A Novel Tensile Test Method to Assess Texture and Gaping in Salmon Fillets

ABSTRACT: A new tensile strength method was developed to quantify the force required to tear a standardized block of Atlantic salmon muscle with the aim of identifying those samples more prone to factory downgrading as a result of softness and fillet gaping. The new method effectively overcomes problems of sample attachment encountered with previous tensile strength tests. The repeatability and sensitivity and predictability of the new technique were evaluated against other common instrumental texture measurement methods. The relationship between sensory assessments of firmness and parameters from the instrumental texture methods was also determined. Data from the new method were shown to have the strongest correlations with gaping severity (r =−0.514, P < 0.001) and the highest level of repeatability of data when analyzing cold-smoked samples. The Warner Bratzler shear method gave the most repeatable data from fresh samples and had the highest correlations between fresh and smoked product from the same fish (r = 0.811, P < 0.001). A hierarchical cluster analysis placed the tensile test in the top cluster, alongside the Warner Bratzler method, demonstrating that it also yields adequate data with respect to these tests. None of the tested sensory analysis attributes showed significant relationships to mechanical tests except fillet firmness, with correlations (r) of 0.42 for cylinder probe maximum force (P = 0.005) and 0.31 for tensile work (P = 0.04). It was concluded that the tensile test method developed provides an important addition to the available tools for mechanical analysis of salmon quality, particularly with respect to the prediction of gaping during factory processing, which is a serious commercial problem. Practical Application: A novel, reliable method of measuring flesh tensile strength in salmon, provides data of relevance to gaping.     

Textural Changes of Canned Chum Salmon Related to Sexual Maturity

Eating quality of chum salmon decreases as the fish migrate towards natal streams to spawn. Fish were assigned to maturity grades according to outward appearance and processed according to normal commercial practice. Texture of the canned product was assessed by nine trained sensory judges and by instrumental texture profile analysis (TPA). Both methods revealed significant differences between grades but the sensory method was more sensitive. Standardization of scores of each judge reduced error due to tendency of judges to use different portions of continuous scoring lines. Major textural changes in canned salmon were not evident before the transition from grade 3, dark to grade 4, spawning fish.     

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).     

The Effect of Stunning Methods on Rigor Mortis and Texture Properties of Atlantic Salmon (Salmo Salar)

Shear force and rigor mortis were used to evaluate the post‐mortem changes of muscle texture in Atlantic salmon (Salmo salar). The fish were either stunned with carbon dioxide (CO₂), electricity, or percussion prior to slaughter. The pre‐mortem stress during CO₂ stunning resulted in an earlier onset and resolution of rigor mortis, and accelerated post‐mortem softening of the muscle tissue as compared to the other stunning methods. No significant differences, either in development of rigor mortis or shear force, were seen between fish that were stunned with electricity or by percussion. Consequently electricity can be used for stunning fish prior to slaughter.     

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.     

The Effect of Stunning Methods and Season on Muscle Texture Hardness in Atlantic Salmon (Salmo salar L.)

Commercially collected records of Atlantic salmon (Salmo salar L.) muscle texture hardness were used to evaluate the effect of slaughter procedures and seasonality on texture quality. A database collected by Marine Harvest® contained flesh hardness records of Atlantic salmon slaughtered at processing plants in Norway from summer 2010 to summer 2011. The fish were slaughtered either by (1) percussion followed by automated bleeding (“Percussive”) or (2) live chilling with exposure to carbon dioxide (CO₂) followed by manual severing gill arches and bleeding (“CO₂”) or (3) live chilling with exposure to CO₂ followed by percussive stunning and at the end automated bleeding (“CO₂·percussive”). Hardness in salmon muscle cutlets was measured in Newtons (N) by Materials Testing Machine Zwick 500N. The hardness in salmon varied significantly over the study period (P < 0.05, mixed effect model) and showed the softest value of 21.2 (± 0.7) Newton (N) in summer 2011 and hardest 24.1 (± 0.2) N in autumn 2010. Slaughter procedures had a significant effect on salmon muscle hardness (P < 0.05, mixed effect model), where percussion followed by automated bleeding resulted in the hardest value (24.0 ± 0.4 N) as compared with CO₂ stunning (21.8 ± 0.2 N) and combination of CO₂ and percussive stunning (23.1 ± 0.15 N). CO₂ is suspected as a causal factor in accelerated postmortem softening of the salmon muscle.     

Effect of Modified Atmosphere Packaging and Superchilled Storage on the Microbial and Sensory Quality of Atlantic Salmon (Salmo salar) Fillets

ABSTRACT: Fresh Atlantic salmon fillets packaged under modified atmosphere (MA) (CO²:N² 60:40) and air was stored at superchilled (-2 °C) and chilled (+4 °C) temperatures. Changes in sensory scores, microbial growth, headspace gas composition, water loss, and pH were monitored during 24 d of storage. The superchilled MA packaged salmon maintained a good quality, with negligible microbial growth (<1000 colony-forming units [CFU]/g) for more than 24 d based on both sensory and microbial analyses (aerobic plate count, H2S-producing, and psychrotrophic bacteria). Superchilled salmon in air had a 21-d sensory shelf life, whereas MA and air-stored fillets at chilled conditions was spoiled after 10 d and 7 d, respectively.     

