Soluble solids content, variety and origin of grapes are three relevant features to determine wine quality. Soluble solids content is directly related to ripeness. The capacity to certify the origin or variety of a grape is of major interest for wine makers. The aim of this paper was to study whether near infrared refl ectance (NIR) spectroscopy could be used to determine soluble solids content and to identify different varieties and origins of grapes. Samples of Viura and Chardonnay grapes were collected in two locations (Cadreita and Villamayor de Monjardin) which varied in environmental conditions. Mass and sugars content measured by a refractometer and NIR (800-500 nm) refl ectance spectra were obtained. A partial least squares regression (PLS) was made to calibrate the NIR spectra. The regression models for Chardonnay grapes were more robust than for Viura grapes, showing coeffi cients of determination for calibration and validation of 0.75 and 0.70 and a standard error of cross-validation of 1.27. Therefore, NIR technology is suitable to determine the soluble solids content although it requires a calibration model for each variety, using a large number of data points and variables. The combined variety model showed a residual predictive deviation of 1.33, while Viura and Chardonnay models showed 1.54 and 1.88, respectively. The results of discriminant analysis using variables from the NIR spectrum showed a percentage of well-classifi ed grapes according to the variety to which they belonged of 97.2% and a 79.2% of well-classifi ed Chardonnay grapes according to their origin. In conclusion, NIR technology is a useful alternative for identifying the variety and origin of grapes.

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Potato (Solanum tuberosum L.) is one of the most important crops in the world being considered as a staple food in many developing countries. The potato industry like other vegetable and fruit industries is subject to the current demand of quality products. In order to meet this challenge, the food industry is relying on the adoption of nondestructive and environmentally friendly techniques to determine quality of products. Near-infrared spectroscopy (NIRS) is currently one of the most advanced nondestructive technologies regarding instrumentation and application, and it also complies with the environment requirements as it does not generate emissions or waste. This paper reviews research progress on the analysis of potatoes by NIRS both in terms of determination of constituents and classification according to the different constituents of the tubers. A brief description of the fundamentals of NIRS technology and its advantages over other quality assessment techniques is included. Finally, future prospects of the development of NIRS technology at the industrial level are explored.

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This study was carried out to evaluate the sorption isotherms of peanut pods, kernels and hulls for several temperature and humidity conditions and to fit different mathematical models to the experimental data, selecting the one best fitting the phenomenon. The dynamic method was applied to obtain the hygroscopic equilibrium moisture content. The environmental conditions were provided by means of an atmospheric conditioning unit, in which removable perforated trays were placed to allow air to pass through peanut mass, each one containing 50 g of the product. The mathematical models frequently used for the representation of hygroscopicity of agricultural products were fit to the experimental data. Based on those results, it was concluded that peanut pods, kernels and hulls presented differentiated hygroscopicity. The equilibrium moisture content for peanut pods, kernels and hulls increased with an increase in the relative humidity at any particular temperature and decreased with increase in temperature at constant relative humidity. At a constant water activity, peanut hulls samples had higher equilibrium moisture content than the pods and kernels samples. Based on statistical parameters, the modified Henderson and Chung-Pfost models were found to adequately describe the sorption characteristics of peanut pods, kernels and hulls. Isosteric heat of desorption were evaluated by applying the Clausius—Clapeyron equation to experimental isotherms and decreased with increasing moisture content. The peanut hulls had higher isosteric heat of sorption than that peanut pods and kernels.

The present characterisation of cultivars and breeding lines with high concentrations of phytochemicals is an important step both to support the consideration of specialty potatoes as a source of healthy compounds, and to obtain new cultivars with positive nutritional characteristics. Moreover, by using near infrared spectroscopy a non-destructive identification and classification of samples with different levels of phytochemicals is achieved, offering an unquestionable contribution to the potato industry for future automatic discrimination of varieties.

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