A LARGE-SCALE EXPERIMENTAL COMPARISON OF THE TETRAD AND TRIANGLE TESTS IN CHILDREN

Sensory Analysis and Consumer Preference: Best Practices

Sensory science is a multidisciplinary field that encompasses a wide variety of established and newly developed tests to document human responses to stimuli. Sensory tests are not limited to the area of food science but they find wide application within the diverse areas of the food science arena. Sensory tests can be divided into two basic groups: analytical tests and affective tests. Analytical tests are generally product-focused, and affective tests are generally consumer-focused. Selection of the appropriate test is critical for actionable results. This review addresses an overview of sensory tests and best practices.

Children's perceptions of fluid milk with varying levels of milkfat

Schools participating in federal meal programs are limited to serving skim or low-fat (≤1%) flavored and unflavored milk. Few studies have directly addressed child perceptions and preferences for milk containing different amounts of milkfat. The objective of this study was to determine whether children can differentiate between flavored and unflavored fluid milk containing varying levels of milkfat and whether preferences for certain levels of milkfat exist. Flavored and unflavored milks containing 4 different percentages of milkfat (≤0.5, 1, 2, and 3.25%) were high-temperature, short-time processed, filled into half-gallon light-shielded milk jugs, and stored at 4°C in the dark. Milks were evaluated by children (ages 8-13 yr) following 7 d at 4°C. Acceptance testing and tetrad difference testing were conducted on flavored and unflavored milks with and without visual cues to determine if differences were driven by visual or flavor or mouthfeel cues. Child acceptance testing (n = 138 unflavored; n = 123 flavored) was conducted to evaluate liking and perception of selected attributes. Tetrad testing (n = 127 unflavored; n = 129 flavored) was conducted to determine if children could differentiate between different fat levels even in the absence of a difference in acceptance. The experiment was replicated twice. When visual cues were present, children had higher overall liking for 1% and 2% milks than skim for unflavored milk and higher liking for chocolate milks containing at least 1% milk fat than for skim. Differences in liking were driven by appearance, viscosity, and flavor. In the absence of visual cues, no differences were observed in liking or flavor or mouthfeel attributes for unflavored milk but higher liking for at least 1% milk fat in chocolate milk compared with skim was consistent with the presence of visual cues. From tetrad testing, children could visually tell a difference between all unflavored pairs except 2% versus whole milk and could not detect consistent differences between milkfat pairs in the absence of visual cues. For chocolate milk, children could tell a difference between all milk fat pairs with visual cues and could tell a difference between skim versus 2% and skim versus whole milk without visual cues. These results demonstrate that in the absence of package-related flavors, school-age children like unflavored skim milk as well as milk with higher fat content in the absence of visual cues. In contrast, appearance as well as flavor and mouthfeel attributes play a role in children's liking as well as their ability to discriminate between chocolate milks containing different amounts of fat, with chocolate milk containing at least 1% fat preferred. The sensory quality of school lunch milk is vital to child preference, and processing efforts are needed to maximize school milk sensory quality.

Application of tetrad testing to the evaluation of blinding strategies for ancillary supplies used in controlled clinical trials

BACKGROUND/AIMS

Ensuring verum and placebo cannot be visually distinguished from each other is a critical aspect of blinded controlled clinical trials. Our objective was to propose a rational approach to the visual evaluation of placebo matching candidates.

METHODS

Verum and placebo samples were prepared in clear clinical ancillary supplies (intravenous bags, syringes and administration lines) covered at different levels using opaque sleeves. Triangle and tetrad tests, two sensory discriminative testing methods widely used in the food industry, were applied to assess visual differences between verum and placebo.

RESULTS

Triangle and tetrad test results allowed defining the level of opaque coverage required to ensure blinding for three biological drug molecules of therapeutic interest. While the limited number of panelists did not allow a statistically sound comparison of triangle and tetrad test methodologies, tetrad test has a theoretical higher power than triangle test, meaning fewer panelists are needed to reach the same statistical conclusion.

CONCLUSION

Tetrad test offers a rational approach to define a blinding strategy for ancillary supplies used in a controlled clinical trial.

Copycat snacks: Can students differentiate between school and store snacks?

In 2014, the national Smart Snacks in School nutrition standards placed regulations on all snack foods sold in schools. Many food companies reformulated common snack food products for sale in schools, called "copycat snacks", which look similar to nutritionally different foods sold in stores. It is possible that these snacks create consumer confusion among students. The purpose of this study was to determine if middle school students could differentiate, in taste and appearance, between school (copycat) and store versions of common snacks. Seventy-six middle school students evaluated three different food products offered in schools: Froot Loops, Rice Krispy Treats, and Doritos. Students tasted snacks in a series of triangle tests for difference, one for each snack food, including school and store versions. Students were also presented with packages, school and store versions of the same products, and asked to determine the expected taste, purchase intentions, and perceived healthfulness. Students could determine taste differences between school and store Rice Krispy Treats yet could not differentiate between Froot Loop and Dorito varieties. Students rated store versions of all three snacks with greater expected taste, higher intention to purchase, and as less healthy. While it seems product confusion concerning copycat snacks may not be severe in this sample, snack food brands are still a prominent feature in schools. It is possible that these copycat snacks can confuse students' perceptions of healthy foods. Alternative packaging for school foods or reformation of store versions of snack foods may be viable solutions to this problem.