Search

In order to monitor the Qingke beer brewing process in real time, this paper presents an analytical method for predicting the content of key components in the wort during the mashing and boiling stages using multi-spectroscopy combined with chemometrics. The results showed that the Neural Networks (NN) model based on Raman spectroscopy (RPD = 3.9727) and the NN model based on NIR spectroscopy (RPD = 5.1952) had the best prediction performance for the reducing sugar content in the mashing and boiling stages; The partial least Squares (PLS) model based on Raman spectroscopy (RPD = 2.7301) and the NN model based on Raman spectroscopy (RPD = 4.3892) predicted the content of free amino nitrogen best; The PLS model based on UV-Vis spectroscopy (RPD = 4.0412) and the NN model based on Raman spectroscopy (RPD = 4.0540) are most suitable for the quantitative analysis of total phenols. The results can be used as a guide for real-time control of wort quality in industrial production., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Recently, there has been an increasing demand for developing a reliable method to assess the quality of liquor in the baijiu industry quickly and accurately. The present study sought to establish a strategy for rapid quantitative analysis of the primary flavor components in Nongxiangxing baijiu. Under the experimental conditions, 7 of the 10 major flavor components in Nongxiangxing baijiu could be quantified effectively, such as ethyl butyrate (R 2 p = 0.9942), ethyl lactate (R 2 p = 0.9438), n-butanol (R 2 p = 0.9048), isobutanol (R 2 p = 0.9696), acetic acid (R 2 p = 0.9600), butyric acid (R 2 p = 0.8448), caproic acid (R 2 p = 0.9971). This result indicates that FT-IR combined with quantitative chemometric modeling could be a potential approach for rapid quality assessment of Nongxiangxing baijiu. Overall, this study provides a theoretical basis for subsequent related studies on Nongxiangxing baijiu., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Drying is an important process in black tea processing, at the same time, catechin is an important factor in determining the sensory quality of black tea. However, there is a lack of effective real-time detection methods for the detection of catechins in black tea drying process. Therefore, we analyzed the trends of catechins in black tea drying process under different drying conditions and further explored the quantitative prediction model of eight individual catechins in black tea drying process by Least squares support vector machine (LS-SVM) based on near-infrared spectroscopy (NIRS) and chemometrics methods. The results showed that the prediction accuracy of the eight monomeric catechins prediction models established based on the extraction of competitive adaptive reweighted sampling (CARS) and successive projections algorithm (SPA) feature spectra achieved the best results, and the correlation coefficient values of the prediction sets (R p) were all greater than 0.98, and the relative percentage deviation (RPD) values were all greater than 5. The gallocatechin gallate (GCG) with the highest prediction accuracy was 0.9977 and the RPD value was 14.8. This study shows that the method based on near-infrared spectroscopy and chemometrics has strong predictive power for catechins in black tea drying process, which is a guideline for controlling the sensory quality of black tea drying. • Different drying temperatures and times affect the catechin content of black tea. • Catechin during black tea drying was monitored using NIR spectroscopy. • Different quantitative prediction models were compared to accurate detection of catechins. • NIR spectroscopy can be used to monitor the drying process of black tea. [ABSTRACT FROM AUTHOR]