Texture Evaluation of Ultrafiltered Teleme Cheese

The texture of traditional and ultrafiltered (UF) teleme cheeses was evaluated using instrumental and sensory texture profile analysis. The UF teleme was made from unheated or heat treated (75°C for 5 minutes) UF milk concentrate. Samples were tested after 2 and 4 mo ripening. Instron variables did not discriminate between the three teleme types but sensory attributes, assessed by a panel discriminated the samples. Weak correlations were obtained between sensory and mechanical variables. Redundancy ordination analysis indicated that textural behavior of each type teleme cheese was characterized by different attributes. Sensory springiness or brittleness, lumpiness and fat content characterized the majority of traditional teleme samples whereas adhesiveness, pH, water soluble and noncasein nitrogen characterized the heat-treated UF samples.     

Swiss-type and Swiss–Cheddar hybrid-type cheeses: effects of manufacture on sensory character and relationships between the sensory attributes and volatile compounds and gross compositional constituents

The effects of manufacturing steps, including rate of acidification in the vat, hot room step, curd wash and ripening temperature, on the sensory character of Swiss-type and Swiss–Cheddar hybrid-type cheeses were determined. In addition, relationships were determined between sensory attributes of cheeses and their gross compositional constituents and volatile compounds. Ten assessors described the sensory characteristics using 12 odour, 19 flavour, four appearance and nine texture attributes. Gross compositional constituents were determined using standard methods. Volatile compounds were isolated using a model mouth apparatus that included a mastication device. Statistical methods were used to reduce the original sensory vocabulary to four odour, eight flavour, three appearance and five texture attributes. Results of a principal component analysis on the sensory data showed clear differences in sensory character between cheese types. For example, the Swiss-type with a low rate of acid production in the vat and a hot room step had a more 'nutty' and 'sweet' flavour than the modified Swiss-type with higher acid production and no hot room step. However, the modified Swiss–Cheddar hybrid with a curd wash step, a higher acid production and no hot room step also had a 'nutty' and 'sweet' flavour. Ripening temperature also has an effect on sensory character. Relationships between sensory character and volatile compounds and/or gross compositional constituents were determined by using partial least squares regression. One odour and one flavour attribute were shown to be correlated with subsets of volatile compounds and gross compositional constituents. Four texture attributes were correlated with subsets of gross compositional constituents. The availability of information on the manufacturing process increased the interpretability of the models.     

Instrumental and Expert Assessment of Mahon Cheese Texture

ABSTRACT: To improve Mahon cheese texture assessment, the relationship between instrumental and sensory measurements was sought. For that purpose 30 pieces of Mahon cheese from different batches and 2 different manufacturers were examined. Textural characteristics at different curing times were evaluated by uniaxial compression, puncture, and sensory analysis. Significant linear correlations were found between instrumental and sensory measurements. A logarithmic model (Weber-Fechner) fitted data better than a linear one. Only 1 factor was extracted when considering all the instrumental and sensory variables, thus indicating that both sets of measurements are related to the same phenomenon. The best predictors for Mahon cheese sensory attributes were found to be cheese moisture, deformability modulus, and slope in puncture.     

Lipolysis,proteolysis and sensory properties of ewe’s raw milk cheese (Idiazabal) made with lipase addition

In this paper, we describe the effect of the addition of pregastric lipase on the composition and sensory properties of Idiazabal cheese. Free fatty acids (FFA), partial glycerides, free amino acids (FAA), gross composition and sensory characteristics were determined at different ripening times in cheeses manufactured with three different amounts of commercial animal lipase or with lipase-containing artisanal lamb rennet paste. The addition of lipase increased the content of total FFA, particularly of short-chain FFA, and that of total partial glycerides in cheeses. Unexpectedly, lipase utilization significantly affected total FAA concentration, which decreased in cheeses elaborated with high lipase amount. In general, Val, Glu and Leu were the major FAA, and their concentrations depended, mainly, on ripening time. Lipase addition had significant influence on the sensory characteristics of the cheeses, increasing scores for most of the flavour and odour attributes of the cheese. Principal component analysis (PCA) was done including dry matter, FFA, FAA, partial glycerides and odour and flavour attributes of the cheeses. It indicated that aroma and flavour parameters of Idiazabal cheese and the content of short-chain FFA and diglycerides were highly correlated to first principal component (PC1), while texture parameters, compositional variables and FAA were correlated to the second principal component (PC2).     

