The most common examples of reducing sugar are maltose, lactose, gentiobiose, cellobiose, and melibiose while sucrose and trehalose are placed in the examples of non-reducing sugars.

Sucrose Absorption and Use Enzymes in your mouth partially break down sucrose into glucose and fructose. However, the majority of sugar digestion happens in the small intestine ( 4 ). The enzyme sucrase, which is made by the lining of your small intestine, splits sucrose into glucose and fructose.

Disaccharides consist of two monosaccharides and may be either reducing or nonreducing. Even a reducing disaccharide will only have one reducing end, as disaccharides are held together by glycosidic bonds, which consist of at least one anomeric carbon.

A nonreducing sugar is a carbohydrate that is not oxidized by a weak oxidizing agent (an oxidizing agent that oxidizes aldehydes but not alcohols, such as the Tollen’s reagent) in basic aqueous solution.

Sucrose is a non-reducing sugar because The two monosaccharide units are held together by a glycosidic linkage between C1 of α-glucose and C2 of β-fructose. Since the reducing groups of glucose and fructose are involved in glycosidic bond formation, sucrose is a non-reducing sugar.

Note that starch and sucrose are blue, classifying them as non-reducing sugars.

Maltose (malt sugar) is a reducing disaccharide while sucrose is a non-reducing one because of the absence of free aldehyde or ketone group in sucrose. In maltose, there are two glucose present. So, this aldehydic group allows the sugar to act as reducing sugar.

Trehalose and Trehalose Oligosaccharides Trehalose (α-d-glucopyranosyl α-d-glucopyranoside) is a non-reducing disaccharide in which the two d-glucose residues are linked through the anomeric positions to one another. Trehalose is widespread in bacteria, fungi, yeast, insects and plants, but is absent from vertebrates.

Following are the examples of non-reducing sugar:

• Sucrose.
• Trehalose.
• Raffinose.
• Stachyose.
• Verbascose.

Sugars that can be oxidised by mild oxidising agents are called reducing sugars. A non-reducing sugar is a sugar that is NOT oxidised by mild oxidising agents. All common monosaccharides are reducing sugars. The disaccharides maltose and lactose are reducing sugars. The disaccharide sucrose is a non-reducing sugar.

Reducing sugars give a dark red color (brick color) when they react with Benedict solution. Non-reducing sugars do not give a red color, instead remains as green in color. Reducing sugars give a positive reaction towards the Fehling’s test. Non-reducing sugars give a negative reaction towards the Fehling’s test.

Benedict’s test distinguishes reducing sugar from non-reducing sugar. Benedict’s reagent contains blue copper (II) ions (Cu2+, cupric ions) that are reduced to copper (I) ions (Cu+, cuprous ions) by carbohydrates.

Xylose is an aldopentose-type reducing sugar. Hemicellulose can be hydrolyzed to pentose sugar, with the help of several hemicellulolytic enzymes.

Because the aglycone is a hemiacetal, lactose undergoes mutarotation. For the same reason lactose is a reducing sugar. The free aldehyde formed by ring opening can react with Benedict’s solution. Thus, a solution of lactose contains both the α and β anomer at the “reducing end” of the disaccharide.

Reducing sugars are always monosaccharides. Means reducing sugars always exist as single molecules. Coming to given options, option B, Gluconic acid. In the name it is mentioned that it has a carboxyl group.

Sugar acids: Oxidation of glucose at carbon 1 produces “onic” acids, such as gluconic acid, and oxidation at carbon 6 produces “uronic” acids, such as glucuronic acid (Fig. 2-9).

Maltose is a reducing sugar; sucrose is not.

Sugar and artificial sweeteners are highly acidic foods, which is one of the reasons the consumption of sweets has recently been linked to so many health ailments. Here is a range of foods from the highly acidic (pH2) to the highly alkaline (ph10). We are aiming to eat foods which are high on the pH scale (above pH6).

Ions can exhibit acidic or basic properties. For example, NH 4+ is acidic, and F – is basic. Salts, being strong electrolytes, dissociate completely in aqueous solution to produce the ions which they are composed of. Therefore, salt solutions can be acidic, basic or neutral.

Please note that a sugar solution is neither acidic nor basic in nature. A sugar solution is neutral. As a result, it will have no effect on any indicator (like litmus paper, phenolphthalein etc).

Soap is a combination of a weak acid (fatty acids) and a strong base (lye), which results in what is known as “alkalai salt,” or a salt that is basic on the pH scale. (See scale below) Sure enough, if you use a pH strip (also known as a litmus test) in soapy water, it often scores an 8 or 9.

-Reducing sugar is any sugar that’s capable of acting as a reducer because it’s a free aldehyde radical or a free group. -All monosaccharides are reducing sugars, alongside some disaccharides, some oligosaccharides, and a few polysaccharides.

For the same reason maltose is a reducing sugar. The free aldehyde formed by ring opening can react with Benedict’s solution. The acetal part of the structure is called the “nonreducing end” of the disaccharide.

Glucose, fructose, mannose, galactose are hexose monosaccharides. The monosaccharirdes have free aldehyde or ketone group which can reduce Cu2+ to Cu. Therefore, these are called reducing sugars.

Sucrose is a non-reducing sugar. A reducing sugar is any sugar that either has an aldehyde group or is capable of forming one in solution through isomerism. The aldehyde functional group allows the sugar to act as a reducing agent.