Texture Profile Panel Research Articles

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 CaSO 4/100 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%).

RELATIONSHIP BETWEEN INSTRUMENTAL AND SENSORY PARAMETERS OF COOKED SWEETPOTATO TEXTURE1

ABSTRACTThis 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.

Physical and Sensory Properties of Sweetpotato Puree Texturized with Cellulose Derivatives

ABSTRACTWe evaluated the physical and sensory characteristics of restructured sweetpotato puree texturized with methylcellulose (MC) or methylhy‐droxypropylcellulose (MHPC). Samples were studied by instrumental texture profile (TPA), dynamic rheometric and sensory analyses, and scanning electron microscopy. Gelation of the gum‐puree mixtures gave maximal values of the storage modulus (G') at 60‐70°C. The TPA curves measured at 60°C for the 0.50%MC or MHPC sample were similar to those of baked sweet potatoes (control). A texture profile panel rated the 60°C samples of the 0.25‐0.50%MC or MHPC product as nearly equal to baked roots for several texture notes. An untrained acceptability panel scored the 0.25%MC and MHPC samples significantly higher in flavor and overall acceptability than baked roots.

Pretreatment Effects on the Texture and Integrity of Aseptically Processed Chicken Meat Particulates

The effect of presoaking and freezing of uncooked spent fowl breast meat prior to aseptic processing on yield, texture, water holding capacity, and volatile profile of meat strips was investigated. Meat strips were submerged for 15 h in a solution of 3.0% salt, .3% sodium polyphosphate, 2% sorbitol, and 2% sucrose, frozen, and heated in a high-temperature, short-time aseptic processor utilizing an aqueous heat exchange medium containing 1.5% salt.The salt and sugar presoak treatment significantly improved the total meat processing yield by approximately 15% over meat strips presoaked in water alone. Furthermore, reductions in Kramer shear values of 36.5%, which agreed with the texture profile panel results, were detected in the strips soaked in salt and sugar. Freezing meat strips prior to heat processing helped to maintain meat integrity throughout aseptic processing. Although textural quality losses due to aseptic processing were minimized by presoaking in salts and sugars, losses in meat moisture content and tenderness were detected throughout 49 days of refrigerated storage. Compared to the water-soaking treatment, lower concentrations of lipid autoxidation products were initially detected in breast strips soaked in the salt and sugar solution. These results indicate that the observed toughening effect, previously detected in aseptically processed chicken meat, can be reduced by presoaking the meat in a salt and sugar solution prior to aseptic processing. Moreover, meat particle integrity can be maintained by aseptic processing of frozen meat.

Effect of Aseptic Processing on the Texture of Chicken Meat

Breast meat containing collagen at high concentrations (spent hen, 20 to 24 mo of age) and low concentrations (broiler, 6 to 7 wk of age) was evaluated for texture following high-temperature, short-time processing at 121, 130, and 145 C in a laboratory scale processing system. Breast meat was evaluated for proximate composition, collagen content, Kramer shear texture, Warner-Bratzler shear texture, and texture profile panel characteristics. Process parameters were adjusted across all processing temperatures to obtain a theoretical 12 log10 population reduction of Clostridium botulinum spores.Aseptic processing resulted in significant moisture losses and toughening of the breast meat, which may be attributed to protein denaturation and myofibrillar shortening. Furthermore, the higher the processing temperature, the tougher and drier the meat and the lower the processing yields. Although the aseptic high-temperature, short-time process extracted and solubilized collagen, the process resulted in a tougher final meat texture. The profile panel identified seven texture characteristics that were significantly affected by aseptic processing. The total energy parameter of the Kramer shear test was significantly correlated to all seven texture characteristics identified by the panel. The results of the present study indicated that both high-temperature, short-time processing conditions and meat type significantly affected the proximate composition and textural characteristics of the finished product.

CHARACTERIZATION OF THE TEXTURAL PROPERTIES OF SPREADABLE PEANUT BASED PRODUCTS 1

Textural characteristics of two peanut butter samples and one peanut paste sample were determined using three instrumental methods and a texture profile panel. In Method A, a penetrometer with a cone‐shaped probe attachment was used. Method B involved the use of a plunger attached to the crosshead of the Instron Universal Testing Machine. Method C was a modified texture profile analysis (TPA). Instrumental measures show that peanut paste was the hardest, exhibited the greatest adhesive force but the least time to break the peanut column, and was the least cohesive. All instrumental methods were acceptable but TPA provided more information than the two other methods in describing texture. The panel rated the paste as firmest, least adhesive, spread least on the tongue, least smooth, most grainy, and most difficult to swallow. Significant correlations were found between several instrumental measures and sensory characteristics.

