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the relationship between cnsumer acceptability and descriptive sensory attributes in cheddar cheese
THE RELATIONSHIP BETWEEN CONSUMER ACCEPTABILITY AND DESCRIPTIVE SENSORY ATTRIBUTES IN CHEDDAR CHEESE* E.L CASPIA1, P.C COGGINS1,2, M.W SCHILLING1, Y YOON1 and C.H WHITE1 Department of Food Science, Nutrition and Health Promotion Mississippi State University Mississippi State, MS 39762 Accepted for publication November 8, 2005 ABSTRACT The relationship between the consumer acceptability of Cheddar cheese and its descriptive sensory attributes was determined using preference mapping and logistic regression for three Cheddar cheeses A trained panel (n = 9) differentiated the cheeses based on taste, aroma and textural attributes The overall order of consumer preference (P ⬍ 0.05) for the three cheeses was 9, and 12 months of aging time, respectively The trained panel characterized the 7- and 9-month-old cheeses as having young/undeveloped flavors such as “cooked,” “buttery” and “creamy” flavors, and had volatiles that were responsible for the creamy flavor in cheeses The 12-month-old cheese was characterized by aged/developed flavors and included volatile compounds responsible for fruity aromas and sulfurous, earthy and free fatty acid flavors External preference mapping revealed six clusters of consumers with varying Cheddar cheese preferences; 74, 95 and 61% of the consumers found 7-, 9and 12-month-old cheeses to be acceptable, respectively INTRODUCTION The demand for dairy products has significantly increased over the past 25 years World cheese production has steadily increased from 1.18 ¥ 1010 to 1.34 ¥ 1010 kg in 1996 and 2004, respectively (US Dairy Export Council * Approved for publication as Journal Article No J-10789 of the Mississippi Agricultural and Forestry Experiment Station, Mississippi State University, CRIS No 501070 Corresponding author: TEL: (662) 325-4002; FAX: (662) 325-8728; EMAIL: pcoggins@ ra.msstate.edu 112 Journal of Sensory Studies 21 (2006) 112–127 All Rights Reserved © 2006, The Author(s) Journal compilation © 2006, Blackwell Publishing SENSORY ATTRIBUTES IN CHEDDAR CHEESE 113 2004) Per capita consumption of cheese in the U.S.A accounted for 13.6 kg in 2003, out of which 4.2 kg consisted of Cheddar cheese (USDA 2004) Consumers have a wide variety of cheese products to choose from, and depending on population segments and regional locations, flavor preferences of consumers also vary Therefore, understanding the development and variations in taste that occur during the maturation process of Cheddar cheese is an important tool in defining consumers’ expectations of taste Aroma and texture of Cheddar cheese also change over ripening time, and although taste changes more readily than other sensory attributes, all may be useful in discriminating Cheddar cheese as well as explaining consumer preferences The heterogeneous nature of milk predisposes its derived products, such as cheese, to a complex biochemical process in which three major catabolic pathways – glycolysis, lipolysis and proteolysis – are involved (McSweeney and Sousa 2000) As a result, new flavor compounds are produced with each reaction Flavor variations are also closely linked to the manufacturing process starting with the quality of the milk, and the aging and maturation conditions At 6–8 months of age, Cheddar cheese develops most of its flavor, and a full Cheddar cheese flavor is generally developed after year of ripening The use of a sensory language for Cheddar cheese is important for research and marketing purposes, and although validated flavor lexicons for Cheddar cheese exist (Drake et al 2001), a variation of references and terms sometimes is needed to best fit with the sensory characteristics of specific Cheddar cheeses Both logistic regression and preference mapping may be useful in explaining the relationship between consumer acceptability, trained descriptive analysis and flavor chemistry Logistic regression is a unique way to link explanatory variables to discrete response ones (Hosmer and Lemeshow 2000) Logistic regression is very similar to multiple linear regression The only major difference in the analyses is the nature of the response variable In multiple linear