Frozen Hake Fillets Quality as Related to Texture and Viscosity By Mechanical Methods

This work aimed to develop a textural quality classification function for frozen hake fillets using instrumental measurements. Frozen hake fillets were stored to provide a wide range of textures. Raw and cooked fillets were analyzed for texture using Kramer and Warner-Bratzler shear cells and a puncture device. Apparent viscosity, dimethylamine and protein solubility were also measured. Principal Component Analysis indicated three factors accounted for 86.5% of the variance. Four clusters were found, ranging from excellent quality (low texture, high viscosity) to very poor (high texture, low viscosity). Parameters required for classification were viscosity, maximum force from Kramer and maximum force and energy from the puncture test.     

Spoilage of King Salmon (Oncorhynchus tshawytscha) Fillets Stored Under Different Atmospheres

ABSTRACT: King salmon ( Oncorhynchus tshawytscha ) packaged in air (AIR), nitrogen (N2), or 40:60 carbon dioxide:nitrogen (CO2N2) was stored (0 °C) for 18, 25, and 54 d, respectively. Air packs (AIR9) were also stored at 9 °C for 4 d. A quality index (QI) method was developed to monitor sensory quality of cooked salmon. First detection of spoilage was 1.5, 15, 15, and 21 d for AIR9, AIR, N2, and CO2N2 treatments respectively. Total aerobic and sulfide-producing bacteria, pH, drip loss, E_h, color, texture, ATP derivatives, trimethylamine, total volatile base nitrogen, thiobarbituric acid numbers, and peroxide values were determined. Only total aerobic counts and hypoxanthine were indicators of sensory deterioration across treatments and times.     

Biochemical and Physicochemical Characteristics of Muscle and Natural Actomyosin Isolated from Young Atlantic Salmon (Salmo salar) Fillets Stored at 0 and 4 °C

ABSTRACT The impact of storage of fillets at 0 and 4 °C within 3.5 h postmortem was studied. Extractability of natural actomyosin (NAM) increased over the first 2 to 3 d, then decreased as storage progressed. Water-binding capacity of fish muscle and apparent viscosity of NAM decreased in the first 2 to 3 d and increased progressively thereafter. Reactive sulfhydryl content and surface hydrophobicity were lowest at 3 d, whereas disulfide content was highest at 2 and 14 d. Water-binding capacity at 2 d and NAM extractability at 5 to 7 d were significantly higher, whereas viscosity, hydrophobicity, and sulfhydryl content were generally lower for fillets stored at 0 than at 4 °C.     

优选法在染整仿样试验中的应用

作者将数学家华罗庚的优选法灵活应用到了印染厂仿样打色板试验中,文中举例说明了"平分法"、"0.618法"和"分数法"三种优选法的使用方法,只要选择得当对于单峰问题各类试验都可应用优选法。     

The texture of Atlantic salmon (Salmo salar) muscle as measured instrumentally using TPA and Warner–Brazler shear test

Muscle texture measurements were performed on Atlantic salmon (Salmo salar) using two different instrumental methods; The Texture Profile Analysis, which is a uniaxial compression test, and the Warner–Brazler shear test. The performances of the two tests were evaluated as to their ability to differentiate between recently killed salmon and salmon stored on ice for up to 24 days. Both tests performed well, but the shear test was slightly more sensitive than the compression test. Further, salmon were either starved or fed for two weeks prior to slaughter. The muscle from fed salmon lost its strength slightly faster than that from starved salmon, but this difference was only detectable during the first two days of chilled storage. The effects of temperature, fish size and degree and mode of deformation on the instrumental test results were studied and were found to be significant. Also, the sample geometry, ie the thickness of the fillet was found to have a very significant effect on the TPA-test results. © 1999 Society of Chemical Industry     

青梅汁酸凝豆腐质构优化及显微结构研究

为了改善青梅汁作为单一酸性凝固剂制作的豆腐硬度低、质构差的缺点,添加天然食用胶与钙盐进行质构的优化研究。以豆腐的硬度与持水力作为响应值,采用响应曲面法优化食用胶与钙盐的最佳添加量。结果表明：食用胶与钙盐的最佳添加量为乳酸钙0.291 mmol/100 mL、卡拉胶0.032 8 g/100 mL,此条件下青梅汁酸凝豆腐硬度为49.3 g,持水力为73.43%。扫描电镜显微观察表明,添加卡拉胶与乳酸钙的豆腐凝胶网络结构更加均匀、致密。     

Histological Changes in Collagen Related to Textural Development of Prawn Meat During Heat Processing

Heat processing enhanced firmness and degree of shrinkage deformation of kuruma prawn Penaeus japonicus meat. In histological experiments, most collagen fiber in perimysium, epimysium, and subcuticular connective tissue maintained structures after heat-processing in hot water at 70°C for 30 min. Crude collagen fiber fractions (residues after alkali extraction, RS-AL) prepared from the muscle were measured for hot-water solubility and compared with the RS-AL from the muscle of carp Cyprinus carpio. Collagen in the RS-AL of prawn muscle had very low hot-water solubility (about 23.5% at 70°C) compared with that of carp. These results suggested that collagen had important functions in promoting thermal shrinkage and hardening of prawn meat and in maintaining mechanical strength of heat-processed meat.     

