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In avocado (Persea americana) oil production, there is a large amount of polyphenol rich biowaste (seed and peel), which could be a potential source of bioactive molecules. The utilization of avoca...

The effect of solid-state fermentation (SSF) of avocado seed with A. niger GH1 on the release of bioactive compounds with antioxidant capacity was studied. The growing conditions of the fungus were optimized. Subsequently, The effect of sterile water and pontecorvo culture medium was evaluated in the SSF. The optimal conditions for SSF were particle size of 2.5 mm, 60 % of humidity, and 120 h. In the assessments of antioxidant capacity by the ABTS and DPPH methods, the increase with respect to the initial values was 33 and 77 % with water and 28 and 42 % with culture medium, respectively. The analysis HPLC showed degradation of catechin and epicatechin polymers, particularly procyanidin B2 dimers resulting in the accumulation of monomers. The ability of the fungus to degrade compounds present in the avocado seed was decisive to enhance the antioxidant capacity. This degradation was related to increased cellulase and xylanase activity.

Avocado peel is a source of bioactive compounds with antioxidant, anti-inflammatory, antiproliferative and antimicrobial capacities, among others. Physical and chemical interactions of phenolic compounds with indigestible polysaccharides could affect their bioaccessibility in the upper gastrointestinal tract, allowing them to reach the colon, where they exert antioxidant effects and related health effects. The objective of the present work was to evaluate the effect of chemical-enzymatic processes of an in vitro gastrointestinal digestion, on phenolic compounds, antioxidant capacity and chemical constituents of avocado peel, and to determine their content in the indigestible fraction. Results showed that most phenolic compounds resist intestinal digestion (66%), of which 954.72 ± 19.45 mg GAE/100 g of dry weight (dw) and 250.72 ± 7.12 mg CE/100 g dw are hydrolysable and condensed tannins, respectively. The highest antioxidant capacity remained in the indigestible fraction (79.4%, 59.8% and 79.6%), with greater predominance in the insoluble indigestible fraction (49.1%, 46.6% and 66.7%) for DPPH, ABTS and FRAP, respectively. Most of the indigestible fraction is insoluble (89.39%), while only 7.46% is soluble. The possible beneficial effects of phenolic compounds and antioxidant capacity of the indigestible fraction of avocado peel must be considered in further studies.

Poor exocarp colour development is a common postharvest problem for early harvested “Hass” avocado fruit during ripening, which affects fruit quality and consumer preference. Therefore, measures to improve “Hass” avocado fruit colour developments are of great importance in the industry. This study investigated the effectiveness of postharvest methyl jasmonate treatment to improve early matured “Hass” avocado fruit exocarp colour during ripening. The results showed that T1 (10 μmol∙L−1) and T2 (100 μmol∙L−1) MeJA treatment increased visual colour, and decreased objective colour parameters (L*, C* and h˚) during ripening when compared with control fruit. Moreover, MeJA treated “Hass” avocado fruits had lower total chlorophyll content and higher total anthocyanin and cyanidin-3-O-glucoside concentration during ripening. In conclusion, “Hass” avocado fruit post-harvest treated with either T1 (10 μmol∙L−1) or T2 (100 μmol∙L−1) MeJA concentration improved exocarp quality attributes such as colour parameters (L*, C* h˚ and visual colour) and pigments (total anthocyanin and cyanidin-3-O-glucoside) during ripening, therefore, can be recommended for avocado fruit.

The industrialisation of ‘Hass’ avocado fruit generates residues such as the epicarp that contains bioactive compounds that can be recovered. The objective of the work was to evaluate the extraction of bioactive compounds from ‘Hass’ avocado epicarp through aqueous two-phase systems (ATPS) in order to increase the added value of the fruit. ATPS based on polyethylene glycol 4000 (PEG4000) with sodium citrate (Na3Cit) or magnesium sulphate (MgSO4) were evaluated, both incorporated with lyophilised epicarp of fruit at consumption maturity. Binodal phase diagrams were developed and the salting-out capacity of each system was assessed, which allowed explaining the systems separation behaviour. The extraction of compounds was equivalent to 89.9% in relation to a process based on methanol. Systems with 24.9–14.5% Na3Cit–PEG4000 and 12.2–15.5% MgSO4–PEG4000 were able to recover more than 82% of soluble phenols, flavonoids, and condensable tannins, from avocado peel, with high antioxidant activity. The epicarp of ‘Hass’ avocado fruit had low concentration of anthocyanins. ATPS showed utility in concentrating compounds by a non-thermal procedure.

