摘要
鱼类宰杀后营养成分在内源酶作用下易发生降解和氧化,如三磷酸腺苷(ATP)的降解、蛋白质变性等,使其品质下降和风味特性变差.为延缓肌苷酸(IMP)降解,保留鱼肉特有风味,通过电子鼻和气相色谱-质谱(GC-MS)等技术探究迷迭香酸和表儿茶素对冷藏海鲈鱼鱼肉风味特性的影响.结果表明:迷迭香酸(RA)和表儿茶素(EC)使海鲈鱼中呈味核苷酸相对含量和K值显著降低,前期IMP含量由原来的0.61 µg/100g分别升至1.70 μg/100g和1.39 µg/100g,此时风味和苦味比最高,2d后IMP开始降解,降解速率系数分别是0.079和0.037,RA和EC均能有效延缓IMP降解.GC-MS结果表明,在贮藏前期共检出挥发性物质25种,其中醛类3种、醇类4种、酯类2种、醚类3种、胺类物质9种、酸类和其它烷烃类4种.在贮藏中期,共检出挥发性物质39种,其中醛类2种、酮类1种、醇类6种、酯类6种、醚类4种、胺类物质10种、酸类和其它烷烃类10种.在贮藏后期,共检出挥发性物质44种,其中醛类2种、醇类7种、酯类3种、醚类3种、胺类物质11种、酸类和其它烷烃类18种.经RA和EC处理的海鲈鱼,其挥发性气味较对照有明显差异,且RA和EC也能减缓海鲈鱼肌肉中水分流失.
Abstract
Fresh fish are susceptible to degradation and oxidation by endogenous enzymes after death,such as degrada-tion of adenosine triphosphate(ATP)and protein denaturation,resulting in reducing quality and flavor characteristics.To delay the degradation of IMP and to preserve the flavor properties of fish,rosmarinic acid(RA)and epicatechin(EC)were used to inhibit ACP activity.The flavor characteristic was investigated mainly by electronic nose and gas chromatog-raphy-mass spectrometry(GC-MS)in sea bass.The results showed that nucleotides content and K value in sea bass treated with RA and EC decreased significantly,and the IMP content increased from 0.61 μg/100 g to 1.70μg/100g and 1.39μg/100g,respectively,when the flavor to bitterness ratio was the highest,and the degradation of IMP started after 2 d,and the degradation rate coefficients were 0.079 and 0.037,respectively,and both RA and EC could effectively retard the degradation of IMP.A total of 25 volatile substances were detected by GC-MS in the pre-storage period,in-cluding 3 aldehydes,4 alcohols,2 esters,3 ethers,9 amines,and 4 acids and other alkanes.In the middle of stor-age,39 volatile substances were detected,including 2 aldehydes,1 ketone,6 alcohols,6 esters,4 ethers,10 amines,10 acids,and other alkanes.44 volatile substances were detected,including 2 aldehydes,7 alcohols,3 esters,3 ethers,11 amine substances,and 18 acids and other alkanes in the late storage period.The volatile odors of sea bass treated with RA and EC were more significantly different from that of the control.RA and EC could also slowdown the water loss in the muscle of sea bass.
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