大豆胰蛋白酶抑制剂对带鱼鱼糜蛋白降解及其凝胶特性的影响

为提高带鱼鱼糜制品品质,以鱼糜蛋白组成、TCA-溶解肽含量及其凝胶强度等为指标,研究大豆胰蛋白酶抑制剂(STI)对带鱼鱼糜蛋白降解及其凝胶特性的影响。结果表明,带鱼鱼糜蛋白的降解与温度显著相关,随温度升高,肌原纤维蛋白重链(MHC)逐渐降解,TCA-溶解肽含量增加,在70℃时达到最高值(1.3μmol酪氨酸·g~(-1))。添加STI能够一定程度抑制带鱼鱼糜凝胶劣化样品和凝胶化样品中肌原纤维蛋白的降解,降低TCA-溶解肽含量。当STI添加量为0.10‰时,凝胶劣化样品和凝胶化样品的TCA-溶解肽含量达到最低值,分别为0.13和0.30μmol酪氨酸·g~(-1),凝胶强度达到最高值,分别为414.74 g·mm和1 262.28 g·mm,而失水率分别下降为5.44%和3.76%;电镜微观结构显示,此时凝胶结构更致密、均匀,但凝胶白度值轻微下降。因此,STI可有效提高带鱼鱼糜制品品质,从而为生产高品质的带鱼鱼糜制品提供参考和依据。     

不同淀粉对带鱼鱼糜凝胶品质的影响

为确定改善带鱼鱼糜凝胶品质的最佳淀粉种类及其添加量,以凝胶强度、质构分析(TPA)值、白度、持水性和凝胶溶解度为指标,探究5种淀粉(小麦淀粉、马铃薯淀粉、木薯淀粉、交联淀粉和羟丙基淀粉)在不同添加量(0、5%、10%、15%和20%)下对带鱼鱼糜凝胶品质的影响。结果表明,不同种类淀粉以及添加量均对带鱼鱼糜凝胶品质有显著影响。当添加量超过15%后,淀粉的添加对带鱼鱼糜凝胶弹性和持水性影响不显著。5种淀粉中,木薯淀粉对带鱼鱼糜凝胶品质的改善效果最好,在鱼糜中添加15%木薯淀粉时,鱼糜凝胶强度、硬度、粘聚性、弹性、咀嚼性、白度值、失水率和凝胶溶解度分别为886.176 g·cm、4 879.56g、0.67、0.87、2 888.86、60.07、5.84%、49.47%。因此,添加15%的木薯淀粉能有效改善带鱼鱼糜凝胶品质。本试验结果为高品质鱼糜制品生产提供了科学依据。     

Quality Characteristics of Tilapia Surimi: Effect of Single Washing Cycle and Different Washing Media

Surimi was prepared by washing with single washing cycle with cold water (T-1), alkaline saline (0.2% NaHCO₃ and 0.15% NaCl; T-2) solution, and with calcium chloride and salt (0.2% CaCl₂ and 0.1% NaCl; T-3), respectively, and compared with conventional washed (CW) surimi. T-2 exhibited significantly (p ≤ 0.05) increased moisture content, which correlated with increased yield, pH and also significantly decreased lipid and ash content. A significant (p ≤ 0.05) decrease in expressible moisture content was also observed in T-2, which suggested higher water holding capacity compared to other treatments. Heat-induced surimi gels exhibited highest L* (p ≤ 0.05), followed by surimi in all the treatments. In the case of L*, T-1 showed highest lightness, followed by T-2, which was comparable to CW. The lowest myoglobin content was exhibited by CW surimi (p ≤ 0.05), which is due to repeated washings. T-2 gel showed higher elasticity, texture, and overall acceptability than others (p ≤ 0.05), except for the whiteness. In all the aspects, T-2 was comparable with CW. Washing with one cycle of T-2 solution can not only improve the quality of surimi but can reduce the wastage of water that is released into the environment without further treatment.     

不同亲水胶体对带鱼鱼糜凝胶品质的影响

为确定合适的亲水胶体种类及其添加量,以带鱼鱼糜为原料,通过测定凝胶强度、质构(硬度、粘聚性、弹性和咀嚼性)、白度、持水性和凝胶溶解度等指标,分析瓜尔胶、魔芋胶和沙蒿胶3种亲水胶体对带鱼鱼糜凝胶品质的影响。结果表明,瓜尔胶、魔芋胶和沙蒿胶均能提高带鱼鱼糜凝胶强度,但相同添加量下魔芋胶的改善效果最好,而瓜尔胶对鱼糜凝胶强度的影响不显著。魔芋胶能显著改进带鱼鱼糜凝胶的质构特性;瓜尔胶添加量为2.0%时鱼糜凝胶硬度、弹性、咀嚼性、粘聚性比对照组低;沙蒿胶对鱼糜凝胶的粘聚性影响显著,当添加量为1.5%或2.0%时,带鱼鱼糜凝胶的咀嚼性、硬度增加,弹性下降。瓜尔胶、魔芋胶和沙蒿胶均能提高带鱼鱼糜持水性,降低鱼糜凝胶白度和溶解度,但对鱼糜凝胶色泽的影响不显著。扫描电镜结果显示,1.5%魔芋胶处理组形成的鱼糜凝胶表面规则有序、网络结构致密均一。综合比较,添加1.5%魔芋胶能有效改善带鱼鱼糜的凝胶品质。本研究结果为提高带鱼鱼糜制品品质及生产研发提供了一定的理论依据。     

