digestion of noodles as well.Therefore,4%may be the most suitable addition amount under this condition.Finally,the reasons for the effect of WPC on noodle quality were preliminarily explored.The results of nuclear magnetic resonance transverse relaxation time?T₂?showed that the addition of WPC can make the moisture binding tighter before cooking,but opposite after cooking.Results of SEM and CLSM showed that the addition of WPC reduced the continuity of the gluten network,increased the pores,interfered with the full formation of the gluten protein network,and increased the starch dissolution during cooking.The results of SDS-PAGE and Fourier transform infrared spectroscopy showed that the addition of WPC did not have a covalent interaction with wheat flour,and affected the original disulfide bond formation in the noodles.It was possible that WPC diluted the gluten and weakened the structure of protein network,resulting in a reduction in noodle quality.