CHANGEABILITY OF CONSUMER PREFERENCES FOR SOME SENSORY FEATURES OF APPLES

Eugenia Czernyszewicz
Department of Horticultural Economics, University of Life Sciences in Lublin, Poland

ABSTRACT

The purpose of the paper was to determine the strength and direction of the effect of demographic and socio-economic features of the consumers on the opinion and declaration concerning some sensory features of apples such as size, colour, taste and texture as well as to find out variability of preferences between the years 2002 and 2006.
The analysis was conducted on the basis of the data from questionnaire studies carried out among the inhabitants of Lublin. Results of the studies point out that the consumers' socio-economic and demographic features significantly differentiated the preferences, especially in 2006. Consumers most frequently prefer medium-sized apples, red or yellow ones with colouring, firm and sweet-sour taste. The year of conducting the studies had no significant effect on consumer preferences concerning the texture, while having an influence on preferences for the size of the fruit, the peel colour and the taste.

Key words: apples, sensory features, preferences.

INTRODUCTION

Apples are the most popular fruits in our country. They dominate in production and consumption. In the years 2001-2006 apple production ranged from 2.1 to 2.5 million tons, and the annual consumption according to the balance data ranged from 17.88 to 23.88 kg/person, and it had a slightly decreasing tendency [4,10,11,13,15]. The decreasing trend in apple consumption is also observed in other countries [1,5,15]. The source supplying household with apples is most often the purchase at a city market and at a grocer's shop [2]. Among the many properties, taste, juiciness and firmness as well as the cultivar have a significant influence on the choice of apples made by the consumers and they are important features determining the quality of the fruits [3,6,7,8,14]. That is the reason why more attention should be paid to the changeability of the buyers' preferences referring to those features with the aim of better satisfaction of their needs. The supply of apples according to the preferences of different groups of buyers can influence increased consumption. These questions are also important from the point of view of the producers since apples are a dominating species also in the fruit production in our country [10,11].

The purpose of the paper was to determine the strength and direction of the effect of demographic and socio-economic features of the consumers on the opinion and declaration concerning some sensory features of apples such as size, colour, taste and texture as well as to find out variability of preferences in the years 2002 and 2006.

MATERIAL AND METHODS

The analysis was conducted on the basis of results of surveys conducted in the years 2002 and 2006 (during the months from April to June) among the inhabitants of Lublin. The sample of the consumers in both periods was a quota sample reflecting the age structure of inhabitants in five age groups (20-29, 30-39, 40-49, 50-59, over 60 years old). In 2002 the studies comprised 394 persons, and in 2006–504 persons. Participation in the study was voluntary. The survey research was carried out with a method of a direct survey. The pollsters distributed the questionnaires to selected people and after they filled in the questionnaires, the pollsters collected them personally. As a result, almost 100% of the questionnaires were collected and the percentage of answers to particular questions was diverse. 86.9% to 97.8% of the answers was obtained in 2006 and 95.9% to 99.7% in 2002.

The questionnaire consisted of twenty-one questions in 2002 and nineteen questions in the year 2006 concerning opinion and declaration about fruit purchase and consumption. The respondents were also asked about sex, age, education, type of family, sources of incomes and monthly disposal incomes per person in family. Seven questions in the year 2006 and five in 2002 concerned opinion and declaration about apple purchase and consumption. In this article analyzed biennial data characterizing favourable sensory features of apples such as size, colour, taste and texture.

As the explanatory variables the analysis took into consideration the consumers' sex, their age (5 groups) and education (4 groups: elementary, vocational, secondary and university level) as well as the type of the family (8 groups: childless couple, family 1 child with, family 2 children with, family 3 children with, family 4 or more children with, single mother (father) bringing child up, childless single person, multigeneration family), monthly disposal incomes per person in the family (4 groups: up to 300 PLN, 301-500 PLN, 501-1000 PLN, over 1001 PLN) and the source of incomes (6 groups in 2002: income from hired work, income from hired work and from private farm in agriculture, income only from private farm in agriculture, self-employed or working in free professions income, retirement, unearned source, and 5 groups in 2006: income from hired work, income from hired work and from private farm in agriculture, self-employed or working in free professions income, retirement, unearned source). The explained variables referred the preferences of selected features of apples, i.e. the fruit size (small, medium, big, unimportant), the peel colour (yellow, green, red, yellow with colouring, green with colouring, unimportant), the texture (firm, soft, unimportant) and the taste (sweet, sweet-sour, sour, unimportant).

The analysis of interrelationships was made on the basis of the coefficient of Pearson's linear correlation. The description of the relations between the explaining and the explained variables was performed by the model of the multiple linear regression. Chi-square and V-Cramer statistics were used in order to find out whether there was a statistically significant variability of preferences in the studied years. The null hypothesis about independence of preferences concerning the sensory properties of apples was verified. The level of significance related to the value of the statistics makes it possible to accept or reject the null hypothesis on independence of preferences of the date of studies. The analysis took into consideration three levels of significance of the test α < 0.05, α < 0.01 and α < 0.001. The necessary statistical calculations were performed in the SAS system version 9.1.

