TASTE GROUP THRESHOLDS AND SENSORY EVALUATION OF SPANISH WINE VINEGARS

Wine vinegar is a product obtained from wine acidification which contains at least 5% by wt. of acetic acid, in general without any additives or colorings.
Aspects studied in this work include: the determination of the taste group thresholds (geometric mean of the individual best-estimate thresholds "BET") of two different acids (citric and acetic acids) in aqueous solution and spanish vinegars produced from table and sherry wines. The results obtained suggest that wine vinegar can be considered something more than just an acidulant agent.
In order to evaluate differences among wine vinegars, discriminant tests for twenty-five spanish vinegars (sherry, table and flavored vinegars) were applied. Six of the twelve attributes freely chosen by assessors allowed grouping of the spanish wine vinegars according to their sensory aspects.     

SENSORY EVALUATION OF IRRADIATED BEEF AND BACON

Vacuum-packed beef and bacon were treated with gamma- radiation (1–10 KGy) from CO⁶⁰ and stored for 3 months at + 4°C. The samples were evaluated by a trained sensory laboratory panel, directly after irradiation, and after 3 months. Samples given 1.0 KGy and higher doses were found to be significant different from nonirradiated samples at both times of testing. A higher intensity of off-taste, rancidity, metallic taste and sweetness, and a lower intensity of juiciness and color saturation were found in all the irradiated samples. Off-taste and rancidity were found to increase with increasing doses, and were best explained when analyzed by Principal Component Analysis (PCA).     

SENSORY EVALUATION OF MANGO DRINKS USING FUZZY LOGIC

Three brands of ready to serve mango drinks namely 'Frooti', 'Real'and 'Slice'that are available in the market were used for sensory evaluation along with the vacuum dried reconstituted mango powder drink. Mango powder was produced from mango pulp of 'Totapuri'variety with addition of Maltodextrin, Glycerol monostearate and Tri calcium phosphate at rate of 0.62, 0.015 and 0.015 kg per kg dry mango solid, respectively. These ingredients were added for getting a nonsticky free flowing powder. The pulp along with the ingredients was dried in a vacuum drier at 70 ± 2C and 710–750 mm Hg vacuum. Fuzzy logic analysis was used for finding out the best of the three market mango drinks. BrimA index (a criterion for acceptance of fruit juice) and total solid (kg per kg drink) of the reconstituted mango drink was adjusted based on the BrimA index and total solid values of the best market drink. The reconstituted mango drink satisfied the quality criteria set for 'mouth feel'but not the color, smell and taste.     

SENSORY EVALUATION METHODS FOR TACTILE PROPERTIES OF FABRICS

Sensory evaluation of tactile properties of fabrics is a subject many researchers have studied for years and which still has importance and is also open to improvements. Particularly for suitings, the sensory evaluation of fabric handle or of other tactile properties has a greater importance. This article explains sensory evaluation techniques for stiffness, thickness and smoothness, which are the components of fabric handle of suitings. These sensory techniques are introduced by the authors and studied in 100% worsted wool suitings. The concordances of sensory test results are investigated by Kendall's concordance test, and correlation analyses are carried out to examine the relations between sensory results.     

SENSORY AND INSTRUMENTAL EVALUATION OF STRAWBERRY YOGURT COLOR

Eleven samples of strawberry yogurt prepared with different red color concentrations using Ponceau 4R (E-124) were evaluated by instrumental and sensory methods. Color intensity evaluation was carried out by a panel of eight assessors specifically trained to measure strawberry color in yogurt. Color acceptability was measured with 120 regular and frequent consumers of yogurt. Color was measured with a Minolta Chroma Meter CR-200b, obtaining parameters L*, a* and b*. Principal component analysis was performed on the instrumental variables. Regression models between the instrumental first principal component, red color concentration, sensory intensity, and acceptability allowed determining quality control limits for red color attribute. These limits may be controlled by selecting either instrumental or sensory methods, being the latter easy to implement and providing dependable results.     

EVALUATION OF WINE QUALITY USING A SMALL-PANEL HEDONIC SCALING METHOD

A hedonic scoring method for evaluating wines with a small panel was examined for reliability, effects of training level and agreement with a traditional 20-point scoring technique. The method was found to differentiate among qualities of 14 domestic Sauvignon Blanc wines with good reliability. Four panels were tested, three with a high degree of experience in wine judging and a fourth consisting of fine wine consumers with no special training. The three experienced panels agreed well about the wines' quality scores. Mean panel scores were less highly correlated (although still positive) with the untrained panel, which showed higher variability and lower reliability. Mean scores from the hedonic method were correlated at r =+0.94 with mean scores from a 20-point quality judging procedure. The small panel hedonic method is suitable for generating quality scores for consumer guidance in large scale wine surveys, as are commonly found in popular wine periodicals.     

COMPARISON OF SIMPLIFIED METHODS FOR EVALUATION OF SENSORY THRESHOLDS OF ADDED SUBSTANCES

Results obtained in the determination of sensory thresholds with three different simplified methods were compared. The methods were: a modification of the ascending method of limits (1), one based on the method of the constant stimuli (2), and one based on the use of scales (3). The study was carried out on two sensorially simple systems, sucrose and aspartame aqueous solutions. The thresholds values for sucrose obtained by method 1 (1.41 g/L) and by method 2 (1.60 g/L) were similar and within the range obtained by method 3 (0.6–1.6 g/L). For aspartame the values obtained with methods 1 and 2 were also similar (0.004 and 0.005 g/L, respectively), but they were below the minimum value of the corresponding range (0.008–0.016 g/L) calculated with method 3. These results suggest that the sensory methods provoked less variability in thresholds values than other noncontrolled factors. The limitations and advantages of each method are discussed considering: experimental work, precision of results and practical validity.     

