Statistical experimental methods are used in product development. In order to adopt the statistical product design or experimental method, it is necessary to understand the basic concepts and terms.
Important ones among these include:
1. Independent variables also known as factors are the parameters or characteristics, including ingredients and processing conditions, which have an effect on product quality.Independent variables can be varied. Amount or type of ingredients, temperature and time of processing and moisture content are examples of common factors in food production.
2. Dependent variables, or the responses are the important measurable food quality indices. These are influenced directly or indirectly by different factors. Some examples of responses are sensory quality, nutritional value, chemical composition, microbiological
characteristics and shelf - life.
3. Test levels or levels are the quantity of factors selected to be tested in the experimental design. A combination of factor levels is chosen according the experimental design.
4. A model is a mathematical equation that describes the relationship between the response values and different factors quantitatively. It can predict optimized combination of factors to obtain products hving required quality.While dealing with the experimental design method, different kinds of system problems are encountered. These are discussed next.