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1.
Food Chem ; 367: 130681, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34359005

RESUMO

Parallel data analysis was investigated to improve performance in variable selection and to develop predictive models for beer quality control. A set of spectral near infrared (NIR) data from 60 beer samples and its primitive extracts as the original concentration was used. The dataset was distributed to Raspberry Pi 3 Model B devices connected to a network that was running a Machine Learning service. With more than 4 devices acting in parallel, it was possible to reduce time in 57% to find the best linear regression coefficient (0.999) with the lower RMSECV (0.216) if compared to a singular desktop computer. Thus, parallel processing can significantly reduce the time to indicate the best model fitted during the variable's selection.


Assuntos
Cerveja , Espectroscopia de Luz Próxima ao Infravermelho , Análise dos Mínimos Quadrados , Modelos Lineares , Controle de Qualidade
2.
Anal Chem ; 92(8): 5682-5687, 2020 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-32207608

RESUMO

A simple, rapid, low-cost method was proposed for the imaging of Pseudomonas aeruginosa biofilms on metallic surfaces using an infrared camera. Stainless steel coupons were cooled to generate a thermal gradient in relation to biofilm for active thermography (AT). Both cooling and image acquisition times were optimized and the images obtained with AT were compared with those from scanning electron microscopy. A free software (Thermofilm) was developed for image processing and the results were compared with the software ImageJ, with good agreement (from 87.7 to 103.8%). Images of coupons treated with sanitizer (peracetic acid) were obtained to show the applicability of the proposed method for biofilm studies. All analytical steps could be performed in 3 min in a noncontact, nondestructive, low-cost, portable, and easy-to-use way.


Assuntos
Aço Inoxidável/química , Termografia , Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Microbiologia de Alimentos , Testes de Sensibilidade Microbiana , Ácido Peracético/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Propriedades de Superfície
3.
Food Chem ; 305: 125456, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31525594

RESUMO

This work developed a new technique and an application of an existing approach to determine sodium in food sauces, involving enthalpimetric reactions in the infrared. Infrared Thermometric Titration (TT-IR) was utilized, with simple analyzers and low-cost measurement instruments for the acquisition of the surface temperature generated in the sodium precipitation reaction and development of software for the acquisition and processing of data using Raspberry Pi. The sodium was also quantified by Thermal Infrared Enthalpimetry (TIE), a recently developed technique. The rapid and simple quantification of sodium by the TT-IR and TIE showed the possibility of a selective reaction for sodium, using aluminum nitrate, potassium and ammonium fluoride in an acid medium, with reduction of the reagents and without the digestion step in the sample preparation. The results acquired through TT-IR and TIE corroborated the Flame Atomic Emission Spectrometry (FAES) with 96 to 103% and 95 to 102%, respectively.


Assuntos
Análise de Alimentos/métodos , Raios Infravermelhos , Sódio/análise , Produtos Vegetais/análise , Compostos de Alumínio/química , Limite de Detecção , Nitratos/química , Sódio/química , Espectrofotometria Atômica , Temperatura , Termometria/métodos
4.
Talanta ; 200: 67-71, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31036226

RESUMO

In this work, a simple and inexpensive flow thermal infrared enthalpimetry (TIE-F) method was developed through a combination of flow injection analysis and thermal infrared enthalpimetry (TIE) to determine the alcohol content of distilled beverages (cachaça, cognac, and vodka). The principle used in this method consisted of monitoring the enthalpy of dissolution of ethanol through a low-cost infrared sensor coupled to a flow system. The results showed an agreement between the proposed method and the conventional method, ranging from 96.5% to 99.0%. The obtained limit of quantification (LOQ, 10σ) of 25.10% (v/v) was enough for distilled beverages, which should present a minimum alcoholic content of 36% according to Brazilian legislation. In addition, the TIE-F instrumentation presented costs that were 100 times lower than the instrumentation that was used in the batch TIE, and the time of analysis was significantly reduced. The amount of residue generated was also reduced, thereby providing significant energy savings and easy adaptation to processes on industrial scales.

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