Stock size fluctuations in chub mackerel (Scomber japonicus) in the East China Sea and the Japan/East Sea

The stock size of chub mackerel (Scomber japonicus) in the East China Sea and the Japan/East Sea has shown a continuous decrease, with fluctuations, from 1975 to 1990. After a remarkable increase in 1992–96, the stock size fell to its lowest level in 1997–99. The spawning success (number of recruits/spawning biomass) fluctuates periodically with a period of several years, although there are no clear relationships between the spawning biomass and the number of recruits. Spawning success was inversely correlated with sea surface temperature (SST). On the contrary, the catch amount and the catch per unit effort (CPUE) of spotted mackerel (Scomber australasicus) has increased since 1997.     

东海南部鲐鱼生物学特征研究

本文根据1999年～2003年7月、8月在东海南部进行的4次鲐鱼围网调查资料，对东海南部海域的鲐鱼生物学特性进行研究。鲐鱼最小叉长为15．4cm，最大为28．8cm，平均叉长22．1cm；优势叉长组为19～25cm，其出现频率为80％。2002年、2003年鲐鱼叉长组成个体比1999年、2001年大；鲐鱼叉长与体重的关系进行拟合后的关系式为：W=0．0034L^3.3404；鲐鱼胃饱满度以0级为主，占70％；年龄组成以当龄鱼为主。     

温台渔场日本鲭的繁殖生物学特征

利用2012年春季在温台渔场对日本鲭(Scomber japonicus)繁殖群体连续6批取样的生物学测定数据,对其繁殖生物学特征进行了研究。结果表明,叉长340 mm以下群体中,雌雄比基本符合1∶1的性比关系;叉长340 mm以上群体中,雌鱼显著多于雄鱼(P0.05)。GSI随时间的变化结果显示,温台渔场日本鲭的主要繁殖期为3月中旬至4月中旬;不同时间段的雌鱼和雄鱼GSI均总体表现为雌鱼大于雄鱼(P0.05)。不同性腺发育阶段的平均摄食强度总体表现为雄鱼大于雌鱼。不同性腺发育阶段的雌性和雄性的肝指数均雌性显著大于雄性(P0.05)。绝对繁殖力范围为44 017~734 684粒/尾,平均值为(173 867±15 719)粒/尾,优势组为(10~30)×104粒/尾,占70.37%;相对繁殖力范围为187~1 403粒/g,平均值为(538±31)粒/g,优势组为(390~700)粒/g,占66.67%。卵径范围为0.27~1.22 mm,平均值为(0.86±0.01)mm,优势组为0.7~1.1 mm。温台渔场日本鲭的绝对繁殖力低于黄海北部而高于台湾海峡,相对繁殖力高于历史水平,平均卵径小于20世纪80年代,雌雄鱼的最小性成熟叉长均有一定程度的降低。以上结果都说明日本鲭为应对高强度捕捞和环境胁迫压力而采取增加相对繁殖力、减小卵径、提早性成熟等繁殖策略来维持种群数量和保证种群的延续。     

Autolysis of Anchovy (Engraulis japonicus) Protein: Evaluation of Antioxidant Properties and Nutritional Quality of Resulting Hydrolysates

Protein hydrolysis of underutilized marine organisms is a method to improve added value. In the present article, anchovy protein was autolyzed at pH 8.5 and 50°C. After autolysis processing for 24 h, total nitrogen recovery reached 92.1%. The protein hydrolysates had antioxidant properties on reducing power, 1, 1-diphenyl-2-picryhydrazyl radical, and hydroxyl radical scavenging activity. More than 79% of the peptides in the hydrolysates had a molecular weight of lower than 3 kDa. Protein hydrolysates had balanced amino acid compositions, and total content of essential amino acids had no significant difference after hydrolysis. Protein hydrolysates from anchovy autolysis have potential in nutritional and functional foods.     

