[Chemistry Class Notes] on Sugar Alcohol Pdf for Exam

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Sugar alcohols are organic compounds which are derived from the sweet tasting soluble carbohydrates and contain one -OH group attached to each carbon atom of the molecule. Sugar alcohols are white, water soluble solid compounds. They can occur naturally and can be synthesized by various methods at industrial level. 

On consumption, sugar alcohol gives a sweet taste and contributes fewer calories than other sugars. That is why they are extensively used in the food industry. You will be surprised to know that nowadays, most of the candies available in the market do not contain sugars due to health concerns and increasing obesity problem among children. Instead, they are composed of sugar alcohols. 

Sugar alcohols come under the class polyols as they contain many hydroxyl groups.

Examples of Sugar Alcohols

Erythritol, Xylitol, mannitol and sorbitol are common examples of sugar alcohols. They are 60-70% as sweet as general sugar but give lesser calories than sugars. 

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General Chemical Structure of Sugar Alcohols

They have following general chemical formula – HOCH2(CHOH)nCH2OH

As you can see in the general formula of sugar alcohols that sugars have two fewer hydrogen atoms than sugar alcohols. As sugar alcohols are derived from pentose or hexose sugars so they have 5-6 carbon atoms in the chain and as discussed above they have one hydroxyl group attached to each carbon atom. Sugar alcohols generally are not found in cyclic structures. Although on dehydration sugar alcohols give cyclic ethers. 

Synthesis of Sugar Alcohols 

Sugar alcohols can be obtained naturally and can be synthesized as well. For example, erythritol is sugar alcohol and can be obtained by the fermentation of glucose and sucrose sugars. While mannitol is produced by hydrogenation of sugars in presence of spongy nickel catalyst. Sorbitol sugar alcohol is also produced as mannitol. 

HOCH2CH(OH)CH(OH)CH(OH)CH(OH)CHO + H2 → HOCH2CH(OH)CH(OH)CH(OH)CH(OH)CHHOH

You can see in the above reaction that sugar contains two hydrogen atoms less than sugar alcohols. 

Characteristics of Sugar Alcohols 

Sugar Alcohols Show Following Characteristics –

• They are not as sweet as general sugars and do not contain as many calories as sugars. 

• Their metabolism is not possible by oral bacteria. 

• They do not turn brown in color on heating like general sugars. 

• Dissolution of sugar alcohols is an endothermic reaction. 

• They give a cooling sensation on consumption. 

• They do not completely get absorbed into the bloodstream. Their rate of absorption is 50% slower than sugars. 

Health Effects of Sugar Alcohols 

Sugar alcohols give many advantages over general sugars. They are replacing sugars in the food due to their low calories and sweet taste. Sugars cause tooth decay while sugar alcohols do not contribute to tooth decay as they cannot be metabolized by oral bacteria. Even xylitol sugar alcohol prevents tooth decay. 

They are absorbed at a lower rate than sugars in the bloodstream. So, they are perfect for diabetic patients. As they have less impact on blood sugar level. Many sweet food items which are prepared for diabetic patients use sugar alcohols as sweeteners. Although unabsorbed sugar alcohols may cause diarrhoea and vomiting, when consumed in insufficient quantities. It happens due to osmotic effects.

 

Uses of Sugar Alcohols

Sugar alcohols are widely used in many industries such as food and pharmaceuticals etc. Few of its uses are listed below –

• They are widely used as food additives. As they are sweet in taste and generate less calories. 

• They are used to reduce the aftertaste of many sweeteners. 

• They do not cause tooth decay and help in prevention of tooth decay. 

• They are widely used by diabetic patients in their sweet food items. 

• Their glycaemic index or GI is low, so they help in maintaining the blood sugar level. 

• Many studies on rats show that xylitol can prevent osteoporosis. As it increases bone volume and mineral content. 

• Xylitol can increase collagen production so it can help to make you skin healthy. 

• Various sugar alcohols are being used in baked food items, candies, chewable vitamins, cough syrups, frostings, ice creams, mouthwashes, toothpastes etc. 

• They are used in the medicines related to eight management.

This ends our coverage on the topic “Sugar alcohols”. We hope you enjoyed learning and were able to grasp the concepts. We hope after reading this article you will be able to solve problems based on the topic. If you are looking for solutions of NCERT Textbook problems based on this topic, then log on to website or download Learning App. By doing so, you will be able to access free PDFs of NCERT Solutions as well as Revision notes, Mock Tests and much more.