阅读说明：本技术 一种测定余甘子氨基酸组成及含量的方法 (Method for determining amino acid composition and content of phyllanthus emblica ) 是由 袁建民 何璐 杨晓琼 孔维喜 许智萍 赵琼玲 瞿文林 雷虓 坝德昆 于 2020-05-27 设计创作，主要内容包括：本发明公开了一种测定余甘子氨基酸组成及含量的方法,包括如下步骤：精确称取余甘子果实干粉100mg-200mg,将样品送至聚四氟乙烯微波水解罐底部,样品水解盐酸的添加样品中精确加入6mol/L HCl 8ml,轻轻摇匀,静置,吹入氮气,约20-30s,氮气压力宜在0.1左右,置于常规水解管中,加入6mol/L HCl 8ml,摇匀静置,同样吹入氮气,封管,置于恒温烘箱中110℃条件下水解22h-24h；按照设定好的微波水解程序进行样品水解,消解完毕后,冷却至室温,混匀,开管,定容至50ml,0.45μm滤膜过滤；吸取水解液0.5ml置于5ml EP管中,温度60℃,置于氮吹仪插孔中赶酸,距离液面0.5cm,加入1-2ml样品稀释液pH为2.2,使氨基酸浓度为50-200nmol/L为宜,震荡混匀,用0.22μm滤膜过滤,供上机测定；本发明提高了余甘子氨基酸测定的精度和效率。(The invention discloses a method for determining the composition and content of amino acid in emblic leafflower fruit, which comprises the following steps: accurately weighing 100-200 mg of phyllanthus emblica fruit dry powder, sending a sample to the bottom of a polytetrafluoroethylene microwave hydrolysis tank, accurately adding 8ml of 6mol/L HCl into an added sample of sample hydrolyzed hydrochloric acid, shaking up gently, standing, blowing nitrogen for about 20-30s, setting the nitrogen pressure to be about 0.1, placing the sample into a conventional hydrolysis tube, adding 8ml of 6mol/L HCl, shaking up, standing, blowing nitrogen in the same way, sealing the tube, and placing the tube into a constant-temperature oven for hydrolysis for 22-24 h at the temperature of 110 ℃; hydrolyzing the sample according to a set microwave hydrolysis program, cooling to room temperature after digestion, uniformly mixing, opening a tube, fixing the volume to 50ml, and filtering with a 0.45-micron filter membrane; sucking 0.5ml of hydrolysate, placing in a 5ml EP tube, keeping the temperature at 60 ℃, placing in a jack of a nitrogen blowing instrument to drive acid, keeping the distance from the liquid level to be 0.5cm, adding 1-2ml of sample diluent with the pH value of 2.2 to ensure that the concentration of amino acid is 50-200nmol/L, shaking, mixing uniformly, filtering with a 0.22 mu m filter membrane, and measuring by using an upper machine; the method improves the precision and efficiency of the determination of the amino acid of the emblic leafflower fruit.)

1. A method for measuring the composition and content of amino acids in phyllanthus emblica is characterized by comprising the following steps:

1. preparation of dried powder of emblic leafflower fruit

Selecting healthy and intact phyllanthus emblica fruits, cleaning, removing kernels, drying, crushing and sieving to obtain phyllanthus emblica fruit dry powder;

2. weighing a sample

Accurately weighing 100-200 mg of the dried powder of the emblic leafflower fruit, sending a sample to the bottom of a polytetrafluoroethylene microwave hydrolysis tank by adopting a paper groove with the size of 297mm multiplied by 40mm,

3. addition of sample hydrolysis hydrochloric acid

Accurately adding 8ml of 6mol/L HCl into the sample, shaking up gently, standing, blowing in nitrogen for about 20-30s, wherein the nitrogen pressure is preferably about 0.1 to avoid blowing out liquid, screwing down the digestion tank to ensure complete sealing, simultaneously placing the sample into a conventional hydrolysis tube, adding 8ml of 6mol/L HCl, shaking up gently, standing, blowing in nitrogen likewise, sealing the tube, and placing the tube into a constant-temperature oven for hydrolysis for 22-24 h at the temperature of 110 ℃;

