Papers by Paulo Henrique Gonçalves Dias Diniz
Goat milk authentication by one-class classification of digital image-based fingerprint signatures: Detection of adulteration with cow milk
Microchemical Journal
Journal of Thermal Analysis and Calorimetry, 2017
Ximenia americana L. is a plant of the Olacaceae family, used in the treatment of infectious dise... more Ximenia americana L. is a plant of the Olacaceae family, used in the treatment of infectious diseases. Dry extracts are API's of great interest for the pharmaceutical industry and have been used as final and intermediate products, resulting in different pharmaceutical forms. The aim of this study is to evaluate the compatibility of dry extract of X. americana with pharmaceutical excipients used in the solid forms. The extract was obtained by spray dryer, and binary mixtures of the dry extract and pharmaceutical excipients were analyzed. The studies were obtained using thermal analysis, X-ray powder diffraction and optical microscopy. With the data obtained from DSC curves, matrices for hierarchical cluster analysis (HCA) were made. The X-ray diffraction analysis showed changes in the mixtures' profile with corn starch, lactose and magnesium stearate. Thermal behavior of the mixtures showed incompatibilities between the extract and lactose, corn starch and magnesium stearate. This study shows the importance of using instrumental analytical techniques in the early stages of development of herbal medicine to ensure the effectiveness, safety and quality of the final product.
Brazilian Journal of Food Technology
The oxidative action of chemical substances present in dairy products may contribute to the darke... more The oxidative action of chemical substances present in dairy products may contribute to the darkening of the product. Product color is one of the first factors to be considered by the consumer for acceptance or rejection. In the food industry, the color parameter is measured using colorimeters and spectrophotometers; nevertheless, the use of digital images for colorimetric tests has been surveyed in the food area. Therefore, the present work aimed at investigating for 45 days the chemical, physicochemical and colorimetric alterations of creamy dairy dessert with white chocolate flavor and strawberry-flavored yogurt. These alterations were monitored by the analysis of the parameters pH, acidity, soluble solids content, in addition to spectroscopy in the middle-infrared region and digital images. The data collected were processed in a computational environment applying chemometric tools. As result, it was verified that there were alterations in the parameters evaluated; nonetheless, t...
Feasibility study on quantification and authentication of the cassava starch content in wheat flour for bread-making using NIR spectroscopy and digital images
Food Chemistry, 2022
This works proposed a feasibility study on NIR spectroscopy and chemometrics-assisted color histo... more This works proposed a feasibility study on NIR spectroscopy and chemometrics-assisted color histogram-based analytical systems (CACHAS) to determine and authenticate the cassava starch content in wheat flour. Prediction results of partial least squares (PLS) achieved coefficient of correlation (rpred) of 0.977 and root mean square error of prediction (RMSEP) of 1.826 mg kg-1 for the certified additive-free wheat flour, while rpred of 0.995 and RMSEP of 1.004 mg kg-1 were obtained for the commercial wheat flour containing chemical additives. Additionally, Data-Driven Soft Independent Modelling of Class Analogy (dd-SIMCA) presented similar predictive ability using NIR and CACHAS for the certified wheat flour, authenticating all target samples, besides correctly recognizing samples that could represent a fraud. No satisfactory results were obtained for the commercial wheat flour. Therefore, NIR spectroscopy is more useful to offer definitive quantitative and qualitative analysis, while CACHAS can only provide an alternative preliminary analysis.
• A Deus, que sempre tem me abençoado, fortalecido e presenteado com dádivas e vitórias sucessiva... more • A Deus, que sempre tem me abençoado, fortalecido e presenteado com dádivas e vitórias sucessivas. • Aos meus amados pais, Mirian Gonçalves e Sebastião Diniz, pelo esforço, empenho, ensinamentos, apoio e incentivo em tudo o que faço. • A minha vó Maria da Penha e minhas tias Isabel Cristina e Marina Lopes pelos ensinamentos, apoio e incentivo.