Beet Pulp and Isolated Pectin Physicochemical Properties as Related to Freezing

Any potential effects of postharvest freezing storage of beets on physicochemical characteristics of isolated pectin and beet pulp were determined. Fresh beets were stored at -20°for up to 3 mo. At the end of storage, beets were thawed and shredded, and sucrose was extracted. Pectin was isolated using a combination of enzyme treatment and acid extraction. Yield, galacturonic acid content, methoxyl ester content, and molecular mass distributions of the isolated pectin were determined. Neutral and acidic sugar compositions in the nonstarchy polysaccharides (NSP) of the beet pulp were determined using enzyme hydrolysis and gas chromatography. Results showed that physicochemical characteristics of isolated pectin, and sugar composition of the NSP in the beet pulp were not notably influenced by the freeze/thaw cycle.     

Textural Properties and Sensory Quality of Processed Sweetpotatoes as Affected by Low Temperature Blanching

Sweetpotatoes (SP) stored for 9–12 mo after harvest were cut into cylindrical pieces and, following factorial experiments and response surface design, were blanched at 50–80°C for 15–274 min. Instrumental textural properties were measured by uniaxial compression and texture profile analysis. Samples of selected blanching treatments were canned in syrup for textural and sensory evaluations. Both blanching temperature and time had significant effects on firmness. Optimal temperature for maximal firmness retention was about 62°C. For canned SP, the 62°C blanched samples were more intact (2–3-fold) and firmer (2–7-fold) than controls. Sensory texture and overall acceptability were greatest for samples blanched at 62°C for 30 or 45 min before canning.     

Development of a Method to Produce Freeze-Dried Cubes from 3 Pacific Salmon Species

Abstract: Freeze-dried boneless skinless cubes of pink (Oncorhynchus gorbuscha), sockeye (Oncorhynchus nerka), and chum (Oncorhynchus keta) salmon were prepared and physical properties evaluated. To minimize freeze-drying time, the kinetics of dehydration and processing yields were investigated. The physical characteristics of the final product including bulk density, shrinkage, hardness, color, and rehydration kinetics were determined. Results showed that freeze-dried salmon cubes from each of the 3 Pacific salmon species can be produced with a moisture content of less that 10% and a_w less 0.4 and freeze-drying time of 9 h. Processing yields ranged from 26% to 28.4%, depending on fish species. Shrinkage was less than 12% and rehydration of freeze-dried cubes was rapid. The value-added products developed have the potential to be utilized as ingredients for ready-to-eat soups, as snack food, salad topping, and baby finger-food. Practical Application: Freeze-drying removes water from food products without heating them; therefore, this type of drying process yields very high-quality dried foods. In this study, a freeze-dry process was established to produce small cubes of Alaska pink, sockeye, and chum salmon. The goals were to shorten typical freeze-drying time while producing acceptable product characteristics. The freeze-drying process developed took only 9 h to remove about 97% of the moisture of diced Pacific salmon fillets. The freeze-dried salmon cubes produced can be used as ingredients for dehydrated ready-to-eat soups, as baby finger-foods, or as salad toppings.     

Yield and Textural Properties of Tofu as Affected by the Changes of Phytate Content During Soybean Storage

ABSTRACT: Soybeans stored under 4 conditions were analyzed for the degradation of phytate and its effects on tofu qualities. Phytate in soybeans was hydrolyzed significantly under the adverse conditions for 9 mo, but decreased slightly under 3 mild conditions for 18 mo. Phytate degradation contributed to an increase in titratable acidity. When the phytate contents of soymilk were selectively reduced by 11.3% and 17.5% by phytase, while other components remained unchanged, tofu yield increased significantly but texture became softer. Tofu yield decreased and hardness increased in beans stored in the adverse conditions. Phytate degradation during adverse storage played a minor, indirect role in the deterioration of soybeans for tofu making.     

Low-Temperature Blanching of Sweetpotatoes to Improve Firmness Retention: Effect on Compositional and Textural Properties

ABSTRACT: Low-temperature blanching of sweetpotatoes (SP) prior to cooking has been shown to significantly increase firmness retention. This research investigated the effect of blanching on firmness, pectin methylesterase activity (PME), pectin methylation, and galacturonic acid and cell wall material concentrations in SP tissue subjected to blanching and cooking treatments. PME activity decreased 82% after 20 min of blanching in water at 62°C, while sample firmness continued to increase with blanching time (3.5 N for unblanched and 19.0 N for 90 min blanched, and cooked tissue), indicating that firming due to pectin demethylation explains part of the observed increased firmness retention caused by low-temperature blanching, but unknown factors also play a role.,