T he age-old art of smoking foods was already well established a few thousand years ago. Smoking together with drying and salting belongs to the oldest food preservation meth-ods highly suited to the relatively primitive conditions of the past (Barylko-Pikielna, 1977).
Although the bacteriostatic and antioxida-tive properties of smoke and smoke flavour-ings are the subject of current research (Schwanke et al., 1996; Wendorff and Wee, 1997) in modern food technology, the smoke-curing or smoke flavouring process has changed from its previous principal objective and should be considered primarily as a flavouring operation (Pszczola, 1995).
Preference for food products is only a part of the reason for food choice and is affected by endogenous (heredity, sex, age, etc.) and exogenous (culture, society, economy, etc.) factors of importance for food consumption (Risvik, 1994). Although preference is not considered a good predictor for repeated consumption, product sensory attributes are considered to be decisive in the determination of one product’s preference over another.
If the sensory attributes are important in consumer acceptance, they are doubly so for smoked foods (Lesimple et al.,1995). In fact, the smoke flavour is used, in many cases, as a novel flavour in several products, contributing desired sensory properties such as coloration (Riha and Wendorff, 1993), texture (Suzuki et al., 1997) and flavour (H elgesen and N aes, 1995). After all, it is the distinctiveness in this regard that is responsible for the continued and increasing demand for smoked foods, even in countries without a tradition of these commodities.
Preference mapping is a form of multivari-ate scaling that allows the identification of each individual and their relative preferences for, or relationship to, a particular set of stimuli (M cEwan, 1996). It is used to answer a number of questions relating to improving the acceptability of the sensory aspects of a product. In the food industry, multivariate
Nutrition & Food Science
Number 6 · November/December 1998 · pp. 338–342 © M CB University Press · ISSN 0034-6659
Spa nish consum e rs f or
sm ok e d f ood
Pedro Bárcenas
Francisco J. Pérez -Elortondo
Jesús S almerón and
M arta A lbisu
The authors
Pedro Bárcenas, Francisco J. Pérez-Elortondo, Jesús Salmerónand M arta Albisu are all at Nutrición y Bromatología, Facultad de Farmacia, Universidad del País Vasco, Vitoria, Spain.
Abstract
The aim of the present study was to reveal if sensory properties of smoked food could be considered as decisive in the determination of one product’s preference over another. In addition to this, this w ork tries to clarify w hether the flavour obtained in commercial smoked products was noticed and clearly recognized. This study consisted of tw o parts; first, a preference testing w ithout physical products (recalled preference) presented using a nine-point hedonic scale, and second, a difference testing w ith selected products using the triangular test. Con-sumers show ed a preference for non-smoked products, particularly for cheese, sausages and chips. The first preference dimension of the internal preference mapping (M DPREF) analysis accounted for 74.6 per cent of total variation indicating overall agreement about likings relating these products, w ith cheese being the most acceptable overall. Analyzing triangular test results it may be concluded that other factors but sensory ones must be defining consumer representations of smoked food, w ithout a correspondence w ith its real organoleptic properties.
T he authors would like to thank the C omisión Interministerial de C iencia y Tecnología for sup-porting this work (C IC YT, ALI94-0989).
scaling methods and in particular internal preference mapping (M D PREF ) have been applied in a variety of areas: meat product evaluations (M arketo et al., 1994), acceptabil-ity of different types of drinking water (Fala-hee and M acRae, 1995), fresh apples charac-terization (D aillant-Spinnleret al., 1996), optimization of a peach nectar formulation (Pastor et al., 1996).
T he aim of the present study was to reveal if sensory properties of smoked food could be considered as decisive in the determination of one product’s preference over another. In addition, this work tries to clarify whether the flavour obtained in commercial smoked prod-ucts was noticed and clearly recognized as what was being sold: a smoked food.
M et hods and m at erials
T his work consists of two parts; first, a prefer-ence testing without physical products pre-sented using a nine point hedonic scale, and second, a difference testing with selected products using the triangular test.