The effects of castration, preslaughter stress and zeranol implants on beef: Part 1—The texture of loin steaks from bovine males

A total of 144 male crossbred calves were allocated to four castration or implant treatments (unimplanted bulls; unimplanted steers; bulls implanted with zeranol at 100 days of age and reimplanted at intervals of 69, 93, and 56 days thereafter; bulls implanted with zeranol at 168 days of age and reimplanted at intervals of 93 and 56 days thereafter) and two preslaughter shipping treatments (minimum preslaughter stress with cattle shipped and slaughtered within 4 h of leaving the feedlot pen; normal preslaughter stress with cattle mixed, trucked 160 km, and slaughtered up to 24 h after leaving the feedlot pen). These cattle were slaughtered and striploins of these steaks were removed after 6 days of post-mortem aging. Evaluations of these steaks were then conducted using both an experienced laboratory taste panel and a highly trained professional texture profile panel. Results indicated that: (1) the differences that existed in palatability between steaks from unimplanted bulls and steers were primarily due to differences in textural properties directly related to tenderness; (2) increases in preslaughter stress levels were detrimental to the eating quality of both intact males and castrates; (3) zeranol implants had little effect on the textural properties of bull steaks when minimum levels of preslaughter stress were applied; (4) zeranol implants in combination with normal levels of preslaughter stress resulted in steaks which readily broke down to a wide range of particle types many of which were inappropriate and detracted from a well balanced beef texture, thereby more than offsetting the beneficial effects observed on textural properties directly related to tenderness, thus, reducing the texture amplitude; and (5) the influence of the combination of zeranol implants and normal preslaughter stress on textural properties may be manifested through the production of ‘dark cutting’ beef.

LITERATURE ABSTRACTS

LITERATURE ABSTRACTS

Effects of Flake Size on Textural and Cooking Properties of Restructured Beef and Pork Steaks

ABSTRACTFlaked and formed beef and pork steaks were manufactured using eleven different Comitrol cutting heads selected to give a wide range in flake size. Data from texture profile panel, Instron and cooking studies were collected. As flake size increased, visually detected fi‐brousness, first bite hardness, cohesiveness of the chewed mass, number of chews required for swallowing, amount of connective tissue detected by sensory panel and shear force all increased, while uniformity of the chewed mass decreased. Textural properties in beef and pork steaks were affected in a similar manner by flake size. Thickness of the flake particle was as important as width of the flake particle in affecting texture.

Effects of Pre‐rigor Pressurization, Method of Restructuring, and Salt Level on Characteristics of Restructured Beef Steaks

ABSTRACTPre‐rigor pressurized beef muscle was processed either by chunking and forming or flaking and forming and then mixed with either 0.00, 0.25 or 0.50% NaCl prior to the manufacture of restructured steaks. To compare the effects of pre‐rigor pressurization, a post‐rigor, nonpressurized, flaked and formed formulation (containing 0.50% NaCl) was also processed. Data from texture profile panel, Instron and cooking studies were collected. Steaks from pressurized muscle were similar in most characteristics to steaks processed from nonpressurized muscle. Chunking and forming produced a more fibrous, harder and cohesive steak with greater detectable connective tissue than flaking and forming. If pre‐rigor pressurized beef is employed in the manufacture of restructured steaks, acceptable texture properties appear obtainable without the use of NaCl.

DEVELOPMENT OF A TEXTURE PROFILE PANEL FOR EVALUATING RESTRUCTURED BEEF STEAKS VARYING IN MEAT PARTICLE SIZE

ABSTRACTA texture profile panel was developed for measuring textural properties of restructured beef steaks differing in meat particle size. For steaks of different particle sizes, considerable differences existed in the type of sample breakdown and shape of chewed pieces after just two chews. Panelists also found restructured steaks made from large meat particle sizes to be visually more distorted and to contain more gristle than steaks made from small meat particle sizes. Several characteristics (chunkiness after two chews, coarseness of chewed mass at 15 chews) were dropped from the profile over time, while several characteristics (type of sample breakdown and shape of chewed pieces at two chews, size of chewed pieces at 10 chews) not used initially, were added. The texture profile panel approach appears suitable for discerning the textural differences in restructured steaks that can arise from using different meat particle sizes during processing.

