Development Of A Small Near-infrared Spectrometer And Its Application In Brewing Raw Materials

With the rapid development of social economy,the demand and quality requirements to traditional brewed food from manufacturers and consumers are constantly improving.In recent years,with the development of microelectromechanical technology and the expansion of its application in industry,instrument manufacturers have accelerated the development of portable,microminiature,and intelligent near-infrared spectroscopy analysis instruments,and special small-micro food quality inspection instruments based on new spectroscopic principles and technologies have been continuously developed.Due to low production efficiency,poor consistency of product quality and relatively weak ability to accept new things and technologies in most traditional domestic fermentation enterprises,the development of traditional fermentation industry has been restricted.This study developed a small near-infrared spectroscopy instrument with the NIRONE-Sensor miniature nearinfrared spectroscopy detector based on MEMS-FPI spectroscopy principle,in combination with national key research and development project.It took the brewing of traditional liquor as an application example,and aimed at the rapid detection of main quality indicators of brewing materials.Combining with the developed spectrometer,the framework of spectrometer control software was designed,compiled and debugged.Verification test of the rapid detection of moisture and crude protein of wheat and corn proved that the developed NIRONE small portable near-infrared spectrometer can be applied in quality control of raw materials for brewing liquor,and it can also be used in the production of other traditional brewing industries.The specific research content is as follows:1.According to relevant technical parameters and characteristics of the NIRONESensor detector,overall design scheme of a small portable near-infrared spectrometer was proposed.A down-illuminated diffuse reflection working mode with a 45° light source incident angle was designed in accordance with the specific application scenarios of measured samples.Combining with 24BYJ48 type stepper motor,a pulse drive circuit based on UCN5804 chip was designed to control the movement of reference whiteboard,and realized the automatic detection of reference spectrum.The CH340 G USB to serial port communication mode was adopted,and the USB Hub was designed based on SL2.1A chip,which can be used for two USB devices to work at the same time.Surface Go tablet computer was selected as the upper computer to achieve good human-computer interaction.2.According to actual application requirements,framework of the NIRONE small portable near-infrared spectrometer control software was designed,and all functions of the NIR?SE?2020 application software were realized by using Visual Studio platform,C# language and other tools.The software functions mainly included user registration/login,communication between upper and lower computers,instrument parameter setting,selection of spectral acquisition mode,model call,data processing and data storage,etc.The upper computer of the instrument can easily realize control of the NIRONE spectrometer by using Surface Go tablet computer,which is fully compatible with the characteristics of Windows 10 and the human-computer interaction interface is very friendly.After testing and debugging,it was proved that the software system is easy to operate and stable in operation.3.Two near-infrared detectors with two bands(1 550 ? 1 950 nm and 1 750 ? 2150 nm)were selected to test performance of the NIRONE spectrometer.The results showed that NIRONE spectrometer of both bands met the requirements of general spectrometers in three performance indexes,which are the stability of dark current and reference spectrum output signal,the reproducibility of the absorbance,and the stability of the baseline.The instrument signal-to-noise ratio of the sub-interval of the two bands fluctuated little over time,indicating that the instrument's signal-to-noise ratio is stable.Taking consistency of the near-infrared spectra of wheat flour of different particle sizes and whole grain wheat as the evaluation index,six particle size tests were carried out.The results showed that the smaller the particle size of the material to be measured,the better the spectral stability of the sample.4.In order to verify practicability of the NIRONE spectrometer detection system,wheat and corn from different regions were taken as research objects.NIRONE spectrometer with two different bands and S450 full-band spectrometer were used to collect sample spectra respectively,and the NIR correction model of moisture and crude protein content was established.Through internal cross validation of the corrected sample set,prediction validation of the predicted sample set,and validation test using10 external samples that were not involved in the modeling,it was proved that prediction ability of the correction model established in the two bands for moisture and crude protein of wheat and corn basically met the requirements of practical applications.And in 1 750 ? 2 150 nm band,wheat moisture and crude protein correction models established by SNV+ detrending and MSC+SGF pretreatment methods respectively had the best prediction results,and corn moisture and crude protein correction models established by MSC and normalized pretreatment methods had the best prediction results.Compared with prediction accuracy results of the calibration model established in the same wavelength band between the S450 grating-type full-wavelength spectrometer and the NIRONE spectrometer,although the calibration model established by NIRONE spectrometer was slightly inferior to that by S450 spectrometer,the NIRONE spectrometer had lower manufacturing cost,higher cost performance,smaller weight,shorter operation time,and better portability,being more promising for application in the traditional brewing industry.