CH 2 FOOD.docx

10 views9 pages
Published on 17 Apr 2013
School
University of Guelph
Department
Food Science
Course
FOOD 2010
CHAPTER 2: FOOD CATEGORIES AND COMPETITION
2.1 Food Composition Tables:
Food Composition The substance or components found in a beverage or food.
- The key nutrients that compose foods include the larger molecular substances, such as
protein, fat (lipids), and carbohydrate (starch, sugars and fibre), as well as the smaller
molecules of water, vitamins, minerals and phytochemicals.
- Raw foods are composed of naturally occurring substances, while processed foods often
contain specific, functional additives.
- Tables of food composition are printed in by the USDA in handbooks. They provide
nutritionist and consumers with info regarding nutrient and calorie content of beverages
and food.
- Food composition info makes comparing nutrients of calories in foods easy. Nutrient
database systems enable international organizations to access food composition data for
calculating food supplies. Epidemiologists use them as well.
Food Categories and the Food Pyramid:
Commodity Refers to raw product, the UDA lists 12 commodities, some are foods: red
meats, poultry, fish and shellfish, eggs, dairy products, beverage milks, fats and oils, fruits,
veggies and coffee.
Processed Commodities Value-added commodities derived from agricultural
commodities that offer convenience, longer shelf life and sometimes added nutrients.
Serving Sizes:
- The quantity of food recommended by the Food Guide Pyramid is termed servings;
product food labels specify serving sizes; tables of food composition employ measures.
- On a food label the serving size is the basis for reporting each food’s nutrient content.
- The Nutrition Labeling and Education Ace (NLEA) defines serving sizes as the amount
of food customarily eaten at one time. The serving sizes on food labels are based on
FDA-established lists of “Reference Amounts Customarily Consumed Per Eating
Occasion”. They must be expressed in both common household and metric measures-
grams and millimeters.
- Tables of food comp do not suggest a serving size, but instead provide a measure of food,
identified by weight, followed by nutrient composition found in that amount.
Beverages:
- A beverage is a drinkable, liquid, consumed for a variety of reasons, including:
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(1) Thirst quenching Water
(2) Stimulant effect Coffee
(3) Alcoholic content Beer
(4) Health value Milk and veggie/fruit juices
(5) Enjoyment Carbonated drinks
Nutrient density = if beverage or food supplies a variety of protein, complex
carbohydrates, vitamins and minerals without excess fat or calories
Sucrose concentration of beverages is measured as: degree Brix = equal to the weight
percent of sucrose in solution (grams of sucrose per 100 grams of sample)
Sucrose inversion = sucrose molecules in solution come apart and yield the two
component sugars: glucose and fructose (sweeter of the two)
Importance of Degree Brix/Acid Ratio
o Ratio varies as the relative proportion of sugar to acid content
Cereals, grains and baked products:
Cereals = among the world’s major crops
o High in carbohydrate content (starch, maltose and fructose and fiber)
o Cereal grains composed of 3 nutritious parts:
1) Endosperm = 83% of kernel
2) Bran layer = 15% of kernel
3) Germ = embryonic or sprouting part
Biological value (BV) = amount of nitrogen derived from food protein that is used in
the body to promote growth
o Related to the amino acid content of a protein
o Food high in BV = high quality protein meaning all of the essential amino acids
are present
o Plant protein sources (cereals, legumes) are deficient in lysine and methionine and
are termed “incomplete” protein sources
Bioavailability = degree to which nutrients are digested and absorbed in the body
Leavening (of baked products) = productions of gases in dough that contributed to
the volume achieved during baking (leavening effect) and the final aerated texture
o Leavening agents function to produce carbon dioxide as the specific leavening gas
o Example: Yeast
Fruits and Vegetables:
Fruit = botanical term, ripened ovary of a plant that contains the seeds
Vegetable = herbaceous plant containing an edible portion such as a leaf, shoot,
root, tuber, flower or stem
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Most fresh fruits and vegetables are high in water content (up to 90%), low in protein (up
to 3.5%) and low in fat (up to 0.5%)
Ripeness = optimum or peak condition of flavour, colour, and texture for a
particular fruit
Maturity = condition of a fruit when it is picked
Harvesting = collection of fruits and vegetables at the specific time of peak quality in
terms of colour, texture and flavour in order to market them
Senescence = decline in quality of stored, respiring fruits and vegetables that occurs
after harvesting
Qualitative characteristics = size, colour, blemishes and bruises, flavour, firmness and
presence of extraneous matter (pits, leaves, stems)
Quantitative characteristics = Degree Brix, microbiological information, moisture
content, pH, and viscosity
Dried fruits are a processed category of fruits created by dehydration
o Dehydration = removed moisture from fruits to prevent microbial and
enzymatic deterioration
Infusion = process used to create dehydrated fruit Using heat and
pressure, fructose is forced into a fruit piece, and this sugar replaces
the water in the fruit; provides a means to add flavour and colour and
certain texture
Legumes and Nuts:
Legumes = edible seeds and pods (beans, peas, lentils, soybeans)
o Low fat, low sodium, high-fibre, vitamin, mineral and protein content
Higher fat legumes include soybeans, cottonseed, sesame seed, sunflower seed and
peanut seed These are termed oilseeds
3 major varieties of peanuts
1) Spanish peanut = small and used in nut clusters and peanut brittle
2) Runner peanut = medium sized and incorporated into confectionary products
3) Virginia peanuts = larger and longer and are the variety used for roasted nuts
Soybeans = dual role: oil bean and a food bean
When soybeans are pressed, soybean oil can be removed and is used as a food-grade oil
and in margarine formulations. The beans that remain after the removal of the oil can be
processed into soy flour, which is high in protein.
Soy milk is made by soaking soybeans in water, followed by grinding to produce a
slurry, which is cooked and filtered. Some of early processed soy milks had a flavor
defect termed “beany” or “grassy”. Enzyme called lipoxygenase present in the bean was
responsible because it converted soy fatty acids to odorous compounds
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Document Summary

Food composition the substance or components found in a beverage or food. The key nutrients that compose foods include the larger molecular substances, such as protein, fat (lipids), and carbohydrate (starch, sugars and fibre), as well as the smaller molecules of water, vitamins, minerals and phytochemicals. Raw foods are composed of naturally occurring substances, while processed foods often contain specific, functional additives. Tables of food composition are printed in by the usda in handbooks. They provide nutritionist and consumers with info regarding nutrient and calorie content of beverages and food. Food composition info makes comparing nutrients of calories in foods easy. Nutrient database systems enable international organizations to access food composition data for calculating food supplies. Commodity refers to raw product, the uda lists 12 commodities, some are foods: red meats, poultry, fish and shellfish, eggs, dairy products, beverage milks, fats and oils, fruits, veggies and coffee.

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