An eco-friendly analytical methodology based on digital images for quality control of commercial Mikania glomerata syrups
Microchemical Journal, 2022
A video processing and machine vision-based automatic analyzer to determine sequentially total suspended and settleable solids in wastewater
Analytica Chimica Acta, 2022
Determinação do teor de NaCl, Glicose e KCI emmedicamentos injetáveis por fotometria usando exploração doefeito Schlieren em Sistemas FIA e PLS1
Neste trabalho foi avaliada a exploracao do efeito Schlieren em sistemas FIA para a implementacao... more Neste trabalho foi avaliada a exploracao do efeito Schlieren em sistemas FIA para a implementacao de uma nova estrategia para determinar o teor de cloreto de sodio, cloreto de potassio e glicose em amostras de soro fisiologico, KCl injetavel e soro glicosado, respectivamente. A metodologia proposta se baseia na diferenca entre os indices de refracao das zonas da amostra e do fluido carregador. Nesta perspectiva, foi empregada deteccao fotometrica baseada em LED e fototransistor para investigar diferentes perfis analiticos associados ao efeito Schlieren em condicoes de baixa vazao. Estudos para ajuste dos parâmetros e configuracoes de fluxo mais adequados nos quais os perfis Schlieren podem ser explorados foram realizados. A metodologia proposta gera uma grande quantidade de informacoes quimicas e, por isso, requer a utilizacao de ferramentas quimiometricas. A avaliacao dos resultados foi realizada com a aplicacao da regressao por minimos quadrados parciais (PLS1), a qual empregou as...
Honey authentication in terms of its adulteration with sugar syrups using UV–Vis spectroscopy and one-class classifiers
Food Chemistry, 2021
This work proposes the use of UV-Vis spectroscopy and one-class classifiers to authenticate honey... more This work proposes the use of UV-Vis spectroscopy and one-class classifiers to authenticate honey in terms of their individual and simultaneous adulterations with corn syrup, agave syrup, and sugarcane molasses. Then, spectra of aqueous authentic (n = 73) and adulterated (n = 162) honey samples were recorded. Before the construction of OC-PLS and DD-SIMCA models, different pre-processing techniques were used to removed baseline shifts. The best result obtained by DD-SIMCA using offset correction, correctly classifying all the samples in the test set. Therefore, the proposed methodology can be used as a promising tool to authenticate honey and prevent fraudulent labeling, affording security to consumers and providing an alternative to regulatory agencies. Moreover, it avoids laborious sample preparation and additional operational costs, since the analytical information is acquired using a routine instrumental technique, without the need for any sample preparation step, other than dilution of the samples in water alone.
Digital image-based tracing of geographic origin, winemaker, and grape type for red wine authentication
Food Chemistry, 2020
This work proposes the development of a simple, fast, and inexpensive methodology based on color ... more This work proposes the development of a simple, fast, and inexpensive methodology based on color histograms (obtained from digital images), and supervised pattern recognition techniques to classify red wines produced in the São Francisco Valley (SFV) region to trace geographic origin, winemaker, and grape variety. PCA-LDA coupled with HSI histograms correctly differentiated all of the SFV samples from the other geographic regions in the test set; SPA-LDA selecting just 10 variables in the Grayscale + HSI histogram achieved 100% accuracy in the test set when classifying three different SFV winemakers. Regarding the three grape varieties, SPA-LDA selected 15 variables in the RGB histogram to obtain the best result, misclassifying only 2 samples in the test set. Pairwise grape variety classification was also performed with only 1 misclassification. Besides following the principles of Green Chemistry, the proposed methodology is a suitable analytical tool; for tracing origins, grape type, and even (SFV) winemakers.
Simultaneous identification of the wood types in aged cachaças and their adulterations with wood extracts using digital images and SPA-LDA
Food chemistry, 2019
Cachaça is a sugarcane-derived alcoholic spirit exclusively produced in Brazil. It can be aged in... more Cachaça is a sugarcane-derived alcoholic spirit exclusively produced in Brazil. It can be aged in barrels made from different types of wood, similar to other distilled beverages. The choice of wood type promotes different effects on color, flavor, aroma and consequently the price of cachaça, favoring fraudulent activities. This paper proposes the simultaneous identification of different wood types in aged cachaças and their adulterations with wood extracts using a digital-image based methodology employing color histograms obtained from digital images associated with pattern recognition methods, without any sample preparation step. Linear Discriminant Analysis, coupled with Successive Projections Algorithm for variable selection (SPA-LDA), obtained the best results, reaching accuracy, sensitivity, and specificity rates higher than 90.0% in the test set. This can be a rapid and reliable tool to prevent fraudulent labeling; ensuring that what is on the label reflects the quality of age...
