Barley for Food and Health: Science, Technology, and Products

134 EVALUATION OF FOOD PRODUCT QUALITY
status studies, to record information related to effects of processing and to provide
reliable values on food labels (Penfield and Campbell 1990). Chemical
analytical methods (moisture, protein, ash, starch, and fiber) are not described
here; the reader is encouraged to refer to standards used in the cereal science
field, such as those developed by the American Association of Cereal Chemists
International (AACC) and the International Association of Cereal Science and
Technology (ICC; www.icc.or.at). In addition, conventional routine physical testing
of the raw, initial grain, such as for hectoliter weight and kernel hardness, will
determine the overall potential for milling and end-use properties. Experimental
milling data also provide important information on probable performance of a
grain in product development on a commercial scale. Microscopic examination,
especially scanning electron micrography (SEM), provides a three-dimensional
image of a structure which is useful in comparing foods subjected to various
treatments, such as extrusion cooking. Study of SEM photomicrographs facilitates
understanding of changes that occur in components such as starch in foods
subjected to various processes. Physical property evaluation such as dough testing
is widely used in testing baking quality and therefore will be the focus of this
chapter, particularly evaluation of bread and pasta, which are popular products
to which barley flour may be added.
Evaluation of Yeast Bread
The initial consideration in testing yeast bread quality is the flour’s ability to
produce a “functional” dough that will produce a high-quality product. The aim
of breadmaking is to convert flour (traditionally, wheat flour) into an aerated and
tasty food. When moistened in dough, the gluten in wheat protein has the ability
to form a cohesive mass that can stretch and trap gases from fermentation. This
action is responsible for the texture and structure of bread, qualities that provide a
palatable product. Achieving these qualities is a challenge when alternative grains
are substituted for part of the wheat, or totally, as in the case of gluten-free breads
for persons with celiac disease. Because bread is a staple food in all cultures,
it is a logical product for inclusion of health-promoting ingredients, such as
barley to provide soluble fiber. Barley flour alone is not appropriate for yeast
breadmaking because it lacks the extensibility property of wheat gluten, therefore
preventing the development of desirable crumb texture and loaf volume. Addition
of barley flour or high-fiber barley milling fractions can also have detrimental
effects on common parameters of quality, such as color and flavor. Therefore,
experimental studies in product development commonly employ physical dough
testing, functionality testing, color evaluation, and sensory testing procedures.
The following is a brief description of the methods that are commonly utilized in
published experimental studies on bread and other baked products using barley
ingredients.
Physical Dough Testing Physical properties of bread dough determine performance
throughout the mixing process and have a pronounced effect on the