TRAINING A SENSORY TEXTURE PROFILE PANEL AND DEVELOPMENT OF STANDARD RATING SCALES IN COLOMBIA

Two texture profile panels and two panel leaders were trained in the General Foods Sensory Texture Profiling Technique in Colombia using Colombian foods as reference points on the standard rating scales. The texture profiling technique adapted to Colombian conditions very successfully. The trained texture profile panel is now playing an essential part in the development of protein-fortified staple foods of acceptable textural quality for Colombia.     

GUIDELINES TO TRAINING A TEXTURE PROFILE PANEL

Abstract. A texture profile panel is a valuable tool for describing and quantifying textural characteristics of food products when the panel is carefully selected, trained and maintained. Guidelines to accomplishing this goal are presented.     

TEXTURE PROFILE OF IRRADIATED MANGOES AND PEACHES*

The mechanical characteristics of the texture profile of Kent mango and Loring, Redskin and Suwannee peach fruits were determined. Irradiation at 150 or 300 krad as well as storage at 20°C decreased all of the measured parameters with the exception of mango cohesiveness which increased during storage. Hardness, gumminess and chewiness of irradiated Loring peaches reflected the sensory hardness ratings to a greater extent than did the puncture or shear forces.     

THE TEXTURE PROFILE: ITS FOUNDATIONS AND OUTLOOK

The origins of the Texture Profile are traced from antecedent developments both in food science and in psychology. A variety of theoretical underpinnings of the Profile are considered: (1) selection of texture variables, (2) problem of standards in texture, (3) appropriate rules for measuring psychological magnitudes, (4) appropriate sensory-instrumental functions, (5) combination rules whereby the observer combines different texture attributes and relates each attribute to a linear combination of others, and (6) interaction between users of the Texture Profile. In each of the above, the underlying assumptions are discussed and possible modifications are suggested in order to generalize the profile procedure.     

TEXTURE PROFILE ANALYSIS AND COMPOSITION OF A MINCED CATFISH PRODUCT1

Texture Profile Analysis of minced catfish products indicated that minced proteins from the belly flap meat have excellent functional properties to form gels or restructured products. Belly flap meat is considered a low‐value trimming, with about 16.9% protein and 11.2% total lipid. Washing of minced catfish trimmings increased the moisture content from 71.5% to 77.9% while reducing mechanical hardness (19.1 N to 11.9 N), chewiness index (14.2 N to 8.83 N) and shear energy (0.82 J to 0.51 J). No significant changes were found in cohesiveness, resilience, and springiness of the minced fish after washing or the addition of 3.3% (v/w) of 4% starch solution. Washing of minced fish reduced the total lipid content from 9.82% to 4.39%. Overall, washed minced channel catfish belly flap meat had functional characteristics that enabled its proteins to be formed and restructured. Products made from minced catfish had acceptable textural characteristics.     

FORCE-DEFORMATION AND TEXTURE PROFILE BEHAVIOUR OF AQUEOUS SUGAR GLASSES

Aqueous sugar glasses, simulating the structure of commercial boiled sweets, were investigated in their temperature transition range by force deformation and texture profile tests using the Instron Universal Testing Machine. Cylindrically cast and thermally equilibrated aqueous glucose-sucrose model systems having 2—2.3% moisture (w/w) and containing glucose to sucrose ratios (%w/w) of 100/0, 70/30, 55/45 and 35/65 were used. Force-deformation tests revealed that the Young's modulus was independent of the glucose-sucrose ratio and decreased drastically with temperature from 820 MN/m² at 3°C to 30MJV/m² at 30°C. Texture profile tests were carried out on a model system (35/65 glucose-sucrose blend) and on a commercial hard boiled sweet. Experimental profiles for both systems were largely similar and permitted evaluation of the textural parameters of hardness and cohesiveness. Composite force-strain or force-penetration curves were constructed from series profile tests on the same sample and demonstrated that (a) high values of hardness were found with a flat probe and low temperatures; (b) low values of hardness were found with cone and wedge probes and high temperatures. Cohesiveness generally decreased as the initial applied strain increased, because higher strains resulted in greater sample fracture and/or plastic flow. On the other hand, temperature and probe type had little effect on cohesiveness. The difficulties experienced in bridging the gap between the empirical and the fundamental approaches to texture profiling of food are discussed.     

BI-CYCLICAL INSTRUMENT FOR ASSESSING TEXTURE PROFILE PARAMETERS AND ITS RELATIONSHIP TO SENSORY EVALUATION OF TEXTURE

The most popular instrumental imitative test is the Texture Profile Analysis (T.P.A.). It was originated in the General Foods Laboratories (Szczesniak et al. 1963) and adapted to the Instron by Bourne (1978). T.P.A. involves a double compression test that uses flat plates attached to an Instron Universal Testing Machine (I.U.T.M.). Several instrumental parameters can be extracted from the force/deformation curve generated by the test (e.g. hardness, cohesiveness, springiness, and chewiness). Recently developed in our laboratory, the Bi-cyclical Instrument for Texture Evaluation (B.I.T.E. master) uses the I.U.T.M. to generate its motion and features a set of artificial dentures as well as a tri-dimensional movement simulating a chewing motion. Five parameters were extracted from the force/deformation curve to evaluate their potential use for the prediction of cohesiveness.     