During the last years, the world avocado trade is on the rise, however, approximately 20% of the production is rejected for low caliber. This avocado discarded by low caliber can be used in the elaboration of other products, to give it added value. The objective of this study was to determine the shelf life of Hass avocado oil, type of discard, obtained by: (a) Drying by stove/Soxhlet (b) Lyophilized/Expeller. For the physicochemical characterization of the oil, density, melting point, acidity index, refractive index, iodine index and peroxide index were determined. The induction time was carried out by the RANCIMAT method, for which three temperatures of 140 °C, 160 °C and 180 °C were used and the shelf life of the oil was obtained by extrapolation at 25 °C. The results indicate that there is a significant statistical difference in the physicochemical characteristics of both oils. The shelf life was for the oil obtained by drying stove/Soxhlet 5.94 years and for the oil obtained by freeze-dried/Expeller 4.41 years, since both oils had a high content of unsaturated fatty acids 16.98% and 17.12%, respectively. In conclusion, it is possible to reduce post-harvest losses by obtaining avocado oil with high nutritional and functional qualities.

Avocado is an excellent source of phytochemicals with remarkable bioactive properties. This study evaluated the effect of ripeness stage of ‘Hass’ avocado on the profile and content of lipophilic and hydrophilic phytochemicals and their in vitro cytotoxic activity. Qualitative and quantitative analyses of the major phytochemicals were conducted in four stages of ripeness, using gas and liquid chromatography analyses. In general, phenolics, carotenoids, tocopherols, and phytosterols tended to increase during ripening. A decrease of individual phytochemicals was observed, namely, protocatechuic acid (0.36 to 0.03 mg 100 g−1 dw) and β-carotene (0.9 to 0.4 mg 100 g−1 dw), while quercetin and δ-tocopherol were only detected in a single ripeness stage (1 and 3, respectively). The major phytochemicals quantified at the end of ripening were epicatechin (12.66 mg 100 g−1 dw), lutein (0.5 mg 100 g−1 dw), α-tocopherol (12.4 mg 100 g−1 oil) and β-sitosterol (35.6 mg 100 g−1 dw) for phenolics, carotenoids, tocopherols and phytosterols, respectively. The cytotoxic activity of methanolic extracts of avocado was tested against RAW 264.7 and HeLa cells, where all RS showed a dose-dependent effect. We conclude that ripeness stage influences the concentration of specific compounds in each group of phytochemicals, as well as its in vitro cytotoxic activity, something that must be considered in future studies on the potential health benefits of avocado.

Biofilms arise as an alternative to replace synthetic polymers, which have generated environmental pollution. The aim of this work was to extract starch from Hass avocado seeds (Persea americana Mill) to produce biofilms. Starch was extracted using the wet method and characterized by infrared spectroscopy. Moisture, ash content, gelatinization temperature, and color were determined. Two types of biofilms were produced: T1 (starch) and T2 (starch and glycerol). The colour was measured, and the films were characterized by mechanical tests. A yield of 11.38% was obtained for the isolated starch. Glycerol addition significantly influenced the tensile strength being T1 higher than T2. In elongation percentage, T1 was lower than T2. The results indicate that it is possible to use Hass avocado seed waste for starch extraction and produce biofilms to give it added value. This biofilm can be used in low moisture food coatings.

In this work, poly(lactic acid) (PLA)/gelatin/PLA multilayer films supplemented with cellulose nanocrystals and antioxidant extract from almond shell (AS) by-products were developed by solvent casting technique for active food packaging. The almond shell antioxidant extract (ASE) was obtained by microwave-assisted extraction, while cellulose nanocrystals (CNCs) were extracted from AS by a sequential process of alkalization, acetylation and acid hydrolysis. Four formulations were obtained by adding 0 (control), 6 wt.% of ASE (FG/ASE), 4.5 wt.% of CNCs (FG/CNC) and 6 wt.% + 4.5 wt.% of ASE + CNCs, respectively, (FG/ASE + CNC) into fish gelatin (FG). PLA/FG/PLA multilayer films were prepared by stacking two outer PLA layers into a middle FG film. A surface modification of PLA by air atmospheric plasma treatment was optimized before multilayer development to improve PLA adhesion. Complete characterization of the multilayers underlined the FG/ASE + CNC formulation as a promising active reinforced packaging system for food preservation, with low values of transparency, lightness and whiteness index. A good adhesion and homogeneity of the multilayer system was obtained by SEM, and they also demonstrated low oxygen permeability (40.87 ± 5.20 cm3 mm m−2 day) and solubility (39.19 ± 0.16%) values, while mechanical properties were comparable with commercial plastic films. The developed multilayer films were applied to Hass avocado preservation. The initial degradation temperature (Tini), DSC parameters and in vitro antioxidant capacity of the films were in accordance with the low peroxide and anisidine values obtained from avocado pulp after packaging for 14 days at 4 °C. The developed PLA/FG/PLA films supplemented with 6 wt.% ASE+ 4.5 wt.% CNCs may be potential bioactive packaging systems for fat food preservation. This research was funded by Conselleria de Educación (Spain), APOSTD/2016/093 Postdoctoral Research Training Grant.