Descriptive statistics of the consumer sample in the years 2002 and 2006 are given in Table 1. Women, who generally do the shopping in a household, dominated (61-62%) among the examined persons. The studied sample of the consumers included 75-83% of the persons with at least secondary education and in the years 2002 and 2006 they comprised 41 and 33% of those with university education, respectively. From 42 to 47% of the respondents declared their monthly incomes per person in the family within the range of 501-1000 PLN, and in the examined period, respectively, 12 and 25% – over 1001 PLN. The incomes of 13 to 7% of the respondents were at the level up to 300 PLN. For 55% of the respondents in 2006 and for 37% in 2002 the prevailing source of maintaining the family were the incomes from hired work, for 21% and 27%, respectively, it was their pension, while for over 15-23% – incomes from their own economic activity. The greatest percentage of the respondents came from the families of 2 or more children – over 45%, where 2-children families were represented most numerously (respectively, 28 and 31% of the respondents).

RESULTS AND DISCUSSION

It follows from the results in Table 2 that preferences for some sensory properties of apples are significantly correlated with some of the consumers' demographic and socio-economic features such as age, education, disposal incomes per person in the family and the source of incomes. Age significantly influenced the respondents' declaration as far the apple texture is concerned, and in 2006 – as far as the peel colour and the taste are concerned. Education was significantly correlated with the declaration as for the apple texture, like it was in 2006 in the case of the source of incomes. The surveyed persons' incomes had a significant relation with preferences concerning the fruit size, especially in 2006, and the apple texture in 2002. In the case of the other relations the conclusion can be drawn on the lack of any linear relation between the variables. This does not mean that such relationships do not exist; they can only have other (non-linear) character. Trębacz [14] also observed the effect of education, age and incomes on the preferences of Poznań inhabitants. She found out that those features differentiate the importance of the criteria for choosing the fruit.

Pointing to the preferred properties of apples depending on the respondents' age is illustrated in Table 3. It follows from these data that the surveyed consumers in Lublin prefer medium-size apples (55-60% of the total in the years 2002-2006), red ones (33-40%), firm (51-52%) and of sweet-sour taste (43-56%). In the studies conducted in 2005 among the inhabitants of Skierniewice and the vicinity, the young consumers preferred red and sweet apples. The youth chose firm apples more frequently, whereas children preferred soft ones. The properties that were important to adult consumers included juiciness, taste, sweetness as well as firmness. Like it was the case in Lublin, adults most often chose medium-size and red apples [6].

In the studied period the percent of people for whom the fruit size and peel colour were of no importance increased. The fruit size was also a less important feature for the inhabitants of Hamburg, where in 1998 a consumer test conducted [12]. In Lublin medium-size (about 70 mm in diameter) and red apples are preferred by the people from all age groups, while firm ones – first of all by people from younger age groups. This is understandable because older people may have problems with eating such apples, which is why they choose soft apples. The problem of how easy it is to consume different fruit species was studied by Roininen et al. [9] among the consumers in Finland and Great Britain. It follows from those studies that apples were perceived by older consumers as rather troublesome in eating like pineapples, oranges, water melons, kiwi fruit, figs and black currant. The fruit were easy to consume if there were initially processed, easy to prepare, bite and chew, while being problematic if they were hard, fibrous, they stuck to the teeth and required preparation. Besides, as follows from the studies by Karlsen et al. [7], the texture is important because it affects the perception of certain properties referring to the smell and taste of the fruit.

Sweet apples were equally often chosen by young and old alike, and the greatest differentiation was observed in the studied years within the age groups of 40-49 and 50-59. The relations between the apple properties and the demographic-social and economic variables in the years 2002 and 2006 were described by means of the following linear regression equations:

in 2002:

in 2006:

It can be inferred from the above equations that passing to the group of a higher level of education caused that in 2002 the preferences concerning the texture and the taste decreased by, respectively, 0.178 and 0.119 points in the scale of 3- and 4-points, correspondingly (equations 1 and 2). In 2006 passing to the next (older) age group referred to changed preferences referring to the peel colour and the taste by 0.194 and 0.08 points, respectively, in the scale of 6- and 4- points (equations 4 and 6). With given education, preferences concerning the fruit size increased by 0.182 point together with passing to the next (higher) income group, while in a given income group the preferences concerning the fruit size decreased by 0.1 point together with passing to the group of a higher level of education (equation 3).

Next, an attempt was made to verify the hypothesis about the variability of consumer preferences in the years 2002 and 2006. Chi-square and V-Cramer statistics were used to find out whether there was a significant variability of preferences in time. The values of both statistics and probability are presented in Table 4. The null hypothesis assumed that the term of studies had no influence on their results in the sphere of the examined sensory properties of apples.