Determination of fat content in chicken hamburgers using NIR spectroscopy and the Successive Projections Algorithm for interval selection in PLS regression (iSPA-PLS)
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, Jan 17, 2017
Determining fat content in hamburgers is very important to minimize or control the negative effec... more Determining fat content in hamburgers is very important to minimize or control the negative effects of fat on human health, effects such as cardiovascular diseases and obesity, which are caused by the high consumption of saturated fatty acids and cholesterol. This study proposed an alternative analytical method based on Near Infrared Spectroscopy (NIR) and Successive Projections Algorithm for interval selection in Partial Least Squares regression (iSPA-PLS) for fat content determination in commercial chicken hamburgers. For this, 70 hamburger samples with a fat content ranging from 14.27 to 32.12mgkg(-1) were prepared based on the upper limit recommended by the Argentinean Food Codex, which is 20% (ww(-1)). NIR spectra were then recorded and then preprocessed by applying different approaches: base line correction, SNV, MSC, and Savitzky-Golay smoothing. For comparison, full-spectrum PLS and the Interval PLS are also used. The best performance for the prediction set was obtained for ...
Food Chemistry, 2016
In this work we proposed a method to verify the differentiating characteristics of simple tea inf... more In this work we proposed a method to verify the differentiating characteristics of simple tea infusions prepared in boiling water alone (simulating a home-made tea cup), which represents the final product as ingested by the consumers. For this purpose we used UV-Vis spectroscopy and variable selection through the Successive Projections Algorithm associated with Linear Discriminant Analysis (SPA-LDA) for simultaneous classification of the teas according to their variety and geographic origin. For comparison, KNN, CART, SIMCA, PLS-DA and PCA-LDA were also used. SPA-LDA and PCA-LDA provided significantly better results for tea classification of the five studied classes (Argentinean green tea; Brazilian green tea; Argentinean black tea; Brazilian black tea; and Sri Lankan black tea). The proposed methodology provides a simpler, faster and more affordable classification of simple tea infusions, and can be used as an alternative approach to traditional tea quality evaluation as made by skilful tasters, which is evidently partial and cannot assess geographic origins.
LWT - Food Science and Technology, 2015
The pleasant taste and flavor of coffee are responsible for making it one of the most preferred a... more The pleasant taste and flavor of coffee are responsible for making it one of the most preferred and consumed beverages around the world. Industrial coffee plants usually roast both coffee and adulterants together, which affects directly the quality of the product, specially the sensorial characteristics of the drink. Therefore, this work aims the identification of adulterations in ground roasted coffees (due to the presence of husks and sticks) using ultravioletevisible spectroscopy and the Successive Projections Algorithm for variable selection in association with Linear Discriminant Analysis (SPA-LDA). For this purpose, extracts of ground roasted coffees prepared in hot water alone (representing the final product as ingested by the consumers) were then analyzed. The proposed methodology obtained a 100% classification in both training and test sets, providing a simple and fast analysis of the aqueous extracts of ground roasted coffees. Moreover, it can also afford security to coffee consumers and regulatory agencies, preventing the fraudulent labeling.
Using iSPA-PLS and NIR spectroscopy for determination of total polyphenols and moisture in commercial tea samples
Anal. Methods, 2015
The determination of total polyphenols and moisture in commercial tea samples using iSPA-PLS and ... more The determination of total polyphenols and moisture in commercial tea samples using iSPA-PLS and NIR spectroscopy.
Talanta, 2015
This work proposes a simple, rapid, inexpensive, and non-destructive methodology based on digital... more This work proposes a simple, rapid, inexpensive, and non-destructive methodology based on digital images and pattern recognition techniques for classification of biodiesel according to oil type (cottonseed, sunflower, corn, or soybean). For this, differing color histograms in RGB (extracted from digital images), HSI, Grayscale channels, and their combinations were used as analytical information, which was then statistically evaluated using Soft Independent Modeling by Class Analogy (SIMCA), Partial Least Squares Discriminant Analysis (PLS-DA), and variable selection using the Successive Projections Algorithm associated with Linear Discriminant Analysis (SPA-LDA). Despite good performances by the SIMCA and PLS-DA classification models, SPA-LDA provided better results (up to 95% for all approaches) in terms of accuracy, sensitivity, and specificity for both the training and test sets. The variables selected Successive Projections Algorithm clearly contained the information necessary for biodiesel type classification. This is important since a product may exhibit different properties, depending on the feedstock used. Such variations directly influence the quality, and consequently the price. Moreover, intrinsic advantages such as quick analysis, requiring no reagents, and a noteworthy reduction (the avoidance of chemical characterization) of waste generation, all contribute towards the primary objective of green chemistry.