S tudy 1. P reference questionnaire
T he panel consisted of 300 persons among students, faculty and staff at the Facultad de Farmacia in the Basque C ountry U niversity; 30 per cent were students and the rest staff.
For the first part of this work, a question-naire based on the scale developed by Peryam and Pilgrim (1957) and the Product Attitude Survey suggested by Stone and Sidel (1993) was designed. C onsumers were asked to rate different kinds of food (cheese, smoked cheese, smoked curd, sausages, smoked sausages, bacon, lard, smoked chorizo, salami, smoked salmon, smoked sardine, smoked herring, chips-snacks and smoked chips-snacks), with special emphasis on smoked ones, on a nine-point hedonic scale for overall preference (1 = dislike extremely; 5 = neither like nor dislike; 9 = like extreme-ly). Q uestionnaires were given to the candi-dates to be filled at their own homes.
T he assessment of smoked foods did not include tasting the products, this way the so-called “reso-called preference” could be evaluat-ed. Standards were not provided because they might have altered the representations people had of the concept, thus subjects made their judgements using their own past experiences with smoked products.
S tudy 2. D ifference testing
It was intended to select smoked commodities belonging to fish, meat, vegetable and dairy products. Samples of cheese, salmon pâté, chips and sausages, smoked and non-smoked were purchased from local supermarkets in Vitoria (Spain). C are was specially taken that samples were exactly the same in all aspects except for the smoked character (same brands).
Salmon pâté was selected because the direct presentation of salmon, sardine or herring to consumers was impossible. T hese types of products are generally consumed after a cooking process, thus another variable had to be considered. In order to simplify this approach, and taking into account the high consumption of these foods, salmon pâté was found adequate and representative of fish products.
After purchasing they were stored at 7ºC until required and held at ambient tempera-ture for two hours before sensory evaluation. Samples, randomly coded, a glass of water and a cracker were distributed to the con-sumer group. T hese tests were carried out in purpose-built sensory booths. Panelists were asked to distinguish among the samples and if so to characterize these differences using the triangle test method (Stone and Sidel, 1993).
Dat a analysis
S tudy 1. P reference questionnaire
AN OVA was used and differences between means were tested using F isher LSD (least significance difference) test (p < 0.05).
T he Taguchi’s signal to noise ratio (SN R) was calculated according to G acula (1993):
SN R = –10 log [(1/y2)(1+ 3s2/y2)]
where y and s2are sample mean and variance respectively.
weight. In order to perform the analysis, missing values were replaced with the mean (H edderley and Wakeling, 1995).
S tudy 2. D ifference testing
D ata obtained from triangular tests were analysed by comparison with tabulated values (O ’M ahony, 1986).
Result s and discussion
P reference testing
F rom the 300 people interviewed only 101 consumers (34 per cent) returned the ques-tionnaire. As observed in Table I, hedonic scores given to cheese, smoked salmon and chips were statistically higher (p < 0.05), while smoked herring, smoked sardine and smoked curd were the least preferred prod-ucts.
Bartholomew and O suala (1986) suggested that scores of six and above using a nine-point hedonic scale assigned by the consumer panel to meat products might be commercially acceptable. In the present study it can be observed that nine products in the ballot obtained a hedonic score over six so they might be successfully commercialized; howev-er, lard, smoked sausages, smoked herring, smoked sardine and smoked curd did not, so special considerations should be taken by the manufacturers in order to improve their sensory quality or to modify consumers’ representations of them. Interviewed con-sumers did, generally, present a clear prefer-ence tendency toward non-smoked products against smoked ones particularly for cheese, sausages and chips.
Some authors observed that there was no doubt that smoked products were preferred over the same products which have received no smoke processing (Bairdet al., 1988; Sink, 1979). T he variations among these results may be due to the different habit of consum-ing smoked foods of our assessors and the consumers they used in their tests as suggest-ed by G ormley (1992).
