Product Yield and Gaping in Cold-smoked Atlantic Salmon (Salmo salar) Fillets as Influenced by Different Injection-salting Techniques

Product yield and fillet gaping severity were determined in cold‐smoked Atlantic salmon fillets subjected to injection‐salting. Effects of process parameter settings (brine injection pressure, number of repeated injections, needle speed, injection of brine in 1 or 2 directions, and chilled fillet resting before smoking) were tested. Repeated injections increased the yield up to 5.3% (wt/wt). Increasing injection pressure significantly increased the severity of fillet gaping in smoked fillets by 18%. Brine injection directions or needle speed did not affect smoking yield. The stability of the injection system was high. The results show that choice of process parameter settings during injection‐salting affects product yield after smoking.     

高效液相色谱法快速鉴别人工合成虾青素养殖的三文鱼

建立了虾青素手性异构体分离和检测的HPLC 方法。条件：采用手性固定相色谱柱;Pirkle L- 亮胺酸(4.6mm × 25cm,5μm); 流动相：正己烷- 四氢呋喃- 异丙醇- 三乙胺(77:17:3:3,V/V);紫外检测波长：474nm;流速：0.75ml/min。本法可应用于快速鉴别养殖三文鱼是否使用了人工合成虾青素,并可以初步判断是否为野生三文鱼。     

Influence of Salmon Provenance and Smoking Process on Muscle Functional Characteristics

ABSTRACT: Ocean-ranched and farm-reared Atlantic salmon were compared on the basis of compositional and functional/mechanical properties of the raw and the corresponding smoked muscle. Several procedures based on different salting methods (brine and dry salting) and smoking temperature (20 °C and 30 °C) were tested, as well as an electrostatic smoking method. Also, raw material samples were studied without and with frozen storage (-20 °C) for 30 d prior to salting/smoking, and the effect of frozen storage on the smoked muscle was evaluated. The electrostatic method induced considerably lower shear force values than the other smoking treatments. Ocean-ranched salmon were more susceptible to protein aggregation and loss of binding properties (water and fat) than farmed fish as a consequence of frozen storage of the raw material or smoking treatment.     

Effects of Freezing on Quality of Cold-smoked Salmon Based on the Measurements of Physiochemical Characteristics

ABSTRACT: How the quality of cold-smoked Atlantic salmon ( Salmo salar ) is affected by freezing the raw fish as whole fish, as gutted fish, and as fillets before smoking, and by freezing the finished product after smoking was studied. Freezing before smoking resulted in increased product yield and water content, but softer texture and increased K-value. Freezing reduced the content of astaxanthin but increased the lightness and the color intensity of the flesh. Gaping increased when the fish was frozen as fillets before smoking. Freezing only after smoking led to fewer changes in quality than freezing before smoking, whereas refreezing the finished products had little additional effect on quality.     

温度和pH值对Phaffia rhodozyma生长和虾青素积累的影响

研究了不同温度和 pH值对红发夫酵母PhaffiarhodozymaAs2 15 5 7生长及虾青素积累的影响。结果表明 ,2 0℃对红发夫酵母生长及虾青素合成有利 ,pH 5 91时有利于生长 ,pH4 97时有利于虾青素积累。     

Cold Smoking of Atlantic Salmon (Salmo salar) Fillets with Smoke Condensate—an Alternative Processing Technology for the Production of Smoked Salmon

ABSTRACT:  Two different protocols for the production of cold smoked salmon were investigated. All fillets were dry salted (18 h, 4 °C) before being allotted to a smoke condensate/liquid smoke protocol (SCP), which included drenching (1 min) in smoke condensate [1:3 (v/v) smoke:water] and drying (150 min, 28.4 ± 2.2 °C) or a wood chips protocol (WCP) that included drying and smoking in a regular smoking chamber (23 °C, 480 min) using wood chips for smoke production. Quality assessments were performed on the smoked fillets at day 0 and after 7, 14, and 31 d of storage (3.4 ± 0.7 °C). Application of the SCP resulted in a significantly higher ( P < 0.01) processing yield (89.6%± 0.7%) as compared to the WCP (88.6%± 0.5%). On day 0, the SCP fillets were significantly ( P < 0.01) less light ( L *) and yellow ( b *) and had a lower chroma ( C *) and hue ( h *) compared to the fillets processed with WCP. From 7 d until the end of storage time, small differences in color were observed. After 31 d of storage, the SCP fillets had a significantly higher ( P < 0.05) intensity of oily texture and lower intensity of salty and smoke taste. Texture profile analysis (TPA) showed few significant differences between the processing protocols, although the WCP fillets were significantly harder than the SCP fillets when recording the force at 60% compression of the fillet height. The use of smoke condensate and drenching technology is a way of producing cold smoked salmon with quality characteristics quite similar to those found in commercial "traditional" products, although processors who want to use this technology have to optimize the drying step and the smoke condensate formulation to their specifications.     

