宰前二氧化碳麻醉对罗非鱼肉品质影响的研究

研究了宰前二氧化碳麻醉对罗非鱼肉肉品质的影响。本研究以敲头作为对照组,比较二氧化碳麻醉放血宰后于1±1℃下贮藏,测定7 d各组僵直度、pH值、质量耗损率、挥发盐基氮、感官评价、质构硬度和剪切力等指标。结果表明:宰前二氧化碳麻醉能延迟进入僵直期的时间,且有较高的初始pH和较低的最终pH。随贮藏时间的延长,两组的质量耗损率呈显著上升趋势,在宰后3 d内两组间无显著性差异,却在宰后4到7 d内,二氧化碳麻醉组要明显低于对照组。除宰后0 d和4到5 d外,二氧化碳麻醉组的TVB-N均明显低于敲头对照组。另外,两组间的质构恶化和感官评价在宰后无显著差异,但两组的剪切力和硬度以及感官评价在宰后第7 d要明显劣于0 d。结合各项指标,宰前二氧化碳麻醉比敲头致晕更适合于罗非鱼鱼片的生产加工。     

运输应激对鱼类生理特性和肌肉品质影响的研究进展

应激反应是生物界中普遍存在的一种生理反应,它会直接影响生物的代谢过程和理化状态,并可能对动物的肌肉品质造成不利影响.运输是鱼类生产过程中必不可少的中间环节,也是引发鱼体应激的重要原因.因此,本文结合已有文献中应激对鱼类生理特性、肌肉品质以及代谢的影响,同时对应激状态下运输如何影响肌肉品质代谢途径进行讨论,并列举目前缓解...     

Precooked Reduced-Fat Beef Patties Chemical and Sensory Quality as Affected by Sodium Ascorbate, Lactate and Phosphate

Beef-carrageenan (BC; 10% fat) patties—with sodium ascorbate (0.05%), sodium lactate (3%), sodium tripolyphosphate (0.3%), ascorbate-phos-phate, ascorbate-lactate, or none—and 20%-fat all-beef patties were cooked, aerobically or vacuum packaged, and stored at 4°C or ?20°C. Fat level had a greater effect on texture than did additives. Lactate and phosphate increased cooking yield of BC patties. Phosphate was antioxidative but not antimicrobial. Ascorbate was antioxidative and reduced aerobic plate counts (APCs) of aerobically packaged refrigerated BC. Lactate reduced APCs of both aerobically and vacuum packaged BC patties. Lactate had a prooxidative effect in aerobically-packaged/frozen patties but showed no such effect in vacuum-packaged/frozen patties or refrigerated patties. Ascorbate-phosphate was most effective in minimizing flavor deterioration in refrigerated BC patties.     

Profiles of New Zealand Snapper (Pagrus auratus) Postmortem Metabolism as Affected by Acclimated Temperature and Postmortem Storage Temperature

ABSTRACT: Chemical anesthesia (AQUI-S^TM) was used to harvest tank-reared snapper ( Pagrus auratus ) from late summer (19.6 °C) and winter (11.9 °C) acclimated populations in a "rested" state. Carcasses were stored in seawater at temperatures between 2 and 20 °C to investigate the effects of acclimation and storage temperature on the postmortem metabolic rate. Contour plots of postmortem muscle pH [lactic acid] and adenosine triphosphate/inosine monophosphate measurements revealed critical temperature transitions: 16 to 18 °C (coinciding with seasonal behavioral changes) and 4 to 6 °C (consistent with cold injury). DC eye surface potential (ESP) was evaluated as a noninvasive indicator of tissue-temperature interactions and showed similar patterns of critical temperature transitions.     