regression, the response is a continuous variable, while in logistic regression, the response is a categorical/discrete one This analysis has vast applications and is underutilized in sensory experimentation, but it has shown merit in explaining consumer acceptability of tenderness in chicken breasts (Schilling et al 2003) Such statistical modeling may be useful in determining the consumer acceptability of Cheddar cheese, and its usefulness in explaining consumer acceptability should be compared to preference mapping because it is the method most frequently used to relate consumer acceptability data to descriptive sensory attributes The objectives of this study were to determine how descriptive attributes including taste, aroma and textural attributes in commonly consumed Cheddar cheeses as well as volatile compounds present at concentrations greater than 100 ppb relate to consumer acceptability using preference mapping and logistic regression 114 E.L CASPIA ET AL MATERIALS AND METHODS Cheddar Cheese Sampling Cheddar cheese (9.1 kg) blocks were ripened for 7, and 12 months and then sampled in triplicate (three replications of each aged Cheddar cheese from three different batches of milk) from the Mississippi State University Dairy Plant After aging, the cheese blocks (9.1 kg) were cut into 0.45-kg ones, waxed, vacuum-sealed and stored at 7C in the dark for months prior to starting the study Each panelist received triplicate samples from each 7-, 9and 12-month-treatment block (9.1 kg) for each replication Training of Panelists Nine panelists (six women and three men) were selected from the University based on availability, previous training and liking of cheese The panelists were trained for 30 h using previously identified languages for sensory evaluation of Cheddar cheese (Murray and Delahunty 2000; Drake et al 2001), and the majority of them had greater than 100 h of training regarding the evaluation of dairy products Food and chemical references as well as cheese samples were used in the training A 15-point intensity line scale where = “not detected” and 15 = “extremely strong” in respect to the sensory attributes was used Some anchors in the scale were generated during the panelists’ training Sample Preparation Each 0.45-kg block of Cheddar cheese used for panelists’ training was cut into nine blocks that were approximately 2.45 ¥ 6.35 cm in dimension The cheese blocks were prepared h prior to testing, wrapped in aluminum foil and placed on plastic plates (RS6BPY, 125/5 7/8 in., Sweetheart Cup Company, Inc Chicago, IL) The temperature of the cheese was approximately 10C (Avsar et al 2004) at the time of serving The panelists were provided with unsalted crackers (Premium, Nabisco, NJ), water (Mountain Spring Water, Blue Ridge, GA) and expectoration cups to cleanse their palate between samples Testing was conducted at the same time every day References were prepared according to the spectrum intensity scale values of the four basic tastes or intensity references (Meilgaard et al 1991) Flavor terms and references were obtained from standards selected to reference terms of Cheddar cheese flavor language (Murray and Delahunty 2000) and the Cheddar cheese lexicon (Drake et al 2001) Some of the reference terms, definitions and food references from these lexicons were screened and modified by the panel during the training sessions for suitability with the SENSORY ATTRIBUTES IN CHEDDAR CHEESE 115 cheese analyzed Flavor terms of the Cheddar cheese lexicon consist of 17 terms, some of which were modified such as the case of the terms “diacetyl” and “milkfat,” which were replaced by “buttery” and “creamy,” respectively, as used by Murray and Delahunty (2000) Spectrum references were also used for panelist training for aroma and textural attributes After the training period, the panel, without access to references, evaluated three samples of Cheddar cheese, one for each ripening period for days This analysis was performed in triplicate during three consecutive months The presentation of the sample was the same as for each of the training sessions Each plate had a three-digit random number The panelists were provided with unsalted crackers and ambient temperature spring water (Mountain Spring Water) for cleansing the palate The panelists