The data shows that by level of significance of the test α < 0.05 null hypotheses about independence preferences of fruit size, peel colour and taste from term of studies is rejected. It means that preferences of analyzed features depend on term of surveys, so it was significantly differed between the years 2002 and 2006. In case of preferences of texture don't have basis to reject null hypothesis, it means that time has no significantly influence on preferences of the analyzed features.

CONCLUSIONS

1. Consumers' demographic and socio-economic features in Lublin were related to their preferences concerning the fruit size, their colour, apple taste and texture. The feature that differentiated those preferences the most was age, as well as education, income per person in the family and the source of incomes in the family.

2. Consumers in Lublin prefer medium-size, red apples, firmness and a sweet-sour taste. In the examined period the percentage of people for whom the fruit size and the peel colour were of no importance increased.

3. The date of studies had no effect on the results of preferences concerning the apple texture, while it did on the fruit size, the peel colour and the taste.

REFERENCES

1. Barritt B.H., 2002. The Apple in the Word of 2002: Present Situation and Developments for Producers and Consumers. Interpoma 7-9 November, Bolzano, Italy, 11-19.

2. Czernyszewicz E., 2004. Preferencje konsumentów w zakupie i spożyciu jabłek [Consumer preferences in the purchase and consumption of apples]. Annales UMCS, sec. EEE, vol. XIV, 13-23 [in Polish].

3. Czernyszewicz E., 2007a. Konsumenckie spojrzenie na jakość jabłek [A consumer's look at the apple quality]. Annales UMCS, sec. EEE, Vol. XVII(2), 70-82 [in Polish].

4. Czernyszewicz E., 2007b. Changes in fruit and fruit products consumption in the social-economic group of households during 1990-2005. EJPAU 10(4), #37, http://www.ejpau.media.pl/volume10/issue4/art-37.html.

5. Ellinger W., 2006. Konsumtrends bei Äpfeln und Apfelsorten [Trends in consumption of apple and their cultivars]. Interpoma 2006, Bolzano, Congress Paper, 17-31 [in German].

6. Jesionkowska K., Konopacka D., Płocharski W., 2006. The Quality of Apples – Preferences among Consumers from Skierniewice, Poland. J. Fruit Ornam. Plant Res, 14, 173-182.

7. Karlsen A.M., Aaby K., Sivertsen H., Baardseth P., Ellekjaer M.R., 1999. Instrumental and sensory analysis of fresh Norwegian and imported apples. Food Quality and Preference 10, 305-314.

8. Péneau S., Hoehn E., Roth H.-R., Escher F., Nuessli J., 2006. Importance and consumer perception of freshness of apples. Food Quality and Preference 2006, 17, 9-19.

9. Roininen K., Filion L., Kilcast D., Lähteenmäki L., 2004: Exploring difficult textural properties of fruit and vegetables for the elderly in Finland and the United Kindom. Food Quality and Preference, 15, 517-530.

10. Rynek owoców i warzyw. Stan i perspektywy [Fruit and vegetable market. State and perspectives], nr 27, kwiecień 2005, Warszawa, 7 [in Polish].

11. Rynek owoców i warzyw. Stan i perspektywy [Fruit and vegetable market. State and perspectives], 31, listopad 2007, Warszawa, 24 [in Polish].

12. Stehr von R., 2001. Erfahrungen zu ausgewählten schorfresistenten Apfelsorten – Teil 2: Ergebnisse von Verbrauchertests und Befragungen auf Groβhandelsebene, Mitteilungen des Obstbauversuchsringes des Alten Landes. [Knowledge of the scrab resistant cultivars of apple – part 2: Results of consumer's tests and survey among a wholesalers and report from Alten Landes fruit production regions], 56/7, 226-234 [in German].

13. Strojewska I., 2006. Konsumpcja owoców i warzyw w Polsce i w UE [Fruit and vegetable consumption in Poland and EU]. Przemysł Fermentacyjny i Owocowo-Warzywny, 10, 26-28 [in Polish].

14. Trębacz A., 2000. Preferencje konsumentów owoców a rynek jabłek deserowych [Preferences of fruit consumers and market of dessert apples]. Mat. Konf. "Szanse i zagrożenia dla krajowego ogrodnictwa po przystąpieniu Polski do Unii Europejskiej", 13-14 grudzień 2000, wyd. AR Lublin, 233-242 [in Polish].

15. Wieland S., 2002. Äpfel sind das beliebteste Obst in Deutschland [Apples are the most favourite fruit in Germany]. Obstbau 1, 36-37 [in German].

Accepted for print: 28.01.2009

Responses to this article, comments are invited and should be submitted within three months of the publication of the article. If accepted for publication, they will be published in the chapter headed 'Discussions' and hyperlinked to the article.