Evaluation of Food Quality

Abstract

Food quality is an important concept because the food people choose depends largely on quality. Consumer preference is important to the food manufacturer, who wants to gain as wide a share of the market for the product as possible. Quality is difficult to define precisely, though it refers to the degree of excellence of a food and includes all the characteristics of a food that are significant and that make the food acceptable.

Glossary

Affective or acceptance/preference tests

Used to determine whether a specific consumer group likes or prefers a particular product.

Ballot

Sheet of paper on which the panelist receives pertinent sample information and instructions, and on which observations are recorded during a sensory test.

Descriptive tests

Specialized difference tests used to describe specific flavor attributes of a product, or to describe degree of difference between products.

Discrimination or difference tests

Used to determine if there is a perceivable difference between samples.

Duo–trio test

Samples include a reference food and two samples, one of which is the same as the reference.

Elasticity

Ability of a material to stretch when a force is applied and to return to its original position when the force is removed.

Likeability test

Panelists rate a sample on a hedonic scale from “dislike extremely” to “like extremely.”

Master sheet

Details the specific three-digit product numbers and positions for every panelist in a sensory test. Used to ensure that each product is seen an equal number of times in each position, so that bias is avoided.

Mouthfeel

Textural qualities of a food as perceived in the mouth.

Newtonian liquid

The viscosity is independent of the shear rate. Stirring or shaking does not make the liquid runnier or thicker. Examples are water, sugar syrups, and wine.

Non-Newtonian liquid/fluid

Apparent viscosity depends on the shear rate. Catsup gets thinner with increasing shear rate, whereas some gums thicken with increasing shear rate.

Objective evaluation

Involves use of physical and chemical techniques to evaluate food quality, instead of variable human sensory organs.

Plasticity

Material flows when subjected to a certain minimum force; material can be molded.

p-Value

Statistical probability that a result is significant. A p value of 0.01 indicates 99 % confidence that a result is significant. In other words, out of 100 trials, the same result would be expected 99 times. The probability of the opposite result occurring is only 1 in 100 trials.

Ranking test

Panelists rank two or more samples in order of preference or intensity for a particular attribute.

Rheology

Science of the deformation and flow of matter, how a food reacts when force is applied; includes elasticity, viscosity, and plasticity.

Sensory testing

Use of senses to evaluate products; involves consumer opinion.

Threshold

Concentration required for identification of a particular substance.

Triangle test

Three samples, two of which are alike, one is odd.

Umami

Savory taste, given by substances such as monosodium glutamate.

Viscosity

Resistance to flow of a liquid when a shear force is applied. Liquids with a low viscosity flow readily, whereas liquids with a high viscosity flow slowly.