evaluated the cheese samples in an odor-free room dedicated to sensory analysis Consumer Acceptability Consumer acceptability was evaluated in three consecutive months, each within weeks of the cheese descriptive evaluation by the trained panel The consumers (n = 140) evaluated the three cheeses in individual booths illuminated with white lighting The samples were assigned with three-digit random numbers and served under identical conditions to the trained descriptive testing Consumers ranked the three cheeses in their order of preference, and then evaluated them using a hedonic scale ranging from (“dislike extremely”) to (“like extremely”) (Meilgaard et al 1991) Each consumer evaluated each cheese for overall acceptability, overall flavor, aroma, texture and appearance Instrumental Analysis of Cheddar Cheese Extraction of Volatile Compounds Samples were prepared first by removing a 0.2-cm layer from each surface of the cheese to minimize flavor migration The cheese was grated using a manual cheese grater Nineteen grams of sample was then placed in a 40-mL amber glass vial (Supelco, Bellefonte, PA), which was tightly closed Each cap possessed a 1.5-cm-wide hole in the center equipped with Teflon-faced silicone septum (22-mmwide ¥ 2-mm-thick, Supelco) The samples in the amber glass vial were held at 60C in a water bath (Isotemp 1016S, Fischer Scientific, Inc., Pittsburgh, PA) for 40 (Chin et al 1996) Solid phase microextraction (SPME) was used to analyze the volatile flavor compounds in the Cheddar cheese treatments A two-phase fiber (carboxen/polydimethylsiloxane, Supelco) was inserted into the vial through the septum, exposed to the headspace and held for 20 at the same temperature (60C) 116 E.L CASPIA ET AL Gas Chromatography-Flame Ionization Detector The analyses of the volatile compounds adsorbed on the fiber were carried out in triplicate for each cheese treatment over three consecutive months using a Varian CP-3800 gas chromatograph (GC) equipped with a flame ionization detector (Varian Analytical Instruments, Walnut Creek, CA) and Star 5.0 Workstation data acquisition software (Palo Alto, CA) The type of column used was a 30-m ¥ 0.25-mm i.d ¥ 0.25-mm film thickness DB-WAX capillary column (J&W Scientific, Folsom, CA) The samples were analyzed under the following GC conditions: (1) 42-min total run time; (2) 225C injector temperature; (3) 40–250C column temperature at 5C/min ramp rate; and (4) 250C detector temperature To obtain the retention indexes of the different compounds, 0.5 mL of alkane standards (C11–C25) was injected into the GC with the same program conditions, and volatile compounds were identified using Flavor Net (Acree and Arn 2004) Statistical Analyses A randomized complete block design with three replications was used to determine differences among the descriptive attributes (P ⬍ 0.05) for the Cheddar cheese treatments for flavor, aroma and textural attributes Least significant difference test was used to separate means when differences occurred The descriptive data were further analyzed using principal component analysis (PCA, SAS 8.1, Cary, NC) (SAS Institute, Inc 1999) to differentiate among Cheddar cheese treatments A randomized complete block design with three replications was used to analyze the effects of three different ripening periods of Cheddar cheese on consumer acceptability Agglomerate hierarchical clustering was performed to cluster consumers together based on their liking of Cheddar cheese Both external preference mapping and logistic regression were conducted on the descriptive attribute data and the consumer acceptability scores to determine the relationship between sensory attributes and consumer preference This analysis was performed on nine products (three treatments replicated thrice to make preference mapping and PCA possible) RESULTS AND DISCUSSION Descriptive Analysis Flavor The descriptive flavor attribute intensity means (n = 9) for 7-, 9and 12-month Cheddar cheeses are listed in Table Taste attributes such as whey, brothy, nutty, cowy, yeasty, earthy and salty were not significantly SENSORY ATTRIBUTES IN CHEDDAR CHEESE 117 TABLE DESCRIPTIVE FLAVOR ATTRIBUTE INTENSITY MEANS (n = 9) FOR THE THREE MATURITY LEVELS OF CHEDDAR CHEESE* Cheese flavor terms 7-month 9-month 