4. microwave hydrolysis program set-up

Hydrolyzing the sample according to a set microwave hydrolysis program, cooling to room temperature after digestion, uniformly mixing, opening a tube, fixing the volume to 50ml, and filtering with a 0.45-micron filter membrane;

5. removing acid from hydrolysate

Sucking 0.5ml of hydrolysate, placing in a 5ml EP tube at 60 deg.C, placing in a jack of a nitrogen blowing instrument to drive acid, keeping a distance of 0.5cm from the liquid surface, evaporating to dryness, adding a little deionized water if necessary, and repeatedly evaporating to dryness for 1-2 times;

6. on-machine sample preparation

Adding 1-2ml sample diluent with pH of 2.2 to make amino acid concentration of 50-200nmol/L, shaking, mixing, filtering with 0.22 μm filter membrane, and measuring with an apparatus;

7. preparation of Standard Curve

Sampling 17 amino acid standard samples (2.5 umol/L, cysteine halved, diluted 25 times to 100 nmol/L) for measurement by an upper machine, respectively sampling 5ul, 10ul, 20ul and 50ul, and making a standard curve;

8. sample detection

Sequentially feeding 50ul samples, measuring peak area, and calculating amino acid composition and content in the dried emblic leafflower fruit powder according to a standard curve;

9. test for recovery with addition of standard

Precisely adding a certain amount of mixed amino acid standard solution into a dry powder sample of the emblic leafflower fruit with known content, and measuring the recovery rate of the mixed amino acid standard solution;

10. repeatability test

Respectively sucking 50ul of samples 1, 2 and 3, analyzing by an amino acid analyzer, and calculating the measurement result.

Technical Field

The invention belongs to the technical field of food detection, and particularly relates to a method for determining amino acid composition and content of emblic leafflower fruit.

Background

Emblic leafflower fruit (phyllanthusemblica l.), commonly known as phyllanthus emblica, phyllanthus of euphorbiaceae, is a very unique resource plant distributed in dry and hot valley areas. Native to India, Pakistan, etc. The distribution area is the largest in China and India at present, and the yield is the highest. The resource of the emblic leafflower fruit in China is quite rich, the large-area cultivation is carried out by Fujian, Guangxi, and the wild resource is most rich in Yunnan. The emblic leafflower fruit has rich nutrition, unique flavor and dual purposes of medicine and food, contains various trace elements beneficial to human bodies, is rich in chemical substances such as vitamins, phenols, flavones, polysaccharides, amino acids and the like, has pharmacological health-care effects of resisting oxidation, inflammation and tumors, resisting viruses, resisting aging, reducing blood pressure, blood sugar, blood fat and the like, and has extremely high development and utilization values.

According to the research, only one of nearly 150 thousands of animals, 30 thousands of plants and 20 thousands of microorganisms on the earth is in nature, and the 'life is the existence mode of proteins, and the essence of the existence mode is the continuous self-renewal of chemical components of the proteosome'. The chemical component of the proteosome is the basic unit of the constituent protein, namely amino acid, and the continuous self-renewal is the continuous rearrangement and combination of the amino acid. Therefore, the method has important significance for analyzing and detecting the composition and the content of the amino acid.

Compared with the wild emblic leafflower fruit, the research on the development and utilization of the emblic leafflower fruit amino acid is relatively less in China, so that the research on the composition and the content of the emblic leafflower fruit amino acid has better application prospect. At present, the research on the analysis of the amino acid of the emblic leafflower fruit is few, most of the research refers to the national standard (GB/T5009.124-2003) to determine the content of the amino acid in the food, and a constant-temperature oven is adopted for carrying out conventional acid hydrolysis, so that the hydrolysis process is complex, the reagent dosage is large, the temperature control is inaccurate, the time and the labor are wasted, the hydrolysis is incomplete, and the potential safety hazard is large. However, at present, a whole set of methods for performing sample pretreatment by microwave hydrolysis and then measuring the amino acid of the emblic leafflower fruit by an amino acid analyzer are not available, and the accuracy and precision of the amino acid of the emblic leafflower fruit measured by the existing method are poor, and the repeatability is not high.

