冰鲜时间对不同性别青爪乌鸡和黄麻鸡鸡肉中肌苷酸含量的影响

为研究品种、性别及冰鲜时间对鸡肉肌苷酸(IMP)含量的影响,选取甘肃省渭源县黄香沟牧场养殖的青爪乌鸡和黄麻鸡2个鸡种作为试验对象,采用高效液相色谱法分析了不同性别鸡肉肌苷酸含量及不同冰鲜时间条件下肌苷酸含量变化情况。结果表明:IMP含量在0~4℃条件下随着保鲜时间延长呈先上升再下降的趋势,8 h时出现峰值,青爪乌鸡肉中肌苷酸含量大于黄麻鸡(p<0.05);对青爪乌鸡和黄麻鸡而言,母鸡肉肌苷酸含量大于公鸡肉(p<0.05)。在4℃冷藏8 h后,青爪乌鸡鸡肉中IMP、腺苷二磷酸(ADP)、次黄嘌呤(Hx)、肌酐(HxR)含量显著高于黄麻鸡鸡肉(p<0.05),AMP含量稍高于黄麻鸡鸡肉;青爪乌鸡母鸡肉中IMP、HxR含量显著高于公鸡肉(p<0.05),AMP、ADP、Hx含量高于公鸡肉(p>0.05);ATP均未检出。因此得知:冰鲜时间对青爪乌鸡和黄麻鸡肉中IMP的降解有显著影响,推荐鸡肉在0~4℃条件下保鲜8 h食用风味最佳。本实验为鸡屠宰采后肉质保鲜技术的利用提供参考依据。     

草鱼贮藏期间肌肉ATP关联物及K值的动态变化

为了明晰冷藏(4℃)过程中草鱼宰杀后背腹部肌肉ATP关联物含量变化与鲜度变化的关联,研究了贮藏期间草鱼背腹部肌肉ATP关联物及K值随时间的动态变化规律。结果表明:冷藏期间草鱼背腹部肌肉ATP关联物的变化趋势相似,但相对含量有明显区别,背部和腹部肌肉肌苷酸(IMP)含量先增加后减少,而草鱼背部IMP含量远大于腹部;次黄嘌呤(Hx)和次黄嘌呤核苷(HxR)含量均随贮藏时间延长不断增加;新鲜草鱼背、腹部肌肉K值分别为7.72%,7.78%,随着贮藏时间的增加,K值不断增大,6d时,两者均接近60%。故4℃贮藏条件下草鱼的货架期为6d。     

常温与冷藏条件下不同阶段鸡肉呈味核苷酸及游离氨基酸含量的变化

研究鸡肉在常温与冷藏条件下呈味核苷酸及游离氨基酸含量的变化。结果表明:常温条件下,6 h时鸡胸肉和鸡腿肉肌苷酸(IMP)含量达到最高,分别为2.27、1.97 mg/g,然后开始显著下降(p0.05);宰后随贮藏期延长,测定的17种游离氨基酸含量均有不同程度增加,鸡胸肉和鸡腿肉风味氨基酸占比分别在6 h和12 h时达到最大值,依次为59.3%、61.8%。冷藏条件下,IMP含量随时间延长呈先升后降的规律,鸡胸肉和鸡腿肉分别在48 h和36 h时IMP含量达到最大值,即3.14 mg/g和2.81 mg/g,而后缓慢降低;鸡胸肉和鸡腿肉风味氨基酸占比峰值均出现在宰后低温下48 h时,分别为67.1%、66.4%。因此,低温贮藏可以抑制鸡肉中IMP在贮藏过程中的降解,相对于常温贮藏,冷藏可以促进鸡肉中游离氨基酸的生成,有利于提高鸡肉的食用风味。     

草鱼冷藏期间ATP关联物含量及新鲜度变化

目的：分析草鱼冷藏期间腺嘌呤核苷三磷酸关联物含量的变化,研究草鱼肉中各核苷酸的含量与其新鲜度的相关性。方法：利用强碱将不稳定的核苷酸关联物反应生成其钠盐形式,通过高效液相色谱法检测核苷酸含量,并通过总挥发性盐基氮含量和感官性状的变化进行鲜度评价。结果：生成钠盐形式的腺嘌呤核苷三磷酸关联物能通过色谱很好地分离。新鲜鱼肉中含有高含量的肌苷酸,达504.34 mg/kg。冷藏2 d内草鱼腺嘌呤核苷三磷酸、肌苷酸含量快速下降,次黄嘌呤含量则迅速增加。冷藏后腺嘌呤核苷三磷酸未检出,肌苷酸下降幅度达92.77%,次黄嘌呤增加幅度达89.82%。冷藏期间挥发性盐基氮含量一直上升,冷藏6 d后超出最大值限度,冷藏草鱼的贮藏期限为6 d。     

