鲢鱼鱼糜蛋白质凝胶特性的研究

研究了鲢鱼鱼糜在不同的加热条件下 ,其凝胶的色泽、强度及显微结构的变化。结果表明 ,鲢鱼鱼糜在 60℃时达到较理想的色泽 (白色 ) ,较佳的凝胶条件为 ,先经过 3 5～ 40℃、60min的凝胶化 ,再经过 85℃、3 0min加热。在 5 0℃加热时 ,出现凝胶劣化现象     

不同漂洗方式的白鲢鱼糜品质比较

为解决鱼糜漂洗用水量较大这一问题,该实验以白鲢为原料,减少一次漂洗,以清水+清水为对照,比较壳聚糖溶液+清水,壳聚糖溶液+盐水,壳聚糖溶液+臭氧水和清水+臭氧水4种漂洗方式对鱼糜质构、风味等品质的影响。结果显示,壳聚糖溶液+清水或清水+臭氧水漂洗,鱼糜得率分别为21.78%和21.26%,均高于对照组的鱼糜得率19.21%;在4种漂洗方式中,壳聚糖溶液+臭氧水漂洗组的鱼糜白度最高,清水+臭氧水组的凝胶强度最大;电子鼻雷达图显示壳聚糖溶液+清水,壳聚糖溶液+臭氧水和壳聚糖溶液+盐水组的T70/2（芳香族化合物）响应值较低,而对照组和清水+臭氧水组的T70/2（芳香族化合物）响应值较高。综上所述,4种漂洗方式中清水+臭氧水漂洗可以有效地改善鱼糜品质和风味;同时,两次漂洗与传统的三次漂洗相比,减少了漂洗次数,可节约用水约1/3。     

鲢鱼新鲜度对鱼糜凝胶品质的影响

通过对4 ℃条件下鲢鱼死后10 h感官特性、pH值和僵直指数的变化过程以及鲢鱼死后不同时间鱼肉的挥发性盐基氮（total volatile basic nitrogen,TVB-N）值和Ca2＋-ATP酶活性变化的检测,研究鲢鱼肉新鲜度对鱼糜凝胶品质的影响。结果表明：鲢鱼在死后2～3 h开始进入僵直期,鱼体僵直指数升高,pH值下降;随着鲢鱼死后时间的延长,鱼肉的TVB-N值显著升高,Ca2＋-ATP酶活性显著降低。采用死后不同时间的鲢鱼肉制作的鱼糜凝胶,其凝胶强度、保水性和白度均有显著差异,其中以新鲜鲢鱼为原料制作的鱼糜凝胶的凝胶强度最高,而鱼糜凝胶的保水性和白度在鱼肉的僵直期最差。     

Comparison of Gel-forming Properties of Silver Carp (Hypophthalmichthys molitrix) Surimi Prepared in Different Seasons

ABSTRACT: The gel-forming properties of silver carp surimi made in different seasons were compared. Surimi prepared in winter and spring formed gel at 30°C, while autumn and summer surimi required a higher temperature of 40°C for gel formation. All surimi showed marked disintegration when incubated at 60°C. Ca²⁺-ATPase inactivation rate of myofibrils prepared from 4 surimi samples showed that myofibrils in autumn and summer surimi were much more stable than those in winter and spring surimi by about 10°C. These results demonstrated a close relationship between the gel-forming temperature of surimi and the thermal stability of myofibrils in surimi, namely that autumn and summer surimi containing stable myofibrils required higher temperature than winter and spring surimi for the gel formation.     

白鲢鱼鱼糜凝胶过程中水分及凝胶特性的变化

本文研究了白鲢鱼鱼糜凝胶过程中的水分及凝胶特性变化规律,主要考察了鱼糜在凝胶过程中持水力、低场核磁T2横向弛豫时间及T2峰比例、凝胶特性、色差及凝胶微观结构指标的变化,并通过TG-DTGA(Thermogravimetric-Derivative Thermogravimetry Analysis)分析鱼糜凝胶在两段式加热中的结晶水含量变化。鱼糜与淀粉、水、盐混合斩拌后,采用两段式凝胶进行凝胶化。结果发现,加热过程中鱼糜持水力显著增加,在第二段加热25 min时达到最大值为96.93%;T23弛豫时间呈现下降的趋势,并在第二段加热过程中下降速度较快,在第二段加热30 min时达到最低值为30.51 ms;T23峰比例呈现上升趋势且在第一段加热过程中升速较快,在第二段加热10 min后达到最大值为93.97%;弹性、硬度等显著增加;亮度和白度呈现显著上升的趋势;结晶水含量在二段加热中呈现先增加后减少的趋势,在第一段加热30 min时达到最大值为6.59%。     

