Search Results (131)

Avocado fruits unsuitable for consumption are often used to produce oil, prized by food and cosmetic industries. This research assessed how press-extraction temperatures (20 °C and 80 °C) and cultivars affected avocado oil color, antioxidants, fatty acids composition, physico-chemical parameters, saponification value, nutritional and health-related indices and stability. Fruits and oils from cultivars Fuerte, Gween, Hass, Topa Topa, and Zutano were evaluated, and significant differences (p ≤ 0.05) among varieties as well as between extraction temperatures were detected for most traits. Fresh avocado pulp contained 13.6–15.7 g/100 g lipids; the extraction yield was 36.5% at 20 °C and 49.8% at 80 °C. In general, 20 °C better preserved chlorophyll (61.5 mg/kg) than 80 °C (43.8 mg/kg). The carotenoid β-cryptoxanthin was lower in the samples extracted at 80 °C. Gween oil had the highest tocopherol content (on average, 229.8 mg/kg); β-tocopherol (susceptible to extraction temperature) was the most abundant (49.10%), followed by α-tocopherol (38.15%) and γ-tocopherol (12.75%). The oils extracted at 80 °C showed higher density, viscosity and acidity but inferior refractive index, peroxide and iodine than those extracted at 20 °C. The oxidative stability index at 110 °C, measured by Rancimat, decreased in oils extracted at 80 °C compared to those extracted at 20 °C (9.1 vs. 10.4 h). Pressure-extracted avocado oil maintained excellent qualitative and technological properties at both extraction temperatures, thus suggesting its suitability for several food uses, including salad dressing and, thanks to its thermal stability, cooking. Full article

Frost damage to reproductive tissues is a major constraint to stable yield in ‘Hass’ avocado (Persea americana Mill.) orchards, yet practical protected-cultivation strategies for mature trees remain limited. While shading nets are widely used to mitigate heat stress, their potential to reduce frost damage in mature, bearing avocado trees remains insufficiently understood. We evaluated the effects of winter deployment of high-density (60%) silver shading nets on microclimate, physiological performance, and productivity of mature ‘Hass’ avocado trees over two consecutive winters. During a severe frost event (minimum −3.5 °C; approximately 11 h below 0 °C), shading nets had little effect on minimum nighttime temperatures but reduced daytime solar irradiance and maximum temperatures. Following the frost event, control trees suffered extensive vegetative and reproductive damage, whereas net-covered trees exhibited substantially lower injury, with floral bud damage declining from 80% to 22%. Net-covered trees exhibited significantly higher maximum quantum efficiency of photosystem II (Fv/Fm; 0.74 vs. 0.48 in control trees). These responses were associated with greater flowering intensity and, in a within-year comparison following the severe frost event, a significant yield advantage in the subsequent season (16 vs. 0.4 kg tree⁻¹). In contrast, no statistically significant treatment differences were detected during a frost-free winter. These findings indicate that winter deployment of shading nets may help sustain reproductive performance in mature avocado trees following severe frost events, although this interpretation is based on a single frost-affected season and requires validation across additional frost events. Full article

Soil monitoring is a key component of precision agriculture and environmental sensing systems, where reliable measurements support irrigation management and crop monitoring. Although high-end sensing platforms provide accurate measurements, their cost limits widespread adoption, particularly in resource-constrained agricultural environments. Low-cost soil sensors, such as widely available 7-in-1 probes capable of measuring soil moisture, temperature, electrical conductivity, and pH, offer a scalable alternative for distributed monitoring; however, their limited accuracy raises concerns regarding their reliability for decision-support systems. This study investigates whether measurements from a single low-cost 7-in-1 soil sensor contain sufficient information to reconstruct the outputs of a commercial high-end sensing platform (CropX), specifically volumetric water content (VWC) and pore-water electrical conductivity (ECpw). Field data were collected in a tropical Hass avocado orchard in Colombia, and four machine learning models were evaluated to reconstruct CropX measurements from low-cost sensor signals at three soil depths (20, 41, and 66 cm). Random Forest achieved the highest reconstruction performance, with coefficient of determination R2 values between 0.9965 and 0.9986 and consistently low root mean square error (RMSE) and mean absolute error (MAE) across depths. Out-of-bag validation and multi-seed stability analyses confirmed the robustness of the models despite the limited dataset size. A chronological validation (80–20%) showed substantially reduced performance, indicating that the proposed approach is more suitable for reconstructing high-end sensor signals under concurrent measurement conditions than for strict temporal extrapolation. Therefore, the framework should be interpreted as a virtual sensing strategy for reconstructing simultaneous CropX measurements from low-cost sensor observations rather than as a standalone model for predicting future soil conditions without periodic recalibration. These results demonstrate that low-cost multi-parameter sensors can support high-fidelity virtual reconstruction of high-end soil measurements, contributing to the development of scalable and cost-effective soil monitoring systems for precision agriculture. Full article

