Original article: Effect of modified atmosphere packaging using different CO2 and N2 combinations on physical,chemical, microbiological and sensory changes of fresh sea bass (Dicentrarchus labrax) fillets

The effect of different modified atmosphere packaging (MAPs) on physical, chemical, microbiological and sensory changes of sea bass fillets when stored at 4 °C and standard light conditions was investigated for up to 21 days and compared to a control batch stored in overwrap. Sea bass fillets were packed using different CO₂ and N₂ combinations (40% CO₂–60% N₂; 50% CO₂–50% N₂; 60% CO₂–40% N₂), and quality assessment was based on instrumental, chemical, microbiological and sensory analysis. The results showed that MAP extended shelf‐life of sea bass fillets from 7 days (overwrap packaging) to 14 days. Drip loss, pH values and thiobarbituric acid reactive substances (TBARS) measurements were higher in overwrap samples but no differences (P ≤ 0.05) were found between MAP samples. Bacteria grew most quickly and showed higher counts in overwrap samples followed by 40% CO₂–60% N₂; 50% CO₂–50% N₂ and finally 60% CO₂–40% N₂. Sensory analyses were in good relation with chemical and microbiological results establishing best scores and an extended shelf‐life for MAP samples especially in MAPs with high CO₂ levels.     

Effects of differences in diet and seasonal changes on the fatty acid composition in fillets from farmed and wild sea bream (Sparus aurata L.) and sea bass (Dicentrarchus labrax L.)

The effects of dietary fatty acids and seasonal variation on the fatty acid profiles of farmed and wild sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax) were determined by analysis of their fillets. Farmed sea bream and sea bass were fed on the same commercial feeds all year. Fatty acid profiles in the fillets reflected the fatty acid profiles of the commercial feeds. The predominant fatty acids in the trial feeds, fillets of farmed and wild sea bream and sea bass were 16:0, 18:1n‐9, 18:2n‐6, 20:5n‐3 and 22:6n‐3. The fatty acid profiles in the fillets of farmed sea bream and sea bass did not differ (P > 0.05) except in the winter season compared with those of their wild counterparts. However, the content of eicosapentaenoic acid (20:5n‐3), docosahexaenoic acid (22:6n‐3) in the fillets of the farmed and wild sea bass were significantly (P < 0.05) higher than the farmed and wild sea bream. The wild sea bream had significantly (P < 0.05) higher total saturated fatty acid and monounsaturated fatty acid (MUFA) levels, and lower total n‐6 and n‐3 polyunsaturated fatty acid (PUFA) levels in winter than in the summer and spring seasons. Similarly, in the fillets of wild sea bass, total n‐3 PUFA levels were significantly (P < 0.05) lower, and the MUFA levels were higher in winter than in the other seasons. These results indicate that the farmed fish fillets were good sources of n‐3 PUFA in each of the three seasons. However, wild fish were good sources of n‐3 PUFA in the spring and summer.     

Effects of gutting and ungutting on microbiological, chemical, and sensory properties of aquacultured sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax) stored in ice

The effect of gutting and ungutting on microbiological, chemical, and sensory properties of aqua-cultured sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax) stored in ice were studied. The total viable mesophilic and psychrophilic bacterial counts increased throughout the storage period of gutted and ungutted sea bream and sea bass. The mesophilic counts reached 8.19 log cfu/g for ungutted sea bream and 7.93 log cfu/g for ungutted sea bass after 14 days of storage. The mesophilic counts reached 8.89 log cfu/g for gutted sea bream and 8.16 log cfu/g for gutted sea bass after 14 days of storage. On day 14 of storage the psychrophilic counts of ungutted sea bream and sea bass were 8.24 log cfu/g and 8.03 log cfu/g, respectively, and for gutted sea bream and sea bass were 8.93 and 8.22, respectively. At the end of the storage period of 14 days, TVB-N, TBA, and TMA-N values of ungutted sea bass were determined as 50.13 +/- 0.25 mg/100 g, 2.66 +/- 0.06 mg malonaldehit/kg, 9.86 +/- 0.01 mg/100 g respectively. TVB-N, TBA, and TMA-N values of ungutted sea bream reached 55.90 +/- 0.36 mg/100g, 2.51 +/- 0.21 mg malonaldehit/kg, 9.79 +/- 0.01 mg/100 g on day 14 respectively. And also at the end of the storage period of 14 days, TVB-N, TBA, and TMA-N values of gutted sea bass were determined as 48.00 +/- 0.26 mg/100 g, 2.48 +/- 0.03 mg malonaldehit/kg, 8.71 +/- 0.06 mg/100 g respectively. TVB-N, TBA, and TMA-N values of gutted sea bream reached 49.66 +/- 0.77 mg/100g, 2.64 +/- 0.07 mg malonaldehit/kg, 8.97 +/- 0.01 mg/100 g on day 14 respectively. The result of this study indicates that the shelf-life of whole ungutted sea bass and sea bream stored in ice as determined by the overal acceptibility sensory scores, chemical quality, and microbiological results show us that the fish were spoilt on day 14. Each chemical, sensory, and microbiological result for sea bream showed us that there was a correlation and similarity and on day 14 it was spoilt.     