扇贝加工废弃物的酶解技术研究

由正交试验确定的两种酶酶解的最佳水解结果表明枯草杆菌中性蛋白酶最佳水解条件为:加酶量为3.0%,温度为60℃,pH为7.0,时间为4 h,蛋白质水解度为91.3%;木瓜蛋白酶酶解的最佳酶解条件为:加酶量为3.0%,温度为65℃,pH为7.0,时间为4 h,蛋白质水解度为85.3%。SephadexG-15葡聚糖凝胶柱层析对扇贝加工废弃物水解产物的分析结果表明两种酶酶解产物的分子量分布均集中在682 Da,这说明酶解产物是小分子蛋白肽和游离氨基酸,可深加工利用制备水解蛋白制品。     

东海中部日本鲭(Scomber japonicus)产卵群体繁殖力特征

利用2010–2012年春季在东海中部获得的日本鲭产卵群体样品的生物学及繁殖力测定数据,对其群体结构、性腺指数GSI和繁殖力特征进行了研究。结果显示,目前东海中部日本鲭产卵群体年龄结构由1–5龄组成,以2–4龄占优势。日本鲭的个体绝对繁殖力为24770–734684粒,平均为(145575±10067)粒;纯体重相对繁殖力为175–1404 grain/g,平均为(524±24)grain/g;叉长相对繁殖力为102–2070 grain/mm,平均为(483±29)grain/mm。ANOVA分析结果显示,不同叉长组间的性腺指数GSI(F=2.34,P0.05)、绝对繁殖力(F=8.57,P0.01)和叉长相对繁殖力(F=5.59,P0.05)均有显著性差异,但体重相对繁殖力差异不明显(F=2.03,P0.05)。多元逐步线性回归和非线性回归分析显示,绝对繁殖力与体高、肝重关系密切。为了应对高强度的捕捞压力,日本鲭主要采用降低性成熟年龄,减小最小性成熟叉长和卵径、增加繁殖力等策略来维持种群的延续。     

缢蛏肉的蛋白酶水解工艺研究

实验研究了用枯草杆菌中性蛋白酶水解缢蛏肉的工艺条件,通过单因素试验和正交实验,得出了最适水解工艺条件为加酶量2.4％,水解温度50℃.料水比1:3。pH值为中性,时间为6h.水解产物的水解率和总的氮收率分别为42.46％和83.04％。水解液经脱腥等处理后可用于复合调味料和营养口服液的生产。     

Temperature conditions in the Argentine chub mackerel (Scomber japonicus) fishing ground: implications for fishery management

We describe the seasonal migrations of Argentine chub mackerel ( Scomber japonicus ) into the fishing ground in relation to sea surface temperature conditions and analyse the temperature evolution during the fishing season on the basis of 1955–97 time-series. The upper temperature limit for the presence of schools was around 19°C. At higher values, most schools leave coastal waters (< 50 m) for the shelf. An inverse relationship was observed between catches per unit of effort (CPUE) of the inshore fishery and sea surface temperature. The highest standardized CPUE values corresponded to temperatures lower than 19°C. Above this temperature, the probability of obtaining a standardized CPUE higher than 1 was extremely low, and the standard deviations were minimal. The economic benefit from catches was also analysed through the different months of the fishing season. It was found that the mean benefit corresponding to temperatures lower than 19°C exceeded approximately 15 times that obtained at higher temperatures. A simple fishing strategy was proposed to the commercial fleet in order to improve the economic benefit of the catches. The migratory pattern followed by mackerel during the spawning period was also analysed in relationship to other environmental factors like food availability. Zooplankton composition, size structure and abundance in coastal and shelf waters are described, and their implications for feeding ecology of larvae and adults of the species are discussed.     

酶法提取4种淡水鱼鱼鳞胶原蛋白的研究

对4种常见淡水鱼鱼鳞的基本成分和氨基酸组成进行了测定,研究了酶解鱼鳞制备水解胶原蛋白的工艺,并采取正交试验对水解条件进行了优化。试验结果表明,淡水鱼鳞主要由蛋白质和灰分组成,粗蛋白含量高达55%以上;氨基酸组成显示淡水鱼鳞羟脯氨酸含量丰富,是制备水解胶原蛋白的良好原料。正交试验结果表明,55℃、E/S3%、酶解2h、料液比1∶10(即底物质量浓度为100g/L)时水解效果最好,此时,水解产物分子量较小,且分布集中。     

响应面法优化四角蛤蜊酶解工艺条件

为提高四角蛤蜊的利用率,采用木瓜蛋白酶对其软体部位进行酶解。在单因素试验的基础上,研究温度、pH和酶加量对酶解过程的影响,通过三因素三水平的Box-Behnken响应面分析法优化其酶解工艺条件。试验结果表明,所建立的响应面模型极显著（ P＜0．0001）,可以很好的反映各因素与水解度之间的关系,且由模型得出木瓜蛋白酶酶解四角蛤蜊的最佳工艺参数为温度48℃、p H 7．2、酶加量3000 U/g、料液比3∶100（g/m L ）和时间3 h ,在此条件下水解度为37．05％,从而为四角蛤蜊的精深加工利用,尤其是天然海鲜调味料的开发提供理论依据。     

