Method for quickly measuring methanal content in dried beancurd sticks

Abstract

The invention relates to a method for quickly measuring methanal content in dried beancurd sticks, which is characterized by adopting a combined using method of an efficient liquid phase chromatogram method and a viable wavelength detector (VWD) to qualitatively and quantitatively measure methanal content in dried beancurd stick products. The method comprises the steps of using Nash reagent to perform precolumn derivation and chromatographic analysis on derivation products, enabling the detection wavelength of the VWD to be 412nm, and performing gradient elution with a binary system of acetonitrile and water as flow phase. The flow speed is 0.8mL / min to 1mL / min, the judgment standard of the methanal content is that a linear range of the methanal content is 0.00 to 0.80mg / L, the linear equation is that Y is equal to 27.024X, the Y is the peak area of derivation reaction products, and the X is the methanal content. The method has the advantages that compared with GB / T21126-2007, the derivation reaction time is shortened from 40 minutes to 15minutes, products are not required to be extracted by organic solvent, loss of derivation products is reduced, labor intensity is reduced, and chemicals are saved. Methodology experimental results of the method meet analysis requirements of samples, thereby achieving the purpose of quick analysis.

Description

technical field

[0001] The invention relates to the field of food detection methods. In particular, it relates to a method for rapidly measuring formaldehyde content in bean curd sticks. Background technique

[0002] Yuba is obtained by boiling soybean milk, removing the fat and soybean protein conjunctiva and drying it. As the cooking time increases, the conjunctiva becomes less and less, and the remaining carbohydrate-based substances will undergo a "browning reaction" and even turn black. Adding the highly reductive white block can play a "bleaching" effect, which not only changes the color, but also increases the yield. Hanging white block is an industrial raw material, which is used as a reduction catalyst in the printing and dyeing industry and synthetic rubber. It decomposes under acidic conditions to produce formaldehyde. At home and abroad, it is forbidden to use scallops or formaldehyde for food processing.

[0003] In April 2011, an announcement was made on th...

Examples

Embodiment Construction

[0016] (1) Preparation of reagents and standard solutions: formaldehyde standard solution (Tianjin Guangfu Fine Chemical Research Institute, formaldehyde standard solution C=1.000 mg / mL ); anhydrous sodium sulfate, ammonium acetate, glacial acetic acid, and acetylacetone were analytically pure reagents; samples were commercially available bean curd sticks.

[0017] 40 mg / L Preparation of formaldehyde standard stock solution: Accurately absorb formaldehyde standard solution (1.000 mg / mL ) 4.00 mL Make up to 100 with deionized water mL volumetric flask. Store refrigerated.

[0018] 2.0 mg / L Preparation of formaldehyde standard solution: Accurately absorb formaldehyde standard stock solution 5.00 mL Make up to 100 with deionized water mL volumetric flask. Prepare on the day of use.

[0019] Preparation of Nash reagent: 150 g Ammonium acetate, 3.00 mL Glacial acetic acid, 2.0 mL Acetyl acetone, diluted with deionized water to 1 L , stored in a brown bottle a...

technical field

[0001] The invention relates to the field of food detection methods. In particular, it relates to a method for rapidly measuring formaldehyde content in bean curd sticks. Background technique

[0002] Yuba is obtained by boiling soybean milk, removing the fat and soybean protein conjunctiva and drying it. As the cooking time increases, the conjunctiva becomes less and less, and the remaining carbohydrate-based substances will undergo a "browning reaction" and even turn black. Adding the highly reductive white block can play a "bleaching" effect, which not only changes the color, but also increases the yield. Hanging white block is an industrial raw material, which is used as a reduction catalyst in the printing and dyeing industry and synthetic rubber. It decomposes under acidic conditions to produce formaldehyde. At home and abroad, it is forbidden to use scallops or formaldehyde for food processing.

[0003] In April 2011, an announcement was made on th...

Examples

Embodiment Construction

[0016] (1) Preparation of reagents and standard solutions: formaldehyde standard solution (Tianjin Guangfu Fine Chemical Research Institute, formaldehyde standard solution C=1.000 mg / mL ); anhydrous sodium sulfate, ammonium acetate, glacial acetic acid, and acetylacetone were analytically pure reagents; samples were commercially available bean curd sticks.

[0017] 40 mg / L Preparation of formaldehyde standard stock solution: Accurately absorb formaldehyde standard solution (1.000 mg / mL ) 4.00 mL Make up to 100 with deionized water mL volumetric flask. Store refrigerated.

[0018] 2.0 mg / L Preparation of formaldehyde standard solution: Accurately absorb formaldehyde standard stock solution 5.00 mL Make up to 100 with deionized water mL volumetric flask. Prepare on the day of use.

[0019] Preparation of Nash reagent: 150 g Ammonium acetate, 3.00 mL Glacial acetic acid, 2.0 mL Acetyl acetone, diluted with deionized water to 1 L , stored in a brown bottle a...

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