不同饲养方式下北京油鸡产品风味和营养物质差异研究

旨在探讨不同生产方式下北京油鸡风味营养差异,通过对不同饲养方式北京油鸡肌肉和鸡蛋风味物质比较分析,了解北京油鸡风味特征及营养物质与饲养方式间的关系,从而为北京油鸡饲养管理和品质提升提供参考。结果表明,放养方式下北京油鸡肌肉肌苷酸和L-谷氨酸含量高于集约化饲养北京油鸡,肌苷酸差异不显著(P0.05),L-谷氨酸差异显著(P0.05),肌苷则表现相反,且差异显著(P0.05);不同饲养方式北京油鸡鸡蛋营养物质(总氨基酸和总脂肪酸)无显著差异;放养条件下鲜味氨基酸和多不饱和脂肪酸显著高于集约化饲养(P0.05),胆固醇则相反,但差异不显著(P0.05),卵磷脂和n-3脂肪酸在不同饲养方式下差异不显著(P0.05)。表明北京油鸡在不同饲养方式下风味和营养物质存在一定差异,尤其是香味物质、鲜味物质和不饱和脂肪酸在放养方式下表现更佳。     

不同贮藏条件下武定鸡肌肉肌苷酸及相关核苷酸含量的变化研究

实验对150日龄武定母鸡胸肌在不同贮藏温度和时间对其肌苷酸及相关核苷酸的含量影响进行分析,结果表明:18℃贮藏条件下,IMP含量在宰后4 h达到最高值2.00 mg/g,自8 h开始含量显著下降(P<0.05);IMP前体物含量在2 h达到最高测定值1.46mg/g,之后逐渐下降;IMP降解物含量随时间延长逐渐升高;ATP总代谢物含量在4 h含量达到最高值5.71 mg/g,之后逐渐下降;K值随时间延长而增大。4℃贮藏条件下,IMP含量随时间延长呈先升后降规律,24 h含量达到最高1.46 mg/g;IMP前体物含量也存在类似的变化规律,24 h含量达到最高0.91 mg/g,自第3 d开始显著下降(P<0.05);IMP降解物、ATP总代谢物和K值随时间的延长而增加。武定鸡肌肉在相同贮藏温度下,贮藏时间越长,肌苷酸含量越低;贮藏温度越低,肌苷酸降解越缓慢,ATP的整体代谢过程持续时间越长。     

冷藏及冰藏条件下南美白对虾品质变化规律

通过测定南美白对虾在4℃冷藏和冰藏条件下的感官评分、总挥发性盐基氮(total volatile basic nitrogen,TVB-N)含量、菌落总数、肌苷酸(inosinemonpho sphate,IMP)关联物含量及生物胺含量的变化,研究南美白对虾在2种贮藏条件下的品质变化规律,评价加冰贮藏对于4℃贮藏南美白对虾品质的影响,并通过分析IMP关联物各比值与各主要鲜度指标间的相关性探讨更适合于评价南美白对虾品质变化的指标。结果表明:冰藏组南美白对虾的TVB-N值、菌落总数及部分生物胺含量均显著低于冷藏组(P0.05),此外,在鲜度指标K、Ki、G、P、H及Fr值中,Fr值更适于评价该条件下南美白对虾的品质变化。综合感官评分和菌落总数的变化情况,4℃冷藏和冰藏条件下南美白对虾的贮藏期分别为5 d和6 d,冰藏有利于虾肉品质的保持。     

不同贮藏条件下鸡肉肌苷酸降解规律的研究

测定了12只文吕鸡胸肉在冷藏(0～2℃)1～10d和冷冻(-20℃)～90d内肌苷酸(IMP)和肌苷(I)含量的变化.结果显示:冷藏条件下IMP含量由屠宰2h的最高含量(3.583mg/g)开始随时间增加逐渐降低,不同时间点的含量差异极显著(p<0.01),冷藏4d的胸肉仍具有相对较高的食用价值,其IMP含量为宰后2h的73%;冷冻条件下IMP也随时间延长而下降,且不同测定时间测定值间差异极显著(p<0.01),但与冷藏相比,下降幅度明显变小,冷冻20d的肉样IMP的含量介于冷藏24～48h的肉样之间,冷冻90d的肉样IMP含量仍不低于冷藏10d肉样.I的变化趋势与IMP恰好相反,随着冷藏和冷冻时间的增加而逐渐增加.经回归分析,得到IMP含量在冷藏条件下依(t)变化的最佳回归方程为:IMP=0.014t2-0.295t 3.546(校正R2=0.877),在冷冻条件下的最佳回归方程为:IMP=-0.018t 3.470(校正R2=0.823).     