Food Analytical Methods, 2014
In this paper, we propose a new methodology to identify adulterations in ground roasted coffees (... more In this paper, we propose a new methodology to identify adulterations in ground roasted coffees (due to the presence of husks and sticks) using digital images and the successive projections algorithm for variable selection in association with linear discriminant analysis (SPA-LDA). A simple document scanner was used for capturing the images, and a Petri dish support with eight circular holes (one for each sample) to be scanned was employed. Color histograms in the hue-luminosity-saturation (HLS) channels extracted from the digital images were used as input data and statistically evaluated using supervised pattern recognition techniques. For comparison with SPA-LDA, soft independent modeling by class analogy (SIMCA) and partial least squares discriminant analysis (PLS-DA) were also used. In general, SPA-LDA provided significantly better performance than the other classification models, reaching a mean accuracy of 92.5 % for both the training and test sets, while SIMCA and PLS-DA attained only 71.5 and 85.5 %, respectively. More specifically, all of the models presented high rates (above 90 %) for sensitivity and specificity (in the test set samples classification), except SIMCA, which presented a specificity rate of 76 %. Moreover, the SPA-LDA model generally showed the lowest classification error rates. As such, it is a more adequate chemometric tool for discriminating pure coffee samples and adulterated by husks and sticks. The proposed strategy avoided laborious sample preparation, and additional operational costs, assessing coffee adulteration by husks and sticks.
Journal of Food Composition and Analysis, 2015
Talanta, 2013
This paper proposes a flow-batch methodology for the determination of free glycerol in biodiesel ... more This paper proposes a flow-batch methodology for the determination of free glycerol in biodiesel that is notably eco-friendly, since non-chemical reagents are used. Deionized water (the solvent) was used alone for glycerol (sample) extractions from the biodiesel. The same water was used to generate watercavitation sonoluminescence signals, which were modulated by the quenching effect associated with the amount of extracted glycerol. The necessarily reproducible signal generation was achieved by using a simple and inexpensive piezoelectric device. A linear response was observed for glycerol within the 0.001-100 mg/L range, equivalent to 0.004-400 mg/kg free glycerol in biodiesel. The lowest measurable concentration of free glycerol was estimated at 1.0 mg/L. The selectivity of the proposed method was confirmed by comparing the shape and retention of both real and calibration samples to standard solution chromatograms, presenting no peaks other than glycerol. All samples (after extraction) are greatly diluted; this minimizes (toward non-detectability) potential interference effects. The methodology was successfully applied to biodiesel analysis at a high sampling rate, with neither reagent nor solvent (other than water), and with minimum waste generation. The results agreed with the reference method (ASTM D6584-07), at a 95% confidence level.
Journal of Pharmaceutical and Biomedical Analysis, 2012
A flow injection photometric system that exploits Schlieren signals for analytical measurement is... more A flow injection photometric system that exploits Schlieren signals for analytical measurement is described. The system was designed to be used as a new strategy for determining the contents of sodium chloride, potassium chloride and glucose, each respectively in injectable drugs. The proposed methodology was based on the difference between the refractive indices of the sample zone and of the carrier stream. With this perspective, a lab-made photometer based on LED-phototransistor technology was employed as a detection system to investigate the different analytical profiles related to the Schlieren effect in low flow rate conditions. The parameters of the flow system, such as flow-rate, optical path length, and sampling loop, were adjusted in order to obtain suitable Schlieren profiles for the measurements. Data evaluation was performed with the application of partial least squares regression (PLS-1). The obtained results demonstrated the predictive ability of the constructed PLS models, and the predicted concentration values were in agreement with the reference values, with a 95% confidence level.
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Papers by Paulo Henrique Gonçalves Dias Diniz