The worldwide demand for avocados has resulted in the planting of millions of young plants each year. However, global warming, resulting in high temperatures, sensed as heat stress, may severely damage these new plantings. The objective of this study was to assess the risks of heat stress on young avocado plants. We aimed to characterize different physiological parameters of young ‘Hass’ plant leaves following exposure to high temperatures under low light (LL) intensity and to pinpoint the temperature threshold for significant heat stress damage in these plants. To this end, young potted plants were subjected to different temperature gradients in a controlled-climate chamber. Minor and severe leaf damage was apparent in plants subjected to the 51 °C and 53 °C treatments, respectively. Minor and vast reductions in optimal quantum yield efficiency of photosystem II (Fv/Fm) values were observed in plants subjected to 51 °C and 53 °C, respectively. Heat stress treatments significantly reduced CO2 assimilation in plants subjected to 49 °C and higher temperatures. Stomatal conductance to water vapour and substomatal internal CO2 concentration were less sensitive to the heat treatments. These results imply that the heat damage threshold for young avocado plants under LL conditions is between 49 °C and 51 °C, whereas at 53 °C, severe and irreversible leaf damage occurs.

Vegetal wastes are currently a source of pollution due to the excess of organic compounds in the environment. Seeds are the main by-product of the avocado industry and represent 16–22% of the total weight and it is considered a waste without applications. Despite the seed stands out for its high content of phenolic compounds, lack of knowledge regarding of the best processing state using non-invasive and short-time methods are required to take advantage of these nutraceutical compounds. This research aimed to find correlations from physicochemical analysis, color, hardness, and firmness of the whole avocado seeds with its nutraceutical properties as long as the ripeness increased, providing information for further industrial use of this waste. The results indicated that ‘Hass’ avocado fruit ripening positively correlates with the improvement of the physicochemical parameters involved in the fruit processing and the increase of nutraceutical compounds in the seed. The ripeness process decreased moisture (%) and hardness (N) parameters in the seeds (27.69 and 16.4%, respectively), facilitating its processing. Moreover, the ripening increased the antioxidant capacity by DPPH* around 7%, due to the concentration of phenolic compounds in the seed. Seed’s phenolic compounds were positively correlated with the Hue angle at increasing ripeness, becoming a potential physicochemical indicator for the industry. The prediction of changes in nutraceutical compounds and physicochemical properties, as ripening occurred, may reduce analysis times, processes, and guidance to use avocado seeds as a by-product. These results facilitate the seed processing and open up opportunities for its use in the industry.

Background Avocados are a nutrient-dense source of MUFAs and are rich in antioxidants. Avocados have an additional LDL cholesterol (LDL-C) lowering effect beyond that observed when their MUFAs are substituted for SFAs, especially on small, dense LDL (sdLDL) particles, which are susceptible to in vivo oxidation and associated with increased risk of cardiovascular disease (CVD). Objectives We investigated whether a healthy diet with 1 avocado daily decreased the following secondary outcomes: circulating oxidized LDL (oxLDL) and related oxidative stress markers. Methods A randomized, crossover, controlled feeding trial was conducted with 45 men and women, aged 21–70 y, with overweight or obesity and elevated LDL-C (25th–90th percentile). Three cholesterol-lowering diets were provided (5 wk each) in random sequences: a lower-fat (LF) diet (24% calories from fat—7% SFAs, 11% MUFAs, 6% PUFAs) and 2 moderate-fat (MF) diets (34% calories from fat—6% SFAs, 17% MUFAs, 9% PUFAs): the avocado (AV) diet included 1 Hass avocado (∼136 g) per day, and the MF diet used high oleic acid oils to match the fatty acid profile of 1 avocado. A general linear mixed model was used to analyze the treatment effects. Results Compared with baseline, the AV diet significantly decreased circulating oxLDL (−7.0 U/L, –8.8%, P = 0.0004) and increased plasma lutein concentration (19.6 nmol/L, 68.7%, P

