Marcelo Queiroz - Academia.edu (original) (raw)

Papers by Marcelo Queiroz

Proceedings of the XI Congresso Nacional de Engenharia Mecânica - CONEM 2022

Polyphenols in Plants, 2019

Abstract The winery industry is one of the most important industries worldwide, with great econom... more Abstract The winery industry is one of the most important industries worldwide, with great economic and social impacts. As a consequence, the large amount of byproducts generated annually may constitute an important environmental problem with economic dimensions. Thus, there is a growing interest in recycling or reuse of winery wastes due to their antioxidant properties and putative health-promoting effects. Grape stems, one of the byproducts generated seasonally in high amounts (representing 25% of the total byproducts produced by this industry), have been stressed as a valuable candidate to be used by various industrial sectors due to its constitution, rich in phenolic compounds with remarkable biological activities, which would allow replacing the synthetic antioxidants currently used. Therefore, this chapter reviews the phytochemical composition and the health beneficial effects of various phenolic compounds found in grape (Vitis vinifera L.) stems, further supporting their interest and applications as potential bioactive ingredients and, thus, acting as a value-added byproduct of the winery industry.

Food and Bioprocess Technology, 2020

The aim of the present study was the evaluation of the performance of analytical models developed... more The aim of the present study was the evaluation of the performance of analytical models developed with both mid-infrared (MIR) and near-infrared (NIR) spectral data, to assess the phytochemical composition and in vitro antioxidant activity, besides individual phenolic compounds determined by HPLC-DAD, of flours from 21 distinct cultivars of Phaseolus vulgaris L. Partial least squares (PLS) regression was used to develop the analytical models, which were validated with an external set of samples. In MIR, the best prediction models were developed using the first derivative after normalization (R 2 c 0.86-0.99 and R 2 v 0.75-0.94), while for NIR, the use of the first derivative of the spectra after normalization led to the best results (R 2 c 0.94-0.99 and R 2 v 0.85-0.97). Both techniques allowed to ascertain the prediction models to ensure an accurate evaluation of the individual phenolic compounds in concentrations as low as~5 μg g −1 and in vitro antioxidant capacity until the lower limit of 2.1 μmol g −1 dw. Therefore, this study revealed that the spectroscopic methodologies may represent an accurate and rapid method for quantification of phytochemical composition, in vitro antioxidant activity and individual phenolic compounds of bean flours; thus, their applicability in the food industry is representing an alternative to the traditional approaches.

Saudi Journal of Biological Sciences, 2020

The grape is a matrix rich in bioactive compounds and its production generates large quantities o... more The grape is a matrix rich in bioactive compounds and its production generates large quantities of byproducts, such as grape stems, which, to date, present low commercial value. However, there is a growing interest in the application of this material as a source of phenolic compounds. Therefore, the present study aims at assessing the phytochemical profile of (poly)phenolic extracts of white Portuguese grape stem varieties produced in the Região Demarcada do Douro (Portugal). The antioxidant activity determined by several assays, as well as the antimicrobial activity using the disc diffusion method against human gastrointestinal pathogenic bacteria of the hydromethanolic extracts, were evaluated. This work presents very positive results as the rich composition in phenolic compounds (94.71-123.09 mg GA À1 and 0.02-73.79 mg g À1 for the total phenol content and for individual phenolics, respectively) presented by grape stems can explain the high antioxidant (0.37-1.17 mmol Trolox g À1) and antimicrobial activities against, essentially, Gram-positive bacteria, and in some cases with higher efficacy than commercial antibiotics. Thus, demonstrating that this wine by-product should deserve greater attention from the pharmaceutical industries due to its excellent biological properties and characteristics not yet applied.

Antioxidants, 2020

Phaseolus vulgaris L. is the most commonly consumed legume in the world, given its high vegetable... more Phaseolus vulgaris L. is the most commonly consumed legume in the world, given its high vegetable protein content, phenolic compounds, and antioxidant properties. It also represents one of the most sustainable, low-carbon and sources of food available at present to man. This study aims to identify the nutrients, antinutrients, phenolic composition, and antioxidant profile of 10 common bean cultivars (Arikara yellow, butter, cranberry, red kidney, navy, pinto, black, brown eyed, pink eyed, and tarrestre) from two harvest years, thereby assessing the potential of each cultivar for specific applications in the food industry. Navy and pink eyed beans showed higher potential for enrichment of foodstuffs and gluten-free products due to their higher protein and amino acid contents. Additionally, red kidney, cranberry and Arikara yellow beans had the highest content of phenolic compounds and antioxidant properties, which can act as functional ingredients in food products, thus bringing heal...

