COMPARISON OF TWO INSTRUMENTAL METHODS WITH SENSORY TEXTURE OF PROTEIN GELS2

The textural attributes of 8 different heat-induced protein gel preparations evaluated by torsion failure testing and Instron texture profile analysis (TPA) were compared to sensory ratings by a trained texture profile panel. The gels presented a wide range of textural properties as determined by the instrumental and sensory parameters. Among the instrumental parameters, true shear strain at failure was the most frequent and significant predictor of sensory notes. Initial shear modulus and 50% compression force had the poorest correlations with sensory notes. Comparison of the two instrumental tests produced high correlations between shear stress at failure and TPA hardness; true shear strain at failure and TPA cohesiveness; and, initial shear modulus and 50% compression force. High correlations were also observed among various panel notes. Canonical correlation analyses showed that sets of linear combinations of parameters from each one of the 3 tests (torsion, TPA or sensory) were highly correlated to sets from either of the other two. Regression equations relating each of the instrumental tests to sensory notes were developed. Of the torsion failure parameters, the logarithm of true shear strain most commonly appeared in the equations. Of the TPA parameters, cohesiveness and its logarithm were the terms that were most frequent. High R² values were obtained for regression equations developed for predicting torsion failure parameters based on TPA parameters.     

Comparison of instrumental and sensory evaluation of texture of cured and cooked beef meat

The instrumental and sensory texture attributes of beef muscles (M. longissimus dorsi and M. semimembranosus) were compared after curing and thermal treatments. Shear, compression and puncture tests were carried out with an UTM Instron 4301 and the sensory evaluation was made with the score method. The force values obtained for puncture test gave a greater degree of correlation with the sensory tenderness, hardness and elasticity than the shear test forces. The shear test forces were found to significantly correlate with sensory tenderness only for muscles with perpendicular orientation of fibres to the direction of shear blade movement. The evaluation of beef texture with compression test was dependent on the level of sample deformation degree. The force values of compression were found to correlate significantly with elasticity and juiciness of meat up to 60% deformation levels, but at deformation levels higher than 60% appeared significant correlation with tenderness and hardness. The obtained results showed the usefulness of puncture test with proposed parameters for the instrumental measurements of beef texture.     

Correlation between instrumental and sensory ratings by evaluation of some texture reference scales

The objective of this study was to investigate instrumental–sensory relationships of some texture scales using argentine foods as references. Textural characteristics of these foods were instrumentally investigated by the texture profile analysis technique. Principal component analysis (PCA) was used to describe the main attributes of the food samples. High Pearson’s correlation coefficients were found between hardness and fracturability (r = 0.94; P < 0.0001), hardness and gumminess (r = 0.71; P < 0.0001) and springiness and cohesiveness (r = 0.85; P < 0.0001). PCA identified two significant principal components, which accounted for 81.2% of the variance in the instrumental data. Additionally, a trained panel described the texture characteristics of the food samples according to the standard reference scales. The correlation curves showed nonlinear relationships (R² between 85.6% and 99.9%) which were used to predict sensory attributes of other food samples. Some texture attributes like hardness and fracturability were accurately predicted by mechanical properties, while others like cohesiveness and adhesiveness were less representative.     

Textural Measurements and Product Quality of Restructured Sweetpotato French Fries

The objectives of this research were to investigate the applicability of using an alginate-calcium gelling system to produce a French fry-type product using high beta-carotene sweetpotato puree as the main ingredient and to compare four instrumental methods of texture measurement for this product type in relation to sensory textural properties. Sweetpotato puree made with Jewel cultivar sweetpotatoes was restructured using optimized alginate-calcium concentrations. A consumer panel scored sweetpotato fries containing 0.35 g alginate/100 g and 0.5 g CaSO₄/100 g highest for appearance, texture, flavor, and overall acceptability. A trained texture profile panel described the product with 15 texture notes. Of these attributes, nine sensory notes describing hardness, mastication shear, cohesiveness, springiness, moistness, and oiliness were highly correlated with some instrumental parameters (r=0.79-0.92) for measuring textural properties. The instrumental methods evaluated were instrumental texture profile analysis, three-point bending force, Kramer shear force, and puncture force. Among these instrumental methods, Kramer shear appeared to be the method of choice because of method's simplicity and high precision (coefficient of variation ≤10%).     

