Abstract
Reliable estimations of parameter values and associated uncertainties are crucial for crop model applications in agro-environmental research. However, estimating many parameters simultaneously for different types of response variables is difficult. This becomes more complicated for grapevines with different phenotypes between varieties and training systems. Our study aims to evaluate how a standard least square approach can be used to calibrate a complex grapevine model for simulating both the phenology (flowering and harvest date) and yield of four different variety-training systems in the Douro Demarcated Region, northern Portugal. An objective function is defined to search for the best-fit parameters that result in the minimum value of the unweighted sum of the normalized Root Mean Squared Error (nRMSE) of the studied variables. Parameter uncertainties are estimated as how a given parameter value can determine the total prediction variability caused by variations in the other parameter combinations. The results indicate that the best-estimated parameters show a satisfactory predictive performance, with a mean bias of -2 to 4 days for phenology and -232 to 159 kg/ha for yield. The corresponding variance in the observed data was generally well reproduced, except for one occasion. These parameters are a good trade-off to achieve results close to the best possible fit of each response variable. No parameter combinations can achieve minimum errors simultaneously for phenology and yield, where the best fit to one variable can lead to a poor fit to another. The proposed parameter uncertainty analysis is particularly useful to select the best-fit parameter values when several choices with equal performance occur. A global sensitivity analysis is applied where the fruit-setting parameters are identified as key determinants for yield simulations. Overall, the approach (including uncertainty analysis) is relatively simple and straightforward without specific pre-conditions (e.g., model continuity), which can be easily applied for other models and crops. However, a challenge has been identified, which is associated with the appropriate assumption of the model errors, where a combination of various calibration approaches might be essential to have a more robust parameter estimation.

Abstract
BACKGROUND: Freezing represents a common conservation practice regarding vegetal foodstuffs. Since compositional features need to be monitored during storage, the development of rapid monitoring tools suitable for assessing nutritional characteristics arises as a pertinent issue. In this study, cowpea (Vigna unguiculata L.) pods, both fresh and after 6 and 9 months of freezing at -18 degrees C, were evaluated by high-performance liquid chromatography for their content of protein as well as of essential and nonessential amino acids, while their Fourier transform infrared spectra in the mid infrared (MIR) and near infrared (NIR) ranges were concomitantly registered to assess the feasibility of this approach for the traceability of these frozen matrices. RESULTS: For the NIR interval, the application of the 1st derivative to the spectral data retrieved the best results, while for lower concentrations the application of the Savitzky-Golay algorithm was indispensable to achieve quantification models for the amino acids. MIR is also suitable for this purpose, though being unable to quantify amino acids with concentrations below 0.07 mmol g(-1) dry weight, irrespective of the data treatment used. CONCLUSIONS: The spectroscopic approach constitutes a methodology suitable for monitoring the impact of freezing on the nutritional properties of cowpea pods, allowing accurate quantification of the protein and amino acid contents, while NIR displayed better performance. (C) 2017 Society of Chemical Industry

Abstract
BACKGROUND: Freezing represents an important storage method for vegetal foodstuffs, such as cowpea pods, and thus the impact of this process on the chemical composition of these matrices arises as a prominent issue. In this sense, the phytochemical contents in frozen cowpea pods (i.e. at 6 and 9 months) have been compared with fresh cowpea pods material, with the samples being concomitantly assessed by Fourier-transform infrared spectroscopy (FTIR), both mid-infrared (MIR) and near infrared (NIR), aiming to evaluate the potential of these techniques as a rapid tool for the traceability of these matrices. RESULTS: A decrease in phytochemical contents during freezing was observed, allowing the classification of samples according to the freezing period based on such variations. Also, MIR and NIR allowed discrimination of samples: the use of the first derivative demonstrated a better performance for this purpose, whereas the use of the normalized spectra gave the best correlations between the spectra and specific contents. In both cases, NIR displayed the best performance. CONCLUSION: Freezing of cowpea pods leads to a decrease of phytochemical contents, which can be monitored by FTIR spectroscopy, both within the MIR and NIR ranges, whereas the use of this technique, in tandem with chemometrics, constitutes a suitable methodology for the traceability of these matrices. (C) 2017 Society of Chemical Industry

