杂交鲟和金鲳鱼块非冻贮藏过程鲜度变化研究

Freshness comparation of hybrid sturgeon and golden pompano fillet during non-frozen storage

目的考察杂交鲟和釐鲳鱼块非冻贮藏过程中鲜度和品质变化规律,确定最适非冻贮藏条件。方法取中段新鲜鲟鱼肉,去皮后切块;冰鲜釐鲳鱼,取肉切块。将2种鱼块分别在4、-1和-3℃迚行贮藏,定期取样,采用微量扩散法测定鱼肉中的挥发性盐基氮(total volatile basic nitrogen, TVB-N)、高效液相色谱法测定ATP相关化合物含量、电极法测pH、分光光度计法测定硫代巴比妥酸值(thiobarbituric acid reactive substances, TBARS)值,来评价鱼肉鲜度。结果新鲜鲳鱼初始TVB-N、肌苷(inosine,Hx R)、次黄嘌呤(hypoxanthine,Hx)、肌苷酸(inosine monophosphate,IMP)含量及K值均比鲟鱼高,两者初始p H和TBARS值相近。根据TVB-N值, 4、-1和-3℃条件下鲟鱼和鲳鱼块的货架期分别为9 d(鲳鱼一级鲜度期为4 d)、33～36 d(鲳鱼一级鲜度期为15～18 d)、40～45 d以上(鲳鱼一级鲜度期为33～36 d);但根据K值,鲟鱼的货架期则比上述对应温度下的货架期长而鲳鱼货架期则明显缩短。总体上,鲟鱼各鲜度指标变化均比较缓慢,鲳鱼鲜度在4、-1℃的下降速度均比鲟鱼快,但在-3℃则与鲟鱼接近。随着贮藏温度的降低,两鱼贮藏品质均有明显提升,只有脂肪氧化程度无明显降低。对于鲳鱼,-3℃贮藏品质显著优于4和-1℃,而鲟鱼块在-1和-3℃的贮藏品质差异则不如鲳鱼明显。结论 K值不适合用于评价鲟鱼的鲜度,但能够在TVB-N基础上迚一步将一级鲜度期鲳鱼的鲜度迚行更为准确的鲜度分级。新鲜鲳鱼贮藏品质相对鲟鱼而言更易劣变,鲳鱼块的最适非冻贮藏条件为-3℃,而-1℃则是适于鲟鱼的非冻贮藏斱式。

Objective To investigate the freshness change of hybrid sturgeon(HS)and golden pompano(GP)fillet,compare the storage quality profile during non-frozen storage and determine the optimal storage condition for both 2 species of fish.Methods Middle part of fresh HS was cut,peeled and divided into fillets.Iced GP was also filleted.All the fillets were stored at 4,-1,-3℃,respectively.Samples were taken regularly to evaluate the freshness.TVB-N was assayed by micro diffusion method.ATP relevant compound was quantified by HPLC,pH was determined by electrode and TBARS was assayed by spectrophotometric method.Results Initial levels of TVB-N,HxR,Hx,IMP,and K value in GP fillet were higher than those of HS.The initial pH and TBARS value of 2 species were similar.At 4,-1,-3℃,the shelf of HS and GP fillet was 9 d(first grade period lasted 4 d for GP),33-36 d(first grade period lasted 15-18 d for GP),and more than 40-45 d(first grade period lasted 33-36 d for GP),respectively.But according to K value,shelf life of HS was much longer,but shelf life of GP was shortened obviously comparing with that of the above corresponding data.On a whole,changes of the above freshness indexes in HS were relatively steady comparing with those of GP.At 4 and-1℃,freshness deterioration rate of GP fillet was much quicker than HS,but similar with HS at-3℃.With the decrease of storage temperature,storage quality of both 2 species increased obviously except the lipid oxidation level.For GP,storage quality at-3℃was much better than that at 4 and-1℃.The quality difference between-1 and-3℃for HS was not so obvious as that of GP.Conclusion K value might not fit for the freshness evaluation of HS,but could grade more correctively the freshness of GP fillet during the period of first grade judged according to TVB-N value.Quality of fresh GP was more prone to deterioration comparing with HS,optimal condition of non-frozen storage for GP was-3℃,and-1℃was fit for non-frozen storage of HS.