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Chapter 2

Chapter 2.docx


Department
Food Science
Course Code
FOOD 2010
Professor
Massimo Marcone
Chapter
2

Page:
of 12
Kathy Truong
Chapter 2 Food Categories and
Composition
*note: glossary terms are defined as in textbook first followed by semicolon for the back of the
textbook definition*
2.1 FOOD COMPOSITION TABLES
Food composition refers to the substances or components found in a beverage or food
raw foods composed of naturally occurring substances while processed foods contain
specific, functional additives
tables of food compositions are printed by U.S. Department of Agriculture (USDA) for
information of nutrient and calorie (kcal)
Food Categories and the Food Pyramid
commodity a useful consumer good, a product of agriculture, produced and
delivered for shipment; raw product
processed commodities are value-added commodities derived from agricultural
commodities that offer convenience, shelf life, and sometimes added nutrients. Ie.
cocoa, red meats, canned vegetables
food categories used in food industry
1. beverages
2. cereals
3. grains and baked products
4. fruits and vegetables
5. legumes and nuts
6. meat and poultry
7. seafood
8. eggs
9. mmilk and dairy products
10. chocolate and confectionary
Serving Size
serving size according to NLEA(the Nutrition Labeling and Education Act) serving
size is the amount of food customarily eaten at one time; expressed in common household
and metric measures (grams, g and milliliters, mL)
Food Guide Pyramid food labels specify serving size while Tables of Food
Composition employs measures identified by weight with nutrient composition in
grams. Ie. pickle = measure (1 each), weight (65g)
Kathy Truong
Food Guide Pyramid serving depends on food group (1 medium apple = 1 serving of
fruit)
2.2 BEVERAGES
a beverage is a drinkable liquid consumed to:
1. quench our thirst water
2. stimulant effect coffee
3. alcoholic content beer, wine
4. health value vegetable juices, milk
5. enjoyment carbonated soft drink
The Degrees Brix of Beverages
sucrose is a solid particle thus part of the total soluble solids for a beverage
quality of beverage dependent on quantity of sugar
degrees Brix (oBrix) used to measure a beverage sucrose concentration; a measure of a
beverage or liquid’s sugar concentration, equal to the weight percent of sucrose in
solution; grams of sucrose per 100g of solution; tool of measurement: refractometry,
hydrometer device
sucrose inversion when sucrose molecules in solution come apart to yield glucose and
fructose
fructose is sweeter than glucose or sucrose
sucrose inversion promoted by low pH (high acidity), high storage temperature, the
enzyme, invertase
The Importance of the oBrix/Acid Ratio
a 50 percent sucrose-in-water solution = 50oBrix on a weight/weight basis (weight of
sucrose as soluble solid in a weight of water)
fruit juice flavor is a function of sugar content and natural acid content
2.3 CEREALS, GRAINS, AND BAKED PRODUCTS
cereal grains crops high in carbohydrate content such as starch, glucose, maltose,
fructose and fiber; any grain used for food, such as corn, rice, wheat, barley, millet, rye,
sorghum and oats; composed of 3 nutritious parts/structures endosperm, bran, germ
endosperm major layer in a grain kernel, made up of starch storing parenchyma cells,
and having a content of B vitamins and protein
bran outermost layer in a grain kernel, high in fiber content (cellulose and
hemicelluloses), and also containing protein, B vitamins (niacin, thiamin, and riboflavin),
and iron
germ layer in a grain kernel that is rich in unsaturated fat, specific B vitamins (niacin,
thiamin, and riboflavin) and iron
Kathy Truong
noncereal crops sugar cane and beets
consume directly or processed into food products such as bread, pastas, chips
kernel grain seed. ie. wheat
biological value (BV) (measures protein quality) refers to the amount of nitrogen
derived from food protein that is used in the body to promote growth; expressed as a ratio
of the nitrogen retained to the amount of nitrogen absorbed from food
bioavailability the degree to which nutrients are able to be digested by human enzymes
in the digestive tract and absorbed by the body; dependent on food source (plant vs.
animal), food processing (B vitamins are destroyed by heating)
Leavening of Baked Products
leavening refers to the production of gases in dough that contributes to the volume
achieved during baking (“leavening effect”) and the final aerated texture; production of
gas by yeast fermentation or the production of gas caused by the reaction of an acid with
baking soda, in batter and dough products that contributes to the volume achieved during
baking and to the final aerated texture
leavening agents: yeast, baking soda, baking powder, ammonium bicarbonate
agents primarily produce CO2 gas. Also produces steam contributes to “oven spring”
2.4 FRUITS AND VEGETABLES
fruit in botanical terms is the ripened ovary of a plant, meaning it contains seeds. ie.
tomatoes, squash, avocados; the sweet, edible, fleshy seed-bearing or reproductive part of
flowering plants
vegetable is an herbaceous plant containing an edible portion such as leaf, shoot, root,
tuber, flower or stem
vegetable-fruit the fruit part of a plant that is not sweet, usually served with the main
course of a meal, like cucumbers, squashes and tomatoes
most have the composition: high in water (up to 90%), low in protein (up to 3.5%) and
low in fat (up to 0.5%)
good source for digestible carbohydrates (sugars and starches) and indigestible
carbohydrates (fiber, including cellulose and pectic substances.
beta-carotene precursor to vitamin A found in green leafy veggies and yellow-orange
fruits and vegetables
Health Benefits
high levels of vitamin A, beta-carotene, vitamin C and fibers (pectin) may provide
protective effect against heart disease and some cancers
resveratrol found in fermented grape juice (as red wine) may lower blood cholesterol,
prevent heart disease, and act as an anticancer substance