Research On Extrusion Properties And Product Development Of Defatted Hemp Seed Meal

The protein content of defatted hemp seed meal(HPM)is as high as 60%～70%.After high-moisture extrusion,it will form a fiber structure similar to chicken breast.It can be directly used in meat substitute food,and the amino acid in HPM is rich in composition,and very close to the essential amino acids of human body,it also has high nutritional value.It is an ideal source of high-quality protein.Therefore,studying the application of EHPM in meat substitutes will not only increase the added value of HPM products,but also provide an important process and technical reference for HPM extrusion research.First,the effect of extrusion process parameters’ effects(water addition,extrusion temperature,screw speed,feeding speed)on the quality of EHPM is studied,and the extrusion process is optimized by response surface.The results show that: EHPM has the greatest impact on quality.As the amount of water added increases,L* of the color increase,and hardness and chewiness of the product decrease,and the elasticity and texture reach the highest value when the amount of water added is 50%;as the extrusion temperature increases,the color of the product,Hardness and chewiness increase,elasticity and organization degree reach the highest value at 160℃,screw speed and feeding speed have no significant effect on the quality of EHPM as a whole.The optimal extrusion parameters after response surface optimization are extrusion temperature 160℃,water addition 50%,screw speed 180 r/min,and feed speed 18kg/h.Under this process condition,the predicted value of organization degree is 1.655.Secondly,through DSC and NMR,the state change and migration law of water in the extrusion process under different water additions are discussed.The results show that the combined water content first increases during the extrusion process and then remains unchanged(16%～24%),the free water content is first reduced and then remains unchanged(2%～36%).The state of the water in the extrusion process is converted from free water to bound water,and in the process of low water addition(20%),Almost HPM’s all free water is converted into bound water(22.5%),and in the process of medium and high water addition(40%～60%),HPM mainly exists in the state of free water(32%).Thirdly,the effect of different water addition(20%～60%)on the protein properties of EHPM and the specific water addition(low-20%,medium-40%,high-60%)in the extrusion process of HPM from raw material to the structured product and the change rule of the protein properties during this process.The results showed that the degree of fibrosis of EHPM increased as the amount of water added increased;the 50 KDa band in the SDS-PAGE spectrum became lighter or disappeared,and the low molecular weight 20 KDa band became deeper;the particle size increased from 200 nm to 500 nm,indicating that the protein had occurred Obvious aggregation.The protein solubility experiment proves that this change is the result of the joint action of disulfide bonds and non-covalent bonds;α-helix and β-sheet are reduced from 60.8%to 43.6%,and β-turn and random coils are increased from 41.3% to 59.9%.In the extrusion process with a specific amount of water,as the extrusion process progresses,the protein properties of the HPM in the barrel show similar changes,such as the generation of fiber structure,molecular aggregation,disulfide bonds and non-covalent bonds.The interaction maintains the protein structure,etc.,but the degree of fibrosis is higher during the extrusion process with medium and high water addition,the degree of molecular aggregation and crosslinking is lower,and the secondary structure changes less.Finally,comparing the optimized EHPM with the commercially available textured protein,the brightness L* of EHPM is 68.49,the degree of organization is 1.65,the hardness is 6594.88,the chewiness is 7009.72,the elasticity is 1.18,and the NSI is 90.2%.The quality is better than the commercially available tissue protein;a special processing technology is used to develop an imitation chicken breast product,which is close to commercially available chicken breast products in all aspects of quality.