Industrial Crops and Products, 2018

The wine industry involves the production of large quantities of by-products, characterized by a ... more The wine industry involves the production of large quantities of by-products, characterized by a valuable composition in phytochemicals with putative health-promoting qualities. Additionally, in light of recently revealed multidrug-resistant bacteria framework, the search for natural antimicrobial compounds has focused its attention on these compounds as promising alternatives. In this study, grape stems were assessed on their phytochemical composition and antimicrobial activity throughout storage (64 days). Upon this characterization, stems were noticed as a valuable source of total phenols, ortho-diphenols and flavonoids (42.04-96.29 and 45.52-81.11 mg GA g −1 , and 29.46-76.20 mg CAT g −1 , respectively), and ABTS and DPPH radical scavenging capacity (4.28-8.56 and 0.46-1.00 mmol Trolox g −1 , respectively), which remained stable during storage. In addition, all polyphenolic extracts were competent in inhibiting the bacterial growth of selected Gram-positive and Gram-negative bacteria strains (% of relative inhibition zone diameter ≥47), being quite interesting to the food-pharma industries as functional ingredients.

Food Research International, 2016

To date, grape stems have been partially assessed on their content in phenolics and their radical... more To date, grape stems have been partially assessed on their content in phenolics and their radical scavenging activity, whilst the potential to modulate oxidative stress in biological models remains underexplored. In the present work, the effect of grape stems' phenolics on redox unbalance was evaluated in human keratinocytes (HaCaT cells). Grape stems' extracts were assessed on their phenolic composition by high performance liquid chromatography coupled with photodiode array detection and electrospray ionization-mass spectrometry (HPLC-PAD-ESi-MSn), besides on radical scavenging capacity (ABTS and DPPH). In addition, their protective effect against oxidative stress induced by H 2 O 2 by the determination of the level of glutathione, reactive oxygen species, lipid peroxidation, and overall oxidative stress in HaCaT cells by flow cytometry was evaluated. This characterization allowed to identify five flavonols, one cinnamic acid, and one stilbene. A close correlation between the concentration of these phenolics and the capacity to scavenge free radicals and with the potential to modulate the redox balance in vitro was observed. From the analysis of correlation, the activity of malvidin-3-O-glucoside, malvidin-3-O-(6-O-caffeoyl)-glucoside, and malvidin-3-O-rutinoside with respect to the prevention of basal oxidative stress and the capacity of isorhamnetin-3-O-(6-O-feruloyl)-glucoside and kaempferol-3-O-rutinoside to prevent H 2 O 2-induced redox unbalance were stated. Furthermore, grape stems' phenolics also showed an efficient capacity to modulate apoptosis in HaCaT cells, reducing the frequency of annexin V/PI double positive apoptotic cells by up to 99.5% relative to controls, which was further confirmed by the determination of the appearance of the occurrence of apoptotic bodies and the expression of activated (cleaved) caspase-3 by flow cytometry and western-blot, respectively. These results supported the potential of individual phenolics from grape stems to modulate oxidative stress, allowing to envisage dedicated combinations of single compounds for the development of efficient formulations efficient against oxidative stress.

Fitoterapia, Jan 16, 2017

The antioxidant potential of grape (Vitis vinífera L.) stems has been reported in the last decade... more The antioxidant potential of grape (Vitis vinífera L.) stems has been reported in the last decade although no identification of the individual compounds responsible for such action has been done. In this work, polyphenolic extract of grape stems was processed resorting to semi-preparative HPLC, allowing to obtain 5 purified polyphenols (caftaric acid, malvidin-3-O-glucoside, quercetin-3-O-glucuronide, mailvidin-3-O-(6-O-caffeoyl)-glucoside, and Σ-viniferin), which were fully characterized by HPLC-PDA-ESI-MS(n). Isolated compounds were featured on their radical scavenging capacity (DPPH and ABTS), cell viability, anti-inflammatory activity, and capacity to modulate the level of reactive oxygen species, glutathione, lipid peroxidation, and overall oxidative stress in a biological model (human keratinocytes) in vitro, under basal and oxidative conditions. The results obtained noticed the combinations malvidin-3-O-glucoside+Vitamin E and quercetin-3-O-glucuronide+vitamin C as the most e...

Revista Odonto Ciência, 2015

Objective: To calculate the major constriction area of the oropharynx, using 3-dimensional images... more Objective: To calculate the major constriction area of the oropharynx, using 3-dimensional images derived from cone beam computed tomography (CBCT), in order to: 1. Obtain normal level indexes according to the age group 2. Correlate the major constriction area of the oropharynx with its sagittal depth and its total volume. Methods: Forty-one scans from the 3D-i-CAT computerized tomograph were evaluated by the software InVivoDental 5.0. Results: The values of the major constriction areas of the oropharynx were obtained, related to the age. There was a positive strong correlation only for the oropharynx major constriction area and its total volume. The correlation between the oropharynx sagittal depth and its major constriction area was positive and moderate. In relation to its sagittal depth and its total volume, the correlation was positive and weak. Conclusions: 1. To the age group 6-12 years, the values ranged from 52.03 to 194.37 mm 2 ; to 13-18 years, ranged from 134.82 to 264.18 mm 2 , and to the age group >19 years, from 95.87 to 229.73 mm 2 ; 2. The linear measurement of the sagittal depth of the oropharynx, as performed over lateral cephalometric radiographs, is not much reliable when compared to those achieved from tomographic images.