海鲈鱼肉蒸制过程中品质及风味特性的变化

以海鲈鱼背部肌肉为原料,对不同蒸制时间鱼肉的质量损失率、色泽、水分分布状态和质构特性变化进行分析,并通过游离氨基酸分析、电子舌和电子鼻评价鱼肉的滋味和气味差异。结果表明,随着蒸制时间的延长,海鲈鱼肉的质量损失率显著上升（P＜0.05）,鱼肉中的不易流动水逐渐向自由水转化并流失,而结合水含量变化不明显;鱼肉的硬度和咀嚼度先下降后又显著增大,而弹性先升高后降低;蒸制后鱼肉的L*值和b*值显著升高（P＜0.05）,a*值显著降低（P＜0.05）。经蒸制后鱼肉中游离氨基酸的总量先增大后降低,在蒸制10 min达到最高值,组氨酸、甘氨酸、丙氨酸、赖氨酸和谷氨酸是海鲈鱼肉中主要的呈味氨基酸;电子舌和电子鼻均能有效区分不同蒸制时间鱼肉的滋味和气味特征。综上,限定规格的海鲈鱼块在蒸制8～10 min的品质及风味较好。     

养殖南方大口鲶肌肉营养成分分析和品质评价

以四川双流养殖南方大口鲶为材料,采用常规生化分析方法对肌肉营养成分进行分析,并对其营养品质进行评价。结果表明：养殖南方大口鲶肌肉中蛋白质、脂肪、灰分和水分含量分别为(18.06±0.49)%、(2.47±1.08)%、(1.17±0.06)%和(78.49±0.45)%;肌肉中含有18种氨基酸,干基总量为(83.59±2.30)%,其中8种必需氨基酸(EAA)总量为(34.43±1.45)%,占氨基酸总量的41.19%,必需氨基酸/非必需氨基酸总量之比为70.04%,其必需氨基酸的构成比例完全符合FAO/WHO评价标准。南方大口鲶的第一限制性氨基酸为缬氨酸,第二限制性氨基酸为(甲硫氨酸+胱氨酸),必需氨基酸指数(EAAI)为74.82;4种鲜味氨基酸(DAA)含量较高,总量为(31.52±1.20)%;共测定出26种脂肪酸,多不饱和脂肪酸总量(PUFA)、二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)含量分别为(41.05±0.77)%、(4.00±0.21)%和(7.80±1.42)%,明显高于斑点叉尾鮰和瓦氏黄颡鱼;脂肪酸动脉粥样硬化指数(IA)、血栓形成指数(IT)分别为0.42、0.35;矿物元素含量丰富,锌铁比合理。研究表明,养殖南方大口鲶肉味鲜美,必需氨基酸含量高、组成均衡,多不饱和脂肪酸、EPA和DHA含量较高,具有较高的食用和营养价值,值得进一步加工和利用。     

Effects of using slurry ice during transportation on the microbiological, chemical, and sensory assessments of aquacultured sea bass (Dicentrarchus labrax) stored at 4 degrees C

Slurry ice, a biphasic system consisting of small spherical ice crystals surrounded by seawater at subzero temperature, was evaluated as a new chilled storage method for whole sea bass (Dicentrarchus labrax) a sparidae fish species of remarkable commercial interests. In this study two different group of chilling methods were used during transportation; in slurry ice packaged (Group A), and flake ice packaged (Group B). The effect of this advanced system during transportation on quality losses and the shelf life of aquacultured sea bass was evaluated. Mesophilic counts for sea bass exceeded 7 log cfu/g, which is considered the maximum level for acceptability for freshwater and marine fish after 13 days for groups A and B. On day 13 TVB-N values of groups A and B, reached the legal limits (35 mg/100 g set for TVB-N) for consumption. According to the results of sensory analyses, up to day 9 all the groups were determined as "acceptable" but on day 13 the groups A and B were no longer acceptable. The main negative aspect related to quality loss in slurry ice group corresponded to the appearance of eyes and gills. Using slurry ice during transportation did not extend the shelf life of sea bass stored at 4 degrees C.     