DEVELOPMENT AND APPLICATION OF TEXTURE REFERENCE SCALES

ABSTRACTStandard texture rating scales of hardness, adhesiveness, fracturability, cohesiveness, and denseness were modified during the training of a Texture Profile panel. New reference materials were selected for each scale to better illustrate the texture characteristics and intensities and to account for previously recommended food products no longer available. In addition, new reference scales for wetness, adhesiveness to lips, roughness, self‐adhesiveness, springiness, cohesiveness of mass, moisture absorption, adhesiveness to teeth, and manual adhesiveness were developed. The application of new texture reference scales reduced the variability among panelists and provided consistent judgments in texture evaluations. Expanded and improved definitions and evaluation procedures for texture attributes are presented. Also, special considerations for the use of reference scales in texture evaluations are discussed.

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.

The Effects of Cooking Methods on the Chemical, Physical, and Sensory Properties of Hard-Cooked Eggs

The effects of three cooking methods on the chemical, physical, and sensory properties of hard-cooked eggs were investigated. Freshly laid eggs were stored at 23 C for 48 hr and then hard cooked by one of three methods: steaming (S) for 20min; severe boiling (B) procedure (water brought to a full boil and maintained for 20 min); and a standard hard cook (SHC) procedure (water brought to a slow boil followed by 20 min simmer). The eggs were peeled, separated into yolk and white, and evaluated for pH, moisture, color, texture by an Instron Texturometer and texture profile panel, and flavor by a trained profile panel, experienced panel, and headspace gas chromatography.Eggs subjected to the B procedure had the highest endpoint temperature (98.7 C) followed by SHC (95.6 C) and S eggs (89.4 C). The cooking rate for S eggs was approximately three times faster than SHC or B eggs. Both egg white moisture and pH values were significantly influenced by cooking method. Severely boiled egg whites had significantly lower pH moisture values than SHC or S eggs. Small but perceivable texture differences due to cooking were found by the texture profile panel in addition to significant egg white and yolk texture differences as measured using the Instron. Severely boiled egg whites had the firmest texture followed by SHC and S egg whites. All treatments had a typical egg aroma and flavor, yet several detectable sensory differences were found between the treatments. There were little qualitative differences in headspace volatiles between treatments, although significant quantitative differences were noted between treatments for eggs yolks and whites.

Improved Utilization of Dairy Proteins: Coextrusion of Casein and Wheat Flour

Coextrudates were produced from mixtures of rennet casein and wheat flour by thermal extrusion using a Creusot-Loire BC 45 twin screw extruder. The influence of casein and moisture in the feed material and processing variables was investigated by response surface methodology. Dependent variables included expansion, Warner-Bratzler shear values, and responses of a trained texture profile panel. All product characteristics investigated, with the exception of flavor, could be predicted from independent variables of the multiple regression equations. Addition of rennet casein did not alter the normally bland flavor of extruded starches. Casein at 10 to 30% of the total solids did not influence significantly any of the extrudate characteristics, which were governed primarily by moisture content. The two major physicochemical reactions thought to be taking place during the extrusion process were starch gelatinization and protein texturization. Although it was not possible to determine directly the degree of each process, an examination of the role of the independent variables, extrudate microstructure and sensory breakdown, suggested that starch gelatinization plays a dominant role in dictating product characteristics. Casein may be used in a protein-fortified, extruded wheat flour-based product at the contents studied without altering the characteristic bland flavor or crisp texture of extruded wheat flour. However, a wide variety of textures may be obtained by altering moisture content and process variables.

EFFECTS OF SOY PARTICLE SIZE AND COLOR ON THE SENSORY PROPERTIES OF GROUND BEEF PATTIES

ABSTRACTA study was conducted to assess the effect of both size and color of textured soy protein particles on the visual and textural properties of extended (20% replacement) ground beef patties. A trained texture profile panel judged the hardness, cohesiveness, chewiness, moistness, and oiliness of nine different samples. In addition, judgments of the visual attributes of darkness, size of particles, and density of particles were made. Significant effects of soy ingredient were found for all judged attributes. It was concluded that soy ingredients having particle sizes smaller than the diameter of the openings of the grind plate used to process the meat/soy mixture produced the greatest change in the texture of the ground beef patties, because these particles passed through the grind plate unscathed, producing an easily discernable matrix of large meat particles and small soy particles. It was also concluded that carmel‐colored soy ingredients produced less lightening of the cooked samples than uncolored soy ingredients.