烟熏工艺对香肠食用品质的影响

采用色差仪、质构仪和气相色谱-质谱-嗅闻联用分别测定香肠色泽、质构和挥发性风味物质,研究木熏工艺和液熏工艺对香肠食用品质的影响。结果表明:不同烟熏工艺下,样品红度(a*)值差异不显著(P0.05);弹性差异显著(P0.05),液熏样品弹性大于木熏样品;木熏样品中检出52种主要挥发性风味物质,其中酚类物质15种;液熏样品检出49种主要挥发性风味物质,其中酚类物质14种。     

虾青素的提取及其稳定性的研究

以虾头、虾壳为原料,研究了有机溶剂提取虾青素的条件及其稳定性。结果表明,用乙酸乙酯在pH4.0、50℃条件下提取2.5h虾青素的产量为49.1μg/g原料。研究还发现:紫外光对虾青素的破坏作用很大,而可见光较小;70℃以下、pH4～11范围内虾青素较稳定;Ca2 、Mg2 、K 、Na 、Zn2 金属离子对虾青素基本没影响,Fe2 、Fe3 、Cu2 有明显破坏作用,Fe3 对虾青素的影响最大。     

Controlling Listeria monocytogenes in Cold Smoked Salmon with the Antimicrobial Peptide Salmine

Listeria monocytogenes (LM) is a major safety concern for smoked salmon producers, as it can survive both the brining and smoking process in cold smoked salmon production. Salmine is a cationic antimicrobial peptide derived from the milt of salmon that has been shown to inhibit the growth of LM in vitro. Commercialization of this peptide would add value to a waste product produced when raising salmon. The purpose of this study was to determine the anti‐listeria activity of salmine in smoked salmon by measuring the viable counts of LM over time. Cold smoked salmon was treated with a salmine solution or coated with agar or k‐carrageenan films incorporating salmine to maintain a high surface concentration of the antimicrobial. Samples were then inoculated with approximately 1.0 × 10³ cells of LM. The viable counts were then enumerated throughout 4 wk at 4 °C storage. It was found that 5 mg/g salmine delayed the growth of LM on smoked salmon. These samples had significantly (P < 0.05) lower LM counts than on the untreated samples on days 13 and 22. Edible films did not significantly (P > 0.05) improve the antimicrobial efficacy of salmine. The peptide combined with biopolymers also had lower antimicrobial activity in vitro when compared to salmine alone. These results suggest there is potential for salmine to be used as a natural hurdle to inhibit growth of LM due to post process contamination; however, future investigations for extending this effect throughout the shelf life of smoked salmon products are warranted.     

Relating Sensory and Instrumental Texture Analyses of Atlantic Salmon

Sensory‐evaluated hardness of smoked Atlantic salmon (Salmo salar L.) was correlated with various response variables from instrumental texture analysis of raw or smoked cutlets (25 mm thick) using 4 different probes: 12.5‐ and 23‐ mm‐dia cylinders, a Warner‐Bratzler blade, and a 25.4‐mm‐dia sphere. Sensory hardness correlated significantly with analyses using all mechanical methods, but it was most accurately predicted by the 12.5‐mm‐dia cylinder in raw salmon (force and area at 90% compression; r = 0.70, P < 0.0001), and by the 23‐mm‐dia cylinder in smoked salmon (force at 90% compression and the area from origo to the 1st significant break; r = 0.63 to 0.64, P < 0.0001).     

Biological Characteristics Affect the Quality of Farmed Atlantic Salmon and Smoked Muscle

Various biological characteristics influencing the quality of farmed salmon and smoked muscle were studied. No great differences in proximate composition were observed among raw fish. Stress produced a slight decrease in protein solubility at 0.8 M NaCl and also slight variations in electrophoretic profile. This was accompanied by a certain degree of muscle softening. Thirty-days starvation produced slight depletion of the sarcoplasmic fraction, collagen insolubilization, and muscle hardening. The effect of triploidy was more evident in sea-caged fish, resulting in lower protein solubility at 0.05M NaCl and lower insoluble collagen than diploids. After smoking, protein solubility at 0.8M NaCl was highest in stressed fish, and non-starved fish collagen became insolubilized.     