In response to the need for a simple, non-destructive method for evaluating avocado ripeness, we measured chlorophyll-related fluorescence and chromaticity of the outer skin using simple optical equipment and evaluated their relationship with whole-fruit compression (wfc), which was used as a firmness-based ripeness index. A compact system consisting of a blue LED excitation source and a small spectrometer was used to measure fluorescence spectra, and a commercially available colorimeter was used to evaluate chromaticity. Hass avocado samples purchased from multiple retail stores in Japan and stored for different periods were examined. The combination of the fluorescence intensity ratio I₇₄₀/I₆₈₅ and the lightness parameter L* showed a moderate correlation with wfc, with R² = 0.48. The fluorescence ratio I₇₄₀/I₆₈₅ was treated not as a direct measure of chlorophyll content, but as a spectral index associated with ripening-related changes in avocado skin, including chlorophyll-related fluorescence and skin optical properties. These results suggest that the combination of simple blue LED-excited fluorescence and chromaticity measurements may be useful as a practical screening approach for roughly estimating avocado ripeness in commercially available fruit. Full article

Superfoods have gained increasing attention for their nutritional and functional properties, with avocado (Persea americana Mill.) among the most prominent examples owing to its health-promoting compounds. However, avocado cultivation is associated with several challenges, including high water demand, environmental impact, seasonal variability, and post-harvest losses. To address these limitations, in vitro plant cell cultures represent a sustainable and controlled alternative for producing avocado-derived material. In this study, avocado var. Hass callus cultures were established and evaluated as a potential source of functional metabolites. Colourimetric assays performed at different growth stages identified 14-day-old callus as the most enriched in phenolic compounds and antioxidant activity; this material was therefore selected for further analyses. LC–ESI–QTOF–MS/MS profiling revealed a phenolic-rich composition, including flavonoids, proanthocyanidins, galloyl derivatives and phenylpropanoid-related compounds, consistent with vegetative plant tissues. Nutritional analysis showed high moisture content and low lipid levels, differing in composition from the avocado pulp, along with a high content of attention-grabbing nutrients, such as protein and fibre. Overall, although further studies are required to confirm compound identity and assess safety for future applications, avocado calli represent a promising sustainable platform for the production of value-added bioactive compounds. Full article

Preharvest climatic conditions and irrigation management are decisive determinants of avocado postharvest performance. Avocado trees are highly susceptible to the water regimen, conditions that disrupt carbon assimilation, mineral nutrient uptake, and biomass partitioning. This study evaluated the effects of deficit irrigation imposed during early stages of fruit growth, coinciding with active cell division, on fruit development and postharvest quality of ‘Hass’ avocado. Deficit and excess irrigation induced physiological stress, reducing stem water potential (≈−1 MPa) and altering photochemical efficiency, while F_V/F_M remained unaffected. Fruit growth was strongly affected, with weight reductions of up to 26% during development and 22% at harvest under severe deficit, resulting in fruits becoming more yellowish-green. In contrast, excessive irrigation promoted larger fruit with darker green skin, with delayed maturation. Metabolomic revealed that the fruit developmental stage was the main driver of metabolic variation, while irrigation effects were minor and stage-dependent, limited to osmotic-related metabolites such as GABA. These findings indicate that early-season water imbalances primarily affect fruit growth through changes in water relations rather than metabolic reprogramming, highlighting the importance of precise irrigation management during critical developmental stages. Fine-tuning water supply during early developmental stages is a strategic tool for optimizing fruit size and postharvest quality in avocado. Full article