Disclosure of Invention

The invention aims to solve the problems of complex sample pretreatment process, incomplete sample hydrolysis, large reagent dosage, inaccurate temperature control, time and labor waste in the hydrolysis process, potential safety hazard and environmental pollution, provides a suitable method for efficiently and accurately measuring the amino acid in the emblic leafflower fruit, and improves the accuracy and the efficiency of measuring the amino acid.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for determining the amino acid composition and content of emblic leafflower fruit comprises the following steps:

1. preparation of dried powder of emblic leafflower fruit

Selecting healthy and intact phyllanthus emblica fruits, cleaning, removing kernels, drying, crushing and sieving to obtain phyllanthus emblica fruit dry powder;

2. weighing a sample

Accurately weighing 100-200 mg of the emblic leafflower fruit dry powder, and conveying a sample to the bottom of a polytetrafluoroethylene microwave hydrolysis tank by adopting a paper groove with the size of 297mm multiplied by 40mm, wherein the sample is weighed too little, and the amino acid peak area is too small; the sample is too large in weight, the concentration of amino acid is too high, and baldness is easy to occur when the peak appears;

3. addition of sample hydrolysis hydrochloric acid

Accurately adding 6mol/L HCl 8ml into the sample, shaking gently, standing, blowing in nitrogen gas for about 20-30s, preferably about 0.1 s to avoid blowing out liquid, screwing down the digestion tank, and ensuring complete sealing. Meanwhile, placing the sample in a conventional hydrolysis tube, adding 8ml of 6mol/L HCl, shaking up gently, standing, blowing nitrogen gas in the same way, sealing the tube, and placing in a constant-temperature oven for hydrolysis for 22-24 h at the temperature of 110 ℃;

4. microwave hydrolysis program set-up

Hydrolyzing the sample according to a set microwave hydrolysis program, cooling to room temperature after digestion, uniformly mixing, opening a tube, fixing the volume to 50ml, and filtering with a 0.45-micron filter membrane;

5. removing acid from hydrolysate

Sucking 0.5ml of hydrolysate, placing in a 5ml EP tube at 60 deg.C, placing in a jack of a nitrogen blower to remove acid, wherein the nitrogen pressure is not too high and is 0.5cm away from the liquid surface, preferably no liquid is blown out. Evaporating to dryness, adding a little deionized water if necessary, and repeatedly evaporating to dryness for 1-2 times;

6. on-machine sample preparation

Adding 1-2ml sample diluent with pH of 2.2 to make amino acid concentration of 50-200nmol/L, shaking, mixing, filtering with 0.22 μm filter membrane, and measuring with an apparatus;

7. preparation of Standard Curve

The standard samples of 17 amino acids, namely 2.5umol/L, cysteine is halved, diluted by 25 times to 100nmol/L, supplied to an upper machine for measurement, and injected with 5ul, 10ul, 20ul and 50ul respectively to prepare standard curves. The detection conditions are chromatographic column: LCAK 06/Na; column temperature: gradient temperature control at 58-74 ℃; 0.45ml/min of an elution pump and 0.25ml/min of a derivatization pump; detection wavelength: 570nm +440 nm; the reactor temperature was 130 ℃; standard hydrolysis time of 45 minutes;

8. sample detection

Sequentially feeding 50ul samples, measuring peak area, and calculating amino acid composition and content in the dried emblic leafflower fruit powder according to a standard curve;

9. test for recovery with addition of standard

Precisely adding a certain amount of mixed amino acid standard solution into a dry powder sample of the emblic leafflower fruit with known content, and measuring the recovery rate of the mixed amino acid standard solution;

10. repeatability test

Respectively sucking 50ul of samples 1, 2 and 3, analyzing by an amino acid analyzer, and calculating the measurement result.

Has the advantages that: compared with the prior art, the invention has the following advantages:

1. the sample pretreatment process is simple; 2. the sample is hydrolyzed completely; 3. the reagent consumption is saved; 4. the temperature control is accurate; 5. the hydrolysis process is safe and time-saving, and the efficiency is improved; 6. safe operation and little environmental pollution.

Detailed Description

The present invention will be further described with reference to the following examples for facilitating understanding of those skilled in the art, and the description of the embodiments is not intended to limit the present invention.