阅读说明：本技术 一种用于淀粉类掺假判别的碳量子点荧光传感方法 (Carbon quantum dot fluorescence sensing method for distinguishing adulteration of starch ) 是由 付海燕 韦柳娜 陈亨业 兰薇 佘远斌 于 2020-06-01 设计创作，主要内容包括：本发明公开了一种基于碳量子点荧光传感技术判别食品中淀粉类掺假物质的方法,首先以富含碳元素的生物质材料为前驱体进行水热反应合成碳量子点荧光材料,然后采用荧光分光光度计测得已知淀粉类掺假物质含量的掺假食品样品与碳量子点荧光材料所得检测溶液的荧光光谱,并利用偏最小二乘法,对所得荧光光谱数据进行处理分析,建立基于荧光光谱的智能化识别模型库,从而实现对食品样品中的淀粉类掺假物质的准确判别。该方法具有快速、简便、准确、安全环保等优点,可为淀粉类掺假物质的高效鉴别提供一条全新思路。(The invention discloses a method for distinguishing starch adulteration materials in food based on a carbon quantum dot fluorescence sensing technology, which comprises the steps of firstly, taking a biomass material rich in carbon as a precursor to carry out hydrothermal reaction to synthesize a carbon quantum dot fluorescent material, then measuring the fluorescence spectrum of a detection solution obtained by an adulteration food sample with known content of the starch adulteration materials and the carbon quantum dot fluorescent material by using a fluorescence spectrophotometer, processing and analyzing the obtained fluorescence spectrum data by using a partial least square method, and establishing an intelligent identification model base based on the fluorescence spectrum, thereby realizing accurate distinguishing of the starch adulteration materials in the food sample. The method has the advantages of rapidness, simplicity, convenience, accuracy, safety, environmental protection and the like, and can provide a brand new idea for efficiently identifying the starch adulteration substance.)

1. A method for distinguishing starch adulteration materials in food based on a carbon quantum dot fluorescence sensing technology is characterized in that fluorescence spectra of detection solutions obtained by measuring adulteration food samples with known starch adulteration material content and carbon quantum dot fluorescent materials are measured, obtained fluorescence spectrum data are processed and analyzed by a partial least square method, and an intelligent recognition model base based on the fluorescence spectra is established so as to realize the distinguishing of the starch adulteration materials in the food samples.

2. The method according to claim 1, wherein the carbon quantum dot fluorescent material is synthesized by hydrothermal reaction with a biomass material rich in carbon as a precursor.

3. The method of claim 2, wherein the hydrothermal reaction step comprises the steps of: the biomass material and water are mixed evenly, then the mixture is transferred into a polytetrafluoroethylene liner, the mixture reacts for 4 to 10 hours at the temperature of 160-240 ℃, and the microfiltration is carried out after natural cooling.

4. The method as claimed in claim 1, wherein the fluorescence spectrum is measured with an emission wavelength of 400-650nm, a slit width of 10-15nm, and a measured intensity of 600-1500a.u.

5. The method as claimed in claim 1, wherein the starch-based adulterant is one of sweet potato starch, wheat flour, whole wheat flour, rice flour and corn flour, and the fineness is 50-200 meshes.

6. The method of claim 1, wherein the amount of starch-based adulterant powder in the adulterated food sample is 1-50 wt%.

7. The method of claim 1, wherein the concentration of the carbon quantum dot fluorescent material in the detection solution is 2.8-6.7 × 10^-4g/mL。

8. The method of claim 1, wherein the concentration of the adulterated food sample introduced into the testing solution is 0.002 to 0.02 g/mL.

9. The method of claim 1, wherein the response time of the adulterated food sample and the carbon quantum dot fluorescent material in the detection solution is 2-10min of mixing at room temperature.

Technical Field

The invention belongs to the field of preparation, analysis and detection of sensors, relates to a carbon quantum dot fluorescence sensing method, and particularly relates to a carbon quantum dot fluorescence sensing method for judging adulteration of starch substances in food.

Background

Adulteration of food has been known for a long time, and people pay more and more attention to the adulteration problem of the food in recent years. Starch-based materials, because of their low cost, are often used in food adulteration to gain benefits and have a serious impact on the stability of market order. The starch used as the food adulterant is non-toxic and harmless, but can affect the flavor and mouthfeel of the food and even change the functional characteristics of the food. Sellers or manufacturers often adulterate high value foods such as chocolate, coffee, milk powder, cocoa powder, lily powder, and kudzu powder with high starch content powders produced from low value raw materials such as rice, corn, potato, and wheat.

Currently, the starch substances incorporated in food products are difficult to identify due to the influence of the processing mode and the texture of the food products. The developed common technologies for identifying adulteration in food mainly comprise methods such as near infrared spectroscopy technology, microscopic identification, electronic nose and tongue technology, high performance liquid chromatography, stable carbon isotope, chemical sensing and the like, and few researches on the research of adulteration of starch substances are carried out. The methods have the defects of low sensitivity, poor anti-interference performance, high technical requirement, expensive instrument, long time consumption, high biological toxicity and the like. And because of the influence of the texture of the food, the starch substance has hiding property and is difficult to be found when being mixed, and even the starch substance is easy to be converted into other substances under certain conditions, so that the identification difficulty is increased. Therefore, a method for rapidly and accurately judging the adulteration of the starch in the food is urgently needed to be developed.