The fresh-cut avocado processing generates significant amounts of by-products, mainly peel and seed, with the peel representing a valuable source of phenolic compounds. In this context, the growing demand for sustainable technologies encourages the use of green solvents for bioactive compound recovery. In this study, natural deep eutectic solvents (NaDES) were evaluated as environmentally friendly solvents for the extraction of phenolic compounds from Hass avocado peels through ultrasound-assisted extraction and for their potential application in fresh-cut avocado. Phenolics were extracted using acidic water, ethanol, and NaDES based on choline chloride as a fixed hydrogen bond acceptor (HBA) and hydrogen bond donors (HBDs; lactic acid, glycerol, and citric acid) with the ultrasound-assisted system. The stability of the extracts was monitored for eight weeks (four weeks in darkness followed by four weeks under light exposure). Among the tested formulations, the lactic-acid-based NaDES showed the highest extraction efficiency and the best stability of phenolic compounds during storage (≥20 mg GAE g⁻¹ dw during the storage period). The lactic-acid-based extract was then applied to fresh-cut avocado to evaluate its potential for antioxidant enrichment and browning prevention during refrigerated storage. The treatment increased phenolic content and contributed to improved color stability (during seven days of storage). Overall, lactic-acid-based NaDES represent a promising green solvent system for recovering phenolics from avocado peel and for their functional application in fresh-cut avocado within a circular valorization approach. Full article

With global climate change, heatwaves have become more frequent and severe in avocado-growing regions. High temperatures combined with wind and low humidity are problematic for avocados, especially during the early developmental stage of the young fruitlets. Hence, heatwaves during this phenological stage are considered a major limiting factor for avocado productivity. This study evaluated the effects of operating pulsing sprinklers or sprayers installed above the canopy during spring heatwaves over three consecutive seasons in a Hass avocado orchard. We evaluated foliage and fruitlet temperature (using remote and proximal sensing), stem water potential, stomatal conductance, salt accumulation on the leaves, and productivity. The cooling system reduced the foliage temperature by 6–8 °C and fruitlet temperature by 5–10 °C with respect to uncooled trees. Stem water potential was increased by 0.8–2.0 MPa in the treatment plots compared to the control. The cooling treatments led to an average 42% yield increase over the next 3 years. No significant differences were found between the sprinklers and sprayer for any of the measured parameters. Results indicate the effectiveness of an evaporative cooling system for mitigating heatwave damage and improving avocado productivity. Full article

Brazil, as one of the world’s leading fruit producers, faces increasing challenges arising from climate change, particularly in avocado cultivation, where excessive solar radiation and high temperatures impair plant metabolism, yield, and fruit quality. This study evaluated the use of a calcium and magnesium hydroxide-based sunscreen in mitigating heat stress in eight-year-old ‘Hass’ avocado trees. The experimental design was a randomized complete block design in a 4 × 8 factorial arrangement, with five replicates. Sunscreen applications were performed at full bloom and at the initial fruit development stage (18 mm). Leaf temperature, fruit drop rate, yield-related traits, fruit classification, and the percentage of fruit lesions were evaluated. Applications of the calcium and magnesium hydroxide-based sunscreen at concentrations of 3.0% and 4.5% (w/v) reduced leaf temperature and improved fruit biometric attributes compared to the control, although the maximum fruit diameter was achieved at the 2.6% concentration. The 4.5% sunscreen concentration reduced leaf temperature and fruit drop in ‘Hass’ avocado trees by 1.5 °C and 24.5%, respectively, compared with the control and decreased the percentage of small and damaged fruits. The application of sunscreen improved fruit weight and the percentage of fruits with higher market value, while the fruit diameter presented higher values at intermediate concentrations. Full article

