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Method for directly detecting tea glucoside combined state aroma precursor substances

A technology of precursor substances and combined states, which is applied in the direction of measuring devices, instruments, scientific instruments, etc., can solve the problems of low flux, incomplete enrichment, cumbersome extraction and purification process of precursor substances, etc.

Inactive Publication Date: 2018-10-23
ZHEJIANG UNIV
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Problems solved by technology

Among them, the enzymatic hydrolysis and GC-MS detection technology needs to extract the free and glycoside-bound aroma precursors in the tea sample with water or buffer solution, and repeatedly extract and remove the free-state aroma substances with solvents such as ether. The extract of aroma precursors is mixed with glucosidase or pectinase to hydrolyze and release aroma substances, and then the aroma substances are enriched by solid phase microextraction (SPME) or simultaneous distillation extraction (SDE), and then through GC- MS can qualitatively and quantitatively extract the aroma substances. This method can only indirectly estimate the aglycone properties of the bound glycoside precursors, but cannot obtain the information of the sugar groups. Moreover, in the process of enzymatic hydrolysis of glycosides and the enrichment of the released aroma, it is often There are also problems such as incomplete hydrolysis and incomplete enrichment
Glycoside-bound aroma precursor derivatization combined with GC-MS analysis method, the main process is to extract and purify the glycoside-bound aroma precursor in samples such as tea, and mix it with trifluoroacetamide reagent or silanization reagent after fully drying The derivatization treatment introduces volatile acetyl or silane groups, and the precursor substances after derivatization and conversion are qualitatively and quantitatively analyzed by GC-MS; The precursor substance process is cumbersome, and the subsequent processing of the analysis data is complicated, because GC-MS obtains the information of the derivatized glycoside substance, and it also needs to restore the original glycoside precursor information obtained by deconvolution and other processes
When using UPLC-MS SIM to detect glycoside-bound aroma precursors, it is necessary to extract the glycoside-bound aroma precursors in tea, and after purification by column chromatography and other means, they are separated by UPLC. According to the glycoside-bound aroma precursors Molecular weight characteristics SIM is used to collect and quantify the signal of a single target; although this method can directly measure the glycoside-bound aroma precursor substances, the extraction and purification process of the precursor substances is cumbersome, and it is necessary to remove as many interfering impurities as possible. Because there are often interfering substances with similar molecular weights in the precursor extract; and this analysis method has a low throughput, and only one glycoside-bound aroma precursor substance can be detected at a time, and a sample needs to be tested many times before it can be detected. Precursors fully detected
So far, there is still a lack of rapid and direct methods for the efficient detection of tea glycoside-bound aroma precursors

Method used

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  • Method for directly detecting tea glucoside combined state aroma precursor substances

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Embodiment 1

[0048] Embodiment 1. A method for directly detecting tea glycoside-bound aroma precursor substances, the following steps are carried out in sequence:

[0049] 1) Extraction of glycoside-bound aroma precursors in fresh tea leaves:

[0050] Harvest new shoots with 1 bud and 2 leaves in spring of 'Zhenong 113', use a hole puncher with a diameter of 0.5cm to punch holes in the harvested shoot leaves, weigh a leaf disk equivalent to 0.1g dry weight, and place In the homogenizer, add 10mL of pre-cooled (-5°C) 95% methanol and mix, then homogenate for 10 minutes at a speed of 1200-2000r / min (low speed can be used for young samples, and high speed can be used for coarse and old samples) , transfer the homogenate to a 50mL centrifuge tube, centrifuge at 5000r / min, 4°C for 5min, absorb all the supernatant and transfer to a new centrifuge tube; mix the residue with 10mL pre-cooled methanol (-5°C) again, and sonicate (40W) Extract for 20 minutes, centrifuge at 5000r / min at 4°C for 5 minu...

