高水分挤压南极磷虾在不同干燥方式下的品质变化规律研究OA

As a key species in the Southern Ocean,Antarctic krill is hailed as the world's largest undeveloped animal protein reservoir.Nutritional analysis reveals that its dry-basis protein content is as high as 65％,with an amino acid score(AAS)considerably superior to that of traditional animal proteins,demonstrating substantial potential for food development.However,its endogenous low-temperature autolytic enzymes trigger rapid autolysis,leading to an excessively short processing window,which severely constrains its industrial process ability.There is an urgent need to address this critical challenge through innovative processing technologies.High-moisture extrusion(HME)induces directional reorganization of the protein matrix via thermomechanical energy conversion,facilitating the formation of anisotropic fibrous structures at moisture levels exceeding 40％.Compared to conventional thermal processing,this technology offers the following advantages:(1)minimized nutrient loss due to reduced heat exposure time;(2)shear-induced biomimetic alignment of myofibrils,which imparts a meat-like texture;(3)synergistic regulation of raw material formulation and process parameters enabling precise textural design;and(4)inactivation of endogenous autolytic enzymes during HME heating,thereby inhibiting autolysis in Antarctic krill. These characteristics make HME an ideal choice for developing novel marine protein-based meat analogs.In the study here presented,we successfully prepared HME-textured Antarctic krill meat(HMEAKM)with fibrous meat-like structure and favorable morphology through high-moisture texturization technology utilizing Antarctic krill,wheat protein,yeast protein,and konjac glucomannan.The study confirmed that HMEAKM possesses outstanding nutritional quality and serves as an ideal substitute for traditional livestock and poultry meat.However,high-moisture texturized products have high water activity,making them prone to microbial growth and unfavorable biochemical reactions.These factors result in a short shelf life and difficulties in ambient storage and long-distance transportation,which limits their commercial promotion.Drying is a key post-processing step to address these issues.Through drying,product shelf life can be extended,stability improved,and product diversification and added value can also be achieved.The drying process of HMEAKM involves simultaneous heat and mass transfer,constituting a complex physicochemical process.Water removal inhibits microbial activity while also inducing a series of changes in the physical,chemical,and structural properties of HMEAKM,affecting the final product quality. Both domestic and international research on high-moisture texturized proteins primarily focuses on raw material formulation and process parameter optimization.Meanwhile,studies on the impact of subsequent drying processes on product quality are still lacking.There is a scarcity of in-depth investigations into the mechanisms by which different drying methods affect product quality.To address these challenges,this study compared the effects of four drying methods-hot air drying(HAD),cold air drying(CAD),infrared drying(IFD),and microwave drying(MVD)—on the quality characteristics of HMEAKM,aiming to elucidate their underlying mechanisms and identify the optimal method.The results indicate that the drying method plays a decisive role in the product's microstructure,texture,protein structure,functional properties,and water distribution.MVD leveraged its internal and external heating mechanisms and ensured extremely high drying efficiency while effectively avoiding surface hardening,thereby promoting the formation of a porous,loose,honeycomb-like microstructure within the sample.This resulted in the lowest hardness,best elasticity,and highest degree of fibrillation among the products.In contrast,IFD,due to strong surface absorption of radiant energy,led to the rapid formation of a dense,hard crust on the sample surface,causing substantial macroscopic shrinkage.This resulted in extremely high product hardness and the poorest elasticity and chewiness.As traditional convective drying methods,HAD and CAD are relatively mild but suffer from long drying cycles and low efficiency.Samples generally exhibited shrinkage;however,they better preserved product elasticity and chewiness.Among them,CAD helped retain more bound and immobilized water,while HAD induced further protein unfolding and substantial fluorescence quenching.At the protein structure level,IFD and MVD caused more pronounced denaturation of secondary structures,manifested as the conversion of α-helices toβ-sheets.All four drying methods disrupted the proteins' tertiary structure to varying degrees,leading to the exposure of internal tryptophan residues to hydrophilic environments.Regarding chemical bonds,HAD samples had the highest free sulfhydryl content but failed to effectively form disulfide bonds,whereas MVD likely led to the lowest free sulfhydryl content due to rapid protein aggregation.Rheological property analysis showed that HAD and CAD samples exhibited higher initial apparent viscosity.Meanwhile,IFD and MVD,due to their rapid and intense energy output,inhibited the formation of molecular cross-linking networks,resulting in lower viscosity.LF-NMR water analysis further confirmed the differential effects of drying methods on water states.CAD was most conducive to maintaining bound and immobilized water,MVD samples retained more internal free water,and IFD fundamentally altered the water binding state.Comprehensive analysis suggests that MVD demonstrates the most advantages in terms of drying efficiency,formation of excellent porous structure,achievement of desirable texture,and enhancement of protein solubility.Although IFD is efficient,the surface hardening and texture deterioration that it causes represent major drawbacks.Although HAD and CAD are milder processes that preserve certain ordered protein structures and rheological properties,their low efficiency and structural shrinkage remain critical limitations.Therefore,this study ultimately selected MVD as the foundational method for subsequent in-depth research and industrial development.This investigation fills a research gap in the post-drying treatment of high-moisture texturized proteins,providing a theoretical framework and robust data to support the industrial drying processing of HMEAKM.Furthermore,it establishes a solid scientific foundation for the secondary processing and quality control of texturized protein products.