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This paper aims to determine and evaluate the calibration curve for low-cost electronic sensors in soils from a reclaimed and degraded area in the Brazilian semiarid region.

The probes were made, programmed and inserted in soil previously conditioned in polyethylene cylinders. The sets “cylinder + probe + soil” were subjected to saturation for a period of 24 h and, subsequently, gravitational drainage at room temperature and daily weighings were performed. When the set reached constant weight, the samples were taken to dry in an oven at 105°C to determine the dry mass and later, determine the gravimetric moisture and convert it into volumetric. The volumetric moistures obtained were related to measured frequency variations and the adjustments were analyzed by regression, which was subjected to analysis of variance (p = 0.05), and related by a third-degree polynomial equation whose quality of the fit was verified with coefficient of determination (R²).

The obtained moistures were related to the estimated moistures and evaluated by the root-mean-square error and straight 1:1. The results demonstrate that the sensors are not accurate for moistures in saturation, but representative and statistically acceptable results for moistures up to field capacity.

This paper has not been published before in its current, or similar form.

The aim of this study was to evaluate the effect of ultrasound (US) treatment on the postharvest of “Isabella” grapes and the consistency of the obtained results regarding the composition of anthocyanins in grape juice over three successive harvest years using a combination of analytical techniques.

Juices produced from “Isabella” grapes sonicated for different durations (3, 5, 7 and 10 min) were analysed. The grapes were harvested and sonicated in 2013, 2014 and 2015, and each treated sample was stored for 1, 3 and 5 days in order to verify the time necessary for the development of the US response. The juices were analysed through physicochemical analysis (total monomeric anthocyanins). The anthocyanin profiles were quantified and identified using high performance liquid chromatography coupled to photodiode array and mass spectrometry detectors (HPLC-PDA-MSn).

The results demonstrated the potential of US in improving the quality of grape juice. In all three harvests, it was observed that the treatments were effective in increasing the concentration of anthocyanins. For the 2013 harvest, the application of US for 5 min led to a 103% increase in juice pigments. However, the US response profile varied among the three harvests, indicating that the US effect was influenced by the ripening conditions of the fruit. In total, 33 anthocyanins were identified in the grape juice. For the first time, peonidin-3-p-coumaroyl glucoside-5-glucoside was identified in “Isabella” juice.

The results of this study validated US treatment as a simple and effective physical method that can be used as an alternative technology for improving the general quality of products such as juice by increasing the pigment concentrations that are linked to the colour and antioxidant potential of drinks. Moreover, the results demonstrate that US treatment may be less effective in the case of a sample with distinct phenolic maturation.