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Yellow pitahaya (Selenicereus megalanthus Haw.) is an exotic fruit with great potential for exportation in Ecuador. The research was carried out with the objective of evaluating the fruit growth and ripening as affected by four elicitors: salicylic acid (SA), methyl salicylate (MeSa), methyl jasmonate (MeJa), and oxalic acid (OA), all of them at 1, 5, and 10 mM concentration, compared with untreated plants (control). For each elicitor, nine plants were selected, and on each plant, three fruits were marked to follow up the growth by measuring polar and equatorial diameters. At harvest, yield (kg plant−1 and number of fruits plant−1), fruit weight, percentage of pulp and skin, total soluble solids (TSS), titratable acidity (TA), and firmness were determined. Treated plants enhanced fruit size, crop yield, and fruit weight compared with control fruits, although results depended on the elicitor tested and applied doses. The highest and lowest TSS were found in 10 mM MeSa and 5 mM MeJa-treated fruit, respectively, while the highest TA content was shown in 5 mM SA. Firmness was only enhanced in MeJa-treated fruits. Overall, results suggest that preharvest use of elicitors could modulate the pitahaya ripening and could improve quality attributes at harvest. [ABSTRACT FROM AUTHOR]

Fourteen Russian potato cultivars (cvs.) grown for three years in the field plots of VIR (North-Western region of the Russian Federation) were evaluated annually for productivity and 12 biochemical parameters of tubers one month after harvesting and after cold storage (at 2–4 °C). The aim of this study was to quantify the level of biochemical components in tubers and to determine the influence of the environment on their content. The results indicated a substantial variation in different nutrients in potatoes during cultivation for three consecutive years. The nutritional value of tubers (the content of dry matter, sugars, starch and protein) was determined to a greater extent (38–49%) by varietal characteristics, rather than by meteorological conditions in the vegetation period. The content of vitamin C, carotenoids, protein and anthocyanins varied depending on the year. Of the cultivars, 'Kumach' has the highest productivity, but the nutritional value of tubers is lower than that of standard 'Nayada'. Cv. 'Fioletovyi' is suitable for consumption as part of a low-calorie diet because of a low amount of starch (11.8–12.7%) and a higher anthocyanins content (102.0–103.9 mg/100 g). Cv. 'Sokur' is distinguished by its high nutrition because of its high content of dry matter (24.3%) and protein (more than 2.0%). Cv. 'Plamya' is remarkable for the lowest content of reducing sugars (0.24–0.47%) in tubers during the post-harvest and post-storage analysis. [ABSTRACT FROM AUTHOR]

In the pursuit of enhancing the wine production process through the utilization of new technologies in viticulture, this study presents a novel approach for the rapid assessment of wine grape maturity levels using non-destructive, in situ infrared spectroscopy and artificial intelligence techniques. Building upon our previous work focused on estimating sugar content ( ∘ Brix) from the visible and near-infrared (VNIR) and short-wave infrared (SWIR) regions, this research expands its scope to encompass pH and titratable acidity, critical parameters determining the grape maturity degree, and in turn, wine quality, offering a more representative estimation pathway. Data were collected from four grape varieties—Chardonnay, Malagouzia, Sauvignon Blanc, and Syrah—during the 2023 harvest and pre-harvest phenological stages in the vineyards of Ktima Gerovassiliou, northern Greece. A comprehensive spectral library was developed, covering the VNIR–SWIR spectrum (350–2500 nm), with measurements performed in situ. Ground truth data for pH, titratable acidity, and sugar content were obtained using conventional laboratory methods: total soluble solids (TSS) ( ∘ Brix) by refractometry, titratable acidity by titration (expressed as mg tartaric acid per liter of must) and pH by a pH meter, analyzed at different maturation stages in the must samples. The maturity indicators were predicted from the point hyperspectral data by employing machine learning algorithms, including Partial Least Squares regression (PLS), Random Forest regression (RF), Support Vector Regression (SVR), and Convolutional Neural Networks (CNN), in conjunction with various pre-processing techniques. Multi-output models were also considered to simultaneously predict all three indicators to exploit their intercorrelations. A novel multi-input–multi-output CNN model was also proposed, incorporating a multi-head attention mechanism and enabling the identification of the spectral regions it focuses on, and thus having a higher interpretability degree. Our results indicate high accuracy in the estimation of sugar content, pH, and titratable acidity, with the best models yielding mean R 2 values of 0.84, 0.76, and 0.79, respectively, across all properties. The multi-output models did not improve the prediction results compared to the best single-output models, and the proposed CNN model was on par with the next best model. The interpretability analysis highlighted that the CNN model focused on spectral regions associated with the presence of sugars (i.e., glucose and fructose) and of the carboxylic acid group. This study underscores the potential of portable spectrometry for real-time, non-destructive assessments of wine grape maturity, thereby providing valuable tools for informed decision making in the wine production industry. By integrating pH and titratable acidity into the analysis, our approach offers a holistic view of grape quality, facilitating more comprehensive and efficient viticultural practices. [ABSTRACT FROM AUTHOR]