云南剥隘鸡与河南肉鸡肌肉中肌苷酸含量的 比较研究

目的比较研究不同月龄、性别的云南剥隘鸡与河南肉鸡肌肉中不同胴体部位的肌苷酸含量。方法随机选取健康5月、7月龄左右的云南剥隘鸡、河南肉鸡,公母各10只,屠宰取胸肌和腿肌待测。采用高效液相色谱法测定出不同月龄(5、7月龄)、性别及胴体部位(胸肌、腿肌)的云南剥隘鸡和河南肉鸡肌肉中肌苷酸含量。结果云南剥隘鸡、河南肉鸡肌肉中肌苷酸含量分别为2.4374~3.3192 mg/g、2.2095~3.0220 mg/g;5月、7月龄的云南剥隘鸡肌肉中肌苷酸含量均显著高于同月龄的河南肉鸡(P0.05);云南剥隘鸡肌肉中肌苷酸含量高于同性别的河南肉鸡,其中2种品种的母鸡肌肉中肌苷酸含量差距更显著(P0.05);云南剥隘鸡胸肌、腿肌中肌苷酸含量均显著高于相同胴体部位的河南肉鸡(P0.05)。结论不同月龄、性别、胴体部位对2个品种鸡肌肉中肌苷酸含量的差异性均产生显著影响,云南剥隘鸡肌肉中肌苷酸含量要高于相同条件下的河南肉鸡。     

不同贮藏条件下草鱼肌肉挥发性成分的变化分析

为了探讨不同贮藏时期草鱼肌肉挥发性成分的变化情况,采用固相微萃取-气相-质谱联用法(SPME-GC-MS)检测冷藏(0~4℃)及常温(25℃)条件下不同贮藏时间点草鱼肌肉的风味成分组成。本研究共检出9大类物质,主要是醛酮类、醇类、酸类、胺类、烃类及少量其他类化合物,并分析了主要挥发性成分的含量、气味及其可能的来源。研究结果表明,新鲜至冷藏9 d和常温6 h的草鱼肌肉挥发性成分以羰基化合物和醇类为主导风味,且醇类物质含量较多,此时青草味、土腥味明显;冷藏9 d及常温6 h后,酸类、胺类等低阈值物质明显增加,加之醛类物质的作用,此时表现为酸腐味和氨臭味明显;常温贮藏条件下,草鱼肌肉产生特征腐败气味速度更快,即与冷藏相比,腐败更为迅速。     

不同贮藏条件下鸡肉肌苷酸含量的变化规律

为了探讨肌苷酸在冷藏和冷冻期间产生和降解规律,以70日龄黄羽肉鸡为实验材料,连续7 d测量4 ℃冷藏期间胸肌IMP、HxR、Hx、ADP、AMP和IMPc含量以及-20 ℃不同冷冻时间鸡肉IMP及其代谢物含量。结果显示:冷藏第2 d和第5 d IMP含量有显著降解,分别为屠宰后4 h的66%和45%。Hx含量在第2 d和第5 d极显著增加,分别为屠宰后4 h的2.6倍和4.6倍。HxR含量第4 d达到最大值,之后快速下降。IMPc含量从第5 d开始降解趋势明显。冷冻1周内IMP、Hx和HxR含量变化均不大。IMP含量冷冻1个月、210 d和540 d后分别为屠宰后4 h的65%、41%和6%,冷冻1个月到4个月之间变化不大。Hx和HxR含量分别在冷冻30 d和300 d时最高。IMPc含量冷冻210 d和540 d时下降极显著,分别为屠宰后4 h的84%和42%。因此,建议鸡肉4 ℃冷藏保存时货架期4 d为宜;-20 ℃冷冻保存时1周最宜,鸡肉冷冻保存时间最好不超过4个月。     