东海区鲐鱼生物学特征及其渔业现状的分析研究

本文以1960～1961年、1973～1975年、1982～1986年和1999～2002年4个年代的东海区渔业资源监测调查资料为依据,比较分析了东海区鲐鱼的种群结构、生长和死亡等生物学性状的动态变化特征。结果表明,东海区鲐鱼从20世纪60年代起至今,经过近40年时间的开发利用,目前该种群的低龄化、小型化现象较为明显;其平均叉长从343．14mm下降到193．66mm,平均体重从588．79g下降到96．89g;种群的个体生长内禀动力发生了较大变化,生长参数K从0．22提高到0．81,渐近叉长从486．84mm减小到367.50mm,体重的生长拐点年龄从4．48龄逐渐减小到1．27龄。尽管东海区鲐鱼目前渔获产量仍维持在较高水平,但种群已长期处于生长型捕捞过度状态。     

Isolation and Characteristics of Anti-Inflammatory Peptides from Enzymatic Hydrolysates of Sandfish (Arctoscopus japonicus) Protein

In the present study, a peptide showing anti-inflammatory activity was isolated from Arctoscopus (A.) japonicus sandfish protein hydrolysate by hydrolysis and analyzed using ultrafiltration (UF), prep-high-performance liquid chromatography (HPLC), and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Effects of heat, pH, salt, and intestinal proteases on stability of the isolated anti-inflammatory peptide were determined. The nitric oxide (NO) scavenging activities of the peptide from meat and roe hydrolysates were 18.43 ± 3.21% and 52.35 ± 8.85%, respectively, at a concentration of 0.1 mg/mL. The anti-inflammatory peptide maintained a similar level of NO scavenging activity to the control in the presence of salt, whereas it showed no resistance to heat, pH, and intestinal proteases. These results suggest that the anti-inflammatory peptide derived from A. japonicus could be used for producing functional foods, protein supplements, and pharmaceutical agents. However, it is necessary to find methods for protection against heat, pH, and proteolysis.     

基于鱼卵仔鱼数据的东海中南部日本鲭产卵场分析

利用2016年4—5月在东海中南部海域的调查数据,对该海域日本鲭(Scomber japonicus)鱼卵仔鱼的分布特征进行了研究,并对产卵场的划分展开讨论及提出保护措施和管理建议。结果显示:4月,日本鲭鱼卵仔鱼主要出现在台湾海峡和东海南部海域,出现率均大于25%,但仔鱼在东海南部外海的出现率和丰度均较低,分别为5.00%和0.01个·100m^-3。5月,日本鲭鱼卵仔鱼在台湾海峡的出现率和丰度均显著降低,分别下降至5.88%和0.22个·100m^-3;东海南部外海日本鲭鱼卵仔鱼的出现率和丰度则均显著升高,分别升至50%和36.48个·100m^-3,其中鱼卵集中出现在南部外海,出现率和丰度分别达到了40%和36.46个·100m^-3;东海中部外海从5月开始出现日本鲭鱼卵和仔鱼。结合历史资料,可以判断东海中南部日本鲭产卵场主要有台湾海峡、东海中南部近海、东海南部外海、东海中部外海等4个。日本鲭鱼卵丰度与表层水温呈显著相关关系(R=0.37,P<0.05),与表层盐度无显著相关关系(P>0.0...     

草鱼酶解技术研究

应用对比试验和正交试验方法对草鱼进行酶解技术研究。试验结果表明,胃蛋白酶酶解草鱼酶用量为（E／S）0．6％,温度55℃,pH2．0,酶解5h氨基态氮含量较高,为0．0190g／L;枯草杆菌蛋白酶酶解草鱼酶用量为（E／S）0．01％,温度45℃,pH6．5,酶解4h氨基态氮含量较高,为0．0417g/L;胰蛋白酶酶解草鱼酶用量为（E／S）0．64％,温度50℃,pH8．0,酶解5h氨基态氮含量较高,为0．0472g／L。通过对3种蛋白酶在最优条件下酶解草鱼肉的比较可知,枯草杆菌蛋白酶和胰蛋白酶酶解效果较好。为草鱼深加工提供了一定的科学依据。     

Efficacy of a Fructus mume Extract Combination with Stable Chlorine in Preventing Bacterial Contamination in Frozen Mackerel (Scomber japonicus) Fillets