ICP-AES法测定水产品贝壳肉中16种金属元素

利用ICP-AES法测定钱塘江近海水域水产品贝壳肉中Al、Ca、Cr、Cu、Fe、Mg、Mn、Ni、Se、Sb、Sn、V 、Zn、Cd、As、Pb、Hg十六种金属元素含量。结果表明:所采样品金属元素含量丰富,对铅、铝的吸附量相对较高,部分样品金属元素含量相对偏高,不宜多食。ICP-AES法具有检测灵敏度高、回收率好、快速、简便等好的检测效果。     

Differences in Gelation Characteristics of Natural Actomyosin from Two Species of Bigeye Snapper, Priacanthus tayenus and Priacanthus macracanthus

ABSTRACT: Natural actomyosin (NAM) of P. tayenus exhibited higher turbidity and storage modulus (G') upon heating, compared to that of P. macracanthus , suggesting the higher protein aggregation and rigidity. At temperature above 35 °C, P. tayenus NAM had higher surface hydrophobicity and disulfide bond formation than P. macracanthus NAM. The α-helix content of NAM from both fish species decreased as the temperature increased, indicating changes in structural conformation during heating. NAM gel from P. tayenus rendered more three-dimensional network than that from P. macracanthus. These results indicated that P. tayenus NAM possessed superior gelling characteristic to P. macracanthus NAM due to the higher aggregation of protein caused by both hydrophobic interaction and disulfide bond.     

加工前净化处理对团头鲂肌肉品质的影响

采用循环水净化装置净化处理团头鲂（Megalobrama amblycephala）,研究净化时间（0～10 d）对团头鲂肌肉品质的影响。结果表明：净化处理对团头鲂肌肉的理化成分、风味、质构及感官品质均有显著影响;随着净化时间延长,团头鲂肌肉的粗脂肪含量、总糖含量、水溶性蛋白含量、总挥发性盐基态氮（total volatile base nitrogen,TVB-N）含量、羰基值（carbonyl value,COV）和硫代巴比妥酸（thiobarbituric acid,TBA）值明显下降,游离氨基酸含量和灰分含量显著增加（P＜0.05）;质构、电子鼻及感官评价结果表明,净化处理可显著增加鱼肉的弹性、咀嚼性和甜味,降低其腥味及异味;净化处理8 d的团头鲂肌肉TVB-N含量、COV和TBA值分别比对照组（未净化处理）样品降低12.73%、20.35%和35.13%,鱼肉中的游离氨基酸含量则比对照组样品提高43.83%。综上所述,在加工前对团头鲂净化处理8 d可显著改善鱼肉的食用品质。     

Quality of Shredded, Packaged Carrots as Affected by Different Washing Treatments

ABSTRACT: Different washing treatments with chlorinated and ozonated water were applied to carrots ( Daucus carota L.) on an industrial scale to improve the sensorial and microbial quality of packaged ready-to-eat produce. Quality of shredded carrots was determined by sensory evaluation and microbiological analysis. Washing shredded carrots resulted in increased sugar leaching and loss of sensorial quality, whereas prewashing uncut carrots with chlorine ensured sugar retention, reduced microbial load, and concurrently minimized cross-contamination. Comparable germ reduction was not achieved by prewashing with ozone. These findings demonstrated that prewashing uncut carrots with chlorine provided sufficient microbiological safety paired with improved sensorial properties.     

Soft Flesh Problem in Freshwater Rainbow Trout Investigated by Magnetic Resonance Imaging and Histology

ABSTRACT: To investigate the soft flesh problem in rainbow trout, the dynamics of water in postmortem white muscle were studied by magnetic resonance imaging, histology, and rigor index (θ r ) measurements. At 24-h postmortem, the trout identified as having the soft flesh problem (θ r ≥ 40°) differed from the others (0°≤θ r ≤ 20°) by longer transverse relaxation time (T₂≥ 45 ms) and smaller diffusion anisotropy (DA ≤ 1.3), which proved to be the most relevant nuclear magnetic resonance parameter for an early diagnosis of the soft flesh problem. To interpret these results, we hypothesized an early and exacerbated tenderization phenomenon because of protein denatur-ation, inducing important modifications in fine connections that anchor the 3-dimensional structure of the tissue. The incidence of 3 slaughtering procedures on rigor were tested, and no differences were detected for trout presenting the soft flesh problem.     