12-month Cooked Whey Buttery Creamy Sulfur Free fatty acid Brothy Nutty Cowy Yeasty Earthy Pungent Prickle/bite Bitter Salty Sweet Sour Umami 2.2b 1.5a 1.4b 0.9b 3.7b 2.6b 1.4b 0.7b 1.4b 0.8a 1.1b 2.6b 1.9a 3.1b 2.8a 0.4b 2.9b 1.4b 2.9a 1.6a 2.2a 1.4a 3.0c 2.1b 1.8a 0.9a 1.0c 0.9a 1.0b 1.5c 1.1b 1.8c 2.9a 0.9a 2.5b 2.1a 1.6c 1.1b 1.1b 0.7b 5.8a 4.1a 1.7ab 0.9a 1.7a 0.9a 1.6a 3.5a 2.3a 4.1a 2.9a 0.5b 3.6a 1.8a Means in a row with different superscript letters (a, b and c) represent significant difference (P ⬍ 0.05) * Intensities scored on a 15-point line scale different (P ⬎ 0.05) among the three ripening periods These results were first based on differences among treatments (yeasty and salty) and then on panelists’ treatment interaction (whey, brothy, nutty, cowy and earthy) When the interaction plots among panelists revealed a large amount of variation among panelists for a certain attribute and did not follow the same or similar trend, the data produced led to nonsignificant differences These irregular trends in the interaction among panelists could mean that the panelists did not distinguish differences among treatments or that no perceivable differences existed among the treatments As found by Young et al (2004), most of the intensities for the different attributes fall between and on a 15-point line scale The Cheddar cheeses that were ripened for an average of and months had higher intensity scores (P ⬍ 0.05) than those for 12 months, for the attributes classified as young/ undeveloped flavors by Drake et al (2001) such as “cooked,” “buttery” (diacetyl) and “creamy” (milkfat) (Table 1, Fig 1) The Cheddar cheese that was ripened for 12 months had higher (P ⬍ 0.05) scores for most of the attributes classified as aged/developed flavors such as “sulfur,” “free fatty 118 E.L CASPIA ET AL Umami 12-month Sweet Earthy Sulfur Free fatty acid Sour 9-month Buttery Creamy Cooked Bitter Pungent Principal component (70%) Prickle bite 7-month Principal component (15%) FIG PRINCIPAL COMPONENT BIPLOT OF DESCRIPTIVE ANALYSIS FOR FLAVOR ATTRIBUTES OF CHEDDAR CHEESES AGED 7, AND 12 MONTHS acid,” and “earthy,” “pungent,” “prickle bite,” “bitter” and “sour.” Young et al (2004), characterized the flavor attribute terms of 1-, 2- and 4-month-ripened Cheddar cheeses as cooked/milky, whey, diacetyl and milkfat/lactone Cheeses with more than year of ripening were characterized by “sulfur,” “brothy,” “nutty,” “free fatty acid” and “catty” attribute terms (Young et al 2004) In comparison with results obtained in this research, flavor attribute terms such as “brothy” and “nutty” were not significantly different among the three cheeses, and the term “catty” was only used to characterize aroma Bitterness is usually regarded as a defect in Cheddar cheese (Suriyaphan et al 2001) The sensory term “fruity” was excluded from the data after the initial statistical analysis of taste attributes (during training) because of a low perceivable intensity of this attribute by the panelists; however, a slight fruity aroma was present in all Cheddar cheese samples (Table 2) The principal component analysis biplot for flavor (Fig 1) reveals that the 9-month-ripened cheese had a more cooked, buttery and creamy taste than the other cheeses The 12-month-ripened Cheddar cheese was differentiated from the other two cheeses because it possessed the characteristic aged Cheddar cheese tastes, such as “sulfur” and “free fatty acid” flavors This cheese was SENSORY ATTRIBUTES IN CHEDDAR CHEESE 119 TABLE DESCRIPTIVE AROMA ATTRIBUTE INTENSITY MEANS (n = 9) FOR THE THREE MATURITY LEVELS OF CHEDDAR CHEESE* Cheese aroma terms 7-month 9-month 12-month Cooked Whey Buttery Creamy Fruity Sulfur Free fatty acid Brothy Nutty Cowy Sweaty Earthy Pungent Yeasty Catty 2.6a 1.5a 2.1a 1.3a 1.3b 3.1b 2.1b 0.9a 0.7b 1.2b 1.2b 1.0b 1.5b 0.8a 1.2b 2.7a 1.6a 2.4a 1.5a 1.1b 2.9b 1.7c 1.1a 0.9ab 1.2b 1.2b 1.1ab 1.1b 1.1a 1.1b 1.7b 1.1b 1.6b 0.9b 2.3a 5.0a 3.2a 1.2a 1.0a 1.9a 1.7a 1.4a 2.5a 1.1a 1.8a Means in a row with different superscript letters (a, b and c) represent significant difference (P ⬍ 0.05) * Intensities scored on a 15-point scale also bitterer, sourer and earthier, and had a more “prickle bite” taste than the 7- and 9-month-aged Cheddar cheeses According to the eigenvalues (percentage