scholarly journals Edible Oils Differentiation Based on the Determination of Fatty Acids Profile and Raman Spectroscopy—A Case Study

2020 ◽  
Vol 10 (23) ◽  
pp. 8347
Author(s):  
Florina-Dorina Covaciu ◽  
Camelia Berghian-Grosan ◽  
Ioana Feher ◽  
Dana Alina Magdas

This study proposes a comparison between two analytical techniques for edible oil classification, namely gas-chromatography equipped with a flame ionization detector (GC-FID), which is an acknowledged technique for fatty acid analysis, and Raman spectroscopy, as a real time noninvasive technique. Due to the complexity of the investigated matrix, we used both methods in connection with chemometrics processing for a quick and valuable evaluation of oils. In addition to this, the possible adulteration of investigated oil varieties (sesame, hemp, walnut, linseed, sea buckthorn) with sunflower oil was also tested. In order to extract the meaningful information from the experimental data set, a supervised chemometric technique, namely linear discriminant analysis (LDA), was applied. Moreover, for possible adulteration detection, an artificial neural network (ANN) was also employed. Based on the results provided by ANN, it was possible to detect the mixture between sea buckthorn and sunflower oil.

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1565
Author(s):  
Eleni Kakouri ◽  
Panagiota-Kyriaki Revelou ◽  
Charalabos Kanakis ◽  
Dimitra Daferera ◽  
Christos S. Pappas ◽  
...  

Olive oil is among the most popular supplements of the Mediterranean diet due to its high nutritional value. However, at the same time, because of economical purposes, it is also one of the products most subjected to adulteration. As a result, authenticity is an important issue of concern among authorities. Many analytical techniques, able to detect adulteration of olive oil, to identify its geographical and botanical origin and consequently guarantee its quality and authenticity, have been developed. This review paper discusses the use of infrared and Raman spectroscopy as candidate tools to examine the authenticity of olive oils. It also considers the volatile fraction as a marker to distinguish between different varieties and adulterated olive oils, using SPME combined with gas chromatography technique.


2021 ◽  
Vol 30 (1) ◽  
pp. 893-902
Author(s):  
Ke Xu

Abstract A portrait recognition system can play an important role in emergency evacuation in mass emergencies. This paper designed a portrait recognition system, analyzed the overall structure of the system and the method of image preprocessing, and used the Single Shot MultiBox Detector (SSD) algorithm for portrait detection. It also designed an improved algorithm combining principal component analysis (PCA) with linear discriminant analysis (LDA) for portrait recognition and tested the system by applying it in a shopping mall to collect and monitor the portrait and establish a data set. The results showed that the missing detection rate and false detection rate of the SSD algorithm were 0.78 and 2.89%, respectively, which were lower than those of the AdaBoost algorithm. Comparisons with PCA, LDA, and PCA + LDA algorithms demonstrated that the recognition rate of the improved PCA + LDA algorithm was the highest, which was 95.8%, the area under the receiver operating characteristic curve was the largest, and the recognition time was the shortest, which was 465 ms. The experimental results show that the improved PCA + LDA algorithm is reliable in portrait recognition and can be used for emergency evacuation in mass emergencies.


Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1537
Author(s):  
Aneta Saletnik ◽  
Bogdan Saletnik ◽  
Czesław Puchalski

Raman spectroscopy is one of the main analytical techniques used in optical metrology. It is a vibration, marker-free technique that provides insight into the structure and composition of tissues and cells at the molecular level. Raman spectroscopy is an outstanding material identification technique. It provides spatial information of vibrations from complex biological samples which renders it a very accurate tool for the analysis of highly complex plant tissues. Raman spectra can be used as a fingerprint tool for a very wide range of compounds. Raman spectroscopy enables all the polymers that build the cell walls of plants to be tracked simultaneously; it facilitates the analysis of both the molecular composition and the molecular structure of cell walls. Due to its high sensitivity to even minute structural changes, this method is used for comparative tests. The introduction of new and improved Raman techniques by scientists as well as the constant technological development of the apparatus has resulted in an increased importance of Raman spectroscopy in the discovery and defining of tissues and the processes taking place in them.