酵母抽提物主要滋味成分分析及其对鱼糜制品风味的影响

以4种酵母抽提物(KA66、FA28、KU012、FA01)为原料,通过分析其金属离子、游离氨基酸、总氨基酸和核苷酸的组成,以滋味活度值(TAV)和味精当量(EUC)为指标分别评价各滋味成分对酵母抽提物滋味的贡献程度和鲜味物质间的协同增鲜作用;并将其加入到鱼糜制品中,通过感官评价和电子鼻分析探究其对鱼糜制品风味的影响。结果表明,酵母抽提物KU012中谷氨酸、丙氨酸、5′-IMP、5′-GMP等滋味物质含量最高,TAV值最大,而FA01中丙氨酸、5′-IMP、5′-GMP含量最低,TAV值最小;FA28中总氨基酸含量最高,谷氨酸含量最高;KU012的EUC值最高,1g KU012产生的鲜味强度相当于125.22g单一味精(MSG)所产生的鲜味强度,为125.22gMSG/g;感官结果表明,酵母抽提物可显著改善鱼糜制品的滋味,对腥味也有一定掩蔽作用,KU012感官评分最高;电子鼻的结果表明,加入不同的酵母抽提物后,鱼糜制品的挥发性成分区别较大。     

近红外光谱技术在鱼糜定性和定量上的应用

以海水鱼糜(包括狭鳕、带鱼、鲷和混合鱼糜)以及淡水鱼糜(包括鲢和草鱼鱼糜)为研究对象,应用傅立叶近红外光谱技术结合化学计量学对鱼糜进行定性和定量分析。用聚类分析和线性判别的方法建立海水和淡水鱼糜的定性鉴别模型,并应用偏最小二乘法(PLS)分别建立海水鱼糜水分含量和蛋白质含量的近红外定量分析模型。结果表明,海水和淡水鱼糜的定性鉴别模型预测率达100%;建立的近红外定量分析模型中,海水鱼糜的水分和蛋白质的模型的相关系数分别达0.98和0.96以上,模型能较为准确、快速地预测定海水鱼糜中水分和蛋白质含量,有很大的潜力可应用于实际生产。     

Effects of Whitening Agents and Frozen Storage on the Quality of Sardine (Sardina pilchardus) Surimi: Physicochemical and Mechanical Properties

This work is focused on the effect of using whitening agents (WA) during a process followed by frozen storage (4 months at ?18°C) on the whiteness, quality parameters, and mechanical properties of sardine surimi. The whiteness of surimi exhibited a significant improvement when whitening agents (calcium carbonate and peroxide hydrogen) were used (48.75 to 60.24). Dynamic rheological measurement showed that storage moduli, G′, was considerably higher than loss moduli, G″, for both surimi with WA and control; however, the highest viscoelastic moduli were found in the treated surimi. In addition, the microstructure of surimi with WA showed more compact matrix and higher water holding capacity. On the other hand, most tested indexes showed quality losses throughout the frozen storage in both samples. Proteins underwent denaturation as indicated by the reduction in band intensities, especially myosin heavy chain (MHC) bands. Peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) measurements showed that lipid oxidation took place during storage; however, the degree of lipid oxidation was not relevant. Therefore, it was proved that the addition of whitening agents had a marked effect on the production of surimi with better functional attributes including whiteness, water holding capacity, and mechanical properties.     

东、黄海带鱼的摄食习性及随发育的变化

对2000年10月～2002年8月期间收集的1986尾带鱼食性的分析,发现带鱼的食物包括80余种生物种类,主要以甲壳类和鱼类为食,其余类群所占的比例很少。带鱼在生长发育过程中,摄食生态位发生转移和扩大,食性类型由浮游生物食性逐渐转变成游泳动物食性,摄食范围由狭食性逐步向广食性转变。这些转变既减少了大个体与小个体之间的食物竞争,又增强了带鱼摄食的种间竞争能力。另外,结果还表明带鱼的摄食强度在发育过程没有显著的变化。     

盐酸-壳聚糖絮凝耦合处理回收鲢鱼糜漂洗液中的肌浆蛋白

为提高鱼糜漂洗液中肌浆蛋白的利用率,以鲢鱼糜为研究对象,采用单一壳聚糖絮凝法和盐酸-壳聚糖絮凝耦合处理回收鲢鱼糜漂洗液中的肌浆蛋白,并通过单因素试验和Box-Bechnken中心组合设计对盐酸-壳聚糖絮凝耦合处理的絮凝条件进行优化。结果发现：盐酸处理（pH 3.0）可以显著提高壳聚糖作为单一絮凝剂时的肌浆蛋白回收率（从35.52%提高到81.54%）,肌浆蛋白的最佳回收工艺确定为：pH 6.5,壳聚糖用量250 mg/L,温度30℃,时间90 min。在此条件下,可以获得85.23%的高蛋白质回收率以及73.32%的COD去除率。同时,此方法引入鱼糜漂洗液中的NaCl质量分数为0.006%,不会使后续废水处理成本增加,具有一定的可行性。     

Effects of Olive Leaf Powder on Mechanical Properties of Heat-Induced Surimi Gel

The effects of addition of olive leaf powder (OLP) to surimi on the mechanical properties of surimi gel were investigated. The OLP contained a high polyphenol content of 7% (w/w). The breaking stress and breaking strain of surimi gel increased with increasing OLP concentration. The addition of 0.3% OLP increased the breaking stress of surimi gel by 80% and the breaking strain by 38%. The addition of 2.0% OLP resulted in a 100% increase in the breaking strain. The OLP gels had finer and denser protein networks than the control gel, probably due to integration of additional crosslinks into the protein networks via polyphenols or their derivatives. Although the addition of OLP had a detrimental effect on whiteness of surimi gel, OLP is still a useful functional ingredient for improving mechanical properties of surimi gel products in which the color is not an important quality.