by which variation is explained in the biplot), 70% of the variation is explained by dimension 1, and almost 15% of the variation is explained by dimension This means that taste attributes that are closer to dimension (horizontal) are major determinants of variation in the three maturation levels of Cheddar cheese It is apparent from the taste data that Cheddar cheeses between and 12 months of aging can be differentiated from each other using descriptive taste attributes Aroma The results for aroma were similar to those found in flavor There was a significant difference (P ⬍ 0.05) in the mean intensities of young/ undeveloped flavors and aged/developed flavors (Table 2) Aroma attributes such as “fruity,” “sulfur,” “free fatty acid” and “pungent” were noticeably higher in the 12-month-ripened cheese The 7- and 9-month-ripened cheeses were clearly characterized by “cooked,” “whey,” “buttery” and “creamy” aromas During maturation of Cheddar cheese, there is an increase in the ratings for sulfur aroma (Muir et al 1995) According to Dacremont and Vickers (1994), the most important compounds for Cheddar cheese aroma are butyric 120 E.L CASPIA ET AL 9-month Buttery Creamy 12-month Sulfur Principal component (93.06%) Fruity Cooked Free fatty acid Pungent 7-month Principal component (3.94%) FIG PRINCIPAL COMPONENT BIPLOT OF DESCRIPTIVE ANALYSIS FOR AROMA ATTRIBUTES OF CHEDDAR CHEESES AGED 7, AND 12 MONTHS acid, diacetyl and methional In the aroma attribute terms used in the descriptive analysis, these can be described as “free fatty acid,” “buttery” and “sulfur” aromas The principal component analysis biplot for aroma (Fig 2) clearly differentiates the three cheeses Sulfur-containing compounds and free fatty acids are mainly responsible for the aroma in Cheddar cheese and have a much higher content in the oldest cheese Texture Texture terms with significant differences among treatments were firmness and slipperiness for mouth evaluation terms, and firmness and slipperiness for hand evaluation terms This reveals that texture may change as a result of ripening, but is not as helpful at differentiating the evaluated cheeses as taste and aroma Using texture profile analysis methodology, Creamer and Olson (1982) and Charalambides et al (1995) found significant differences in firmness and crumbliness after analyzing cheeses from to 12 months of age As shown by their results, differences may be able to be measured instrumentally for cheeses with ripening periods from to 11 months but were not highly perceivable by panelists in this experiment According to Pollard et al (2003), firmness of cheese decreases during maturation because of the breakdown of SENSORY ATTRIBUTES IN CHEDDAR CHEESE 121 the casein matrix in proteolysis and a slight increase in solid fat because of moisture loss Volatile Compounds Volatile compounds identified by the SPME method using the GC-flame ionization detector were shown in Table Odorant compounds responsible for fruity aromas identified in the 12-month Cheddar cheese were ethyl butyrate and hexanone Compounds such as acethylthiophene were responsible for sulfur flavors found in the 9-month Cheddar cheese Hexanoic and decanoic acids are free fatty acids defined as strong contributors of rancid and sweaty flavors Other compounds identified include isobutyl methoxypyrazine, which contributes to an earthy flavor, and ketones such as nonanone and hexanone responsible for green, fruity flavors, etc Suriyaphan et al (2001) confirmed that an “earthy” flavor in cheese was because of 2-isopropyl-3methoxypyrazine and at much lower odor intensity, this same compound contributed to a “bell pepper-like” note Some of the identified odorants of the 7- and 9-month cheeses were 2-hexenol with a green leaf/wine odor, and some lactone compounds with green leaf, soap, fruity odors such as g-nonalactone and z-octalactone Ethyl butyrate was only found in the 12-month cheese This compound has an apple odor Manning and Robinson (1973) characterized Cheddar cheese as mainly containing volatile compounds such as hydrogen sulfide, methanethiol and dimethyl sulfide Dimethyl pyrazine was only identified in the 9-month-ripened cheese According to Christensen and Reineccius (1995), other volatile compounds indicative of age in Cheddar cheese