Stabilizing Smoked Salmon (Oncorhynchus gorbuscha) Tissue after Extraction of Oil

ABSTRACT: Alaska salmon oils are rich in n-3 polyunsaturated fatty acids and are highly valued by the food and pharmaceutical industries. However, the tissue that remains after oil extraction does not have an established market. Discarded pink salmon (Oncorhynchus gorbuscha) tissues were preserved using a combination of smoke-processing and acidification with lactic acid bacteria (LAB). All samples were analyzed for moisture, protein, ash, and lipid contents. Bacterial cell counts, pH, and lactic acid concentrations were recorded as a measure of LAB viability. Neither raw nor smoked salmon were free from spoilage during 60 d of storage. Only fermented samples successfully stabilized below pH 4.7, while retaining lactic acid concentrations over 15 g/L during storage. When smoked, fermented salmon head tissues were dried, the pH of the resulting high-protein “cracker” was significantly lower than when crackers were prepared only from the smoked (but not fermented) salmon material. Both cracker varieties retained valuable polyunsaturated fatty acids. This research suggests that salmon-head tissues discarded after oil extraction represent a good source of protein and high-value fatty acids in a shelf-stable form. Practical Application: Alaska salmon oils are rich in n-3 polyunsaturated fatty acids and are highly valued by the food and pharmaceutical industries. However, the tissue that remains after oil extraction does not have an established market. Material produced from salmon tissue discarded after oil extraction may represent a valuable resource for preparing high-protein crackers and other fish-based food products. In addition to providing a unique smoke-flavoring, the smoked, fermented fish material may also impart antioxidant factors thereby extending the shelf life of the product.     

Modeling the Growth Characteristics of Listeria monocytogenes and Native Microflora in Smoked Salmon

ABSTRACT:  Smoked salmon contaminated with Listeria monocytogenes has been implicated in foodborne listeriosis. The objectives of this study were to model the growth characteristics and examine the growth relationship of L. monocytogenes and native microflora in smoked salmon. Smoked salmon samples with a native microflora count of 2.9 log₁₀ CFU/g were inoculated with a 6-strain mixture of L. monocytogenes to levels of log₁₀ 1.6 and log₁₀ 2.8 CFU/g, and stored at 4, 8, 12, and 16 °C. Growth characteristics (lag phase duration [LPD, h], growth rate [GR, log₁₀ CFU/h], and maximum population density [MPD, log₁₀ CFU/g]) of L. monocytogenes and native microflora were determined. At 4 to 16 °C, the LPD, GR, and MPD were 254 to 35 h, 0.0109 to 0.0538 log₁₀ CFU/h, and 4.9 to 6.9 log₁₀ CFU/g for L. monocytogenes , respectively, and were 257 to 29 h, 0.0102 to 0.0565 log₁₀ CFU/h, and 8.5 to 8.8 log₁₀ CFU/g for native microflora. The growth characteristics of L. monocytogenes or the native microflora were not significantly different ( P > 0.05), regardless the initial levels of L. monocytogenes . Mathematical equations were developed to describe the LPD, GR, and MPD of L. monocytogenes and native microflora as a function of storage temperature. The growth relationship between L. monocytogenes and native microflora was modeled and showed that the LPD and GR of L. monocytogenes were similar to those of native microflora. These models can be used to estimate the growth characteristics of L. monocytogenes in smoked salmon, and thereby enhance the microbiological safety of the product.     

不同地区大西洋鲑鱼无机元素含量的对比分析

建立了电感耦合等离子体质谱法(ICP-MS)的碰撞模式测定大西洋鲑鱼中Ca、Fe、Zn、Cu、Mn、Pb、As、Cr、Cd、Al 10种无机元素含量的方法。采用HNO₃-H₂O₂体系进行微波消解后直接进行测定,以⁷²Ge、¹¹⁵In、⁴⁵Sc、²⁰⁹Bi作为内标元素消除基体干扰,选用He碰撞模式的动能歧视(KED)技术消除多原子干扰,对来自挪威、澳大利亚、智利3个产地进口的大西洋鲑鱼中10种无机元素含量进行测定,并结合聚类分析进行归类。结果表明:各元素检出限为0.005~0.058 mg/kg,加标回收率为93.5%~98.2%,相对标准偏差(RSD)为0.73%~3.15%。3个产地大西洋鲑鱼样本间Ca、As含量存在显著差异(P<0.05);挪威与澳大利亚样本之间Ca、Fe、Mn、As、Cr、Al含量差异显著(P<0.05),Cu、Zn、Pb含量无显著差异(P>0.05);挪威与智利样品之间Ca、Cu、As、Cr含量差异显著(P<0.05),Fe、Mn、Zn、Pb、Al含量无显著差异(P>0.05);澳大利亚与智利样品之间Ca、Fe、Cu、Mn、As、Al含量差异显著(P<0.05),Zn、Pb、Cr含量无显著差异(P>0.05)。聚类分析将样品分成三个大类,选择Ca、Fe、As、Cr、Al共5个对区分大西洋鲑鱼产地方差贡献较大的元素含量为自变量建立大西洋鲑鱼3个产地的Fisher判别模型,利用判别模型对样品进行归类,三地样本的判别准确率达到100%。     