冷藏期内猪肉肌苷酸与生物胺两者变化关系的研究

采用高效液相色谱法测定生鲜猪肉的背最长肌在4℃温度条件下肌苷酸(IMP)和腐胺、尸胺、组胺、酪胺、亚精胺、精胺这六种生物胺含量的变化情况,从而进一步分析它们之间的相关性。结果表明,随着货架期的延长,IMP含量呈先上升后降低的趋势,并在第2d达到最高;精胺含量基本保持在4.0mg/kg左右,组胺的含量始终很低,其它的胺类物质都有所增加,尸胺的变化最为突出;虽然腐胺和亚精胺的含量比较低,但是仍然有明显的变化;酪胺变化也非常明显。从Person积差相关系数可以看出,IMP与其他指标相关系数呈负相关显著,有的指标是不显著的;在0.01水平上,IMP与亚精胺之间的负相关性最强,达到了-0.981;其次是尸胺与IMP之间,相关系数是-0.960,呈显著负相关;酪胺也与IMP显著负相关;IMP与腐胺、组胺、精胺的相关系数都不显著。因此,通过测定IMP含量变化可以预测猪肉新鲜度,且可作为猪肉保藏与加工过程中品质控制的重要指标之一。     

Muscle High-Energy Phosphates and Stress Affect K-Values during Ice Storage of Atlantic Salmon (Salmo salar)

Initial levels of white muscle high-energy phosphates, IMP, ATP:IMP-ratio, adenylate energy charge and pH were used as indicators of handling stress when Atlantic salmon were slaughtered. Ante-mortem handling included fish that were either anesthetized (baseline), quickly netted and killed by a blow to the head (unstressed) or chased to exhaustion in the holding tank (stressed). During subsequent storage in ice, freshness was evaluated in terms of IMP, HxR, Hx and K-values. HPLC showed initial differences in distribution of metabolites induced by struggling gradually fell during storage. K-values were different only for 2 days post mortem, but the effect of handling stress was discernible as higher mean K-values and different IMP and HxR contents for up to 7 days post mortem.     

Effect of ginger extract and vinegar on ATP metabolites,IMP‐related enzyme activity,reducing sugars and phosphorylated sugars in silver carp during postslaughter storage

This study aimed to investigate the utilisation of ginger extract and vinegar for retarding decomposition of inosine monophosphate (IMP), and IMP‐related enzyme activity (the activity of acid phosphatase (ACP) and alkaline phosphatase (ALP)) in salted silver carp (Hypophthalmichthys molitrix) during early postslaughter and chilled storage. We also quantified the decomposition pathway of ATP‐related compounds, the reducing and phosphorylated sugar, and free amino acids (FAAs) in samples. Rapid glycolysis in control occurred during postmortem storage. Vinegar and ginger extract inhibited the activity of ACP and ALP, thereby inhibiting the decomposition of IMP and the increase in hypoxanthine (Hx). IMP concentrations in treated sample were significantly higher than those of the control. Moreover, vinegar and ginger extract promoted the increase in FAAs. Therefore, vinegar and ginger extract could inhibit ACP and ALP activities and contributed to the accumulation of IMP and FAAs in silver carp during chilled storage.     

北京油鸡肉4 ℃贮藏过程中的品质及风味变化

北京油鸡是我国珍贵地方品种,为了解其鸡胸肉在4 ℃真空包装冷藏过程中的风味及品质变化规律,测定 其在贮藏过程中的挥发性盐基氮含量、菌落总数、感官评分、硫代巴比妥酸反应物值、总脂肪酸、肌苷酸及其他三 磷酸腺苷代谢物含量的变化,并利用电子鼻技术测定其在贮藏过程中的挥发性风味整体变化,与感官评分建立回归 方程。结果表明：综合各项理化、微生物及感官指标,真空包装北京油鸡鸡胸肉在4 ℃冷藏过程中的贮藏期为6 d; 脂肪氧化、不饱和脂肪酸和鲜味核苷酸的含量影响其贮藏过程中风味的劣变,并且利用电子鼻检测技术可以有效预 测其品质变化。     

Comparative Rates of IMP Degradation in Unfrozen and Frozen-and-Thawed (Slacked) Fish

