| Squid,also known as calamari,belongs to the mollusk cephalopod.From the nutritional point of view,squid is a high-protein,low-fat food rich in taurine,collagen,vitamins,amino acids and other nutrients and popular with people.Peruvian squid（Dosidicus gigas）has great potential for development and application because of its short growth cycle,large catch,low price and rich nutrition.Common squid snack foods such as shredded squid,baby squid,and grilled strips all need to go through key processes such as precooking（blanching）in the production and processing process to achieve the purposes of deodorization,aging,and shaping.This paper first studied the thermal processing characteristics of Dosidicus gigas carcass meat（compared with Ornmastrephes bartrami）at different heating temperatures,and further explored the mechanism of the change of Dosidicus gigas carcass meat quality by studying the thermal processing characteristics of Dosidicus gigas carcass meat myofibrillar protein,and finally studied the flavor change of Dosidicus gigas carcass meat during the precooking process,in order to provide reference for the deep processing of Dosidicus gigas products.（1）Research on thermal processing characteristics of Dosidicus gigas carcass meat:In this paper,the change trend of thermal processing characteristics of Dosidicus gigas carcass meat at different heating temperatures were studied with Ornmastrephes bartrami as control.The results showed that the thermal processing characteristics of two kinds of squid carcass meat had the same change trend.With the increase of temperature,the cooking loss,L*value,b*value,whiteness value and elasticity of two kinds of squid carcass meat showed an increasing trend;the hardness and chewiness showed an increasing trend and then decreasing trend.At the same heating temperature,the cooking loss,a*value,hardness and chewiness of Dosidicus gigas carcass meat were significantly higher than those of Ornmastrephes bartrami（P<0.05）;there was no significant difference in L*value,whiteness value and elasticity of two kinds of squid carcass meat（P>0.05）.The water distribution results showed that the Dosidicus gigas carcass meat had poorer water holding capacity compared to the Ornmastrephes bartrami.DSC scanning patterns showed that the soluble protein of Ornmastrephes bartrami and Dosidicus gigas carcass meat was completely denatured at around77.73°C and 74.2°C respectively.Combined with SDS-PAGE and SEM results,the thermal denaturation of water-soluble protein and salt-soluble protein in squid carcass meat is a key factor affecting the quality of squid carcass meat during thermal processing.Correlation analysis showed that the cooking loss,whiteness,hardness,elasticity,chewiness and other quality characteristics of squid carcass meat had a good correlation with the concentration of salt-soluble protein and water-soluble protein.Salt-soluble protein and water-soluble protein are the two most abundant proteins in muscle tissue,which determine the cohesive structure and firm texture of meat products.The thermal denaturation of soluble protein during heating will have a huge impact on the texture and other quality characteristics of fish meat.（2）Research on the thermal processing characteristics of Dosidicus gigas carcass meat myofibrillar protein:the results showed that with the increase of temperature,the turbidity,particle size and ultraviolet absorption intensity of Dosidicus gigas carcass meat myofibrillar protein continued to increase;Ca2+-ATP Enzyme activity,total sulfhydryl content,and endogenous fluorescence intensity showed a general downward trend;surface hydrophobicity first increased and then decreased;the relative content ofα-helix decreased,while the relative content ofβ-sheet and random coil increased.With the increase of temperature,under the action of heat,the structure of Dosidicus gigas myofibrillar protein in carcass began to expand,the hydrophobic group was exposed,and the denatured protein continuously gathered to form aggregates under the action of hydrophobic force or other forces.（3）Flavor changes in the precooking process of Dosidicus gigas carcass meat:the results showed that the cooking loss of Dosidicus gigas carcass meat in the precooking process showed a trend of increasing first and then gradually slowing down;the elasticity and the chewiness first increased and then decreased;while the hardness decreased continuously;the non-flowing water content in the precooking process of Dosidicus gigas carcass meat first decreased and then gradually slowed down.In terms of taste,the main flavor amino acids in the precooking process of Dosidicus gigas carcass meat are alanine,methionine,histidine,and arginine;the results of electronic tongue showed that the taste components of precooked Dosidicus gigas carcass meat and raw squid carcass meat were quite different.Gas chromatography-ion mobility spectroscopy（GC-IMS）technology was used to analyze the changes of volatile flavor compounds in the precooking process of Dosidicus gigas meat,and a total of 59volatile compounds were identified,among which the relative content of aldehydes was the highest.The fingerprint showed that there were significant differences in flavor substances of Dosidicus gigas carcass meat with different pre-cooking time,and GC-IMS technology could well distinguish the flavor compounds of Dosidicus gigas carcass meat under different precooking times.The results of the electronic nose showed that the flavor of raw squid meat samples,2 min treatment group and other treatment groups were very different.Considering the changes of squid carcass meat texture,cooking loss,taste and flavor during the precooking process,the quality of Dosidicus gigas carcass meat with limited specifications is the best when the precooking time is 2-4 min. |