超声-咖啡酸联合处理对海鲈鱼冷藏期间品质变化的影响

为研究超声-咖啡酸联合处理对冷藏海鲈鱼品质变化影响,将新鲜鲈鱼片随机分为5 组,分别为20 kHz、600 W超声处理10 min（US组）,2.0 g/L咖啡酸浸渍10 min（CA组）,超声联合咖啡酸处理10 min（20 kHz、600 W超声处理5 min后,咖啡酸浸渍5 min）（US＋CA组）,无菌水（空白,CK组）与体积分数1%乙酸（对照,AA组）分别浸渍10 min。将5 组样品处理后沥干,装于聚乙烯保鲜袋中,置于4 ℃冷藏。每2 d测定样品的微生物指标（菌落总数）、理化指标（pH值、总挥发性盐基氮（total volatile base nitrogen,TVB-N）含量、硫代巴比妥酸（thiobarbituric acid,TBA）值、质构特性、持水力）等,结合内源荧光强度与感官评价,综合评价超声-咖啡酸联合处理对冷藏鲈鱼的保鲜效果。结果表明：US与CA处理能明显抑制样品贮藏期间菌落总数的增长,在第10天,CA组与US组样品的菌落总数比CK组分别低18.49%与15.53%,其pH值与TVB-N含量上升速度明显缓于CK组样品。贮藏第10天时,CK组样品的TVB-N含量已超过腐败限值,达（33.88±0.56）mg/100 g,而此时US＋CA组样品的TVB-N含量为（16.71±0.41）mg/100 g,明显低于CK组。US处理使鱼肉的保水性明显改善,CA处理对抑制鱼肉的脂肪氧化有较好效果,其还能使样品的持水力得到较高提升;其中以US＋CA联合处理组样品总体品质最佳。与CK组相比,US＋CA处理对鱼肉品质保持效果较好,联合处理可使海鲈鱼的冷藏货架期至少延长4 d。     

热加工方式对鱼汤营养成分及食用品质的影响

以新鲜乌鳢为原料,分别在常压、高压处理方式熬制鱼汤。通过营养成分、色泽、滋味物质等指标的测定,结合感官评价,探究不同热加工方式对鱼汤营养成分及食用品质的影响。结果表明,与传统热加工方式相比,高压处理的鱼汤可溶性固形物含量与粗蛋白含量均达到4%以上;矿物质元素Na和K含量达到8 000 mg/L以上,Ca和Mg含量达到1 000 mg/L以上;水解氨基酸总量达到300 mg/L以上。其中,必需氨基酸、水解氨基酸含量分别高出常压处理约6倍和3倍。高压处理方式下,鱼汤游离氨基酸总量和鲜味氨基酸含量均提高1倍以上,与电子舌鲜味检测结果一致。常压处理后鱼汤虽然香气较好,接受度较高,而其滋味和营养成分要逊于高压处理鱼汤。结论:高压处理的鱼汤能较好地保持乌鳢的营养性能,鱼汤香气较浓郁,口感好。该加工方法在鱼汤制备中的应用,可有助于实现乌鳢资源的全效利用,提高资源利用率和经济效益。     

Effect of salt and MTGase on the production of high quality gels from farmed sea bass

In order to obtain low salt fish products, the effects of the addition of 0.5% (w/w based on whole product, wp) MTGase and different levels (0.25%, 0.50%, 1.00% and 2.50%, w/w wp) of sodium chloride salt to heat-induced gels from farmed sea bass (Dicentrarchus labrax) trimmings were tested and compared with gels without salt and/or without MTGase.MTGase and salt addition, both, had a favourable effect on texture. However, only salt incorporation augmented water holding capacity (WHC).A synergistic effect was detected between MTGase and salt for several important textural properties, particularly, gel strength, which reached 64.3 ± 8.1 N mm, a value comparable to those of best quality surimi. Moreover, MTGase required addition of salt to the product for its effect to be felt, however only a minimal amount (0.25%, w/w wp) sufficed. In fact, the addition of MTGase enabled reduction in salt content to 1.0% (w/w wp), without significant loss of textural and overall quality.     

海地瓜，黑乳参和乌皱辐肛参营养成分对比

通过对干海参海地瓜,黑乳参和乌皱辐肛参体壁组成,氨基酸组成,脂肪酸组成,多糖组成,矿物质和微量元素组成成分的分析,来比较这三种海参的营养品质。结果显示三种海参都具有共同的特点：高蛋白,低脂肪。鲜味氨基酸（DAA）包括：谷氨酸,天冬氨酸,甘氨酸,苏氨酸和丙氨酸。在这三种海参中鲜味氨基酸是含量最多的氨基酸,在海地瓜,黑乳参和乌皱辐肛参中分别占61.6%、58.1%、59.7%。亮氨酸/精氨酸的比值在这三种海参中都非常低,范围在0.39~0.46。相较于其他两种海参,海地瓜含有较少的饱和脂肪酸（21.4%）和较多的不饱和脂肪酸（67.1%）,其中多不饱和脂肪酸主要为花生四烯酸（C20:4）。这三种海参中Fe（16.3 mg/kg~24.1 mg/kg）和Zn（11.7 mg/kg~19.0 mg/kg）含量较高,As (0.58 mg/kg~0.66 mg/kg) 和Cd（0.49 mg/kg~0.21 mg/kg）的含量相对较低。通过比较分析表明：海地瓜体壁要比黑乳参和乌皱辐肛参具有更高的营养价值。     

热处理方式对鲈鱼游离氨基酸及品质影响

海鲈鱼因其味道鲜美、肉质细嫩深受消费青睐.不同的热处理方式对于鱼肉的品质影响较大.通过结合烹饪损失、感官评定、色泽、质构和游离氨基酸含量等多项指标,评估传统沸煮和低温真空烹饪对鲈鱼品质的影响,结果表明低温真空烹饪的鲈鱼无论是在烹饪损失、质构,还是在游离氨基酸含量方面均具有较好的优势,在感官评定上可接受度较高.该研究结果...