鲢鱼糜凝胶力学性能对热处理方式的响应性研究

本文通过比较不同热处理方式下鱼糜凝胶的力学特性,探寻满足特异性消费需求的鱼糜热处理方式,进而为食品工业生产鱼糜凝胶制品提供理论支持。实验以鲢为原料进行采肉,添加适量微生物转谷氨酰胺酶,在不同凝胶化条件及鱼糕化条件下制备鱼糜凝胶,采用质构仪的穿刺测试、TPA测试、剪切测试、应力松弛测试和蠕变测试模式对鱼糜凝胶力学性能进行表征。研究结果表明:采用40℃保温1 h后于90℃加热30 min所形成鱼糜凝胶的破断强度(1359 g)、硬度(8863 g)和内聚性(0.82)最高,适合生产高凝胶强度鱼糜凝胶制品。采用4℃保温24 h后于90℃加热30 min所形成的鱼糜凝胶脆度(2785 g/min)最高,适合生产高脆性鱼糜凝胶制品。无论采用哪种凝胶化条件,微波加热都不利于鱼糜的鱼糕化,与其他鱼糕化方式相比,降低了最终鱼糜凝胶的强度和脆性。     

富钙白鲢鱼糜凝胶的制备及其营养分析

为提升淡水鱼类加工副产物的综合利用水平,同时提高淡水鱼糜制品的营养价值,本文研究了富钙白鲢鱼糜凝胶的制备及鱼骨泥对鱼糜凝胶特性的影响,并对鱼骨泥及鱼糜凝胶的营养成分进行了分析。以凝胶强度、白度、持水性为指标,采用单因素试验及感官评分确定了鱼骨泥的适宜添加量;并采用SDS-PAGE凝胶电泳、扫描电镜等方法,进一步研究添加鱼骨泥对鱼糜凝胶的影响。结果表明,添加质量分数为3%的鱼骨泥有利于提高鱼糜凝胶强度以及制备营养型鱼糜,此时鱼糜凝胶强度为282.44 g·cm,而不加鱼骨泥的普通鱼糜仅为239.89 g·cm;钙、磷含量分别为1697.69μg/g和1278.16μg/g,是普通鱼糜的4.6倍和2.2倍,且钙磷比为1.33:1,利于钙磷吸收;此外,氨基酸比例(EAA/TAA和EAA/NEAA)均符合FAO/WHO的推荐标准。因此,富钙营养型白鲢鱼糜可以作为人体健康的一种潜在优质蛋白来源。     

鱼糜副产物酶解物对冻融鲢鱼鱼糜品质的影响

为了解鱼糜加工副产物（鱼头、鱼骨、鱼鳞、鱼鳍等）酶解物的添加对冻融鲢鱼鱼糜品质及凝胶特性的影响,对酶解物的体外抗氧化性及反复冻融鱼糜的盐溶性蛋白含量、巯基含量、Ca2＋-ATP酶活性、表面疏水性、凝胶特性、凝胶持水性及色泽进行研究。结果表明：与其他酶相比,经胰蛋白酶及碱性蛋白酶酶解后,鱼糜加工副产物酶解物的体外抗氧化活性最强;与对照组及蔗糖添加组鱼糜相比,鱼糜加工副产物酶解物的添加能够有效减缓反复冻融后鱼糜肌原纤维蛋白的冷冻变性及氧化速率,鱼糜的盐溶性蛋白含量、巯基含量、Ca2＋-ATP酶活性较高,表面疏水性较低;同时,鱼糜加工副产物酶解物的加入增强了鱼糜凝胶的初始凝胶特性及持水性,并能够有效延缓鱼糜凝胶破断力、凹陷度及凝胶强度的劣变,改善鱼糜凝胶的持水性。     

性早熟蟹肉和白鲢鱼糜混合凝胶工艺优化及其凝胶特性

通过向白鲢鱼糜中添加蟹肉和0.3%谷氨酰胺转氨酶（transglutaminase,TG）,以凝胶强度和持水性为指标,研究蟹肉比例、凝胶化时间以及凝胶化温度3 个因素对混合凝胶特性的影响。在单因素试验基础上,采取3因素3水平的Box-Behnken设计进行响应面分析,得到最佳工艺条件为：蟹肉比例10%,凝胶化时间3.0 h,凝胶化温度35 ℃。验证实验结果显示,与传统鱼肠相比,优化后的鱼糜与蟹肉混合肠,其凝胶强度有显著的提升（P＜0.05）,持水性略有降低,但并不显著（P＞0.05）;聚丙烯酰胺凝胶电泳和扫描电镜结果表明,TG的添加可使混合凝胶中肌球蛋白重链明显减少,且凝胶表面更均匀、致密。     

