MEASURING THE LONG TERM ACCEPTABILITY OF FOODS: EFFECTS OF SWEETNESS

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: NRI COMPETITIVE GRANT
• Reporting Frequency: Annual
• Accession No.: 0187166
• Grant No.: 2001-35503-10023
• Proposal No.: 2000-01688
• Project Start Date: Dec 15, 2000
• Project End Date: Dec 31, 2003
• Grant Year: 2001
• Program Code: [(N/A)]- (N/A)

Recipient Organization
UNIV OF MINNESOTA
(N/A)
ST PAUL,MN 55108

Performing Department
FOOD SCIENCE & NUTRITION

Non Technical Summary
A food with long-term acceptability is a food that can be repeatedly (daily, weekly) eaten even though other acceptable foods are available and the consumer has the necessary resources to obtain them. Our long-term goal is to determine the features of foods necessary for them to have long-term acceptability. The primary goal of this proposal is to test the hypothesis that overly sweet foods scoring highly in a taste test will decrease more in liking, consumption or choice when repeatedly eaten as compared to less sweet versions. This hypothesis has been developed on the basis of strong preliminary data suggesting that preferred levels of sweetness in taste tests do not predict the preferred levels of sweetness in either single consumption tests or repeated consumption tests. Our other goals are to compare methodologies for determining long-term acceptability and to determine whether measurements of sensory specific satiety can be used as a rapid method for predicting long-term acceptability. The rationale for the research is that once we understand the attributes that increase or diminish long-term acceptability, we will be able to design foods that have it. The very high rate of product failures in today's market shows the inadequacy of current methods of measuring food acceptability. The outcomes of this research will have significance because they will aid in developing test methods for measuring the long-term acceptability of foods and because they will increase our knowledge of sensory attributes important for repeated eating.

Animal Health Component

50%

Research Effort Categories

Basic

50%

Applied

50%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
502	5010	3090	100%

Knowledge Area
502 - New and Improved Food Products;

Subject Of Investigation
5010 - Food;

Field Of Science
3090 - Sensory science (human senses);

Keywords

consumer acceptance

food quality

sensory evaluation

quality evaluation

long term

sweetness

food consumption

food acceptance

eating behavior

product improvement

comparative analysis

sensitivity

variability

diet

satiety

questionnaires

data analysis

regression analysis

statistical analysis

food products

Goals / Objectives
The long-term goal to which this proposed research contributes is to determine the features of foods necessary for the foods to have (or not have) long-term acceptability. To support this goal we have the following three specific objectives for this proposed research: 1) To compare the long-term acceptability of foods with no, low and high sweetness. 2) To compare the sensitivity of 2 methods for determining the long-term acceptability of a food when a) the participants are allowed to choose among a variety of products and b) the participant must eat only the product of interest. 3) To determine if sensory specific satiety can serve as a rapid method for indicating long-term acceptability.

Project Methods
We proposed to do two separate studies differing in the food product examined since manipulations of sweetness are always confounded with changes in other sensory attributes. All products used in a specific test will be matched for caloric density, generally by substituting equivalent calorie amounts of fat or a non-sweet glucose polymer for the sugar. For the long-term acceptability studies involving choice we will purchase products of the same class from local grocery stores. Fifty subjects will participate in each of these tests. They will taste several versions of a specific food product that vary in sweetness. They will rate the sweetness and their liking for the product as well as several other sensory attributes that are likely to differ due to the sweetness manipulations. The goal of these tests will be to provide information on which to base our selection of two to three sweetness levels in a product for a long-term acceptability test. Information acquired from these taste tests will be representative of that obtained from a central location consumer test assessing several different versions of a product. For the long term acceptability studies we will have the subjects come daily and complete 20 visits within a 4-5 week period. Each visit is scheduled to represent a normally eaten meal or snack. At each visit subjects first complete a questionnaire about their level of hunger and their desire to eat the product. They are then given a large serving of the food and can eat as much of it as they wish. When they have finished eating, they will complete another questionnaire asking them to rate statements relating to their hunger and liking of the food. We will weigh the food before and after they eat to determine the quantity consumed. We will analyze the data by comparisons of the visit number and use regression analysis to describe liking or consumption trends over the 20 visits and to determine relationships among the variables measured. Our main focus will be the comparison between the liking ratings, desired consumption, actual consumption and, if applicable, choice frequency between the more and less sweet products. Choice frequency measurements will be analyzed by counting the number of switches, etc. Statistical analysis of these data will be done using chi squared analyses. Sensory Specific Satiety Tests: Subjects rate their hunger and their liking for small pieces of different foods. Next they are given a large serving of the test food and asked to eat the entire amount. Immediately after consuming the test food the subjects retaste and rerate another set of the small food items. Sensory specific satiety is measured as the change in liking for the eaten food compared with the mean change in liking of the uneaten foods in the rating set. Subjects participating in the sensory specific satiety tests will be different people from those participating in the long-term acceptability tests. We will analyze the sensory specific satiety test results by ANOVA for main effects of the sweetness level.

Progress 12/15/00 to 12/31/03

Outputs
We completed a study to investigate 1) the effect of long-term exposure on the acceptance of tea with two sucrose levels, 2) whether long-term consumption of tea at a specific sucrose level would shift the optimum sucrose level, and 3) whether sensory specific satiety can serve as a predictor for the long-term acceptability of tea. This study had four parts: an initial consumer taste test to determine the optimum and low levels of sucrose, a 6-week long-term acceptability test during which 2 groups of subjects consumed tea with the optimum and low sweetness levels respectively, a second consumer taste test, and a sensory specific satiety test. The liking for the low-sweet tea increased over time. The optimum group liked their tea more than did the low group, but they also became more tired of their tea. Sensory-specific satiety did not predict the long-term acceptability of these teas.

Impacts
Our observation that the level of sugar found to be best in a taste test was higher than the optimum level desired over long term consumption is important because taste tests are currently used to determine optimum concentrations. These results will increase pressure on researchers to find methodology that can predict optimum concentrations for long term acceptability using more rapid methodologies.

Publications

• No publications reported this period

Progress 01/01/02 to 12/31/02

Outputs
We have completed a study examining the effect of sweetness on the long term acceptability of oatmeal. We measured the optimum level of sugar in oatmeal for each of 36 people and divided them into 2 groups. One group subsequently received that optimum level of sugar in their oatmeal; the other group received a noticeably lower level. All participants attended 18 sessions during which they ate a serving of oatmeal and rated their liking of the oatmeal they ate and and how tired they were of eating it. The group that consumed their optimum level of oatmeal had higher liking ratings than the group consuming a lower than optimum level. Neither liking ratings nor consumption decreased over the study. Ratings of tiredness increased equally for both groups. We are currently conducting a similar study with tea - examining the effect of sweetness on repeated consumption of the tea. For this experiment we have used a different methodology to determine the optimum sugar levels.

Impacts
Consumer sensory testing often involves a single brief exposure to a small portion of food. Results from these tests often do not accurately predict a product's acceptability when eaten normally. To develop better sensory testing methods, we need to understand why consumer acceptance for a product changes with repeated exposure. These studies examine the level of sweetness as a possibly influence on repeated eating.

Publications

• No publications reported this period

Progress 01/01/01 to 12/31/01

Outputs
The graduate student hired to work on this project arrived at the end of August, 2001 and has reviewed the literature and the experimental plan. We have started to examine some food systems for use in the project, and we are in the process of developing criteria for these food systems.

Impacts
This research should provide improved methods for setting optimum levels of ingredients such as sweeteners or flavors.

Publications

• No publications reported this period