Disclosure of Invention

The invention mainly aims to provide a carbon quantum dot fluorescence sensing method for judging the adulteration of starch substances aiming at the defects of the existing starch substance detection technology, the method has the advantages of rapidness, convenience, accuracy, safety, environmental protection and the like, can realize the specificity and high sensitivity detection of the starch adulteration substances in food with complex components, and has important practical popularization value.

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

a method for distinguishing starch adulteration materials in food based on a carbon quantum dot fluorescence sensing technology is characterized in that a biomass material rich in carbon elements is used as a precursor to carry out hydrothermal reaction to synthesize a carbon quantum dot fluorescent material, then a fluorescence spectrophotometer is adopted to measure the fluorescence spectrum of a detection solution obtained by adulteration food samples with known starch adulteration material content and the carbon quantum dot fluorescent material, a partial least square method is utilized to process and analyze the obtained fluorescence spectrum data, and an intelligent recognition model base based on the fluorescence spectrum is established to realize accurate distinguishing of the starch adulteration materials in the food samples.

In the scheme, the biomass material rich in carbon elements is green natural substances such as grape seeds, medlar or green tea.

In the above scheme, the hydrothermal reaction step includes the following steps: the biomass material and water are mixed evenly, then transferred into a polytetrafluoroethylene liner, reacted for 4-10h at the temperature of 160-240 ℃, and naturally cooled and then filtered through a 0.22 mu m microporous filter membrane.

In the scheme, the solid-to-liquid ratio of the biomass material to water is 1 (11-45) g: ml.

In the above scheme, the detection conditions of the fluorescence spectrophotometer are as follows: an excitation voltage of 700V, an emission wavelength of 400-650nm, a slit width of 10-15nm, and a measured intensity of 600-1500a.u.

In the scheme, the starch adulterant is one of high-starch-content substances such as sweet potato starch, wheat flour, wholemeal flour, rice flour, corn flour and the like, and the fineness is 50-200 meshes.

In the scheme, the content of the starch adulteration material powder in the adulteration food sample is 1-50 wt%.

Preferably, the adulterated food sample is added into water and is subjected to ultrasonic treatment at the temperature of 80-90 ℃ for 5-15min to obtain an adulterated food extracting solution; wherein the concentration of the adulterated food sample is 0.02-0.2 g/mL.

In the scheme, the concentration of the carbon quantum dot fluorescent material in the detection solution is 2.8-6.7 × 10^-4g/mL。

In the scheme, the concentration of the adulterated food sample introduced into the detection solution (or the dosage of the adulterated food sample introduced into the adulterated food extracting solution) is 0.002-0.02 g/mL.

In the scheme, the intelligent identification model library adopts partial least square discriminant analysis based on vector coding to construct a PLSDA model, and analyzes input fluorescence spectrum data to determine the adulteration of starch substances in food samples.

According to the scheme, the response time in the specific application method is 2-10min of mixing at room temperature.

Compared with the prior art, the invention has the beneficial effects that:

1) the method has the advantages of rapidness, convenience, accuracy, safety, environmental protection and the like, can realize the specificity and high sensitivity detection of the starch adulteration substances in the food with complex components, and has important practical popularization value.

2) The invention utilizes the carbon quantum dot fluorescent material synthesized by the biomass material, the synthesized carbon quantum dot can be reacted with components in the starch adulterant through the surface rich in carboxyl, hydroxyl and other groups through the action of hydrogen bonds, and then the specific fluorescence spectrum can be rapidly obtained, the starch adulterant with different concentrations and types in food can be identified, and a brand new thought is provided for the simple, convenient and efficient identification of the starch adulterant.

Drawings

FIG. 1 is a schematic diagram of the operation of a carbon quantum dot fluorescence sensing method for starch adulteration discrimination; wherein A is a fluorescence spectrogram of the carbon quantum dots, and B is a fluorescence spectrogram of the carbon quantum dots for identifying the adulteration of the starch.

FIG. 2 is a schematic diagram of fluorescence spectrogram data for starch adulteration discrimination obtained by using the carbon quantum dot fluorescence sensing method of the invention.

FIG. 3 is a partial least squares discriminant analysis training set virtual code diagram for the discrimination of starch adulteration in 7 coffees by the carbon quantum dot fluorescence sensing method.

FIG. 4 is a partial least squares discriminant analysis prediction set virtual code diagram for discrimination of starch adulteration in 7 coffees by the carbon quantum dot fluorescence sensing method.

FIG. 5 is a schematic diagram of fluorescence spectrogram data for starch adulteration discrimination obtained by a fluorescence sensing method without adding carbon quantum dots.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the following examples, the fluorescence spectrum measurement conditions are an excitation voltage of 700V, an emission wavelength of 400-650nm, an excitation wavelength of 370nm, a slit width of 10-15nm, and a measured fluorescence intensity of 750.

In the following examples, 7 coffees from different producing areas of Yunnan province were selected as adulterated objects, and 4 kinds of starch substances including rye whole wheat flour, sweet potato starch, unpeeled wheat flour and peeled wheat flour were selected as adulterated samples (see table 1).

TABLE 1 coffee and starch-based adulterant numbering information