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Publicações

Publicações por Nelson Machado

2021

Kaolin impacts on hormonal balance, polyphenolic composition and oenological parameters in red grapevine berries during ripening

Autores
Bernardo, S; Dinis, LT; Machado, N; Barros, A; Pitarch Bielsa, M; Gomez Cadenas, A; Moutinho Pereira, J;

Publicação
JOURNAL OF BERRY RESEARCH

Abstract
BACKGROUND: Kaolin particle-film application is a well-known strategy to avoid fruit damage. However, its putative role in balancing berry ripening under a changing climate remains poorly explored. OBJECTIVE: We assessed kaolin treatment effect on several ripening berry components, hormonal balance and oenological parameters of the field-grown Touriga-Franca (TF) and Touriga-Nacional (TN) grapevine varieties at veraison (EL35) and ripening (EL38) during two growing seasons (2017 and 2018). RESULTS: Under the adverse summer conditions (two heatwave events) of 2017, kaolin application increased 211.2 % and 51.4 % the salicylic acid (SA) and abscisic acid (ABA) levels in TF berries at EL38, while no significant differences were observed in TN. Conversely, TF, and TN kaolin treated berries showed lower SA and ABAaccumulation in 2018, respectively. Tartaric acid content increased about 17.2 %, and 24.2 % in TF and TN treated berries at stage EL35 in the 2017 growing season. Though kaolin treatment had no consistent effect on anthocyanins accumulation, flavonoids, ortho-diphenols and tannins increased in kaolin treated grapevines in 2017. CONCLUSIONS: This study highlights the key role of climate in triggering ripening related processes and fruit quality potential. Nevertheless, kaolin treated grapevines displayed an improved response to oxidative stress signals by increasing secondary metabolites accumulation in warm vintages. Kaolin application promoted different varietal responses, with a possible ripening delaying effect in TF, reinforcing its efficiency in alleviating severe summer stress impacts.

2022

Uncovering the effects of kaolin on balancing berry phytohormones and quality attributes of Vitis vinifera grown in warm-temperate climate regions

Autores
Bernardo, S; Dinis, LT; Machado, N; Barros, A; Pitarch Bielsa, M; Malheiro, AC; Gomez Cadenas, A; Moutinho Pereira, J;

Publicação
JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE

Abstract
BACKGROUND The application of kaolin particle film is considered a short-term strategy against several environmental stresses in areas with a Mediterranean-like climate. However, it is known that temperature fluctuations and water availability over the season can jeopardize kaolin efficiency in many Mediterranean crops. Hence, this study aims to evaluate the effects of kaolin foliar application on berry phytohormones, antioxidant defence, and oenological parameters at veraison and harvest stages of Touriga-Franca (TF) and Touriga-Nacional (TN) grapevines in two growing seasons (2017 and 2018). The 2017 growing season was considered the driest (-147.1 dryness index) and the warmest (2705 degrees C growing degree days) of the study. RESULTS In 2017, TF kaolin-treated berries showed lower salicylic acid (-26.6% compared with unsprayed vines) and abscisic acid (ABA) (-10.5%) accumulation at veraison, whereas salicylic acid increased up to 28.8% at harvest. In a less hot season, TN and TF kaolin-treated grapevines showed a twofold in ABA content and a threefold increase in the indole-3-acetic acid content at veraison and lower ABA levels (83.8%) compared with unsprayed vines at harvest. Treated berries showed a decreased sugar content, without compromising malic and tartaric acid levels, and reactive oxygen species accumulation throughout berry ripening. CONCLUSION The results suggest kaolin exerts a delaying effect in triggering ripening-related processes under severe summer stress conditions. Treated berries responded with improved antioxidant defence and phytohormone balance, showing significant interactions between kaolin treatment, variety, and developmental stage in both assessed years. (c) 2021 Society of Chemical Industry.

2021

Potential of Legumes: Nutritional Value, Bioactive Properties, Innovative Food Products, and Application of Eco-friendly Tools for Their Assessment

Autores
Carbas, B; Machado, N; Pathania, S; Brites, C; Rosa, EAS; Barros, AIB;

Publicação
FOOD REVIEWS INTERNATIONAL

Abstract
Legumes are an important and sustainable source of protein, dietary fiber and phytochemicals. Due to their composition, legumes have been used in enriched foodstuffs and recognized as a vital food resource for human diet, reducing the risk of cardiovascular disease and cancer. In the last years, in order to replace conventional analysis, more eco-friendly and faster methodologies have been applied to evaluate legumes' quality. The aim of this review is to encourage the consumption and production of legumes by promoting their dissemination, understanding their nutritional and functional value, and promoting the use of innovative methodologies to assess the composition of legumes.