SENSORY TEXTURE PROFILE OF AFRICAN FOODS MADE FROM YAM AND CASSAVA

The textural characteristics of African foods made from yam and cassava were characterized by the sensory profile technique. Products with identical processing techniques reconstituted to the same moisture content showed similar characteristics of firmness, adhesiveness and ease of working to a spherical mass. The important attributes of smoothness, springiness or bounciness, and ease of swallowing without mouth coating were common to all the products and are good measures of their overall acceptability. This method is simple and provides a method of quality control that could be used by industrial manufacturers of these products.     

GENERAL MICROBIAL PROFILE OF LOW-FAT FRANKFURTERS FORMULATED WITH SODIUM LACTATE AND A TEXTURE MODIFIER1

Frankfurters formulated with starch-isolated soy protein (starch-ISP) alone, or with starch-ISP and sodium lactate were compared with controls for purge and microbial quality during storage. No significant difference was detected in purge or in initial moisture content between frankfurters containing the additives. However, there was a significant difference between these samples and controls, with the former retaining more water. Samples containing lactate had significantly lower numbers of lactic acid bacteria than samples containing starch-ISP or controls. All samples showed an increase during storage followed by a decrease, but frankfurters containing lactate decreased 7 days earlier. There was significant inhibition of psychrotrophs in samples containing the additives, with controls showing 10⁴ cells/g within 14 days compared with no counts in the treated samples. Frankfurters containing starch-ISP eventually showed growth after 42 days, while samples containing lactate showed no counts at any time during storage.     

MODIFICATIONS AND APPLICATIONS TO FOODS OF THE GENERAL FOODS SENSORY TEXTURE PROFILE TECHNIQUE

The primary attributes of the General Foods sensory texture profile technique are standardization, reproducibility, and ease of correlation with instrumental measurements. Since the original publication in 1963, the method has undergone modifications and refinements such as: addition of an initial stage for evaluation of surface properties, evaluation of certain mechanical characteristics of elasticity and cohesiveness on specific products, and development of texture profile techniques and terminology for the evaluation of semi-solids. Application of this expanded texture profile method is demonstrated using foods such as vanilla cookies, frankfurters, and whipped toppings.     

NEW PARAMETERS FOR INSTRUMENTAL TEXTURE PROFILE ANALYSIS: INSTANTANEOUS AND RETARDED RECOVERABLE SPRINGINESS

Cylindrical samples of gelatin, K-carrageenan/locust bean gum and gellan gum gels were subjected to two successive cycles of compression at three predetermined deformation levels corresponding to 25, 50 and 75% of their respective degrees of compression at failure. Values of "recoverable instantaneous springiness" (S_ins) and "recoverable retarded springiness" (S_ret) were measured. Values of S_ins and S_ret for the gelatin samples were similar and close to 1, indicating a very fast and almost complete recovery of their initial height. By contrast, for K-carrageenan/locust bean gum and gellan gels the values of S_ins and S_ret were quite different, indicating that recovery was retarded. These parameters seem to be a good index of the relative magnitude of elastic and viscous components of foods. This was confirmed by relaxation tests.     

INSTRUMENTAL MULTIPLE TEXTURE PROFILE ANALYSIS OF COOKED GROUND BEEF PATTIES AND SMOKED BEEF

An instrumental texture profile for cooked hamburger patties was obtained by repeated tests on the same samples in the wire extrusion cell of the Ottawa Texture Measuring System. The correlation between sensory and instrumental texture profile parameters was increased when two or more instrument test cycles were applied to each sample in the same test cell. Tests with smoked beef and hamburger patties showed that the change in textural characteristics with repeated cycles depended on the texture of the food.     

SENSORY TEXTURE PROFILE, GRAIN PHYSICO-CHEMICAL CHARACTERISTICS AND INSTRUMENTAL MEASUREMENTS OF COOKED RICE

Three samples of raw-milled rice, and 4 differently parboiled rices were used to study and to relate sensory perception to instrumental measurements. Variance analysis showed that some physico-chemical characteristics indicated great differences among rice samples: thickness of cooked grain, length/width ratio, water uptake, elastic recovery, white core rate and amylose and protein contents. The most discerning sensory attributes were: elasticity, stickiness, pastiness, mealiness, length of grain, firmness, crunchiness, time in mouth, brittle texture and juiciness. The correlation circle of the principal component analysis (PCA) showed high correlation between some sensory characteristics and instrumental measurements. Melting texture, surface moistness, juiciness, were positively correlated with water uptake (r = 0.70, 0.61, 0.71). Granular texture, crunchiness, brittleness and mealiness were significantly affected by white core presence (r = 0.81, 0.74, 0.86, 0.83). Elasticity was dependent upon elastic recovery and firmness measured by the Viscoelastograph, but not linearly. Length of cooked grain was correlated with the length/width ratio of raw grain (r = 0.83). Pastiness, compactness, stickiness were slightly influenced by the thickness of raw grain (r = 0.81, 0.67, 0.72). To a weaker extent, the sensory firmness was associated with the firmness measured by extrusion force using an Ottawa cell (r = 0.58). PCA showed greatdifferences in texture between rices. Two of the parboiled rices were very elastic, another was firm, granular, crunchy and mealy. The remaining two, cooked longer, were moister and more melting. Among the 3 samples of raw-milled rices, differences in grain length feeling and melting-granular-brittle characteristics. were distinguished.