Monitoring of sensory attributes used in the quality payment system of Trentingrana cheese

Trentingrana is a Protected Designation of Origin (PDO) hard cheese manufactured in the valleys of Trento province (eastern Italian Alps) by several small cooperative dairies linked in a consortium. Nine months after production, wheels are delivered to a shared facility, ripened up to 18 mo, and assessed by a panel of 8 experts for 7 sensory attributes; namely, external aspect, rind thickness, paste color, texture, odor, taste, and aroma. The evaluation takes place every 2 mo on wheels sampled within each dairy. Based on the results of the assessment, dairies receive a price premium or penalty depending on a quality index, which is the weighted sum of the scores attributed to each sampled wheel. Sensory scores and quality index of 652 wheels representing 11 dairies and 10 yr of production were analyzed using a model that included fixed effects of dairy, year, and season of production, and first-order interactions between them. The coefficients of determination ranged from 0.50 (texture) to 0.66 (aroma). All factors significantly affected the studied traits, with the exception of interactions between dairy and season of production for texture and external aspect, and between year and season of production for odor. Dairy was the most important source of variation for visually assessed traits (external aspect, rind thickness, paste color, and texture) and for quality index, whereas year of production was the most important for flavor attributes (odor, taste, and aroma). The latter traits were always highly correlated among them and with the quality index, whereas correlations among visually assessed attributes, between them and flavor attributes, and between them and the quality index were more erratic. The sensory evaluation performed by the panel of experts has proven to be a useful tool to define the quality index and address the payment system of Trentingrana cheese, but it has some limitations in correctly describing the sensory profile of cheese and identifying specific defects and possible remedies.     

PREDICTION OF SENSORY TEXTURE OF FETA CHEESE MADE FROM ULTRAFILTERED MILK BY UNIAXIAL COMPRESSION AND SHEAR TESTING

The ability to predict sensory texture properties of Feta cheese made from ultrafiltered milk (UF-Feta) from uniaxial compression, small shear deformation measurements (frequency sweep, strain sweep, relaxation) and indices of proteolysis was studied. In principal component analysis (PCA) some of the instrumental variables were highly correlated, e.g. the moduli from uniaxial compression and shear measurements; and strain at fracture from uniaxial compression and indices of proteolysis. PCA of the six sensory attributes determined by a trained panel showed that mainly one type of information was present in the sensory results. Partial Least Squares regression (PLS) of all results revealed that stress at fracture from uniaxial compression was the individual instrumental parameter having the highest correlation with the sensory texture attributes. Of these, the three firmness attributes were best predicted by the instrumental parameters. As the shear measurements were not very useful for prediction of sensory texture properties by themselves, and as the increase in prediction precision by inclusion of these measurements was marginal, it is suggested that either stress at fracture alone, or together with three other parameters from uniaxial compression should be used to describe texture properties of UF-Feta cheese.     

Vane Rheometry for Textural Characterization of Cheddar Cheeses: Correlation with Other Instrumental and Sensory Measurements

The relationship between instrumental (vane method, texture profile analysis (TPA), uniaxial compression) and sensory texture measurements of Cheddar cheeses was investigated. A Haake VT 550 viscotester equipped with a four-bladed vane rotor was used for the vane test. Instrumental TPA was performed with a TA.XT2 Texture Analyser, and compression variables were calculated from TPA data. Vane parameters were significantly correlated with respective variables of compression and TPA (r=0.56-0.91), and sensory tests (r=0.54-0.88). Multivariate analysis indicated that seven sensory attributes of ten commercial Cheddar cheeses were satisfactorily predicted (calibration regression coefficient,R_cal >0.62) by variables of the vane, uniaxial compression and TPA tests. In particular, cheese firmness and cohesiveness evaluated by sensory panel were well described by vane stress and apparent strain. The results validate the vane method as an alternative to the existing cheese testing methods for rapid evaluation of cheese texture.     

