物理场辅助解冻对蓝鳍金枪鱼肌肉品质及肌红蛋白特性的影响OA

[Objective]To improve the thawing quality of frozen bluefin tuna products.[Methods]Frozen Thunnus maccoyii was used as the research material and thawed by four methods:cold storage thawing(CST),microwave thawing(MT),magnetic field thawing(MFT)and low-voltage electrostatic field thawing(LEFT).The changes in water-holding capacity,water distribution,color,myoglobin redox substances,textural properties,freshness and volatile flavor compounds were systematically investigated.[Results]The CST group exhibited the most serious quality deterioration,and its cooking loss rate,centrifugal loss rate and thawing loss rate were significantly higher than those of other groups(P<0.05).The proportion of methemoglobin reached up to 31.93％,the thiobarbituric acid(TBA)value and total volatile basic nitrogen(TVB-N)content were 0.19 mg MDA/kg and 0.185 9 mg/g,respectively,with a relatively high relative concentration of 2-pentanone.Meanwhile,the CST group showed the highest myoglobin oxidation degree and a low α-helix content(19.83％),which was unfavorable to the stability of myoglobin secondary structure.The MT group better maintained the color of Thunnus maccoyii,and its a*/b* value(2.97)was significantly higher than that of other groups.However,the uneven heating of MT treatment led to inhomogeneous water distribution and poor water-holding capacity of muscle tissue,accompanied by severe oxidative denaturation of myoglobin.MFT could inhibit the formation of large ice crystals and significantly maintain the water-holding capacity and textural properties of Thunnus maccoyii.The hardness(566.73 g)and chewiness(228.98 mJ)of the MFT group were significantly higher than those of other groups,and its total sulfhydryl content was the highest(277.05 nmol/mg),which could inhibit the oxidative denaturation of myoglobin to a certain extent.The LEFT group showed the optimal overall quality maintenance with favorable water-holding capacity,and the proportion of immobilized water reached up to 97.33％.It had the lowest TVB-N content(0.157 2 mg/g),the smallest particle size(199.95 nm)and the highest solubility(84.37％),which effectively reduced the oxidative denaturation degree of myoglobin.Moreover,both the ultraviolet absorption spectrum and intrinsic fluorescence spectrum of myoglobin in the LEFT group presented the highest absorption peaks,contributing to better stability of myoglobin tertiary structure and intact muscle tissue.In addition,70 volatile flavor compounds were identified in the four treatment groups,mainly including aldehydes,esters,alcohols and ketones.[Conclusion]LEFT has obvious advantages in inhibiting myoglobin oxidative denaturation,maintaining freshness and muscle tissue integrity,and can be used as an effective strategy to improve the thawing quality of Thunnus maccoyii.