2014 ◽  
Vol 1618 ◽  
pp. 141-151 ◽  
Author(s):  
Ma. A. García-Bucio ◽  
E. Casanova-González ◽  
J. L. Ruvalcaba-Sil

ABSTRACTOutstanding information about the material composition and pictorial techniques of the New Spain Colonial painting can be obtained via a full characterization using a set of analytical techniques. Given the cultural importance of this painting, a non-invasive approach is preferred. Moreover, the preparation and use of reference materials using original recipes is necessary for a correct interpretation of the spectroscopic data from historical objects. Here, we present the results obtained via an in-situ Raman spectroscopic analysis of a set of pictorial reference materials, created according to XVI and XVII centuries’ recipes. Several difficulties were encountered, such as the low Raman detection signal, an intrinsic fluorescence of the material, and in some cases even laser-induced degradation. For this reason, the usual molecular Raman analysis was extended to Surface Enhanced Raman Spectroscopy (SERS), which enhances the Raman signal and quenches the fluorescence. It was then applied to the analysis of two wood paintings from the ex-convent San Francisco Tepeyanco, in Tlaxcala.


2012 ◽  
Vol 18 (6) ◽  
pp. 1494-1494
Author(s):  
Sebastian Schlücker

Confocal Raman Microscopy. Thomas Dieing, Olaf Hollricher, and Jan Toporski (Eds.). Springer, New York, 2011, 289 pages. ISBN 978-3642125218Raman microscopy is the combination of Raman spectroscopy with optical light microscopy and was first presented in the mid-1970s. It combines the advantages of vibrational Raman spectroscopy as a noninvasive technique providing a wealth of chemical information on the properties of molecules and solids with the imaging capabilities and small sample volume requirements of an optical microscope. “Seeing is believing”: Raman microscopy can visualize the inherent chemical inhomogeneity of a sample without the need of external labels, information that cannot be obtained from simply looking at an unstained sample in the standard optical microscope. During the last decade, confocal Raman microscopy has gone through a rapid development with respect to instrumentation and software as well as the diversity of applications.


2021 ◽  
pp. 131471
Author(s):  
Hefei Zhao ◽  
Yinglun Zhan ◽  
Zheng Xu ◽  
Joshua John Nduwamungu ◽  
Yuzhen Zhou ◽  
...  

Author(s):  
Carlos Eduardo Thomaz ◽  
Vagner do Amaral ◽  
Gilson Antonio Giraldi ◽  
Edson Caoru Kitani ◽  
João Ricardo Sato ◽  
...  

This chapter describes a multi-linear discriminant method of constructing and quantifying statistically significant changes on human identity photographs. The approach is based on a general multivariate two-stage linear framework that addresses the small sample size problem in high-dimensional spaces. Starting with a 2D data set of frontal face images, the authors determine a most characteristic direction of change by organizing the data according to the patterns of interest. These experiments on publicly available face image sets show that the multi-linear approach does produce visually plausible results for gender, facial expression and aging facial changes in a simple and efficient way. The authors believe that such approach could be widely applied for modeling and reconstruction in face recognition and possibly in identifying subjects after a lapse of time.


Author(s):  
Peter Vandenabeele ◽  
Jan Jehlička

Raman spectroscopy has proved to be a very useful technique in astrobiology research. Especially, working with mobile instrumentation during fieldwork can provide useful experiences in this field. In this work, we provide an overview of some important aspects of this research and, apart from defining different types of mobile Raman spectrometers, we highlight different reasons for this research. These include gathering experience and testing of mobile instruments, the selection of target molecules and to develop optimal data processing techniques for the identification of the spectra. We also identify the analytical techniques that it would be most appropriate to combine with Raman spectroscopy to maximize the obtained information and the synergy that exists with Raman spectroscopy research in other research areas, such as archaeometry and forensics.


2015 ◽  
Vol 78 (7) ◽  
pp. 1414-1419 ◽  
Author(s):  
SHENG WANG ◽  
RUI NIAN ◽  
LIMIN CAO ◽  
JIANXIN SUI ◽  
HONG LIN

The presence of fish bones is now regarded as an important hazard in fishery products, and there is increasing demand for new analytical techniques to control it more effectively. Here, the fluorescent properties of cod bones under UV illumination were investigated, and the maximal wavelengths for excitation and emission were determined to be 320 nm and 515 nm, respectively, demonstrating significantly different fluorescence characteristics and much higher fluorescence intensity compared to those of fillet muscles. Based on the results, UV fluorescence-assisted candling for the detection of bones in fishery products was developed for the first time. Using cod fillets as samples, the detection ratio of this technique was calculated as 90.86%, significantly higher than that of traditional candling under daylight (76.78%). Moreover, the working efficiency of the new technique was about 26% higher than that of the traditional method. A UV fluorescence imaging framework was also developed, and a method for automatic identification of the fish bones in the cod fillets based on the linear discriminant analysis proposed by Fisher was preliminarily realized, but the detection ratio was demonstrated to be relatively poor compared to those of candling techniques. These results allow us to suggest UV-based methods as new and promising approaches for routine monitoring of bones in fishery products.


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