Embodiment 2

[0072] Embodiment 2, a method for directly detecting tea glycoside-bound aroma precursor substances, the following steps are carried out in sequence:

[0073] 1) Extraction of green tea glycoside-bound aroma precursors:

[0074] Grind the Maofeng green tea sample with a sample mill, pass through a 60-mesh sieve, weigh a sample equivalent to 0.05g dry weight in a 50mL centrifuge tube, add 10mL pre-cooled (-5°C) 90% methanol ultrasonic (40W) leaching After 20min, centrifuge at 5000r / min, 4°C for 5min, transfer all the supernatant to a new centrifuge tube; extract the residue again with 10mL pre-cooled 90% methanol ultrasonic (40W) for 10min, and centrifuge, absorb all supernatant, combine 2 supernatants; add 3.0 μL of 4-nitrophenyl-β-D-glucoside (1 mg / mL) as an internal standard to the combined supernatant, add 0.2 g of insoluble polyvinylpyrrolidone pre-swelled with ultrapure water PVPP, mix well to precipitate polyphenols, let it stand for 60 minutes, centrifuge at 10000r / min...

Embodiment 3

[0080] Embodiment 3, a method for directly detecting tea glycoside-bound aroma precursor substances, the following steps are carried out in sequence:

[0081] 1) Extraction of aroma precursors in the glycoside-bound state of Oolong tea:

[0082] Sampling the shake green leaves in the process of oolong tea processing, weigh the shake green leaf samples equivalent to 0.1g dry weight, place in a homogenizer, add 10mL pre-cooled (-5°C) 95% methanol homogenate for 20min, Centrifuge at 5000r / min, 4°C for 5min, transfer all the supernatant to a centrifuge tube; mix the residue with 10mL pre-cooled 95% methanol again, and extract with ultrasonic (40W) for 20min, centrifuge, absorb all the supernatant, and combine twice supernatant; add 3.0 μL 4-nitrophenyl-β-D-glucoside (1 mg / mL) to the combined supernatant as an internal standard, add 0.1 g of insoluble polyvinylpyrrolidone PVPP pre-swelled by ultrapure water, Mix well to precipitate polyphenols. After standing still for 60 minutes,...

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Abstract

The invention discloses a method for directly detecting tea glucoside combined state aroma precursor substances. According to the invention, fresh tea leaves, a tea product being processed or a tea finished product are used as a to-be-measured sample, the method comprises the following steps: 1) extracting a glucoside combined state aroma precursor from the to-be-measured sample, 2) performing a UPLC-MS / MS analysis on the glucoside combined state aroma precursor in an extract, and 3) calculating the content of the tea glucoside combined state aroma precursor substances: by taking a 4-nitrophenyl-beta-D-glucoside internal standard as a reference, obtaining 9 glucoside combined state aroma precursor substances of benzyl alcohol primrose gluocoside, methyl salicylate primrose glucoside, phenylethyl alcohol primrose glucoside, cis 3-hexenol primrose glucoside, linalool oxide I primrose glucoside, linalool oxide II primrose glucoside, linalool oxide primrose glucoside III, linalool primroseglucoside, and geraniol primrose glucoside. The method has high detection efficiency on the glucoside combined state aroma precursor substances.

Description

technical field [0001] The invention relates to a method for detecting aroma precursor substances in a glycoside-bound state in tea, specifically a method for directly detecting A method for rapid and efficient detection of glycoside-bound aroma precursors in fresh leaves of tea trees, tea products in process and dry tea. Background technique [0002] Aroma is an important tea quality factor. The aroma components in tea mainly include alcohols, aldehydes, ketones, esters, heterocyclic compounds, etc., among which alcohol compounds are the most important aroma components. Tea alcohol aroma substances can be divided into three types of compounds, terpene alcohols, aromatic alcohols and fatty alcohols, and terpene alcohols and aromatic alcohols often have floral aroma characteristics, which make an important contribution to the aroma quality of tea. Common terpene alcohols in tea include linalool, linalool oxides (I, II, III, IV), geraniol, nerolidol, nerolidol, etc., and aro...

Claims

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Application Information

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IPC IPC(8): G01N30/02G01N30/06
CPCG01N30/02G01N30/06
Inventor 陆建良李达马一校胡慈杰郑新强叶俭慧梁月荣
Owner ZHEJIANG UNIV
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