| With the world’s growing population,increasing demand for protein and the saturation of the traditional livestock industry,plant-based meat is gaining widespread interest as an important complement to traditional meat products.High moisture extrusion(HME)is a commonly used technology for the production of green,efficient and continuously produced textural protein with the potential to mimic the texture of meat.Current research on HME focuses on formulation and process optimisation;less research has been done on the extruder“black box”process and the moisture content of the textural protein.Peanut protein(PP)contained in peanut cake meal has potential for plant meat applications,but at present peanut cake meal is mostly used as feed,and the added value needs to be improved.Gluten protein(WG)is often used as a raw material to enhance the fibrous structure of textural protein because of its good ductility and elasticity,and therefore gluten powder(VG)is often used as a raw material.Therefore,this project systematically investigates the HME process of the VG/PPP complex protein system,revealing the multi-level relationship between raw material properties,system response parameters and protein conformation from the perspective of“raw material properties-system response-product performance”,and illustrating the textural pattern of the VG/PPP complex protein system.On this basis,the effects of carboxymethyl cellulose(CMC)and sodium alginate(SA)on the quality of VG/PPP formulated high-moisture textural protein were further investigated;finally,plant-based meat patties were developed and compared with commercially available plant-based meat patties.The main research elements are as follows:Firstly,the"raw material properties-system response-product performance"relationship was established for different ratios of VG/PPP based compound protein systems.The results show that the higher creep deformation and irrecoverable deformation caused by the addition of VG increases the die opening pressure(3.56 MPa to 4.70 MPa),which in turn accelerates the evaporation and dissipation of water from the extrudate at the extruder die exit.The qualitative results show that the addition of VG enhances the strength of the protein 3D network structure,enhances the elastic solid characteristics,leads to higher torque and specific mechanical energy(SME)during the HME process,contributes to the formation of a dense fibrous structure and higher tensile strength The moderate addition of VG(≤50%)also helps to enhance the springiness and soften the texture of the extrudate,but excessive addition can have the opposite effect(12.81 kg hardness and 0.91 elasticity at 100:0).When the VG/PPP protein blend is 50:50,the extrudate has a soft and springy texture(2.76 kg hardness and 0.95springiness),while retaining the most moisture and the best quality.Secondly,the changes in protein conformation before and after extrusion at different ratios of the VG/PPP complexed protein system were investigated.By comparing the differences in protein multilayer structures before and after extrusion,the histochemical behaviour and patterns of the VG/PPP complex protein system during HME were analysed.The results showed that HME induced the conversion of raw proteins fromα-helix toβ-sheet;however,at high VG ratios(≥70%),the conversion ofα-helix to random coils occurred,and the disorder of protein secondary structure in the extrudate increased.HME also induced an increase in protein surface hydrophobicity at PPP ratios(≤50%)and a decrease in protein surface hydrophobicity at high VG ratios(≥70%),which was associated with a change in protein conformation.HME also induced disulfide cross-linking,which increased protein aggregation,with the highest degree of protein disulfide cross-linking occurring at a 70%ratio of VG.Then,the quality of the dual-protein high-moisture textural protein was systematically investigated by the correlation model of“raw material characteristics-system response parameter-protein conformation-product performance”,which was used to study the effect of carboxymethyl cellulose(CMC)and sodium alginate(SA)on the quality of the dual-protein high-moisture textural protein.The results of the analysis showed that:the results showed that the addition of polysaccharide colloids promoted the conversion of weakly bound water to strongly bound water and reduced the water activity;reduced the brightness of the extrudate L~*and increased the a~*and b~*;also increased the hardness,elasticity and texture properties of the extrudate;the effect of SA addition was better than that of CMC,and the effect was optimal at0.5%.The results of the“raw material characteristics-extruder response-protein conformation”analysis showed that the addition of 0.5%SA increased the WAI of the raw materials,resulting in a more pronounced elastic solids profile and a decrease in die pressure(3.66 MPa)and die temperature(100.20°C),which had a positive effect on the moisture distribution of the extrudate.The 0.5%SA addition also induced the formation ofβ-folding,which increased the degree of order in the secondary structure of the protein(40.35%).It also induced further folding of the tertiary structure of the protein,reducing the degree of aggregation and disulfide cross-linking of the protein molecules.Finally,the textural proteins obtained in this study were applied to the development of plant-based meat patties and compared with commercially available plant-based meat patties.The five selected textural proteins(30:70,50:50,CMC-2,SA-0.5,SA-1)were optimally screened for sensory scores to produce plant-based patties and compared with two commercially available plant-based patties for sensory comparisons,and a textural protein formulation(SA-0.5)was further optimised for sensory scores;and a comparison of the freeze-thaw stability of the plant-based patties made from this textural protein with the two commercially available phyllo-based patties showed that the plant-based patties made with a50:50 ratio of VG to PPP and a 0.5%SA addition had the lowest water loss during repeated freeze-thaws. |
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