Define Sugars - Chemistry and Functionality?

In this section we will learn about the simple carbohydrates called sugars. As you may already know, those carbohydrates that cannot be hydrolysed into simpler forms are known as 'Monosaccharides' or simple sugars. Monosaccharides may be made up of 3-8 carbon atoms. Chemically, these are Poly hydroxy aldehydes or ketones. Depending upon the presence of aldehyde or ketone group in the structure, the carbohydrates may be aldoses or ketoses, and depending upon the number of carbon atoms present in the structure, these may be called as pentose (5 carbon monosaccharide) or a ketohexose (6 carbon monosaccharide) and depending upon the presence of aldehyde or a keto group, it may be called a aldohexose or ketohexose. A list of commonly occurring aldoses and ketoses is given below:

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We will not dwell on the structure and properties of simple sugars here. Our focus in this course is to understand the functional role of these molecules in our diet. This information, we repeat, is crucial for your understanding of the functions of sugars. But, first let us look at the common sources of sugars.