Abstract
Olive fruits, as well as their corresponding oil, represent an interesting source of phytochemicals, mainly phenolic compounds, which arise as secondary metabolites, resulting from the plant's response to biotic and abiotic stresses. Therefore, olive fruits from three distinct cultivars ("Cobrancosa," "Galega Vulgar," and "Picual") grown in Portugal and displaying different degree of resistance to biotic and abiotic stresses have been studied in relation to the concentration of total phenolic compounds, orthodiphenols and flavonoids, besides antioxidant capacity (DPPH, ABTS, FRAP, and ORACFL), in three maturation stages and two distinct harvest seasons (2012-2013). Generally, a decrease of all phenolic contents throughout the maturation stages has been observed, while, concerning cultivar, green olives of "Cobrancosa" showed the highest values for all contents assessed, denoting a strong influence of the genetic background. The same trend has not been observed regarding antioxidant activity, since Cobrancosa and Galega Vulgar cultivars presented the highest values only for the DPPH and ORACFL assays. Moreover, multivariate analyses pointed to the preponderance of the cultivars' phenolic composition in the semiripe stage for the resistance to biotic stress, with "Galega" the most susceptible cultivar, presenting the lowest contents at this maturation stage, whereas "Picual" displayed the most pronounced phytochemical response.

Abstract
The olive tree (Olea europaea L.) can be affected by Colletotrichum acutatum, causing a loss of yield and quality of the final products, whilst the incidence of this fungal infection depends on several factors, including cultivar susceptibility. Thus, the effect of C. acutatum infection in cultivars displaying different susceptibilities to this fungal disease (Galega Vulgar' - susceptible, Cobrancosa' - moderately susceptible, Picual' - tolerant) has been assessed through spectrophotometric methods and HPLC, while the FTIR spectra of the cuticles have been concomitantly registered, resorting to the ATR accessory. With the support of multivariate analysis, these spectra allowed to discriminate olives with distinct infection times, besides retrieving evidences concerning the different susceptibility of each cultivar, while these observations were reinforced by the spectrophotometric and chromatographic methods. Furthermore, the assessment of the phenolic profile evidenced individual compounds in the distinct cultivars, so as their variations in response to the fungal infection. Distinct olive cultivars were inoculated with Colletotrichum acutatum. The most resistant olive tree cultivars display the highest content in phenolics. FTIR-ATR-based analyses allow to monitor the response of olive fruits to C. acutatum.

Abstract
Among the groups of naturally occurring pigments, carotenoids serve numerous purposes in plants, including antioxidant activity and protection of the photosynthetic apparatus from the excess of light. Alongside with essential mineral elements, these pigments are well known to have high impact on human health. Therefore, accumulation of carotenoids in wheat grain is an important trait in view to improving nutritional value of cereals. Wheat is one of the major staple foods in Portugal because of its agronomical adaptability and the usage of its flour into various traditional products. In the present investigation, the seeds of ninety-four Old Portuguese wheat cultivars grown over two years were analysed. Significant genetic variability for content of carotenoids was observed in the studied lines. Within the 47 bread wheat genotypes the Yellow Pigment Content (YPC) values varied from 2.7 - 5.8 mu g/g and 3.0 - 8.0 mu g/g for 2004/2005 and 2009/2010, respectively. On the other hand, during 2004/2005 and 2009/2010, the 47 durum wheat cultivars exhibited the YPC values from 1.1 - 8.0 mu g/g and 3.4 - 8.3 mu g/g, respectively. In addition, multivariate methods were also explored to assess the wheat grains quality, resorting to FTIR spectroscopy (Figure 1). Preliminary analyses of FTIR spectra clearly revealed differences among the distinct studied genotypes. Thus, in order to find spectroscopical patterns related to carotenoids accumulation and antioxidant activity, efforts are being made to develop a model that will allow the assessment of these parameters through FTIR, in the near-future. (C) 2015 The Authors. Published by Elsevier B.V.