THE STATE OF DATA MANAGEMENT IN SENSORY EVALUATION: RESULTS FROM A WEB-BASED SURVEY

Sensory evaluation departments (SEDs) in most companies underutilize the expertise of the internal information technology departments (ITDs). This research reports on the state of sensory evaluation data management practices (SEDMP) and the level of interaction with the ITD. An Internet‐based survey was distributed to sensory evaluation professionals (n = 378) and 21.4% responded. About half (50.6%) of the respondents were satisfied with SEDMP while 40.7% were not. Inadequate data storage systems and the lack of resources negatively influenced their satisfaction with SEDMP, while interaction with the ITD had a positive effect. Excel, MS Access and Oracle were used by 67.9%, 38.2% and 2.4% of the respondents, respectively. Most sensory professionals (86.4%) reported not having training in data management. Although 48.2% of the SEDs had the ability to develop relational databases, this skill was not reflected in how data were being managed.     

INSTRUMENTAL AND SENSORY EVALUATION OF TEXTURAL ATTRIBUTES IN CHEESE ANALOGS: A CORRELATION STUDY

The objective of this study was to investigate the usefulness of an array of statistical techniques to describe relationships between instrumental data and non‐oral sensory texture profiling scores by using a range of model processed cheese analogs as example. Pairwise correlation, used as an exploratory tool, showed no significant correlation for flexibility and greasiness with any individual instrumental parameter. Stepwise regression, principal component regression and partial least squares regression were used to generate models for firmness, stickiness and curdiness of the analogs studied. No models could be generated for flexibility and greasiness, and models for rubberiness had poor quality of fit compared with the other sensory attributes. In general, firmness, stickiness and curdiness were satisfactorily modeled by using chemical data and small deformation rheological parameters. Compression data (large deformation), often used in correlation studies regarding the texture of cheese, did not necessarily lead to better correlation results in comparison with other instrumental parameters used in this research.     

DIFFERENCE TASTE THRESHOLDS FOR SUCROSE IN WATER AND IN ORANGE JUICE: AN INTERLABORATORY STUDY

Difference taste thresholds, expressed as jnd values or Weberratios, were determined for sucrose in water and in orange juiceat laboratories in Sweden, U.S.A., Poland and Switzerland usinga method of constant stimuli. The following total arithmeticmean values of all 172 individual jnd values were obtained:0.266 and 0.400% sucrose at 2 and 5% sucrose in water, respectively;0.977 and 1.19% sucrose at 1.5 and 3.75% sucrose in orange juice,respectively. The frequency distributions of the individualvalues were asymetrical and showed a large variation among subjects.The results of some additional experiments at 2 and 5% sucrosein orange juice, performed only by the Polish laboratory, arereported also. Significance analyses performed according to one parametricmethod (t-test), using pooled data of groups of subjects, andone non-parametric method (Mann-Whitney's U-test), using individualthreshold values, gave the same conclusion in practically allcases. The data indicated that females had slightly lower average discriminationthresholds than males. There was a significant degree of correlationbetween subjects' discriminatory ability at different concentrationsof sucrose in each of the two media. Few significant differences between the laboratories were foundfor sucrose in water, whereas for sucrose in orange juice thefollowing rank order, from lowest to highest average jnd value,among the laboratories was obtained for both concentrationstested: Poland < U.S.A. < Sweden = Switzerland. Some speculationswere advanced as partial explanation for the differences amongthe laboratories. ^*Formerly Johansson     

SUCROSE INVERSION BY BAKERS' YEAST AS A FUNCTION OF TEMPERATURE

Inversion of sucrose by bakers'' yeast follows the same course as inversion catalyzed by yeast invertase. Rate of inversion increases exponentially with temperature; the temperature characteristic in the Arrhenius equation is 10,700 below 13–17°C., and 8,300 above that temperature. Temperature inactivation occurs above 40°C. The effects of temperature upon rate of inversion were the same using Fleischmann''s yeast cake, the same yeast killed with toluene, and a pure strain (G. M. No. 21062) of bakers'' yeast. The last differed from the other two only in the fact that its critical temperature was 13°C. as compared with 17°C. for the others. The catalytic inversion is associated with enzyme activity inside the cell, not in the medium, and is independent of any vital processes inside the cell such as respiration and fermentation. Since invertase activity is the same inside the cell as it is after extraction, it appears possible to relate the temperature characteristics for physiological processes to the catalytic chemical systems which determine their rate. At least two enzymes are capable of inverting sucrose in the yeast cell. The familiar yeast invertase (µ = 10,700) is active below 13–17°C. while a second enzyme (M = 8,300) plays the dominant role above that temperature.     

甜叶菊中Stevioside的测定

在硅胶G薄层板上用氯仿:甲醇:水(38:12:2)分离出Stevioside。用蒽酮—硫酸试剂显色,然后用上海72型—分光光度计在620nm波长比色,测出甜叶菊中Stevioside的含量。本法回收率为96.50±0.539％。     

DETERMINATION OF GUSTATORY SUCROSE THRESHOLD IN WATER BY USE OF A LINEAR SUCROSE GRADIENT

A novel experimental method was developed which allows the determination of the threshold concentration of sucrose by use of a linear sucrose gradient in water. With this method a continuous tasting of the test-liquid is possible. A panel of 15 persons experienced in taste-testing was used. Three gradients of different steepness were applied: 0 to 1.5% (w/w) sucrose in 2 min (I), 3 min (II) and 4 min (III). The results of the new method were compared with those of the standard method (DIN). With gradients I and II we found values which were significantly higher than those of the standard method (I: 0.49% (w/w); II: 0.46% (w/w); DIN: 0.31% (w/w)), whereas with gradient III the same threshold value was found as with the DIN-Method (III: 0.32% (w/w)).     

FACTORS INFLUENCING THE EFFICIENCY OF INCOMPLETE BLOCK DESIGNS IN SENSORY EVALUATION EXPERIMENTS

The efficiencies of incomplete block designs were investigated by comparing two hundred and twenty eight analyses from eleven trials using hedonic scales with corresponding randomized complete block analyses. Of the ten explanatory factors examined, only the panelist, the product type, the number of samples per session and the average score of the data had an effect on the efficiency of incomplete block designs. The effect of product type was attributed to influences of produce consumed outside the trial, and the effect of the data mean reflected decreased conscientiousness with products the panelists disliked. With three and four samples per session, incomplete block designs were 31 % and 2 % more efficient, respectively, than randomized complete block designs. When five or more samples were tested, the incomplete block designs were markedly less efficient. The practical implications of all these effects on experimental design are discussed.     

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).     

COMPARISON OF SINGLE PRODUCT SCALING AND RELATIVE-TO-REFERENCE SCALING IN SENSORY EVALUATION OF DAIRY PRODUCTS

Single product scaling and relative-to-reference scaling were compared on the basis of numbers of significant differences among chocolate milks and among vanilla yogurts using both trained and untrained panels. The study involved 920 comparisons among product means with appearance, flavor and mouthfeel attributes. Although there were a greater number of significant t-tests when the relative-to-reference scales were used by both trained and untrained panels, the differences between scale types were minor. Panels showed no advantage with the type of scale they used first. The two methods may be used with equal efficiency for sensory evaluations.