Determination of soluble sugar content in plants (anthrone method)

Summary

The determination of soluble sugars in fruits and vegetables can be used to: understand and identify the quality of fruits and vegetables.

Operation method

Determination of soluble sugar content in plants (anthrone method)

Principle

Furfural or hydroxymethylfurfural is further condensed with anthrone reagent to produce a blue-green substance, which has the maximum absorption at 620 nm in the visible region, and its light absorption value is directly proportional to the content of sugar within a certain range. This method can be used for the determination of monosaccharides, oligosaccharides and polysaccharides, and has the advantages of high sensitivity, simplicity and rapidity, and is suitable for the determination of trace samples.

Materials and Instruments

Plant material
Standard glucose Anthrone reagent Concentrated sulfuric acid
Spectrophotometer Plugged graduated test tubes Constant temperature water tank Funnel Volumetric flasks Test tubes Test tube racks Mortar and pestle

Move

1.The production of glucose standard curve

Take six 20ml cold test tubes, numbered, according to the data in the table below to prepare a series of different concentrations of standard glucose solution.

Add 0.5ml of anthrone reagent in each tube, then slowly add 5ml of concentrated H2SO4, shake well, open the test tube plug, set in boiling water bath for 10 minutes, take out and cool down to room temperature, colorimetry at 620nm wavelength, measure the optical density value (OD) of each tube solution, take the standard glucose content as the horizontal coordinate and the optical density value as the vertical coordinate, make the standard curve.

2.Extraction of soluble sugar in the sample

Weigh 1 gram of cabbage leaves, cut, placed in a mortar, add a small amount of distilled water, grinding into a homogenate, and then transferred to 20 ml graduated test tube, with 10 ml of distilled water to wash the mortar in batches, and the washings were transferred to the graduated test tube. Put in a boiling water bath with a cover and boil for 10 minutes, cooled and filtered, the filtrate was collected in a 100ml volumetric flask, with distilled water to the scale, shake well and standby.

3. Determination of sugar content

Absorb 1 ml of extract into a 20 ml stoppered graduated test tube with a pipette, add 1 ml of water and 0.5 ml of anthrone reagent. Then slowly add 5ml of concentrated H2SO4 (Note: Concentrated sulfuric acid will produce a lot of heat when it meets water!) Cover the tube with a stopper, shake gently, and place in a boiling water bath for 10 minutes (for colorimetric blank, mix 2 ml of distilled water with 0.5 ml of anthrone reagent and keep warm in a boiling water bath for 10 minutes). After cooling to room temperature, colorimetry was carried out at a wavelength of 620 nm, and the optical density value was recorded. The corresponding glucose content (μg) was found on the standard curve.

V. Calculation of results

Caveat

1, when adding concentrated H2SO4 should be added slowly, so as not to produce a large amount of heat and burst boiling, burn the skin, such as the above situation, should be quickly rinsed with tap water.

2， water bath heating should be opened when the test tube plug.

Common Problems

The anthrone method for the determination of soluble sugars is widely used for the determination of soluble sugar content in various plant tissues because of its high accuracy, good reproducibility, easy operation, rapidity and sensitivity.

Reference: "Optimization of conditions for the determination of soluble sugar content in red dates by anthrone method" Food Science

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