EFFECTS OF CURING ON THE FLAVOR AND TEXTURE OF BAKED SWEET POTATOES

ABSTRACTThe objective of this investigation was to determine the quality advantages, if any, of curing whole sweet potatoes prior to marketing during the harvest season. Freshly harvested sweet potatoes were washed, graded, and boxed for shipment and then cured at 30°C and 90% RH for 0, 4 or 7 days prior to shipping. Preparations were timed so that all treatments could be shipped on the same pallet. During 2 yr a total of 8 shipments were made to northern cities (500–600 miles) by truck. Sample potatoes were evaluated by a trained flavor and texture profile panel and by analytical methods. Results indicated that curing for either 4 or 7 days developed a product that was superior in both flavor and texture. Viscosity of purees was lower for cured than for uncured sweet potatoes. Curing slightly reduced ascorbic acid content.

RELATIONSHIPS BETWEEN SENSORY PROFILE PARAMETERS AND FUNDAMENTAL MECHANICAL PARAMETERS FOR RAW POTATOES, MELONS AND APPLES1

ABSTRACTRatings by a trained texture profile panel were compared with the mechanical properties (shear stress at structural failure, normal strain to failure and apparent elastic modulus) determined in torsion and uniaxial compression for apple, melon and Irish potato flesh.Results indicated that, for melon and potato flesh, the structural failure stress levels were more frequent and significant indicators of sensory note magnitudes than the modulus values. The reverse was true for apple flesh. Of the sensory notes, moisture release correlated most consistently with the mechanical properties.Melon flesh failed in uniaxial compression by widespread crushing rather than along a failure plane. Correlation of the mechanical failure stress with the first bite sensory notes dominated in this case. The structural failure of potato flesh in uniaxial compression generally occurred along a single plane of maximum shear stress which left two essentially intact pieces of specimen. First bite and mastication sensory notes for potato flesh correlated with shear stress at failure about equally well. The structural failure of apple tissue in uniaxial compression was caused by general compression failure with many fragmented pieces of tissue remaining. Apple flesh produced the most frequent correlations of both first bite and mastication texture notes with the instrumental modulus and failure values.

SENSORY AND INSTRUMENTAL EVALUATION OF MATERIAL PROPERTIES OF FISH GELS

ABSTRACTOver 100 heat coagulated fish pastes with widely varying sensory texture properties were prepared and evaluated. Variations in species, geographical source of fish, cooking procedure and other variables provided a wide range in material properties. Small strain material properties were evaluated instrumentally using uniaxial sinusoidally varying force at a frequency of 2 Hz and recording stress, strain and the phase angle between the two. A multiblade shear/compression cell mounted in an Instron Universal Testing machine was used to measure the shear/compression failure force. The products were also evaluated by a trained texture profile panel using 13 character notes. The maximum shear/compression cell force was a good predictor of sensory springiness, firmness, cohesiveness, and gel strength for the heat coagulated fish pastes tested. These four sensory notes were good predictors of each other so that a panel rating of any one could be used to rate the other three with numerical ratings for all four being very similar. Gumminess and adhesiveness ratings were also very similar and varied inversely with the shear/compression cell force and with the above four panel notes. These two notes were directly proportional to the loss tangent of the product, which correlated with them about as well as did the shearlcompression cell force. The relationships developed between panel notes support the modification of the General Foods Texture profile suggested by Sherman (1969). Statistically developed equations giving sensory texture notes as functions of instrumental material properties are given and their implications discussed.

TEXTURE EVALUATION OF FRANKFURTERS BY DYNAMIC TESTING*

Abstract. A direct sinusoidal force was applied at six frequencies to four brands of commercial frankfurter samples and the magnitude of deformation was sensed to determine the complex dynamic modulus and energy loss.Instrumental values were individually correlated with 23 characteristics identified by a trained texture profile panel as the texture profile for frankfurters. The results indicated that the dynamic testing method, especially the percent energy loss, provided a highly significant means of determining differences for eight of the frankfurter texture characteristics. Initial hardness, cohesiveness, elasticity, hardness of the cross‐section, ease of swallowing, moisture release, coarseness and skin texture identified by the profile panel had highly significant coefficients of correlation with the energy loss, ranging from—0.612 to—0.984 at 80 Hz frequency. The results indicated that the percent energy loss, as determined by the dynamic modulus technique, described a substantial amount of the total texture profile, probably as complete as any single instrumental method reported to‐date.