高效液相色谱法测定马铃薯薯肉中类胡萝卜素

本实验研究了用高效液相色谱法测定马铃薯薯肉中叶黄素和玉米黄素.采用丙酮:石油醚(1:1,含0.1%BHT)混合液直接提取,用ZOBAX C18(4.6×250mm,5μm)色谱柱,乙腈:甲醇:二氯甲烷(75:20:5,含0.1%BHT)为流动相,进样量为5μ1,流速为1ml/min,柱温为25℃,在450nm下检测类胡萝卜素.研究结果表明,该法可以快速、准确地分离测定马铃薯薯肉中叶黄素和玉米黄素的含量,具有良好的线性(相关系数分别为0.9997和0.9987)和重复性,叶黄素和玉米黄素回收率分别达到92.87%和95.68%.而且本方法可有效防止类胡萝卜素氧化,因而非常适用于大批量样品的分析检测.     

大鲵黏液、皮肤及肉中氨基酸分析

通过对大鲵黏液、皮肤及肉中的氨基酸分析,为其开发利用提供依据。采用氨基酸自动分析仪分析,结果表明：大鲵黏液及皮肤、肉中氨基酸含量分别为77.30%、70.96%、70.76%,氨基酸种类相同,但不同种类的含量有较大差异。     

北五味子种子和果肉中的活性成分比较

目的:比较北五味子种子和果肉中活性成分的差异。方法:采用薄层色谱法比较北五味子种子、果肉和果实中木脂素成分含量;采用苯酚-硫酸法测定种子、果肉和果实及果肉不同组分糖的含量;薄层色谱法分析三氟乙酸水解后,果肉不同组分单糖组成。结果:北五味子木脂素类主要在种子中;北五味子在果肉和种子中的总糖含量分别为169.34、5.366mg/g;果肉中各组分糖含量分别为醇溶组分117.06mg/g、醇沉组分75.67mg/g、多糖组分12.37mg/g。三氟乙酸水解后薄层分析,醇溶组分主要由葡萄糖组成,多糖组分主要由葡萄糖、半乳糖组成。结论:北五味子种子和果肉中活性成分存在明显差异。     

Extension of the Pre-rigor Period in Ischemic White Muscle from Yellow-eye Mullet Aldrichetta forsteri) and New Zealand Snapper (Pagrus auratus) as Affected by Hyperbaric Oxygen Treatment

ABSTRACT: Chemical anesthesia (AQUI-STM Plus) was used to harvest tank-rested yellow-eye mullet ( Aldrichetta forsteri ) and snapper ( Pagrus auratus ) in a "rested" state. Fillets were stored at half the acclimated temperature under hyperbaric, hyperoxic conditions and compared with fillets stored under normobaric, hyperoxic conditions. Postmortem (PM) changes in white muscle (WM) cut-surface pH and key metabolites (lactate, adenosine triphosphate [ATP], and inorganic phosphate [P i ]) were measured. Hyperbaric, hyperoxic storage extended the pre-rigor period in the rested WM by delaying PM changes. Prolongation of pre-rigor was greatest in rested snapper WM. This was attributed to an extended period of aerobic metabolism in PM rested WM.     

Frozen Mushrooms Quality as Affected by Strain, Flush, Treatment Before Freezing, and Time of Storage

ABSTRACT: Four strains of mushrooms ( Agaricus bisporus )—U3, hybrids of U3 (3/1, M-300), and in-between strain No. 200—were treated before freezing: washed in water, washed in water containing sodium metabisulfite (3g·L^-1), and washed in water containing sodium metabisulfite (5g·L^-1) then immersed in boiling water for 20 s. Appearance and whiteness of frozen mushrooms were most affected by the washing in water containing sodium metabisulfite. The residue of sulfur dioxide changed from 52 mg·kg^-1 after 1 d to 27 mg·kg^-1 after 90 d of storage. The whitest mushrooms (fresh and frozen) were for No. 200 strain. Short-time immersion in boiling water markedly increased toughness of stored frozen mushrooms.     