2021

Kaolin Application Modulates Grapevine Photochemistry and Defence Responses in Distinct Mediterranean-Type Climate Vineyards

Autores
Bernardo, S; Luzio, A; Machado, N; Ferreira, H; Vives Peris, V; Malheiro, AC; Correia, C; Gomez Cadenas, A; Moutinho Pereira, J; Dinis, LT;

Publicação
AGRONOMY-BASEL

Abstract
At a local scale, kaolin particle-film technology is considered a short-term adaptation strategy to mitigate the adverse effects of global warming on viticulture. This study aims to evaluate kaolin application effects on photochemistry and related defence responses of Touriga Franca (TF) and Touriga Nacional (TN) grapevines planted at two Portuguese winegrowing regions (Douro and Alentejo) over two summer seasons (2017 and 2018). For this purpose, chlorophyll a fluorescence transient analysis, leaf temperature, foliar metabolites, and the expression of genes related to heat stress (VvHSP70) and stress tolerance (VvWRKY18) were analysed. Kaolin application had an inhibitory effect on VvHSP70 expression, reinforcing its protective role against heat stress. However, VvWRKY18 gene expression and foliar metabolites accumulation revealed lower gene expression in TN-treated leaves and higher in TF at Alentejo, while lipid peroxidation levels decreased in both treated varieties and regions. The positive kaolin effect on the performance index parameter (PIABS) increased at ripening, mainly in TN, suggesting that stress responses can differ among varieties, depending on the initial acclimation to kaolin treatment. Moreover, changes on chlorophyll fluorescence transient analysis were more pronounced at the Douro site in 2017, indicating higher stress severity and impacts at this site, which boosted kaolin efficiency in alleviating summer stress. Under applied contexts, kaolin application can be considered a promising practice to minimise summer stress impacts in grapevines grown in Mediterranean-like climate regions.

2021

Particle film technology modulates xanthophyll cycle and photochemical dynamics of grapevines grown in the Douro Valley

Autores
Bernardo, S; Dinis, LT; Luzio, A; Machado, N; Vives Peris, V; Lopez Climent, MF; Gomez Cadenas, A; Zacarias, L; Rodrigo, MJ; Malheiro, AC; Correia, C; Moutinho Pereira, J;

Publicação
PLANT PHYSIOLOGY AND BIOCHEMISTRY

Abstract
Field-grown grapevines are often exposed to multiple environmental stresses, which challenges wine-growers to develop sustainable measures to sustain vine growth, yield, and quality. Under field conditions this task is demanding, due to differences in the magnitudes of stresses and associated plant responses. In this study we explored the hypothesis that kaolin-particle film application improves grapevine photoprotection through the regulation of xanthophyll cycle genes, limiting the thermal dissipation of excess energy under harsh environmental conditions. Hence, we selected two grapevine varieties, Touriga-Nacional (TN) and Touriga-Franca (TF), grown in the Douro Demarcated Region, and evaluated changes in light dissipation mechanisms, xanthophyll cycle components, and the expression of xanthophyll cycle genes during the 2017 summer season. The results showed that, from veraison to ripening, kaolin triggered the up-regulation of violaxanthin de-epoxidase (VvVDE1) and zeaxanthin epoxidase (VvZEP1) genes, indicating optimised regulation of the xanthophyll cycle. Kaolin treatment also decreased chlorophyll (Chla, Chlb, Chl(a+b)) and carotenoid (Car) accumulation under increasing summer stress conditions in both varieties and lowered the non-photochemical quenching (NPQ) of grapevines on ripening, suggesting a long-term response to summer stress. In addition, kaolin-treated grapevines showed increased Chla/Chlb and lower Chl(a+b)/Car ratios, displaying some features of high light adapted leaves. Overall, this study suggests that kaolin application enabled grapevines to benefit from fluctuating periods of summer stress by managing chlorophyll and carotenoid content and limiting down-regulation of both photochemistry and photoinhibition processes. Under Mediterranean field conditions, kaolin application can be considered an efficient method of minimising summer stress impact on grapevines.

2020

Prediction of Phytochemical Composition, In Vitro Antioxidant Activity and Individual Phenolic Compounds of Common Beans Using MIR and NIR Spectroscopy

Autores
Carbas, B; Machado, N; Oppolzer, D; Queiroz, M; Brites, C; Rosa, EAS; Barros, AIRNA;

Publicação
FOOD AND BIOPROCESS TECHNOLOGY

Abstract
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 similar to 5 mu g g(-1) and in vitro antioxidant capacity until the lower limit of 2.1 mu mol 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.

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