Using shear force,sarcomere length,particle size,collagen content,and protein solubility metrics to predict consumer acceptance of aged beef tenderness

In this study, the relationship between sensory evaluation and several objective metrics of beef tenderness was tested. Objective metrics included shear force, sarcomere length, collagen content, myofibrillar, and sarcoplasmic protein solubility and particle size analysis. These results were compared to consumer panel scores of tenderness for the same aged beef striploin (longissimus lumborum muscle) samples. There was found to be a significant relationship between sarcomere length, shear force, and particle size with tenderness scores. Collagen content and protein solubilities were not associated to tenderness scores (p > 0.05). Sarcomere length contributions for explaining tenderness variation were overlapped by the contributions of shear force (collinearity). Independent models demonstrated that the lower 95% confidence interval of the fitted regression line exceeded 50% acceptance of tenderness when shear force values <42.6 N and when particle size values <198 μm. We can recommend these as thresholds for consumer acceptance of beef tenderness, although considerations of sample type, analytical methodology, and consumer demographics should be made prior to their adoption. This provision was based on the variation in tenderness scores evident between individual panelists and experimental striploins.     

Correlations of Sensory and Instrumental Evaluations of Roast Beef Texture

Beef semitendinosus roasts heated to endpoint temperatures of 60°, 70°, and 80°C were evaluated by a taste panel and by instrumental tests of shear, penetration, and compressive force. Correlations were found between sensory parameters of chewiness, hardness and tenderness and between these parameters and shear parameters of firmness and cohesiveness. Compression-hardness was related positively to panel scores for moisture and negatively to mealiness scores. Compression-cohesiveness was related only to panel scores for oiliness while compression-springiness and penetration hardness were not related to any of the sensory parameters evaluated.     

Instrumental and Sensory Texture Attributes of High‐Protein Nutrition Bars Formulated with Extruded Milk Protein Concentrate

Previous instrumental study of high‐protein nutrition (HPN) bars formulated with extruded milk protein concentrate (MPC) indicated slower hardening compared to bars formulated with unmodified MPC. However, hardness, and its change during storage, insufficiently characterizes HPN bar texture. In this study, MPC80 was extruded at 2 different conditions and model HPN bars were prepared. A trained sensory panel and instrumental techniques were used to measure HPN bar firmness, crumbliness, fracturability, hardness, cohesiveness, and other attributes to characterize texture change during storage. Extrusion modification, storage temperature, and storage time significantly affected the instrumental and sensory panel measured texture attributes. The HPN bars became firmer and less cohesive during storage. When evaluated at the same storage conditions, the texture attributes of the HPN bars formulated with the different extrudates did not differ significantly from each other. However, textural differences were noted most of the time between the control and the HPN bars formulated with extruded MPC80. An adapted HPN bar crumbliness measurement technique produced results that were correlated with sensory panel measured crumbliness (r = 0.85) and cohesiveness (r = –0.84). Overall, the HPN bars formulated with extruded MPC80 were significantly softer, less crumbly, and more cohesive than the control during storage.     

EFFECT, DEVELOPMENT AND OPTIMIZATION OF MIXING TEMPERATURE, TIME AND PARTICLE REDUCTION IN THE MANUFACTURE OF RESTRUCTURED BEEF STEAK

Restructured beef steaks were processed from USDA Select chuck muscles without the use of additives, and three processing variables were utilized at three different levels: -2, 0, +2C for mixing temperature, 12, 18, 24 min for mixing time and 1, 2, 3 passes through a kidney plate for particle size reduction. A sensory panel composed of 149 untrained consumer panelists evaluated the 27 treatment combinations for five sensory attributes. Instrumental determinations were also made. Increasing mixing temperature and decreasing particle size significantly decreased sensory tenderness, flavor and overall acceptance and increased instrumental hardness and springiness of the restructured beef steaks. Increasing mixing time had a significant effect on sensory appearance and on instrumental cohesiveness and gumminess. The means for sensory scores were used for a response surface analysis (RSM) to optimize the three processing variables. Significant models were found for tenderness (P<0.05), overall acceptance (P<0.05) and flavor (P<0.15). Using a sensory score of 6.00 (like slightly) as an acceptable score, optima for the processing variables were determined. To obtain an acceptable product, the meat should be ground by two passes through the kidney plate then mixed at a maximum temperature of 0.67C for 12 min.     

