SENSORY PROFILE DESCRIPTION OF MOZZARELLA CHEESE AND ITS RELATIONSHIP WITH CONSUMER PREFERENCE

The aim of this work was to set up the sensory profile and consumer preference test of three different Mozzarella cheeses (from full-fat cow milk, from low-fat cow milk and from full-fat water buffalo milk). The most remarkable difference in composition was the fat content. Nine commercial Mozzarella cheeses (three for each type) were evaluated in triplicate by a trained panel consisting of 10 assessors. Six Mozzarella cheeses (two for each type) out of the nine samples were selected and used for the preference test by 105 consumers. The three different Mozzarella cheeses were sensorially well differentiated. A good discrimination between the Mozzarella cheeses was obtained using the internal preference map method. The combination of cluster analysis and internal preference mapping has lead to a deeper understanding of consumer liking for Mozzarella cheeses.     

VARIABILITY IN HEDONICS: INDICATIONS OF WORLD-WIDE SENSORY AND COGNITIVE PREFERENCE SEGMENTATION

This paper approaches inter-individual differences in the hedonics of food products as an indication of the existence of different groups of people with different likes and dislikes. Rather than considering the differences as an unpleasant fact of nature, to be ignored, the paper shows how these differences point to segments of consumers in the population. These segments enable the product developer to create different types of food products, in order to satisfy the different tastes. The paper, presenting an algorithm for segmentation of individuals into different groups, results from three studies with foods, and the extension of the particular segmentation algorithm into concepts (with three additional studies). The paper presents both new data and results from previously published research. These data are presented in a case history format.     

THE POWER OF SENSORY DISCRIMINATION METHODS USED IN REPLICATED DIFFERENCE AND PREFERENCE TESTS

Research on the power of discrimination methods in difference and preference tests has both theoretical and practical significance. Power is important to evaluate the sensitivities of tests and determine sample size. Ennis and Bi (1998, 1999) proposed the beta-binomial distribution to model replicated difference and preference tests with inter-trial variation and analyzed in general the power of the tests. In this paper, the power of discrimination methods for replicated difference and preference tests is discussed further. The equations for calculating power for methods based on the BB model are given. Examples with tables and charts for calculating and comparing the power of the methods are also given.     

EFFECT OF QUESTION ORDER ON SENSORY PERCEPTION AND PREFERENCE IN CENTRAL LOCATION TRIALS

In the running of consumer studies aimed at obtaining information about products and services, it has become increasingly popular to include some sensory type questions about the characteristics of the test product as well as the standard question about overall preference. The implications of this for the resultant data are complex, and as Sudman and Schwarz (1989) point out question order effects have been implicated as one of the major causes of unreplicated or unexpected findings in survey research. This study aims to establish the effect of question order on overall preference scores and sensory scores in consumer studies. Results indicate that there is a significant effect of asking sensory questions on overall preference ratings and the position of the preference questions (relative to the sensory questions) also has implications for overall ratings of preference.     

EFFECTS OF DIFFERENT FACTORS ON SENSORY ATTRIBUTES, OVERALL ACCEPTANCE AND PREFERENCE OF ROOIBOS (ASPALATHUS LINEARIS) TEA

Effects of serving size, gender, age, tea type, tea‐making technique and water quality on the sensory attributes (appearance, aroma and taste), overall acceptability and preference of Rooibos tea were investigated. In general, there were significant effects of age and main factor interactions on the attributes and product acceptability (P ≤ 0.05). The interaction of serving size, gender and age affected the acceptability of Rooibos (P ≤ 0.05). Although there was significant difference between natural and vanilla‐flavored tea in terms of color, clarity, odor and taste (P ≤ 0.05), no difference was observed in the product acceptability (P > 0.05). The tea‐making technique only affected the odor, with traditionally brewed tea having lower intensity scores than the infused tea. The tea prepared using natural spring water was found to be clearer and had higher acceptability scores than the tea prepared using tap water (P ≤ 0.05). There was no existing significant preference for the natural Rooibos over the vanilla‐flavored one, and the traditionally brewed tea over the infused one; however, the tea prepared using the spring water was preferred over the one prepared using tap water.     

DIFFICULTIES AND A WAY OUT: A BAYESIAN APPROACH FOR SENSORY DIFFERENCE AND PREFERENCE TESTS

There are some theoretical difficulties in the philosophy and methodology of sensory difference and preference tests. The difficulties lie in the assumption that the subjects have the same response ability, which is in conflict with psychological ideas about the processes of perception and decision. A Bayesian approach may overcome these difficulties by treating the parameter of proportion as a random variable. This paper presents a Bayesian approach for analysis of data from such sensory tests.     

EXPECTATIONS AND STABILITY OF PREFERENCE CHOICE

When identical milk samples are presented, only 30% of participants respond with a “no preference” rating. Stability of the “no preference” rating was studied under a variety of conditions, having consumer panelists rate both identical and different pairs of milk samples with varying fat content. The proportion of participants choosing the “no preference” option, when the samples in the pair were identical, was largely consistent despite manipulation of pretest conditions and changes in test questions and answer formats. However, when the milk preference test was preceded by a same/different test, and those responding “same” were assumed to have no preference, the percent of “no preference” was two to three times larger for identical test samples (60–69%). Thus by branching the question, the “false preference” choice for identical milks was lowered. Among those responding “different” to identical milks, the false‐alarm rate increased to 91%, suggesting that perception of (spurious or momentary) differences is driving at least part of the preference choice.     

稻虱缨小蜂的寄主选择性和适宜性

稻虱缨小蜂Anagrus nilaparvatae Pang &Wang对白背飞虱Sogatella furcifera(HO· rvath)卵龄无明显的寄生选择性,但在新鲜寄主中的发育历期较短,育出的蜂体较大,生殖力较高,而羽化 率和雌雄性比则不受寄主卵龄的影响。在白背飞虱和褐飞虱Nilaparvata lugens (Stal)卵共存时,稻虱缨小蜂明显选择褐飞虱。稻虱缨小蜂在褐飞虱卵中的发育显著地比在白背飞虱卵中的慢;褐飞虱卵育出的 蜂的初羽化成虫怀卵量显著高于白背飞虱卯育出的,虫体大小也类似,且虫体越大,生殖力越高。从白背飞虱卵育出的蜂供给白背飞虱卵(W→W)时,产卵量低于其它育蜂寄主和供给产卵寄主组合(w→B、B→B、B→W)的,其内禀增长力rm较其余者小25%。本文还讨论了应用适宜性指数来综合衡量寄主的适宜性。     

ORIGIN AND MAINTENANCE OF A FEMALE MATING PREFERENCE

We investigated the role of maintenance and origin of female mating preferences in three species of fish. Poecilia latipinna and P. mexicana are sexual species that hybridized to form the gynogenetic clonal P. formosa, which reproduces asexually but requires sperm to initiate embryogenesis. We demonstrate that all three species display almost identical and statistically indistinguishable preferences for large males. Although processes of good genes, runaway sexual selection, and direct selection could maintain preferences in the sexual species, good genes and runaway sexual selection are unlikely to operate in the asexual species. Furthermore, we found that the most likely direct selection benefit, an increase in fecundity, can also be excluded in the gynogens. We conclude that the most parsimonious explanation for this P. formosa preference is that it was inherited from the parental species and is maintained without forces generated by good genes, runaway selection, or direct selection for increased fecundity. This preference may be maintained because of pleiotropic effects (e.g., sensory bias) or mate searching costs.