23 research outputs found
Predicting calcium in grape must and base wine by FT-NIR spectroscopy
Calcium content in sparkling wines may not exceed 80 mg/L due to the risk of aggregation with alginate capsules.
The high calcium content usually found in wine and must emphasizes the need to develop alternative and
appropriate techniques faster and cleaner than atomic absorption spectrometry (AAS). To obtain a robust model
to predict calcium content, FT-NIR spectroscopy was used in 98 base white wine samples and 60 must samples
from an Alentejo winery. The reference method for calcium determination was AAS technique, with a dry ashing
sample procedure, as a prior treatment.
Results confirmed the ability of FT-NIR as an alternative technique to AAS, to predict calcium content in
grape must and base wine. Advance knowledge of the calcium content in the grape must will help avoid obtaining
a mixture of musts with a high calcium content in the same container
Exploring the Applicability of Calorespirometry to Assess Seed Metabolic Stability Upon Temperature Stress Conditions—Pisum sativum L. Used as a Case Study
Original ResearchThe availability of phenotyping tools to assist breeding programs in the selection of highquality
crop seeds is of obvious interest with consequences for both seed producers and
consumers. Seed germination involves the activation of several metabolic pathways,
such as cellular respiration to provide the required ATP and reducing power. This
work tested the applicability of calorespirometry, the simultaneous measurement of
heat and CO2 rates, as a phenotyping tool to assess seed respiratory properties
as a function of temperature. The effect of temperature on seed germination was
evaluated after 16 h of seed imbibition by calorespirometric experiments performed
in isothermal mode at 15, 20, 25, and 28 C on the seeds of three cultivars of peas
(Pisum sativum L.) commonly used in conventional agriculture (cvs. ‘Rondo’, ‘Torta de
Quebrar’, and ‘Maravilha d’América’). Significant differences in metabolic heat rate and
CO2 production rate (RCO2) as well as in the temperature responses of these parameters
were found among the three cultivars. A seed germination trial was conducted during
the 6 days of imbibition to evaluate the predictive power of the parameters derived
from the calorespirometric measurements. The germination trial showed that the optimal
germination temperature was 20 C and low germination rates were observed at extreme
temperatures (15 or 28 C). The cv. ‘Torta de Quebrar’ showed significantly higher
germination in comparison with the other two cultivars at all three temperatures. In
comparison with the other two cultivars, ‘Torta de Quebrar’ has the lowest metabolic
heat and CO2 rates and the smallest temperature dependence of these measured
parameters. Additionally, ‘Torta de Quebrar’ has the lowest values of growth rate and carbon use efficiency calculated from the measured variables. These data suggest
that calorespirometry is a useful tool for phenotyping physiologic efficiency at different
temperatures during early germination stages, and can determine the seeds with the
highest resilience to temperature variation, in this case ‘Torta de Quebrar’info:eu-repo/semantics/publishedVersio
Analysis of Growth Parameters for Crop Vegetables Under Broad and Narrow LED Spectra and Fluorescent Light Tubes at Different PPFs
Several physiological and yield parameters were evaluated in lettuce plants, cv. ‘Trocadero’, while growing at four different photosynthetic photon flux (PPF) (70, 120, 250 and 400 ± 10 µmol m-2 s-1), under four light spectra, white (W), red (R) and blue (B) Light-Emitting Diode (LED) lamps and cool white fluorescent tubes (FL). Yield parameters were also evaluated on spinach, turnip and radish, growing under identical light spectra but using a single PPF (340 ± 10 µmol m-2 s-1). Lettuce development was impaired at PPFs below 250 µmol m-2 s-1 for all tested spectra. At higher PPFs (250 and 400 ± 10 µmol m-2 s-1), for the two broad spectra tested (W LEDs and FL light), no significant differences were registered on all physiological and yield parameters evaluated. On all situations W LEDs performed, at least, as good as the FL light, indicating that actual W LEDs can efficiently replace traditional light sources, with all the inherent benefits, which include significant lower power consumption. For all species, narrow light spectra (R and B LEDs) proved not being able to provide normal plant development. Plants under R LEDs, although presenting, in some situations, a fresh weight higher than those achieved with the broad light spectra, always led to abnormal plant morphology, characterized by expanded petioles and leaf curling. B LEDs, in spite of promoting plant growth with normal morphology, frequently led to a lower number of leaves and consequently to a lower fresh weight
Utilização de dados do satélite Sentinel-2e de espectroscopia NIR para a quantificação de nutrientes na nogueira-comum (Juglans regia L.)