冷熏三文鱼单增李斯特菌热灭菌规律及其品质变化动力学研究

为了给冷熏三文鱼热灭菌提供理论依据,试验研究了热处理对冷熏三文鱼中单增李斯特菌失活及品质变化影响。将接种了一株单增李斯特菌(ATCC19113)菌液的鱼肉密封于毛细管中,分别在58℃、60℃、62℃、64℃和66℃条件下加热处理18 min、8.8 min、4 min、2 min和1 min,考察不同温度条件下存活菌数变化。采用铝制密封加热单元(直径35 mm×高6 mm)研究了冷熏三文鱼(直径30 mm×高6 mm)在50℃、57℃、64℃和70℃条件下加热处理120 min、90 min、60 min和40 min时的品质变化。结果表明:单增李斯特菌的热失活曲线遵循对数线性关系(R2≥0.94);冷熏三文鱼品质指标加热失重率、a*值、b*值及剪切力遵循1级反应动力学规律,L*值遵循0级反应动力学规律;冷熏三文鱼色值a*与单增李斯特菌热失活密切相关,色值a*品质劣变曲线与单增李斯特菌(ATCC19113)死亡曲线重叠区域为热处理温度与时间组合可操作范围,此范围可同时满足杀菌及品质保持要求。     

KNO_3对红发夫酵母生物合成虾青素的影响

比较了红发夫酵母(Phaffiarhodozyma)以KNO3、NaNO3、(NH4)2SO4及蛋白胨为氮源的细胞生长及虾青素合成过程,重点研究了KNO3对红发夫酵母生物合成虾青素的影响。结果表明:低浓度KNO3(0·1~0·9g/L)有利于细胞生长及虾青素合成,而高浓度KNO3(3·0~9·0g/L)抑制细胞生长及虾青素合成。当培养基中含有0·3g/LKNO3时,红发夫酵母的发酵过程不仅表现出细胞二次生长及虾青素二次合成现象,而且发酵周期较长,可获得较高的生物量和干细胞虾青素含量,分别为8·13g/L和0·993mg/g。     

Nondestructive Prediction of Moisture and Sodium Chloride in Cold Smoked Atlantic Salmon (Salmo salar)

ABSTRACT: Salt and moisture contents in cold-smoked salmon were determined using short-wavelength near-infrared (SW-NIR) reflectance spectroscopy (600 to 1100 nm). Partial least square (PLS) regression models yielded the best results among 3 linear regression methods tested. Back-propagation neural networks (BPNN) exhibited a somewhat better capability to model salt and moisture concentrations (Salt: R²= 0.824, RMS = 0.55; Moisture: R²= 0.946, RMS = 2.44) than PLS (Salt: R²= 0.775, RMS = 0.63; Moisture: R²= 0.936, RMS = 2.65). Selection of samples from different axial locations on a fish did not affect the prediction error for salt or WPS but affected the prediction error for moisture.     

Astaxanthin Extraction from Shrimp Wastes and its Stability in 2 Model Systems

Abstract: The objective of this work was to study the stability of astaxanthin, obtained from shrimp wastes, and incorporated to 2 model systems: egg albumin protein solution and sunflower oil. Shrimp wastes were ensiled by a treatment with formic/acetic acids (4%–4% v/w wastes) and stored at 4 °C for 24 h. The pigment was extracted with organic solvents (petroleum ether:acetone:water, 15 : 75 : 10) and concentrated. The storage parameters studied were: illumination (light/dark), temperature (4/20 °C), atmosphere (air/air-free), and storage time (0, 1, 2, 3, 4, 5 wk). Results showed that total xantophylls and astaxanthin were more stable in sunflower oil than in the protein system. Total xantophylls showed more stability than astaxanthin, possibly due to the presence of other, more stable carotenoids quantified together with xantophylls. Astaxanthin concentration was significantly affected by storage time; its degradation followed a first-order reaction rate under all the studied conditions. This pigment was stable only for 17 d, even when stored in air-free flasks, under refrigeration, and in the dark. Practical Application: Shrimp catching and farming generate large amounts of polluting wastes; they can be an important source of added-value red-orange pigments. However, these pigments are highly unstable to various transformation processes and to storage conditions. This research studied the effect of storage on 2 model systems (protein and lipid) on pigment degradation.