Preparation and application of purple onion pigment

An onion and pigment technology, applied in the preparation and application of purple onion pigment, can solve the problems of waste water, waste environmental pollution, expensive indicators, unfavorable large-scale use, etc., achieve a wide range of raw material sources, prevent anthocyanin degradation, and operate simple effect

Inactive Publication Date: 2017-11-03
SHANXI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Commonly used acid-base indicators include phenolphthalein, methyl orange, methyl red, etc., all of which need to go through complex chemical processes, and waste water, waste, etc. are likely to be generated during the preparation process and cause environmental pollution
Moreover, some indicators are expensive, which is not conducive to large-scale use
Traditional indicators generally only have two color changes, so the error in estimating the pH value is large

Method used

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  • Preparation and application of purple onion pigment
  • Preparation and application of purple onion pigment

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] The preparation steps of purple onion pigment:

[0022] 1) Remove the inedible parts of fresh onions, rinse them repeatedly with tap water and distilled water, dry them under natural conditions, take 20g of purple onions, cut them into small pieces, and beat them into a homogenate at 4°C;

[0023] 2) Take the homogenate and add 60 mL of methanol containing 0.1% hydrochloric acid, and sonicate 3 times at room temperature, 10 min each time;

[0024] 3) Buchner funnel vacuum filtration;

[0025] 4) The filter residue was extracted twice with 40 mL of methanol solution containing 0.1% hydrochloric acid, and the filtrates were combined for three times;

[0026] 5) Concentrate in vacuo at 40°C to remove methanol, and dilute to 25 mL with deionized water containing 0.01% hydrochloric acid to obtain a purple onion pigment solution. After calculation, the anthocyanin content in the crude extract obtained in this example is 19.36 mg / g.

Embodiment 2

[0028] Get 1mL of the pigment solution of Example 1, use a pH meter to measure that the purple onion pigment is acidic, the pH is 1.87, and the color is bright red. Add 0.1mol / L NaH dropwise 2 PO 4 Solution, solution pH ≤ 3, showing bright red.

Embodiment 3

[0030] Take 1mL of the pigment solution of Example 1, add 1mol / L NaOH solution dropwise, use a pH meter to measure the pH value of the solution, and observe the color of the solution. The results are as follows: the pH of the solution is 3-5, showing purple and darker color ; Solution pH ≥ 6.5, it is green; solution pH ≥ 12, it is yellow. The color change is obvious and easy to judge.

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Abstract

The invention relates to the preparation and application of a purple onion pigment, which belongs to the preparation of plant natural pigments. Its preparation method: wash the onion, cut into small pieces, grind and homogenate with a juice extractor, ultrasonically extract with methanol containing 0.1% hydrochloric acid, filter with suction, combine the filtrates, spin steam, and finally use 0.1% hydrochloric acid The aqueous solution is constant to volume. Mixing the extracted pigment with solutions of different pH will produce different color changes, so it can be used as an acid-base indicator to detect the pH of the solution. The invention has simple process and simple and easy-to-obtain manufacturing materials.

Description

technical field [0001] The invention relates to the preparation and application of plant pigments, in particular to a method for preparing natural purple onion pigments and the application of the prepared purple onion pigments as acid-base indicators. Background technique [0002] As the development of synthetic pigments is limited, the development of natural pigments is getting more and more attention. [0003] Purple onions contain a large amount of anthocyanins, mainly cyanidin and a small amount of paeoniflorin. Anthocyanins are a class of water-soluble natural pigments, belonging to flavonoids. Anthocyanins are extremely unstable and are easily affected by factors such as temperature, light, and pH. [0004] Anthocyanins have structural interconversion in pH aqueous solution. As shown in the figure, in the acidic aqueous solution, there are three kinds of chemical equilibriums of anthocyanins at the same time: the acid-base balance between the Huang Yang salt cation ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09B61/00C09B67/54G01N21/80G01N31/22
CPCC09B61/00C09B67/0096G01N21/80G01N31/221
Inventor 李甘李勇杜芳芳李明璐双少敏董川
Owner SHANXI UNIV
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