Rheological and Sensory Properties of Reduced-Fat Processed Cheeses Containing Lecithin

Reduced fat processed cheeses were prepared with granular or hydrogenated soy lecithin. Trained sensory panelists (n = 11) determined that reduced-fat cheeses containing lecithin were more similar in texture attributes to full-fat control cheeses than reduced fat cheeses without lecithin (P<0.05). Consumer flavor and acceptance scores (n =60) for cheeses with lecithin were not different from control cheeses, but texture acceptance scores for cheeses with lecithin were higher than scores for reduced fat control cheeses (P.0.05). Cheeses containing lecithin were less elastic than reduced fat control cheeses as determined by sensory panels and instrumental percent creep recovery. Lecithin improved processed cheese texture without negatively affecting acceptance.     

Prediction of sensory attributes of European Emmental cheese using near-infrared spectroscopy: A feasibility study

The present work evaluated the ability of near infrared (NIR) spectroscopy in predicting some sensory attributes of 20 Emmental cheeses originating from different European regions. For the purpose of this study four appearance and texture attributes, namely, adhesivity, friability, elasticity and firmness and six olfacto-gustatory attributes namely, aroma intensity, odour intensity, bitterness, saltiness, acidity and sweetness were selected by the sensory panel. Calibration models between sensory properties and NIR spectra were developed using partial least squares (PLS) regression. The squared correlation coefficients (R²) were greater than 0.5 for adhesivity, elasticity, firmness, aroma, bitterness, saltiness, acidity and sweetness. In addition, a good correlation between sensory attributes and NIR spectra was found using canonical correlation analysis (CCA). Therefore, this work demonstrates the feasibility of NIR to predict some sensory attributes since a relatively high correlation between sensory data and NIR spectra was found. However, further research with a large data bases will be needed in order to validate the method.     

DEVELOPMENT OF A SENSORY TEXTURE PROFILE OF COOKED POTATOES BY MULTIVARIATE DATA ANALYSIS

A sensory texture profile of cooked potatoes ( Solanum tuberosum ) was developed through two training periods in 1995 and 1997. Training time necessary to obtain a reliable sensory panel in assessing texture attributes was studied by the use of univariate and multivariate data analysis. The panel was interviewed and introduced to the Texture Profile Method. A list of texture attributes, ranging from non oral terms to terms evaluated after the first bite and the following mastications, was developed resulting in 14 texture attributes, Analysis of variance (ANOVA), discriminant partial least squares regression (DPLSR) and principal component analysis (PCA) was used to reduce the texture profile to 8 reliable sensory attributes covering the geometrical (reflection, mealiness, graininess), mechanical (firmness, hardness, springiness chewiness) and moistness characteristics. These variables explained 89% and 86% of the total variance in 1995 and 1997, respectively. Relevant criteria for studying panel performance are discussed. Training for more than one day did not significantly improve panel performance. Geometrical attributes as well as moistness were found easier to evaluate than the mechanical attributes.     

Free fatty acid composition of regionally-produced Spanish goat cheese and relationship with sensory characteristics

A study was made of free fatty acid composition and sensory characteristics (odour and taste) in regionally-produced Spanish goat cheeses. The most abundant FFAs were oleic, palmitic, stearic, capric and myristic acid which together accounted for roughly 85% of total FFAs. These cheeses generally underwent a lower degree of lipolysis than did other goat cheeses. Panellists judged the cheeses as having considerable odour and flavour intensity. However, both total FFA content and sensory attributes varied considerably among cheeses due, in all likelihood, to differences in ripening time and to production by different manufacturers. Principal component analysis generated three principal components (PC) that accounted for 70% of total variance; the variables that best correlated with them were long-chain and medium-chain free fatty acids (PC1), brine odour, bitterness and goat milk odour (PC2) and short-chain free fatty acids (PC3).     

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.