A determinação do teor de nutrientes em culturas agrícolas requer
periodicidade na colheita de amostras foliares que serão futuramente
analisadas em laboratórios acreditados para o efeito. Desta forma, são
disponibilizadas aos agricultores recomendações de fertilização baseadas nos
resultados das análises foliares. Este processo é moroso e requer uma recolha
representativa das amostras principalmente em parcelas com um certo nível de
heterogeneidade espacial. A existência de metodologias alternativas que
permitam obter a informação acerca do teor de nutrientes em culturas agrícolas
de forma rápida e mais representativas da parcela, será́ uma mais-valia
importante na gestão da nutrição em qualquer espécie vegetal.
Este trabalho teve como objetivo encontrar metodologias para avaliar o nível
nutricional (teor de azoto (N), cálcio (Ca) e potássio (K)) de um pomar de
nogueiras, recorrendo a informações do satélite de observação da Terra,
Sentinel-2.
Este trabalho decorreu durante a campanha de 2021 num pomar de nogueiras
no Alentejo. Foram recolhidas amostras foliares em 6 datas diferentes e
determinados, pelos métodos analíticos de referência, os teores de nutrientes
de azoto cálcio e potássio, tendo os valores obtidos sido comparados com a
informação das bandas espectrais disponibilizados pelo satélite Sentinel-2 e
dos índices calculados: índice de vegetação por diferença normalizada (NDVI)
e índice de água por diferença normalizada (NDWI). Foi utilizada a regressão
linear múltipla para a obtenção de modelos de predição das variáveis resposta
(teor de N, Ca e K) a partir das variáveis independentes. Os modelos obtidos
para os nutrientes em estudo apresentaram um nível de confiança muito
aceitável sendo considerados modelos relativamente robustos, tendo sido
utilizados para a construção de mapas de distribuição espacial do N, Ca e K na
cultura
Assessment of Total Fat and Fatty Acids in Walnuts Using Near-Infrared Hyperspectral Imaging
“Persian” walnut (Juglans Regia L.) is one of the most consumed tree nuts in the world.
It is rich in several bioactive compounds, with polyunsaturated and monounsaturated
fatty acids (PUFA and MUFA) appearing at high concentrations. Walnut consumption
protects against cardiovascular, carcinogenic, and neurological disorders. The fatty acid
profile has usually been determined by gas chromatography, a reliable and robust tool,
but also complex, polluting, and time consuming. In this study, near infrared hyperspectral
imaging has been used for the screening of total fat, MUFA, PUFA, saturated, and individual
fatty acids in walnuts. Five different walnuts varieties have been considered and modified
partial least square (MPLS) regressions have been performed. The SEs of prediction (SEP)
in external validation (ranged from 2.12% for PUFA to 13.08% for MUFA) suggest that
hyperspectral imaging can be a reliable tool for controlling these parameters in a simple,
non-destructive and environmentally friendly way.FCT – Foundation
for Science and Technology- ref:UIDB/05183/2020;
FEDER and National Funds through the Programa
Operacional Regional ALENTEJO 2020 (ALT20-03-0246-
FEDER-000064) – QualFastNut – Utilização da espectroscopia
NIR para a análise rápida da qualidade em frutos secos
Quality Assessment of Red Wine Grapes through NIR Spectroscopy
Red wine grapes require a constant follow-up through analytical chemistry to assure the greatest wine quality. Wet chemical procedures are time-consuming and produce residues that are hard to eliminate. NIR (near infrared radiation) spectroscopy has been referred as an accurate, rapid, and cost-efficient technique to evaluate quality in many fruit species, both in field and in industry. The main objective of this study was to develop predictive models using NIR spectroscopy to quantify important quality attributes in wine grapes. Soluble solids content (SSC), titratable acidity (TA), total phenolic content, total flavonoids, total anthocyanins, and total tannins were quantified in four red wine grape varieties, ‘Aragonês’, ‘Trincadeira’, ‘Touriga Nacional’, and ‘Syrah’. Samples were collected during 2017 and 2018 along véraison. Prediction models were developed using a near-infrared portable device (Brimrose, Luminar 5030), and spectra were collected from entire grapes under near field conditions. Models were built using a partial least square regression (PLSR) algorithm and SSC, TA, total anthocyanins, and total tannins exhibited a determination coefficient of 0.89, 0.90, 0.87, and 0.88, respectively. The Residual Prediction Deviation (RPD) values of these models were higher than 2.3. The prediction models for SSC, TA, total anthocyanins, and total tannins have considerable potential to quantify these attributes in wine grapes. Total flavonoids and total phenolic content were predicted with a slightly lower capacity, with R2 = 0.72 and 0.71, respectively, and both with a RPD of 1.6, indicating a very low to borderline potential for quantitative predictions in flavonoids and phenols model