ABSTRACT

A combination composed of Fructus mume extract and stable chlorine dioxide was investigated for its antibacterial activity, mechanism of action, and its application against Escherichia coli and Staphylococcus aureus in mackerel (Scomber japonicus) fillets. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values against E. coli and S. aureus ranged from 0.9–1.2 and 1.3–1.6 mg/mL for F. mume extract and 0.004–0.006 and 0.007–0.010 mg/mL for stable chlorine dioxide, respectively. We observed a mechanism of action against E. coli that involved a pore-formation role that led to cell membrane damage. In the case of S. aureus, the mechanism of action is believed to be mediated by the combination’s activity as a metabolite disrupting agent. Here, the amount of bacteria was greatly reduced in mackerel fillets treated with the combination. Moreover, the flavor and texture properties of fillets were not significantly affected by this treatment (p < 0.05). These findings suggested that the combination has promise in being used as an additive to a broader class of foodstuffs.     

Influence of Degree of Hydrolysis on Chemical Composition,Functional Properties,and Antioxidant Activities of Chinese Sturgeon (Acipenser sinensis) Hydrolysates Obtained by Using Alcalase 2.4L

Protein hydrolysates from Chinese sturgeon were prepared using Alcalase 2.4L enzyme. Under the optimum conditions (enzyme–substrate ratio of 3.5%, pH of 8.5, and temperature of 55°C), the degree of hydrolysis (DH) was 13.8%, 16.7%, and 19.1% after 1, 3, and 6 h, respectively. The contents of crude protein and amino acid increased at DH of 19.1% to 86.97% and 78.29%, respectively. There was an obvious increase in the low-molecular-weight peptides, which could enhance the hydrolysate’s functional properties such as solubility, representing more than 90% at different pH levels. The obtained protein hydrolysates revealed good emulsification properties and high oil absorption. Furthermore, good antioxidant activities such as 1, 1-diphenyl-2-picrylhydrazyl (DPPH) inhibition, ferric reducing power, and ferrous ion (Fe²⁺⁾ chelating ability were attained depending on the solution concentration. The findings indicate that the functional and antioxidant properties of protein hydrolysates could be useful in many applications of the food industry.     

Characterization of Flavor Properties from Fish (Collichthys niveatus) Through Enzymatic Hydrolysis and the Maillard Reaction

ABSTRACT

Collichthys niveatus (C. niveatus) is an abundant but underutilized fish species caught in China. In this study, flavor properties of the Maillard reaction products (MRPs) obtained from C. niveatus protein hydrolysates were determined. The optimized fish protein hydrolysates were prepared using commercial Alcalase, and the optimum values of temperature, pH, and enzyme/substrate ratio were 55.6°C, 8.7, and 1.03%, respectively. In addition, the volatile compounds of the MRPs were evaluated using headspace solid–phase microextraction combined with gas chromatography mass spectrometry. A total of 80 volatile compounds were separated and identified. Priazines, alcohols, and aldehydes were the major flavor contributors to the aroma of the MRPs (accounting for 38.86, 9.21, and 8.23%, respectively), while pyrazines were the most abundant group of volatile compounds present, with 2,5-dimethyl-pyrazine, methylpyrazine, and 3-ethyl-2,5-dimethylpyrazine being found in highest quantities (19.83, 5.81, and 5.70%, respectively). Other components—including alcohols, aldehydes, furans, ketones, and esters—were also identified in the MRPs. This study provides a systematic strategy for marine products processing and volatiles characterization. The results point to the information in the volatiles from the MRPs of protein hydrolysis from C. niveatus and pave the way for full utilization of this species.     

Common Kilka Hydrolysis: Investigation of Functional and In Vitro Antioxidant Properties of Hydrolysates Obtained by Kiwifruit and Ginger Proteases

The functional and in vitro antioxidant properties of common kilka fish protein hydrolysates with different degree of hydrolysis (DH) obtained by kiwifruit protease (KP) and ginger protease (GP) were evaluated. The electrophoretic patterns of hydrolysates showed the presence of one major band in different DHs with a molecular weight of less than 25 kDa. Protein solubility was positively correlated with DH, and the solubility of KP and GP hydrolysates (HKP and HGP, respectively) at 15% DH was higher than other DHs (p ≤ 0.05). Higher emulsifying and foaming properties were observed in HKP over a pH range of 2–10 (p ≤ 0.05), and in vitro antioxidant activity was higher in HKP at 15% DH as seen from 2,2-diphenyl-1-picrylhydrazyl radical scavenging and ferric-reducing power. Thus, the results reveal that DH and enzyme type affects functional properties and antioxidant activity of the hydrolysates.