In this activity, students investigate the action of salivary amylase1 on starch2 present in cooked rice. Simple tests for starch and its digestion3 product, maltose, are applied.
By the end of this activity, students should be able to:
- use simple chemical tests to identify soluble starch and reducing sugars like glucose4 and maltose
- safely use their own salivary amylase
- explain in simple terms how the enzymatic5 digestion of starch occurs
- recognise the need for careful control6 of variables such as temperature7 and amount of reactant in activities of this type
- describe how high temperatures can inactivate enzymes8 like amylase.
Download the Word file (see link below) for:
- introduction/background notes
- what you need
- what to do
- student worksheets.
Related content
The article, Rate of digestion, looks at how surface area9, temperature and pH10 all influence the rate of digestion of large food molecules11. The action of salivary amylase on starch is used as an example.
The article Catalysing chemical reactions with enzymes includes an animated video outlining in detail how enzymes work.
See our Enzymes Pinterest board for more resource ideas.
- amylase: An enzyme present in saliva that can digest starch.
- starch: A complex carbohydrate found chiefly in seeds, fruits, tubers, roots and stem pith of plants. Commonly found in foods, such as potatoes, wheat, rice and corn.
- digestion: The mechanical and chemical breaking down of food into smaller components that can be absorbed into a bloodstream.
- glucose: A simple sugar belonging to the group of carbohydrates called monosaccharides. It is the main form of carbohydrate used by the body.
- enzyme: A complex protein that acts as a catalyst (speeds up chemical reactions) in specific biochemical reactions. For example, saliva contains an enzyme called amylase that can break down starch into simple sugars.
- control: 1. Part of a scientific experiment in which no treatment has been applied in order to see whether there are any detectable differences to the experiment that did receive a treatment. 2. To hold in check or to curb.
- temperature: A measure of the degree of hotness or coldness of an object or substance. Temperature is measured with a thermometer calibrated in one or more temperature scales. Kelvin scale temperature is a measure of the average energy of the molecules of a body.
- enzyme: A complex protein that acts as a catalyst (speeds up chemical reactions) in specific biochemical reactions. For example, saliva contains an enzyme called amylase that can break down starch into simple sugars.
- surface area: The total area of an object or surface.
- pH: A measure of the acidity or alkalinity of a substance, based on a scale of 0 to 14. Acidic solutions have pH values less than 7, whereas alkaline solutions have pH values greater than 7.
- molecule: Two or more atoms bonded together. The molecule of an element has all its atoms the same. The molecule of a compound has two or more different atoms.
