https://hdl.handle.net/20.500.12327/4 2026-05-15T14:23:15Z https://hdl.handle.net/20.500.12327/5236 Chilling Requirement: A Main Step to Get Productive Response in Walnut and Pecan Cultivars in Catamarca (Argentina) Delgado, Eber Alexander; Carabajal, Dante Egardo; Flores, Patricia Cecilia; Aletà, Neus; Gariglio, Norberto Francisco The thermal requirements of deciduous fruit trees are crucial for expanding walnut and pecan cultivation in Catamarca, a warm region in northwestern Argentina. This study evaluated the chilling requirements of two Persian walnut cultivars (‘Chandler’ and ‘Trompito INTA’) and three pecan cultivars (‘Stuart’, ‘Pawnee’, and ‘Western’). Well-lignified budsticks, one-year-old branches of 40 cm, were removed from trees twice, in the autumns of 2018 and 2019, without damaging any apical (TB) or lateral buds (LT). They were stored at 5 ± 0.5°C to accumulate chilling hours (CH) across ten treatments (0-1000 CH in 100 CH intervals) before sprouting in greenhouse conditions. Results were quantified as the mean time (days) to reach budbreak (MTB) and as the percentage of budbreak. The ‘Western’ pecan required the least chilling (300-400 CH), followed by ‘Pawnee’ (400-500 CH) and ‘Stuart’ (600-800 CH). It should be noted that the pecan tree in cvs 'Pawnee' and 'Western' sprouted without cold in the first-year trials. Considering walnut, ‘Trompito INTA’ and ‘Chandler’, showed a chilling requirement of 500 and 800 CH, respectively. Persian walnuts needed at least 200 CH to budbreak. The study shows that pecan requires less cold to reach 50% sprouting than to stabilize MTB. ‘Trompito INTA’ stands out as a Persian walnut cultivar with low chilling requirements. This cultivar may be better adapted to milder winters and could contribute to climate change adaptation in walnut-growing regions. These results are valuable for cultivar selection and planning expansion of nut orchards in warm regions of Argentina 2027-01-01T00:00:00Z https://hdl.handle.net/20.500.12327/5235 Rachis browning in grapes: temperature influence, ethylene and respiration rates, and evaluation techniques López-Cristoffanini, Camilo; Bougas, Nina; Mata, Clara Isabel; Echeverria, Gemma Rachis browning is a key postharvest challenge affecting the visual quality and marketability of table grapes (Vitis vinifera L.), yet its physiological basis remains poorly understood, particularly across different cultivars. This study investigated the relationship between rachis browning, endogenous ethylene production, and respiration in two table grape varieties—‘Autumn Crisp’ and ‘Sweet Globe’—under cold (−0.5 °C) and ambient (20 °C) storage. Grapes were evaluated over 12 days for quality parameters, weight loss, gas exchange (CO₂ and ethylene), and rachis browning, assessed visually and through digital image analysis. Overall, storage at 0.5 °C effectively reduced browning and ethylene production compared to 20 °C. However, varietal differences were pronounced: ‘Sweet Globe’ exhibited higher rachis browning than ‘Autumn Crisp’ at 0.5 °C despite similar ethylene and respiration levels, indicating variety-specific susceptibility. At 20 °C, increased ethylene and respiration coincided with more severe browning, particularly in ‘Autumn Crisp’. A strong correlation was found between visual and image-based assessments, though discrepancies emerged under high-stress conditions. The results suggest that while ethylene and respiration are associated with rachis browning, they do not fully explain the varietal differences observed, emphasizing the need to consider cultivar-specific physiological responses. Furthermore, image-based evaluation offers a more consistent method for quantifying browning severity. This study advances our understanding of rachis browning physiology in grapes and highlights the importance of tailored postharvest strategies and objective assessment tools to extend shelf life and maintain visual quality. 2026-03-02T00:00:00Z https://hdl.handle.net/20.500.12327/5234 Visible-near infrared spectroscopy and near-infrared hyperspectral imaging for the detection of T-2 and HT-2 toxins in individual oat grains Teixido-Orries, Irene; Molino, Francisco; Agusti-Fernandez, Pau; Ayibiowu, Ebenezer; Croucher, Derek; Medina, Angel; Marín, Sonia; Verheecke-Vaessen, Carol Oat grains are increasingly consumed worldwide due to their health benefits, yet they are highly susceptible to contamination by Fusarium toxins, particularly T-2 and HT-2 toxins (T-2+HT-2). These toxins pose serious health risks and are unevenly distributed, with a few highly contaminated grains often driving a batch over legal safety limits. Current detection methods are destructive, slow, or inadequate for detecting contamination at the individual grain level. This study is the first to demonstrate the potential of visible–near-infrared (Vis-NIR) spectroscopy and near-infrared hyperspectral imaging (NIR-HSI) to detect T-2+HT-2 in individual oat grains non-destructively. 200 grains were scanned, and their toxin content quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Classification models were developed to identify grains exceeding both the European Union (EU) legal threshold (1250 μg/kg) and a higher risk level (10,000 μg/kg). Both techniques achieved high accuracy (up to 94.5 %) in identifying contaminated grains. Key wavelengths were identified (e.g., 1203, 1419, 1424 and 1476 nm in NIR; 440–455 nm in Vis), and reducing the model to 20 wavelengths preserved performance while simplifying computation. Critically, removing just 21.5 % of the most contaminated grains could reduce overall toxin levels by over 95 %. Moreover, sampling simulations revealed that analysing 30 % of grains guarantees detection of contamination above legal limits, whereas 0.5 % sampling yields only a 25–33 % detection chance. These findings highlight a feasible path for integrating spectroscopic screening into industrial oat sorting lines, improving food safety, reducing economic losses, and overcoming key limitations of conventional mycotoxin monitoring. 2025-08-26T00:00:00Z https://hdl.handle.net/20.500.12327/5233 Multivariate Chemometric analysis of chemical diversity in French winter and spring Lupinus albus L. varieties Ayuso, Manuel; da Silveira, Tayse F.F.; Almeida, Daiana; Harzic, Natalie; Gagnaire, Valérie; Aguiló-Aguayo, Ingrid; Barros, Lillian White lupin (Lupinus albus L.) is a nutrient-rich legume well-adapted to Mediterranean climates and tolerant of abiotic stress. Therefore, lupins represent a sustainable crop option with high potential for use in areas where climate change impacts are intensifying. This study analysed eight cultivars, four winter and four spring ecotypes, to assess differences in nutritional and bioactive compounds. Key compounds studied included proteins, fats, carbohydrates, tocopherols, and phenolics. Spring ecotypes like ‘Sulimo’ and ‘Energy’ showed higher protein and tocopherol content, which may be ideal for protein-rich, antioxidant-rich diets. Winter ecotypes such as ‘Angus’ had more carbohydrates, especially fructose and raffinose, which could benefit energy and gut health. Both ecotypes showed high fibre levels, supporting digestive health. The findings suggest that ecotype influences chemical composition significantly, and each offers distinct benefits for targeted nutritional and functional food applications. 2026-02-02T00:00:00Z