Taguchi’s statistics (SN R) can be used to obtain AN OVA complementary information. T his index takes into account the variability of the individual values and gives a measure of the robustness of the data (G acula, 1993). It can be seen (Table I) the way this index decreases with acceptability scores, that is to say that, the most preferred samples are, at the same time, those having most robust data. T his detail could be of extreme importance in the case of non-significantly different samples, but showing different SN R values, as for example lard and smoked sausages. In this case, lard preference data show higher robust-ness than smoked sausages and consequently its acceptance should be considered higher too.
Internal preference m apping
T he results from M D PREF show that the first two preference dimensions accounted for 79.4 per cent of the variation in the preference data (F igure 1).
Examination of the plot of each consumer’s preference scores revealed that there is a clearly defined zone and direction in which people prefer the samples. C onsumer position shows the directions of increasing liking for the different smoked products. T his vector
Table I Tw o way analysis of variance. M ultiple comparison pf sample means for acceptability data and signal to noise (SNR) values
Source DF CM E F P
Samples 13 123.567 81.53 0.000
Consumers 100 8.996 5.94 0.000
Error 1,300 1.517
Samplea 1 10 13 6 9 4 2 14 8 7 5 12 11 3
Acceptabilityb 8.3a 7.7b 7.3c 6.8d 6.6d 6.5de 6.4de 6.2f 6.1f 5.6g 5.5g 5.3gh 5.1h 4.1i
SNR 18.22 17.17 16.72 16.08 15.91 15.72 15.29 15.21 15.21 14.34 13.97 13.60 13.20 11.34
Notes:
model assumes a linear model such that pref-erence is greatest at the end of the subject vector.
People tend to cluster around the first preference dimension (74.6 per cent of the variation), thus it can be said that there exists an overall agreement about their preferences for the products appearing in the ballot. T his plot is particularly good, as all the consumers prefer the samples on the left hand side of dimension 1, with cheese being the most acceptable overall.
It should be noted that foods located near one another are preferred in a similar way by consumers. Smoked herring and smoked sardine are located near to each other, which may indicate that consumers see those prod-ucts as being very similar, distinguishing them from smoked salmon. It may be due to the luxurious concept of the latter against the other two (H enriket al., 1995).
Based on the relative positions of the foods in the space, it was concluded that raw prod-ucts and their smoked varieties do not display similar spatial configurations, except for smoked and non-smoked sausages. Less preferred items (smoked curd, smoked sar-dine, smoked herring, smoked sausages, lard) have positive coefficients for the first dimen-sion, while those with higher preference scores (cheese, smoked salmon, chips) appear in the negative side of the X axis.
T hese results confirm the acceptability previously found by means of AN OVA, but
revealed that consumers have very similar acceptability criteria.
S tudy 2. D ifference testing
C heese was the least confused product among the four sets presented to the panelists (43 per cent of wrong answers). It may be due to the familiarity and habit of cheese consumption that the consumer panel had. O n the other hand, the higher rate of wrong answers in these tests was observed for the pair chips-smoked chips, where 61.4 per cent of the tests were failed. Salmon pâté and sausages obtained similar results, 60 per cent of the consumers were unable to distinguish amongst smoked and non-smoked varieties.
Statistical testing indicates that chips, salmon pâté and sausages, smoked and non-smoked, were not significatively distinguished (p < 0.05). T he difference between the sam-ples was in no case established, and clearly defined as due to a smoking treatment.
Conclusions
It seems to be obvious, at least studying this kind of product, that people’s concept (recalled preference) of smoked food is not primarily based on its sensory characteristics, because no differences were noticed in several commercial smoked products. Triangular test results hardly accounted for differences due to a smoke treatment; however, survey data revealed different preference scores depend-ing on the items bedepend-ing smoked or not. T his fact indicates that other unidentified factors must be defining consumer representations of smoked items, without a correspondence with its real organoleptic properties.
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