This study investigates the potential of Hass avocado peels as biosorbents for removing the cationic dyes BB3 and BY28 from aqueous solutions. The results demonstrate that agricultural waste can be effectively incorporated into sustainable, environmentally friendly wastewater treatment technologies. The adsorption parameters examined include adsorbent mass (0.1–1.1 g), dye concentration (5–50 mg/L), contact time (5–180 min), stirring speed (100–200 rpm), pH (4–10), and temperature (25–40 °C). UV-Vis spectrophotometric analyses show that the optimum conditions for BY28 removal are 0.3 g/50 mL adsorbent, 5 mg/L dye concentration, 30 min contact time, 200 rpm stirring speed, pH 7, and 40 °C, while those for BB3 are 1.1 g/50 mL adsorbent, 5 mg/L concentration, 45 min contact time, 150 rpm stirring speed, pH 7, and 40 °C. Under the optimized operating conditions, the maximum dye removal efficiencies were 88.24% for BY28 and 99.71% for BB3. This study demonstrates that agricultural waste can be converted into sustainable, reusable biosorbents for removing cationic dyes, thereby contributing to the development of environmentally friendly wastewater treatment technologies. Full article

The export of Hass avocado (Persea americana Mill.) from Colombia requires accurate determination of harvest maturity, currently assessed through destructive dry matter (DM) measurements that are wasteful and limited in throughput. The objective of the article is to propose a low-cost, non-destructive approach to determine the maturity of the Hass avocado crop based on machine learning techniques. The approach consists of a low-cost, non-invasive bioimpedance spectroscopy system operating in the 1–10 kHz range, featuring a custom Analog Front End (AFE) and a tetrapolar surface probe to mitigate skin contact resistance, which collects data for predictive models of avocado maturity. To evaluate the quality of the approach, a longitudinal field study (n = 100) was conducted in a commercial orchard in Cundinamarca, Colombia, tracking complex impedance features—Magnitude, Phase Angle, Resistance, and Reactance—of tagged fruits over 8 weeks across four measurement timepoints. The predictive performance of a classical chemometric model (PLS-DA), non-linear classifiers (SVM, Random Forest), and a temporal Deep Learning (LSTM) architecture was compared using a Stratified Group K-Fold Cross-Validation scheme to prevent data leakage across fruits from the same tree. The 4-electrode configuration successfully isolated mesocarp impedance, identifying the 5–7.2 kHz band as the most sensitive to physiological maturation. In turn, the LSTM model achieved a mean accuracy of 92.0% and an AUC of 0.94, outperforming the other models by 4.0% in mean accuracy. The results demonstrate that modeling the temporal trajectory of impedance, rather than single-point measurements, improves harvest maturity classification in Hass avocados, providing a scalable, low-cost alternative to destructive testing. Full article

Woody tissue diseases of avocado (Persea americana Mill. var. Hass) pose a major phytosanitary threat due to their chronic progression, late symptom expression, and severe impact on tree stability and productivity. Although white rot has traditionally been attributed to saprobic basidiomycetes, increasing evidence suggests corticioid fungi may act as facultative pathogens in agricultural systems. This study examined corticioid basidiomycetes associated with white rot in stems and branches of avocado in Michoacán, Mexico. Field surveys revealed consistent symptoms of structural weakening, branch dieback, and wood decay. Fungal isolates obtained from symptomatic tissues and sporomes were characterized morphologically and identified through ITS-based phylogenetic analyses. Representative isolates of Grammothele spp. and Dentocorticium portoricense were evaluated in pathogenicity assays under controlled conditions. All isolates reproduced field symptoms, confirming pathogenicity, though aggressiveness varied. D. portoricense exhibited the highest incidence, severity, and AUDPC values, indicating greater virulence, while Grammothele isolates showed slower, moderate progression. Phylogenetic analyses provided robust support for D. portoricense, whereas Grammothele was resolved at genus level. Integration of field, pathogenicity, and molecular data demonstrates corticioid fungi are not merely secondary saprotrophs but relevant pathogens in avocado white rot. These findings highlight the need to include corticioid fungi in diagnostic, monitoring, and management strategies for trunk and branch diseases. Full article