SUMMARY— The comparative rates of IMP degradation between fresh and frozen-and-thawed (slacked) fish were compared on six different species of fish. Several factors that could contribute to a rate change of IMP degradation were evaluated. These included freezing temperatures, time in frozen storage, pre- and post-rigor freezing, and method of killing the fish.
English sole and rainbow trout showed slight increases in the rate of IMP degradation when they were frozen and then thawed within 48 hr. Silver salmon and halibut that were frozen and then thawed within 48 hr showed no change in the rate of IMP degradation. Halibut, however, that was frozen and stored at −20°F for 3 months showed a slight decrease in the rate of IMP degradation after it was thawed; but king salmon handled under the same conditions did not.
The method of kill or freezing the fish either pre- or post-rigor did not alter the rate of IMP degradation after the fish was thawed.
No loss of IMP occurred in fish (halibut) stored at −20°F. Over one-third of the original IMP content was lost in halibut stored at +15°F after 3 months of storage.
These results show that there is no significant difference in the rate of IMP degradation between fresh and slacked fish. The flavor-contributing effect of IMP in slacked fish therefore should be the same as in fresh fish, provided the fish was frozen and stored at or near a temperature of −20°F.     

不同水分含量巴西大豆储存期间的品质变化

为科学判定我国进口巴西大豆在储存期间的品质变化,采用模拟储存试验的方式,对不同水分含量巴西大豆在储存过程中粗脂肪、脂肪酸值和脂肪酸相对含量的变化进行监测。结果表明,巴西大豆在储存6周后,营养指标会出现不同程度的变化,储存28周时粗脂肪含量下降0.52~1.76个百分点,脂肪酸值(KOH)升高3.38~105.48 mg/100 g,亚油酸和亚麻酸的相对含量均呈现不同程度的下降。超过安全水分值(12%)越高,大豆品质下降越明显。低于安全水分值的大豆在储存18周后,品质开始发生较明显变化。因此,认为低水分含量(≤12%)大豆最佳储存期在18周内,高水分含量(>12%)大豆最佳储存期在6周内。通过试验不仅能够准确判定巴西大豆储存过程中的品质随时间的变化,也可以指导国家和地方大豆储备库对大豆的管理,保证大豆安全储存。     

Zur Ver?nderung der Inosinmonophosphors?ure und ihrer Spalt-produkte bei kurzzeitiger Lagerung von tierischen Lebensmitteln

Zusammenfassung Der Abbau von Inosinmonophosphorsäure (IMP) und die Anreicherung der Spaltprodukte Inosin und Hypoxanthin wurde in tierischen Geweben während Kühl- und Gefrierlagerung verfolgt. Bei 2 frisch geschlachteten Schweinen wurden in der Muskulatur aus verschiedenen Körperteilen unterschiedliche IMP-Gehalte ermittelt. Während der Kühllagerung fielen die IMP-Werte in Schweinemuskulatur stark ab. In Körpermuskulatur konnten nur geringe AMP-Gehalte festgestellt werden. In Herzmuskulatur vom Schwein übertrafen die AMP-Werte absolut diejenigen von IMP. Die Mononucleotide AMP und IMP zeigten während der Kühllagerung von Herzmuskulatur einen deutlichen Rückgang. Bei der Kühllagerung von Regenbogenforellen und Hähnchen nahmen die ursprünglich hohen IMP-Gehalte rasch ab. Der starke IMP-Abbau bei Regenbogenforellen wurde auch durch Gefrierlagerung weniger verzögert als bei Hähnchen.

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On the changes of Inosinic-Mono-Phosphoric-Acid and its derivates during short storage of animal foodstuffs

Summary The post-mortem changes of nucleotides were investigated in different muscles of pork, chicken and rainbow trout during storage. The IMP degradation and the accumulation of metabolites was very quick during cold storage at 4–5° C. The IMP level in porcine skeletal muscles varied with the location from which the tissue was taken. The concentration of AMP was very low in muscles, however, relatively high in pork heart where it exceeded the amount of IMP. The concentration of the 2 nucleotides decreased during cold storage of heart tissue. A smaller degradation of inosinic acid occurred in frozen storage too. Rainbow trouts were stored for 35 days at —20° C and chickens for six month at —12° C.

     

Spoilage changes in the deep water fish, smooth oreo dory during storage in ice

Smooth oreo dory ( Pseudocyttus maculatus ), a deep water fish, was monitored for changes during storage in ice. Based on the sensory evaluation of the cooked flesh the storage life was 8 days for acceptable quality fish.
Bacterial counts of flesh and surface, the loss of inosine monophosphate (IMP) and the K value showed significant changes during the storage life. Therefore these were found to be useful for monitoring loss of freshness and development of spoilage. After 13 days there were off flavours in the cooked fish, dephosphorylation of IMP had levelled off, and the K value had reached 70%.
The changes that occurred during storage of this deep water species in ice were similar to those changes commonly observed in demersal species from shallow temperate coastal waters.