EVALUATION OF WINE COMPETITION JUDGE PERFORMANCE USING PRINCIPAL COMPONENT SIMILARITY ANALYSIS

Principal component similarity (PCS) analysis was used to evaluate judge performance from a wine competition. Data were analyzed for five international judges and seven wine makers, for 42 white, 30 red and 25 specialty wines, using a 20-point quality scoring system. Principal similarity plots were used to group judges according to judging 'style' and to identify outliers, for each wine category. Judge groupings were consistent when three different references were used; however, the most interpretable PCS plot was obtained when the overall mean-judge-score was used as the reference. Results from PCS were compared to principal component analysis (PCA). PCS analysis allowed the information from all significant principal components to be graphically represented in two dimensions and was more successful in classifying judges than plots based on the first three principal components. The technique of PCS is an important complement to existing methodologies, and can provide wine competition coordinators with an objective technique for judge evaluation and selection.     

WHEELCHAIR-MODIFIED SENSORY BOOTHS DO NOT INFLUENCE EVALUATION OF CHOCOLATE PUDDING

The objective of this study was to demonstrate that the dimensions of a sensory booth modified to comply with the Americans with Disabilities Act of 1990 (ADA) guidelines have no impact on consumer evaluations of chocolate pudding. One set of booths each were constructed per ASTM and ADA guidelines. Control pudding was prepared according to package directions with 2% fat milk; other treatments were modified with red food coloring, sugar or nonfat milk. Twenty-four panelists evaluated instant chocolate puddings in directional difference and hedonic tests in each type of booth. Booth type and test date had no effect on judgments.     

USE OF SENSORY EVALUATION FOR MEASURING DEODORIZING EFFECTS OF AN AIR CONDITIONER

The application of sensory methodology for measuring deodorizing effect of an air conditioner equipped with electric plasma was introduced. Deodorizing effect was measured using chemical and sensory methods at different time (0, 30 and 60 min) and mode (control, blowing and cooling) of an air conditioner. Smoke from a roll of cigarette in a closed room was used as a source of odor and the concentrations of acetic acid and ammonia were measured as odorous chemical components. As one of the sensory methods triangle test was used and as a first step to obtain deodorizing effects by triangle test, the threshold of each panelist was obtained as the log dilution ratio of odor concentration at which the difference from odorless air was detected. The odor concentration at each time and mode was calculated using the threshold of the panel and the deodorizing effect was obtained on the basis of the odor concentration. In addition to a triangle test, scaling methods such as category scaling or magnitude estimation were used to measure deodorizing effect of an air conditioner. Deodorizing effects by scaling methods were calculated based on odor intensity with time at each mode. The regression analysis was done between the efficacy of deodorizing effect by sensory test and those by acetic acid and ammonia, the R² values of the regression equations for triangle test, category scale, and magnitude estimation were 0.84, 0.72 and 0.69, respectively. Deodorizing effect by triangle test explained the decrease of acetic acid and ammonia better than those by category scaling or magnitude estimation while high cost and time consuming labor involved in triangle tests reduced the merit. The results of this study demonstrated that various sensory methods could be used to measure deodorizing effect of air conditioners and further researches on fast and reliable methods are needed to establish the official procedures.     

SENSORY EVALUATION BASED ON VERBAL JUDGMENTS

Studies of the repeatability and the homogeneity of expert panel scores in sensory profiling show that lasting and reliable evaluations of food products are difficult to obtain: strong inter- and intra-individual differences are commonly observed. Our hypothesis is that this variability is due to quantification methods that consist of asking panelists to furnish quantitative values (by attributing a numerical point to perceived intensity) and that using natural language in the form of verbal judgements in a hierarchical tree would allow improving the reliability of sensory evaluations. This hypothesis was tested by comparing a numerical value scale and a specific hierarchical semantic scale that subjects devised themselves prior to the experiment. The products (chocolate dessert creams) were evaluated using each of the two methods. The results show that the capacity to discriminate between products is better when verbal judgements are used. We discuss the advantages of hierarchical semantic scales for sensory profiling.     

A NON-PARAMETRIC RANKING METHOD FOR THE STATISTICAL EVALUATION OF SENSORY DATA

Sensory data are rarely normally distributed and should, therefore,be statistically analyzed by non-parametric techniques. A computerprogram was devised for generating tabular data by which upto twenty samples can be compared following evaluation by asmany as seventy-five panelists. When samples are initially ranked,rank sums for each sample may be compared to appropriate entriesin the tables directly. If scalar values are assigned by panelists,the technique is still useful, but the values must first beconverted to ranks. ^*Scientific Article No. A1857, Contribution No. 4767 of theMaryland Agricultural Experiment Station (Food Science Program).     

SELECTION OF AN ASTRINGENCY REFERENCE STANDARD FOR THE SENSORY EVALUATION OF BLACK TEA

Astringent and bitter sensations are characteristic sensory qualities of black tea. Three different classes of potential astringent reference standards (two concentrations each of alum and tannic acid and three fruit juices) were evaluated in this study. The perceived astringency, bitterness and sourness of each were profiled using computerized time-intensity and compared with the astringent intensity of a standardized brew of black tea. The differences in temporal profiles of potential reference standards across taste attributes were evident and intensity ratings were found to be dependent upon the stimulus and its concentration. Both concentrations of tannic acid were evaluated as the highest in perceived bitterness. For the juices, a strong sour taste was perceived in addition to astringency. It was concluded that the best reference standard for the astringency of black tea is a solution of 0.7 g/L alum as it is low in perceived bitterness and sourness.