Course:FNH200/Lessons/Lesson 02/Page 02.3

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2.3 Summary of Lesson 2

  • Colloidal dispersions allow particles of one substance to be distributed (dispersed) in another substance without dissolving. Foods can have many different types of colloidal dispersions.
  • There are 4 major components of foods: carbohydrates, lipids, proteins and water.
  • Carbohydrates include simple sugars (e.g. glucose and sucrose) and "complex" carbohydrates (e.g. starch, xanthan gum). Carbohydrates can have several functional properties in food, ranging from imparting sweetness to thickening capacity.
  • Fats can be saturated or unsaturated, which affects their physical state (solid versus liquid) and functional properties in food. These functional properties range from tenderizing to emulsifying capacity.
  • Proteins are made of chains of amino acids and serve many purposes in food. They not only impart texture and act as enzymes, but also have other functional properties such as gel and foam formation.
  • Water in food is found in the free and bound form. Water activity is an important measurement of the amount of free water available for microbial, chemical and enzymatic reactions. Water activity can be controlled during processing of foods.
  • The level of acidity in food is measured by the food's "pH". Establishing the acidity of a food is an important factor in controlling the growth of microorganisms. Food scientists use pH 4.6 as the borderline between an "Acid" and "Low acid" food.
  • Pigments and aroma constituents contribute to important characteristics in food. These minor constituents can be easily modified by factors such as pH and temperature.
  • Vitamins can be water or fat soluble. Some vitamins are used as food additives, primarily as "antioxidants".

Watch this video for fun and learn about properties of sugar: Hard Candy Chemistry


FNH 200 Course content on this wiki page and associated lesson pages was originally authored by Drs. Brent Skura, Andrea Liceaga, and Eunice Li-Chan. Ongoing edits and updates are contributed by past and current instructors including Drs. Andrea Liceaga, Azita Madadi-Noei, Nooshin Alizadeh-Pasdar, and Judy Chan.

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1. Which is the following is the most accurate description of milk?

Milk is a liquid.
Milk is aqueous.
Milk is an emulsion.
Milk is an oil-in-water emulsion.
Milk in a water-in-oil emulsion.

2. In addition to acting as a sweetening agent, what is the primary role of sugar in jam?

Browning agent.
Produce hot supersaturated liquid.

3. French fries are quickly prepared in deep fat frying due to oil's ability to:

carry aroma
withstand high temperature

4. Type to match functional properties to the appropriate major food component.

Traps air to form foams and water to form gels.

Carries food aromas, therefore, contributes to food flavour.

Often used as a thickening agent or stabilizer.

5. Which of the following statements is the correct statement about starch?

Granules are insoluble in hot water.
Is indigestible and forms part of dietary fibre.
Does not interact with taste receptors.
Starch undergoes gelatinization which results in a loss of water.