are ethyl acetate, 2-methylbutanal, 3-methylbutanal, 2,3-butanedione, a-pinene, ethyl butyrate, ethyl caproate, 1-octen-3-one, acetic acid, methional, propionic acid, butyric acid, valeric acid, caproic acid, capric acid and lauric acid Consumer Acceptability Significant differences (P ⬍ 0.05) occurred among cheese treatments for consumer acceptability (Table 4) The 9-month Cheddar cheese received the highest mean score of 7.53 for overall liking, which corresponds to between “like moderately” and “like very much” in the hedonic scale According to the descriptive analysis performed by the trained panel (Fig 3), this cheese had stronger “cooked,” “creamy” and “buttery” flavors compared with the other cheeses (7- and 12-month) The 12-month-ripened cheese had the lowest mean score of liking of 5.75, which is categorized as between “like slightly” and “neither like nor dislike” in the 9-point hedonic scale On average, consumers found the 12-month cheese acceptable Bitter flavors were highly perceivable 122 E.L CASPIA ET AL TABLE VOLATILE COMPOUNDS PRESENT IN THE HEADSPACE OF CHEDDAR CHEESES AGED 7, AND 12 MONTHS AS DETERMINED USING A GAS CHROMATOGRAPHY FLAME IONIZATION DETECTOR AND SOLID PHASE MICROEXTRACTION No Compound name DB-WAX RI Odor description 7-month 9-month 12-month Methyl butanoate Methyl methylbutyrate Butanol Ethyl butyrate Hexanone (z)-4-heptenal 2-hexenol 2-octanol Nonanone Ethyl hexanoate Dimethyl pyrazine 990 1015 Ether, fruit, sweet Apple * * * * * 1024 1028 1060 1216 1228 1336 1388 1220 1240 * * 1408 1423 1436 1444 1502 1510 18 19 20 21 2-octenal Linalool oxide Ethyl octanoate 3,6-nonadienal Nonenal Isobutyl methoxypyrazine 2-nonenal Isobutyric acid Ethyl phenyl acetate 2,4-octadienal 22 23 24 25 26 27 28 29 30 31 32 33 34 35 2,4-decadienal (-)-y-elemene Methylbutyric acid 2,4-nonadienal Acethylthiophene Hexanoic acid (e)-oak lactone g-nonalactone 4-propyl guaiacol (z)-decalactone Decanoic acid Isopropyl palmitate Indole Dodecanoic acid 1632 1636 1662 1709 1785 1829 1933 2042 2146 2216 2316 2358 2450 2517 Wine Apple Ether, grape Fatty Leaf, green, wine Mushroom, fat Hot milk, soap, green Apple peel, fruit Nut, peanut butter, meat Green Flower, wood Fruit, fat Fat, soap Paper Earth, spice, green pepper Orris, fat, cucumber Butter, cheese, rancid Fruit, sweet Green, seaweed, cucumber Seaweed Green, wood, oil Cheese, sweat Fat, wax, green Sulfur Sweat Coconut flower Coconut, peach Phenol Coconut Fat Fat Mothball, burnt Metal 10 11 12 13 14 15 16 17 1510 1563 1600 1605 * Found chemicals from the instrumental analysis * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * SENSORY ATTRIBUTES IN CHEDDAR CHEESE 123 TABLE MEAN SCORES FOR CONSUMER ACCEPTABILITY (n = 140) OF CHEDDAR CHEESES AGED 7, AND 12 MONTHS* Cheese ripening period Overall acceptability b 7-month 9-month 12-month Flavor Aroma b 6.66 7.53a 5.75c a 6.26 7.46a 5.46c 6.87 7.08a 6.20b Texture a 7.09 7.25a 6.95a Appearance 7.53a 7.39a 7.36a Means with different superscript letters (a, b and c) are significantly different (P ⬍ 0.05) * Scores based on a 9-point hedonic scale • Umami Cluster Cluster • Sweet Cluster 9-month month • Earthy • Sulfur • Free fatty acid • Sour 12-month 12 month • Buttery • Creamy • Cooked • Bitter • Pungent Principal component (70%) • Prickle bite 7-month month Cluster Cluster Cluster Principal component (15%) FIG EXTERNAL PREFERENCE MAP OF COMBINED CONSUMER DATA WITH DESCRIPTIVE ANALYSIS RESULTS OF CHEDDAR CHEESES AGED 7, AND 12 MONTHS in some of the 12-month cheeses (Fig 3), which influenced consumer preferences The descriptive analysis performed on this cheese revealed that aside from bitterness, taste attributes such as earthy, sulfur, free fatty acid, pungent and prickle bite were characteristic of this cheese The means obtained for flavor were very similar to that obtained for the evaluation of overall liking (Table 4) and were also significantly different (P ⬍ 0.05) This demonstrates that consumer liking of a product is especially based on taste (Avsar et al 2004) For aroma, no significant difference was found between 7- and 124 E.L CASPIA ET AL TABLE MEAN SCORES IN THE HEDONIC SCALE FOR OVERALL ACCEPTABILITY OF THE DIFFERENT CLUSTERS OF CONSUMER SEGMENTS* Cluster Number of consumers 7-month Cheddar cheese 9-month