The must used to make sparkling wine has a low pH value and moderate sugar content, and its potassium content can have a strong influence. An excess of potassium often leads to an insufficient supply of magnesium, since potassium has a strong antagonistic effect on magnesium, and, consequently, to poorer photosynthesis and a poorer quality of the must. The aim of this study was to determine whether the application of foliar fertilizers based on magnesium, phosphorus, and amino acids could reduce leaf potassium content, affecting the reductions in sugar content and pH value and increasing the total acidity of the must. A fertilizer trial with three replicates was conducted on the cultivar Istrian Malvasia (TCtrl—NPK, TMg—NPK + Agromag (6% MgO), TMgP—NPK + Agromag + Fosforo (30% P2O5) i TMgPBS—NPK + Agromag + Fosforo + Bio Prot) in a random complete block design. The NPK fertilizer was applied in the autumn. Foliar fertilization was applied three times during the growing season (31 May, 7 July, and 22 August 2014), and leaf samples were collected for leaf analysis before each application. The results show that foliar fertilization significantly reduced leaf potassium content, especially when treated with magnesium alone (treatment TMg). In addition, foliar fertilization significantly lowered the pH and increased the sugar content of the must. The results obtained in this research give a scientific contribution to the creation of fertilizer treatments for vines with a positive effect on the basic chemical composition of the base wine and provide a good basis for further research in reducing the use of certain enological practices during production. [ABSTRACT FROM AUTHOR]

Presently, there is no information available about the effect of bunch compactness and berry thinning methods on wine grape quality and sensory attributes of wine in the 'Monastrell' cultivar. Thus, the main aim of the present study was to determine the influence of bunch compactness and two berry thinning methods, which consisted of the reduction of 25% and 50% of the number of berries in each bunch, on wine grape quality and organoleptic quality of wine in this cultivar. Non-compact bunches and both berry thinning methods showed a significant reduction in total yield, bunch compactness, and bunch fresh mass compared with compact and control ones, respectively. However, these methods, especially the 50% one, significantly increased the content of total soluble solids and total phenolics. Furthermore, both berry thinning methods promoted the increase in total anthocyanins concentration in berries, as well as the hydrophilic total antioxidant activity. Berry thinning methods led to wines with greater sensory descriptors, such as fruity (odor and flavor), sour, sweet, aftertaste, and color, and were preferred by consumers. Finally, 50% berry thinning is the most useful tool to decrease bunch compactness and improve the overall quality of berries and sensory attributes of wines. [ABSTRACT FROM AUTHOR]

Roasting can increase the Maillard reaction and caramelization of sweet potatoes to create an attractive appearance, color, aroma, and taste, and is rapidly increasing in the commercial market. This study mainly analyzed the influence of roasting sweet potatoes, with and without the peel, on sweet potato quality and flavor characteristics combined with sensory qualities. The results showed that the a* value (1.65–8.10), browning degree (58.30–108.91), total acidity (0.14–0.21 g/100 g, DW), and maltose content (0.00–46.16 g/100 g, DW) of roasted sweet potatoes increased with roasting time. A total of 46 volatile compounds were detected and 2-furanmethanol, furfural, and maltol were identified as the main sources of the aroma of roasted sweet potatoes. A sensory evaluation based on a comprehensive nine-point acceptance test and descriptive analysis showed that roasting for 1 to 2 h resulted in the highest acceptance score (6.20–6.65), including a golden-yellow color, sweet taste, and fibrous texture. The sweet potatoes became brown after roasting for 2.5 to 3 h and gained a burnt and sour taste, which reduced the acceptance score (4.65–5.75). These results can provide a reference for increased quality in the food industry production of roasted sweet potatoes. [ABSTRACT FROM AUTHOR]

Traditionally, the acidity of paper-based relics was determined by an extraction method and using a pH meter. This method could not obtain the total acidity of the paper-based relics because it only detected the concentration of free protons in the aqueous soaking solution. To overcome this defect, a new method for determining the total acidity of paper-based relics has been established by using quaternary alloy quantum dots. The quantum dots, CdZnSeS, modified by p-Aminothiophenol (pATP) were prepared, and their composition and structure were characterized. The fluorescence behavior of prepared quantum dots with acidity was investigated. The following results were obtained. The fluorescence of CdZnSeS-pATP quantum dots could decrease with increases in acidity because pATP dissociated from the surfaces of the quantum dots due to protons or undissociated weak acids. Based on this feature, a method for determining the acidity of paper-based relics was constructed, and this method was used to evaluate the acidity of actual paper-based relics. Obviously, for a given paper sample, since both free protons and bound protons can be determined by this method, the acidity measured by this method is more reasonable than that by pH meter. [ABSTRACT FROM AUTHOR]