漂洗工艺对鲢鱼鱼糜凝胶强度和色泽的影响

探讨清水漂洗次数、盐水漂洗次数和漂洗温度对鲢鱼鱼糜凝胶强度和白度的影响。结果表明:清水漂洗和盐水漂洗可以显著的提高鲢鱼鱼糜的凝胶强度和白度,采用清水漂洗2次再用盐水漂洗1次的漂洗处理,得到的鲢鱼鱼糜凝胶强度和色泽较好。漂洗温度对鲢鱼鱼糜的凝胶强度和白度无显著影响,但为保持鱼肉的新鲜,漂洗温度不宜过高。     

鲢鱼皮胶原蛋白的提取及性质分析

通过热水浸提,醋酸酸提及胃蛋白酶促提从鲢鱼皮中提取得到水溶性胶原蛋白(RSC),酸溶性胶原蛋白(ASC)和酶溶性胶原蛋白(PSC),并分析其部分性质。鲢鱼皮中RSC,ASC和PSC的得率以湿基计分别为13.2%,11.8%和13.6%;RSC,ASC和PSC的紫外光谱分析表明,其最大吸收峰都接近231 nm,但在280 nm处的吸收很小;傅立叶变换红外光谱结果表明鲢鱼皮胶原蛋白具有特殊的三螺旋结构;SDS-PAGE电泳图谱显示鲢鱼皮胶原蛋白有两条α链(α1和α2)和β链,表明该胶原为典型的I型胶原蛋白;鲢鱼皮RSC,ASC和PSC热变性温度分别为27.1℃,31.3℃和30.5℃。这些结果为进一步研究提供了理论依据。     

Quality Changes of Dehydrated Restructured Fish Product from Silver Carp (Hypophthalmichthys molitrix) as Affected by Drying Methods

Restructured fish slices from silver carp (Hypophthalmichthys molitrix) were dried using air drying (AD), freeze drying (FD), and vacuum drying (VD) (4 mm thickness) and microwave-vacuum drying (MVD) (2, 4, 6, and 8 mm thickness). Quality attributes of the dried products were compared in terms of their rehydrated characteristics, change in dimensions, color, texture, sensory values before and after rehydration, and change in volatile compounds. AD, FD, and VD resulted in the different levels of shrinkage while MVD caused some expansion in diameter and thickness in the 4-, 6-, and 8-mm-thickness samples. Rehydration caused significant swelling in AD, FD, and VD products (p?<?0.05) but insignificant change in MVD products (p?>?0.05). Drying methods significantly affected the color and texture of both dried and rehydrated products (p?<?0.05), but slice thickness had no significant effect on the color in MVD products (p?>?0.05). MVD products rehydrated faster and had higher rehydration ratio as well as lower water hold capacity, hardness, springiness, cohesiveness, and chewiness than others. In sensory evaluation, MVD products alone exhibited acceptable crispness and favorable odor. The rehydrated dried products were acceptable by the sensory panelists and were preferred in the order: FD, VD, AD, MVD. Gas chromatography-mass spectrometry revealed that drying significantly decreased the n-alkanals and 1-octen-3-ol content (p?<?0.05) and produced new aldehydes including 2-methyl-propanal, 3-methyl-butanal, and furfural in MVD products. This study demonstrated that drying restructured fish meat can be potentially used to develop the new dried fish products using optimal drying conditions.     

鲢鱼酶解产物对冷冻面团品质特性的影响

为研究鲢鱼酶解产物对冷冻面团品质的影响,在面团中加入2%的系列鲢鱼酶解产物,分析冻融处理前后（第0和4次冻融循环,－18 ℃冷冻18 h,4 ℃解冻6 h为一次冻融循环）面团醒发和焙烤特性、流变特性及显微结构等的变化。结果表明,添加酶解产物能抑制冻融后面团醒发时间延长和面包比容下降,其中30 min酶解产物（SCMH-30）效果最好,醒发时间（121 min）显著低于空白组（170 min）,面包比容（1.72 mL/g）显著高于空白组（1.54 mL/g）,说明其抗冻效果良好;与空白组新鲜面团相比,酶解产物组面团的拉伸强度降低,黏附性和延展性增大,可能与酶解产物中还原性肽的负面作用有关;冻融后所有面团的拉伸强度降低,黏附性和延展性增大,而抗冻性较好的海藻糖组和SCMH-30组面团的变化幅度相对较小。电镜观察表明添加SCMH-30削弱了面团面筋形成,但能较好地维持冻融后面团面筋结构稳定;粉质特性分析说明添加SCMH-30使面粉的面团形成时间、稳定时间、粉质指数均显著降低,弱化度显著上升,而加入葡萄糖氧化酶则可减轻其对面粉粉质特性的不利影响。研究结果为鲢鱼酶解产物在改良冷冻面团中的实际应用及其有效调控提供了理论依据。     