Cheddar cheese 12-month Cheddar cheese 23 24 13 44 29 3.45 6.88 5.31 8.00 7.27 8.28 7.52 7.79 6.15 4.43 8.57 7.10 3.65 3.67 7.77 4.14 6.93 6.83 * Scores based on a 9-point scale hedonic scale 9-month-ripened Cheddar cheeses These cheeses were preferred over the 12-month ones because of flavor attributes The 12-month cheese had the lowest score for aroma with a mean score of 6.20, which corresponds to “like slightly” in the 9-point hedonic scale The trained panel distinguished the classified young/undeveloped aromas such as “cooked,” “buttery,” “whey” and “creamy,” which seemed to be preferred by consumers, as opposed to the aged/developed Cheddar cheese aromas of “cowy,” “sulfur,” “free fatty acid,” “pungent,” “sweaty” and “fruity.” No significant differences existed for consumers’ evaluation of texture and appearance of the cheeses External Preference Mapping External preference mapping was performed to relate descriptive analysis data with consumer acceptability (XLSTAT 7.5, Microsoft Excel) Six clusters of consumers with different (P ⬍ 0.05) cheese preferences were obtained (Fig 3) These results are very similar to those reported by Young et al 2004 These researchers used a greater variety of cheeses as well as different types of cheese from this study and also obtained six clusters of consumers The majority of the consumers were in cluster (44 consumers), followed by cluster (29 consumers, Table 5) These two clusters were characterized by people who liked all three cheeses These two clusters rated all cheeses with scores over 6.5 in the hedonic scale Clusters (23 consumers) and (44 consumers) preferred the 12-month Cheddar cheese This cheese is associated with the young/undeveloped flavors (cooked, buttery and creamy) Cluster (24 consumers) also preferred young/undeveloped flavors from the 9-month Cheddar cheese, followed closely by the 7-month cheese This segment disliked the oldest cheese, possibly for having bitter or aged/developed flavors Cluster (13 consumers) preferred the 12-month Cheddar cheese This SENSORY ATTRIBUTES IN CHEDDAR CHEESE 125 segment preferred aged/developed flavors Cluster (seven consumers) preferred the 7-month-ripened Cheddar cheese with a mean score of in the 9-point hedonic scale Cluster (29 consumers) also preferred the youngest cheese (7-month), but they liked all cheese treatments Logistic regression was also performed in an attempt to predict consumer acceptability based on taste and aroma attributes, but low coefficient of determination (R2 ⬍ 0.40) revealed that logistic regression did not work as well as preference mapping in relating consumer acceptability to trained descriptive analysis This is most likely because of both small sample size and a large amount of variation in Cheddar cheese preference among consumers, because logistic regression should be applicable to acceptability and marketing data when the response variable has -3 categories The differences in preferences of cheese taste among the different consumer segments indicate that specific flavor profiles of Cheddar cheese could be marketed to specific target market segments On the one hand, correlation analysis demonstrated positive correlation among young/undeveloped tastes such as “cooked,” “whey,” “buttery” and “creamy.” On the other hand, these terms are negatively correlated with the aged, developed tastes of Cheddar cheese such as “sulfur,” “free fatty acid,” “cowy,” “earthy,” “pungent” and “prickle bite.” Basic tastes such as bitter and sour are negatively correlated with the young/undeveloped tastes Sweet and umami are positively correlated with young tastes Even though Cheddar cheese can be differentiated by aroma as well as taste attributes, preference mapping revealed that the aroma attributes of these three Cheddar cheeses did not relate well to the segments of consumers (P ⬎ 0.05) for five out of the six consumer clusters CONCLUSION In conclusion, this demonstrates that neither texture nor aroma could be used to relate descriptive sensory analysis to consumer preference, but that taste attributes relate well to consumer preference in this application Presence of flavor compounds at previously mentioned detectable limits using the SPME method also relates well 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