Fast and low-cost method for direct and simultaneous determination of nitrogen and carbon in soybean leaves using benchtop and portable near-infrared devices.

BACKGROUND: The current techniques for determining carbon and nitrogen content to provide information about the nutritional status of plants are time-consuming and expensive. For this reason, the objective of this study was to develop an analytical method for the direct and simultaneous determination of nitrogen and carbon elemental content in soybean leaves using near-infrared spectroscopy and compare the performance of conventional (1100-2500 nm spectral range) and portable equipment (1100-1700 nm spectral range). Partial least-squares regression models were developed using 27 soybean leaf samples collected during the 2021 harvest and applied for the simultaneous determination of carbon and nitrogen in 13 samples collected during the 2022 harvest. RESULTS: The root-mean-square error of prediction values for nitrogen and carbon were low (2.42 g kg-1 and 4.37 g kg-1 respectively) for the benchtop method yielded low but higher for the portable method (3.82 g kg-1 and 10.7 g kg-1 respectively). The benchtop method did not show significant differences when compared with the reference method for determining nitrogen and carbon. In contrast, the portable methodology showed potential as a screening method for determining nitrogen levels, particularly in fieldwork. CONCLUSION: The methodologies evaluated in this study were implemented and evaluated under real crop monitoring conditions, using independent sets of calibration and prediction samples. Their utilization enables the acquisition of cost-effective, safe analytical data aligning with the principles of green analytical chemistry. © 2023 Society of Chemical Industry.

Effect of Adding Matricaria recutita L., Cymbopogon citratus, or Mentha piperita L. Extracts to Fermented Orange Beverage: Sensory Evaluation, Physicochemical Characterization, and Prediction of Toxic Risks and Biological Activity In Silico.

Fermentation is an important tool in producing functional beverages through agro-industrial wastes, and medicinal and aromatic plants due to the specific content of bioactive molecules. Therefore, this study evaluated the contribution of Matricaria recutita (chamomile), Cymbopogon citratus (lemongrass), or Mentha piperita (peppermint) extracts to the phytochemical profile and potential biological effects of a functional fermented orange beverage in vitro and in silico. The concentrations of aromatic herbal extracts that yielded the best sensory performance for fermented beverages were selected for analyses that involved characterizing the fermented beverages. The beverages that received the extracts (2%) had the highest phenolic and flavonoid content and antioxidant potential compared to the control. Hesperidin (124-130 mg L-1), narirutin (66-70 mg L-1), chlorogenic (11-16 mg L-1), caffeic (5.3-5.5 mg L-1), and ferulic (1-1.7 mg L-1) acids were found in the different formulations. The in silico analysis suggested that the evaluated compounds do not present a toxicity risk (mutagenicity, carcinogenicity, hepatotoxicity, and ability to penetrate the blood-brain barrier). Additionally, they can contribute to the biological effects of therapeutic importance, such as antioxidant, gastroprotective, and anti-ulcerative properties, and the Mentha piperita L. extract presented the greatest potential among the evaluated herbs for use in functional fermented beverages.

The application of parallel processing in the selection of spectral variables in beer quality control.

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.

Flow thermal infrared enthalpimetry: Rapid and inexpensive determination of the alcohol content of distilled beverages.

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.

Postharvest UV-C irradiation stimulates the non-enzymatic and enzymatic antioxidant system of 'Isabel' hybrid grapes (Vitis labrusca×Vitis vinifera L.).

Ultraviolet light type C (UV-C) was studied as a tool to increase enzymatic and non-enzymatic antioxidant defenses and phytochemical levels in 'Isabel' grapes (Vitis labrusca×Vitis vinifera L.). Grapes were exposed to 0, 0.5, 1.0, 2.0, or 4.0kJm-2 UV-C and stored for 1, 3, or 5days post-treatment. One day after UV-C irradiation, the activities of grape antioxidant enzymes and thiols were increased, especially at 1.0 and 2.0kJm-2. These doses increased total phenolic content by almost 20%, while 0.5 and 4.0kJm-2 had no effects. Total monomeric anthocyanin content was increased by >35% by UV-C at 1.0kJm-2; however, anthocyanin profile was unchanged. Grape skin antioxidant capacity was also improved by UV-C irradiation. The 1.0kJm-2 UV-C was considered the hormetic dose. Postharvest UV-C had an elicitor effect on 'Isabel' grapes, positively impacting the antioxidant capacity and phytochemical content.

Caracterização, teor de polifenóis totais e atividade antioxidante em diferentes tipos de erva-mate (Ilex paraguariensis St. Hill.) para chimarrão / Characterization and determination of the total polyphenols contents and the antioxidant activity in four types of yerba mate (Ilex paraguariensis St. Hill.) for preparing chimarrão

Considerando-se a ampla utilização das folhas da erva-mate, bem como os benefícios advindos de seu emprego, neste estudo foi avaliada a qualidade de quatro tipos de ervas-mate nativas de espécime chimarrão: tradicional, com adição de 5 % e 10 % de açúcar, e a moída grossa, bem como a homogeneidade em três lotes dos produtos, correspondentes a diferentes semanas de processamento. Foram avaliadas as propriedades físico-químicas, o teor de polifenóis totais e a atividade antioxidante. Os extratos aquosos de erva-mate foram elaborados a 85 ºC, mantidos em de cocção em sistema fechado durante 10 e 30 minutos.As ervas-mate com adição de açúcar apresentaram menores teores de material mineral e de fibra bruta quando comparadas aos tipos tradicional e moída grossa. A erva-mate moída grossa acondicionada em embalagem laminada apresentou os menores valores de atividade de água em relação aos outros tipos de ervas acondicionados em embalagem de papel. A embalagem laminada também contribuiu para a menor absorção de oxigênio, que retarda a oxidação da clorofila e mantém a coloração verde do produto.Os extratos elaborados a partir da erva-mate moída grossa e os que permaneceram por maior tempo em decocção apresentaram maiores teores de polifenóis totais...