采用圆二色谱法研究冬夏鲢鱼鳞胶原蛋白的稳定性

采用圆二色谱法,研究比较了冬夏季鲢鱼鳞胶原蛋白的热稳定性。结果表明,对胶原蛋白溶液于30℃,33℃加热时,冬季鱼鳞胶原蛋白发生解螺旋现象,而夏季鱼鳞胶原仍保持完整的三螺旋结构;变性温度曲线显示,夏季样品的变性温度为36℃,而冬季样品出现2个峰值,分别为30℃和34℃。结果表明,夏季鲢鱼鳞胶原蛋白的热稳定性高于冬季胶原蛋白,这种不同可能与冬夏季鲢鱼生长环境温度的差异有关。     

白鲢鱼背侧肌焦磷酸酶的纯化及酶学特性

通过粗分离、50%～80%饱和度硫酸铵分级沉降、DE-52阴离子交换柱层析等步骤,从白鲢鱼背侧肌中分离纯化出焦磷酸酶。通过变性凝胶电泳分析,该酶在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳图谱中仅有一个分子质量为40 kD的条带。酶学特性研究表明,白鲢鱼背侧肌焦磷酸酶可专一性地水解焦磷酸盐,反应初速率时间范围为0～15 min,最适反应温度为45 ℃,最适反应pH值为7.5。Mg2＋对该酶有明显的激活作用,在Mg2＋浓度为5 mmol/L时酶活力最高。5 mmol/L的Ca2＋、Zn2＋、乙二胺四乙酸（ethylenediaminetetraacetic acid,EDTA）-Na2、EDTA-Na4、KIO3和1 mmol/L的NaF均对该酶有强烈的抑制作用。该酶水解焦磷酸四钠的最大反应速率为0.051 U/mg,米氏常数为0.54 mmol/L。     

Functional Properties of Water-soluble Proteins from Silver Carp (Hypophthalmichthys molitrix) Conjugated with Five Different Kinds of Sugar

Water-soluble proteins (WSP) from silver carp denature easily during thermal processing, leading to the reduction of functional properties. In order to improve the functional properties of WSP and to utilize its resources efficiently, five different kinds of sugars (i.e., xylose, glucose, galactose, oligo-isomaltose, and dextran-10) were used to conjugate with WSP by Maillard reaction. Results suggested that the use of the Maillard reaction improved the solubility, heat stability, and emulsifying properties of WSP. With the increase of molecular weight (MW) of the sugars, the solubility, emulsifying properties, and total sulfhydryl (SH) groups of WSP increased, while the surface hydrophobicity decreased. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of the five Maillard reaction products (MRPs) showed that xylose reacted easily with WSP than did the other four kinds of sugar. Dextran-10 conjugated to WSP could efficiently improve the functional properties of WSP during heat processing.     

Antioxidant Effects of Grape Pomace on the Quality of Silver Carp (Hypophthalmichthys molitrix) Fillets During Refrigerated Storage

This study aimed to determine the phenolic content and antioxidant effect of grape pomace extract on silver carp fillets during refrigerated storage. Total phenolic content of grape pomace extract was quantified by colorimetric methods. Silver carp samples were treated with 0, 2, and 4% of grape pomace extract (g extract/100 g flesh) and stored 15 days in a refrigerator (4°C). Changes in pH, peroxide value, thiobarbituric acid, and heme iron at 0, 3, 6, 9, 12, and 15 days of storage were investigated. Results showed that the values of pH, peroxide value, and thiobarbituric acid increased and iron levels decreased in all treatments during storage (p < 0.05). The phenolic contents were generally much more influenced by the quality parameters treated compared to the control. The addition of grape pomace extract delayed lipid oxidation in silver carp fillet considerably during refrigerated storage. These results suggested that grape pomace extract has the potential to be used as a natural antioxidant.     

白鲢鱼肌原纤维蛋白双向电泳分析体系的建立

以白鲢鱼为研究对象,建立并优化其肌原纤维蛋白的双向电泳技术。结果表明,选用固相p H值梯度预制胶条p H 4~7,上样量120μg,等电聚焦程序Ⅲ(50 V主动水化15 h,250 V、2 h,1 000 V、2.5 h及4 000 V、3 h三段式除盐,8 000 V、2 h和10 000 V、1.5 h两段式升压,10 000 V聚焦80 000 V·h,500 V保持10 h)以及12%的十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分离胶条件下进行双向电泳,凝胶银染后用PDQuest软件分析,得到具有高分离度的肌原纤维蛋白双向电泳图谱,蛋白点清晰。