RELATIONSHIP BETWEEN INSTRUMENTAL AND SENSORY PARAMETERS OF COOKED SWEETPOTATO TEXTURE1

This study compared two instrumental methods, namely uniaxial compression and texture profile analysis (TPA), with sensory evaluation in describing the textural properties of cooked sweetpotatoes. The steamed cooked samples (1.35 × 2.2 cm cylinder) of four cultivars and six selections were subjected to a trained texture profile panel for sensory ratings and the two instrumental methods for determination of the mechanical properties. Factor analysis indicated that the 15 sensory variables were grouped into 3 main factors, namely moistness-firmness (factor 1), particles (factor 2), and fiber (factor 3). Among the instrumental parameters, shear stress of compression and fracturability, hardness, and gumminess of TPA correlated highly (R = 0.73–0.95) with both the mouthfeel and mechanical-type sensory notes. These parameters of the two instrumental methods were linearly related (R²≥ 0.95) and could be converted from one to another with a high degree of reliability. Regression equations based on shear stress significantly explained (R²= 0.71–0.91) eight of the sensory notes. These instrumental parameters can be good predictors of cooked sweetpotato texture.     

A COMPARISON OF THREE INSTRUMENTAL TESTS FOR PREDICTING SENSORY TEXTURE PROFILES OF CHEESE

Multivariate analysis techniques were used to seek correlations between texture sensory attributes assessed by a trained professional panel and instrumental measurements (compression, puncture and penetration) carried out on various types of cheeses. Twenty-nine cheeses were assessed by the panel and instruments. Correlation was sought using Partial Least Squares regression. Hardness (R=0.87), springiness (R=0.98) and cohesiveness of mass (R=0.89) were best predicted by instrumental data from a cone penetration test. The prediction of cohesiveness was acceptable using any of the three instrumental tests performed (0.76相似文献   

TEXTURAL CHARACTERISTICS OF FROZEN BLUE SQUAT LOBSTER (CERVIMUNIDA JOHNI) TAILS AS MEASURED BY INSTRUMENTAL AND SENSORY METHODS

Instrumental and sensory textural characteristics of frozen blue squat lobster (Cervimunida johni) tails stored at ?22C for 0, 15 and 60 days were evaluated. The influence of fishing area (north or south) was also studied. Instrumental texture was evaluated by shear and compression testing using a Warner–Bratzler blade for firmness and a flat plunger with two‐cycle compression for texture profile analysis (TPA) testing. A trained panel was utilized to evaluate textural attributes using the score method. Results showed that fishing area and frozen storage did not affect the textural quality of blue squat lobster tails. However, a strong correlation (r > 0.9) between sensory and instrumental texture parameters was observed. Instrumental chewiness (r = 0.91), cohesiveness (r = 0.96) and sensory hardness (r > 0.84) obtained the strongest correlations. In this way, the use of instrumental analysis may be useful as an alternative to sensory analyses to evaluate the textural characteristics of blue squat lobster tails.     

The Paradox of Toughening During the Aging of Tender Steaks

ABSTRACT:  Aging is the practice of holding meat at low temperatures to improve tenderness that is the most important sensory attribute affecting consumer acceptability of beef. Because of the inconsistencies in measured tenderness changes during aging, we attempted to look at the relationship between aging and initial tenderness irrespective of animal age, genetics, or nutritional status. Cattle were selected to represent a full range of quality grades from Utility to Prime. Steaks from these cattle were aged in vacuum bags for 0, 7, or 14 d and tenderness characteristics were assessed. Steaks were cut from the frozen loin sections, thawed, and cooked on open hearth grills to 70 °C. Sensory evaluation was completed by a 6-member trained sensory evaluation panel and Warner-Bratzler shear was determined. The average shear values decreased with aging time across most grade categories; however, improvement was not uniform. Steaks from Utility grade cattle improved the most while steaks of other grades improved less. Shear values overlapped a great deal across all grades and to gain a better understanding of changes with aging, steaks were grouped based on initial shear value differences of 1 kg. Shear value of the toughest steaks decreased the most during aging (−36%), while those with the lowest shear values increased (16%). The same pattern emerged when steaks were grouped by initial tenderness. These results suggest that initially tough steaks will benefit from aging while very tender steaks may be adversely affected.     