The potential for ‘Hass’ avocado production is predicted to increase with climate warming in New Zealand, a country where avocado orchards often lack irrigation because of a cooler and wetter climate compared to most other major growing regions. However, intermittent summer droughts are also predicted to increase in frequency and intensity. This study assessed the effects of summer soil water deficits on fruit growth of ‘Hass’ avocado in the Bay of Plenty, New Zealand, by comparing irrigated and non-irrigated treatments. Rainfall was variable over the three years of the study (2016–17, 2017–18, and 2018–19), but each summer there was a dry period without any rainfall for 2–3 weeks that decreased soil water content in the non-irrigated treatment. Fruit number and final yields were highly variable between trees and years, an effect of variable fruit set during the spring flowering period, and were not affected by the irrigation treatments because soil water deficits did not occur until later, during the summer. Increasing tree crop load caused decreasing individual fruit weight and dry matter content at harvest. However, in the year with the highest average crop load a dry period occurred during early fruit development, and mean fruit weight at harvest was decreased by 26.4 g (10%) in the non-irrigated treatment, an effect that was only apparent after accounting for the effects of variable crop load. The trees responded to dry conditions by reducing stomatal conductance (g_s) by 20%, preventing midday leaf water potential (Ψ_leaf) from decreasing below −0.25 MPa. Irrigation of avocado under the conditions at this site is therefore recommended when soil tension decreases below −30 kPa at 30 cm depth, and adverse effects on fruit growth are likely when tension decreases below −50 kPa. Irregular bearing of avocado under New Zealand growing conditions causes highly variable crop loads that obscure economically significant effects of mild to moderate water deficits on fruit growth. However, irrigation is still an important consideration for avocado production under current growing conditions and is likely to become more important under future climate scenarios as the risk of summer droughts increases. Full article

In this study, we conducted a comprehensive characterization of avocado accessions from the Canary Islands, focusing on molecular, morphological, phenological, and agronomic traits. A total of 311 trees were initially prospected across Tenerife, La Palma, Gran Canaria, and La Gomera Islands. DNA was extracted from young leaves, and genetic diversity was assessed using 28 microsatelites primers, 14 of which were highly polymorphic, revealing 6937 amplified fragments, 137 of which were polymorphic. The average polymorphism percentage was 85.68%, with an expected heterozygosity of 0.68, indicating high genetic diversity. A dendrogram based on genetic data identified four main groups, two of which are closely related to the most widely cultivated avocado cultivars: ‘Hass’, ‘Fuerte’, and ‘Pinkerton’. Morphological analysis (over three years), using 91 descriptors, revealed a clear differentiation between accessions, with several groups corresponding to specific commercial cultivars. Morphotypes that deviated from the main groupings were specimens obtained through sexual propagation. Principal component analysis revealed that fruit characteristics such as length-to-diameter ratio, seed size, and fruit weight were the most discriminating traits, consistent with findings in the Persea genus. These results highlight the genetic and morphological diversity within the Canary Islands avocado germplasm, providing valuable insights for future breeding and conservation efforts. Full article

Understanding how climatic variability shapes the reproductive behavior of perennial crops is essential for improving their adaptation to tropical mountain environments. This study examined the influence of altitudinal and thermal gradients on flowering synchrony in ‘Hass’ avocado (Persea americana Mill.) cultivated across the tropical Andes of Colombia. Climatic variables and phenological stages were monitored across three elevations (2056, 2212, and 2338 m.a.s.l.) during two production cycles. Principal component, confirmatory factor, and circular statistical analyses were applied to integrate multivariate climatic structure with temporal flowering patterns. Results revealed that temperature was the main climatic driver of phenological variability, with significant differences among altitudes. The study revealed an altitudinal thermal–hydric gradient structuring distinct microclimates between 2050 and 2350 m.a.s.l., which determine the synchrony and rate of ‘Hass’ avocado phenological processes. Anthesis was the most environmentally sensitive phase, showing greater stability at intermediate elevations (~2200 m). Multivariate (PCA, CFA, ANOVA) and circular analyses confirmed that accumulated temperature (GDD) effectively predicts phenological progression, defining an optimal altitudinal range for synchrony and productivity in high Andean temperate zones. Full article