Sensory, Microbiological and Chemical Quality of Mini-Peeled Carrots as Affected by Edible Coating Treatment

The effect of three application rates of an edible cellulose-based coating on sensory, microbiological and chemical quality of mini-peeled carrots was studied during storage at 2°C. Carrots treated with edible coating had reduced levels of white surface discoloration, and higher sensory scores for orange color intensity, fresh carrot aroma, fresh carrot flavor, and overall acceptability than non-coated carrots. Edible coating treatment did not affect levels of total aerobic microorganisms, yeast, mold or lactobacilli. Oxygen, carbon dioxide and ethanol levels in packages, and sugar and soluble phenolic content of mini-peeled carrots were not affected by coating treatment. An edible coating application rate of 0.23–0.49 L/min protected against surface discoloration and retained quality during storage at 2°C.     

高效液相色谱-串联质谱法快速分析鱼肉中的类固醇激素残留

建立了一种快速高效的液相色谱-串联质谱法分析鱼肉中类固醇激素。实验优化了色谱分离条件和三重四级杆质谱检测参数。采用Hypersil GOLD C18色谱柱（150 mm×2.1 mm,i.d. 5 μm）,甲醇-水（含0.1%甲酸,V/V,%）为流动相进行梯度洗脱,在20 min内基本实现了大部分物质基线分离;在电喷雾正离子和选择离子对模式下,结合目标物保留时间和特征离子对信息,对16种激素进行定性和定量分析。结果表明,所有化合物具有良好的线性范围（0.10~3000.00 ng/mL）,相关系数R大于0.9987,检测限介于0.05~5.00 ng/mL范围内。鱼肉样品在液氮中研磨成鱼粉,经过固相萃取法净化处理后,测得氢化可的松药物残留为48.00 ng/g。16种激素的回收率介于82.84%~115.10%之间,RSDs值小于9.30%。该法分离能力强、灵敏度高,适用于水产品中类固醇药物的多残留同时测定。     

水刺托网对产品质量的影响

本文在对水刺非织造布拉伸断裂特征分析的基础上 ,着重介绍了水刺托网影响产品拉伸断裂性能的因素 ,指出提高产品质量应注重对水刺托网结构参数的选择     

Stress Effects on Meat Quality: A Mechanistic Perspective

Stress inevitably occurs from the farm to abattoir in modern livestock husbandry. The effects of stress on the behavioral and physiological status and ultimate meat quality have been well documented. However, reports on the mechanism of stress effects on physiological and biochemical changes and their consequent effects on meat quality attributes have been somewhat disjointed and limited. Furthermore, the causes of variability in meat quality traits among different animal species, muscle fibers within an animal, and even positions within a piece of meat in response to stress are still not entirely clear. This review 1st summarizes the primary stress factors, including heat stress, preslaughter handling stress, oxidative stress, and other stress factors affecting animal welfare; carcass quality; and eating quality. This review further delineates potential stress‐induced pathways or mediators, including AMP‐activated protein kinase‐mediated energy metabolism, crosstalk among calcium signaling pathways and reactive oxygen species, protein modification, apoptosis, calpain and cathepsin proteolytic systems, and heat shock proteins that exert effects that cause biochemical changes during the early postmortem period and affect the subsequent meat quality. To obtain meat of high quality, further studies are needed to unravel the intricate mechanisms involving the aforementioned signaling pathways or mediators and their crosstalk.     

不同种类钾肥对香料烟产质量的影响

本文通过田间试验探讨了施用不同种类钾肥对香料烟产量的影响。试验结果表明:施用氯化钾和硫酸钾均能显著提高香料烟烟叶的产量;同时还能改善烟叶的外观质量和内在品质,主要表现在一级和二级烟叶比例的增大,烟叶含钾量、总糖量、施木克值及K/Cl比值的提高。值得注意的是,完全施用氯化钾处理的烟叶含氟量(0.93%)接近1.0%的临界值,这有可能降低烟叶的燃烧性。试验还表明:香料烟烟叶的含氟量与主要生育期土壤的含氯量呈极显著正相关,这对生产上确定氯化钾的适宜用量具有指导意义,有利于缓解香料烟产区硫酸钾供应紧缺的现状。