Effect of Thermal Treatment on Selected Cereals and Millets Flour Doughs and Their Baking Quality

Selected cereals (rice and sorghum) and millets (finger millet and pearl millet) were steamed for 20 min at ambient pressure. The rheological properties of doughs, made from these steamed as well raw grain flours, were characterized in addition to examining their baking quality. The two-cycle compression test was employed and instrumental values were correlated with sensory attributes (color, aroma, taste, stickiness, chewiness, tearing strength, cohesiveness, and rollability) using principal component analysis (PCA). Rice doughs made from both raw as well as thermally treated flour imparted maximum hardness (96.6–99.3 N) and least cohesiveness (0.05–0.09) with highest stickiness values (105–110°) among all the dough samples at the same moisture content. Pearl millet and raw sorghum flour doughs possessed the least instrumental hardness, adhesiveness, and stickiness and were the easiest to flatten. The PCA biplot showed that sensory and instrumental cohesiveness formed a cluster on the left side on the x axis while shear force, and sensory attributes like tearing strength, chewiness, stickiness, and rollability formed another cluster on the other side of the axis. Raw rice and finger millet doughs were associated with the high extent of instrumental and sensory stickiness. Thermally treated pearl millet and sorghum doughs were the best followed by treated rice and finger millet samples to give the desirable dough characteristics, and were quite close to wheat chapathi in texture.     

Consumer sensory evaluations of aging effects on beef quality

ABSTRACT:  The most important sensory attribute affecting consumer acceptability is tenderness, which is a complex trait. Aging is the practice of holding meat at low temperatures to improve tenderness. In order to assess consumer quality attributes, cattle were selected to represent a range of quality grades from Utility to Prime. Steaks from these cattle were aged in vacuum bags for 0, 7, or 14 d, cut, and cooked on open hearth grills to 70 °C. Sensory evaluation was completed by consumers ( n = 522). Warner–Bratzler (WB) shear and various physical characteristics were also determined. Shear values decreased with aging time and tenderness increased. Consumers perceived the majority of change in tenderness occurred during the first 7 d of aging while change in WB shear was similar during the first 7 d and the second 7 d of aging. Aging had no effect ( P > 0.05) on juiciness, flavor, pH, lipid content, or water content of steaks.     

RELATIONSHIP BETWEEN INSTRUMENTAL AND SENSORY ANALYSIS OF TEXTURE AND COLOR OF POTATO CHIPS

The instrumental and sensory analysis of the texture and color of commercial potato chips were compared. The instrumental measurement was a puncture test with an Intron Universal Testing Machine, and the parameters used were fracture force, deformation and stiffness. The instrumental color quantification was a computerized video image analysis technique, and the color was expressed as L*a*b* values. Sensory evaluation of texture and color was performed by a sensory panel especially trained in evaluating potato chips. The sensory attributes were "hardness", "chewiness", "crunchiness", and "tenderness" for texture analysis, and "yellow color", "burnt aspect", "sugar colored aspect" and "transparency" for color analysis. The factor analysis of the sensory attributes indicated that texture can be divided into two principal components, one represented by "hardness", "crunchiness" and "chewiness", and the other by "tenderness" alone. The factor analysis of the color can be divided into two principal components, one including "yellow color" and "burnt aspect", and the other "sugar colored aspect" and "transparency". Discriminant analysis showed that "tenderness" and "crunchiness" could predict correctly over 90% of the data. Fracture force correlated well with all of the sensory attributes (R² > 0.76), and L* with the sensory color attributes (R² > 0.79). The "Tenderness" was the individual sensory attribute which had the highest correlation (R²= 0.95) with fracture force.