Response of mycorrhizal Touriga Nacional variety grapevines to high temperatures measured by calorespirometry and near-infrared spectroscopy
Heat stress negatively affects several physiological and biochemical processes in grapevine
plants. In this work, two new methods, calorespirometry, which has been used to determine
temperature adaptation in plants, and near-infrared (NIR) spectroscopy, which has been used to
determine several grapevine-related traits and to discriminate among varieties, were tested to evaluate
grapevine response to high temperatures. ‘Touriga Nacional’ variety grapevines, inoculated or not
with Rhizoglomus irregulare or Funneliformis mosseae, were used in this study. Calorespirometric
parameters and NIR spectra, as well as other parameters commonly used to assess heat injury in
plants, were measured before and after high temperature exposure. Growth rate and substrate carbon
conversion effciency, calculated from calorespirometric measurements, and stomatal conductance,
were the most sensitive parameters for discriminating among high temperature responses of control
and inoculated grapevines. The results revealed that, although this vine variety can adapt its
physiology to temperatures up to 40 ºC, inoculation with R. irregulare could additionally help to
sustain its growth, especially after heat shocks. Therefore, the combination of calorespirometry
together with gas exchange measurements is a promising strategy for screening grapevine heat
tolerance under controlled conditions and has high potential to be implemented in initial phases of
plant breeding programsinfo:eu-repo/semantics/publishedVersio
Control of the extractable content of bioactive compounds in coffee beans by near infrared hyperspectral imaging
Control of coffee quality has a great importance for being one of the most important raw materials within the international trade. The extractable composition of coffee has been studied in recent decades and the use of non-destructive methodologies is being continuously promoted. In this study, near infrared hyperspectral imaging has been applied to develop non-destructive methods for the control of extractable contents of caffeine, chlorogenic acid, total phenolics and melanoidins in coffee beans.
Extractable contents and trends obtained among the different coffee types analysed are similar to those obtained previously in other studies. Moreover, modified partial least square (MPLS) regressions produced prediction models with standard errors of prediction in external validation of 12.01%, 15.61% and 17.61% for caffeine, chlorogenic acid and total phenolics, respectively. Therefore, results obtained for these three parameters indicate that NIR spectroscopy has a great potential for their control in coffee beans
Control de calidad en nuez entera mediante análisis de imagen
El consumo de nuez está muy extendido a nivel mundial debido a sus propiedades organolépticas y a su composición rica en compuestos bioactivos potencialmente beneficiosos para la salud. En este estudio se han desarrollado métodos no destructivos para el control varietal y la detección de desperfectos de nueces con cáscara a partir de análisis de imagen digital. Se ha obtenido un porcentaje de clasificación correcta en validación externa del 77% para la identificación de la variedad de nuez y del 100% para la detección de nueces defectuosas. Queda de manifiesto, por tanto, el gran potencial que tiene esta técnica para, analizando la nuez completa con cáscara, evaluar la defectología en su interior
Real-time quantification of crude protein and neutral detergent fibre in pastures under montado ecosystem using the portable nir spectrometer
The Montado is a Mediterranean agro–forestry–pastoral ecosystem. Knowledge of pastures’ nutritional value is critical for farm managers’ decision-making. Laboratory determinations are very expensive, destructive and costly, in terms of time and labour. The objective of this experimental work was to calibrate and validate a portable near-infrared spectrometer (micro-NIR) to predict the nutritive value (neutral detergent fibre, NDF and crude protein, CP) of pastures in the peak of spring 2021. Thus, a total of 87 pasture samples were collected at eight experimental fields located in the Alentejo, Southern region of Portugal. The results show good correlations between in-situ micro-NIR measurements and pasture NDF reference values (R2 of 0.73 and 0.69 for calibration and validation models, respectively), and a moderate correlation between micro-NIR measurements and pasture CP reference values (R2 of 0.51 and 0.36 for calibration and validation models, respectively). These results show the potential of this tool for the quick evaluation of pasture quality and constitute a starting point for future work, which should include the monitoring of temporal variability (throughout the entire vegetative cycle of the pasture) and spatial (with geo-referenced information) diversity of pastures characteristic of the Montado ecosystem in the Mediterranean region.Foundation for Science and Technology UIDB/05183/2020, PDR2020-101-030693, PDR2020-101-03124