Avocado pulp is widely regarded as a great source of edible oil containing fat-soluble vitamins and omega-3 fatty acids (FA). However, avocado peel and seeds are also good sources of edible oil and are less explored byproducts. This paper aimed at determining the proximal composition, FA and tocopherol contents of the pulp, peel, and seeds of Quintal, Fortuna, Margarida, and Hass avocado cultivars. The pulps presented high concentrations of oleic acid. In addition, peel and seeds presented lower omega-6/omega-3 ratios than the pulp. There was also a considerable amount of tocopherol in the peel and seeds, especially in Hass peel (230.7 mg/100 g). According to the results, the peel and seeds of avocado that are considered byproducts, can be utilized in food industry.

Recently, consumers’ awareness is becoming a crucial aspect driving the food industry to develop new products with high nutritional value. The oil industry explores the use of less well-known plant materials such as avocado fruit which is a rich source of bioactive compounds. The objective of this study was to assess the quality and oxidative stability of avocado pulp oils during a 2-month storage period. Two avocado varieties, Hass and Reed, were selected and oil extraction was performed with the use of hexane. The extent of oxidative deterioration and oil stability were tested by measuring the acid value and peroxide value. The PDSC method was applied to evaluate the oxidative induction time. The composition of fatty acids and their distribution in internal (sn-2) and external (sn-1 and sn-3) positions in triacylglycerols were also analyzed. The acid value and the peroxide value of fresh extracted avocado oils reached approximately 0.6 mg KOH g−1 fat and 5 meq O2 kg−1 fat, respectively. Generally, during avocado oil storage both the acid values and the peroxide values were in accordance with Codex Alimentarius requirements (the limit for acid value is 4 mg KOH g−1, while for peroxide value it is 15 meq O2 kg−1). The Hass avocado pulp oil was characterized by a higher value of the oxidative induction time, about 111 min, compared to the oil extracted from Reed avocado pulp (61 min). The GC analysis revealed that avocado pulp oil could be considered a source of monounsaturated fatty acids. The dominant fatty acid found in this group was oleic acid with a percentage share of above 60%. In accordance with the results of fatty acids distribution in triacylglycerol molecules, the main fatty acids in the sn-2 position were linoleic acid and oleic acid and their percentage share in this item was up to 59% and 34%, respectively. It was also noticed that after a 2-month storage period, the acid value and the peroxide value increased about 7-fold and 2-fold, the oxidative induction time decreased about 2-fold and the percentage shares of fatty acid groups changed. In conclusion, the results obtained in this research indicate that storage period has a significant impact on avocado pulp oil quality.

Fatty acid composition and mineral nutrient concentrations can affect the nutritional and postharvest properties of fruit and so assessing the chemistry of fresh produce is important for guaranteeing consistent quality throughout the value chain. Current laboratory methods for assessing fruit quality are time-consuming and often destructive. Non-destructive technologies are emerging that predict fruit quality and can minimise postharvest losses, but it may be difficult to develop such technologies for fruit with thick skin. This study aimed to develop laboratory-based hyperspectral imaging methods (400–1000 nm) for predicting proportions of six fatty acids, ratios of saturated and unsaturated fatty acids, and the concentrations of 14 mineral nutrients in Hass avocado fruit from 219 flesh and 194 skin images. Partial least squares regression (PLSR) models predicted the ratio of unsaturated to saturated fatty acids in avocado fruit from both flesh images (R2 = 0.79, ratio of prediction to deviation (RPD) = 2.06) and skin images (R2 = 0.62, RPD = 1.48). The best-fit models predicted parameters that affect postharvest processing such as the ratio of oleic:linoleic acid from flesh images (R2 = 0.67, RPD = 1.63) and the concentrations of boron (B) and calcium (Ca) from flesh images (B: R2 = 0.61, RPD = 1.51; Ca: R2 = 0.53, RPD = 1.71) and skin images (B: R2 = 0.60, RPD = 1.55; Ca: R2 = 0.68, RPD = 1.57). Many quality parameters predicted from flesh images could also be predicted from skin images. Hyperspectral imaging represents a promising tool to reduce postharvest losses of avocado fruit by determining internal fruit quality of individual fruit quickly from flesh or skin images.

The Hass avocado is a crop with significant growth potential for Colombia as an export product; however, the country has reported quarantine-type pest insect species that limit its export. The objective of this research was to evaluate gamma radiation treatments of fruit in order to study its use as a post-harvest treatment. Gamma radiation levels were evaluated at 100, 200, 400 and 800 Gy and compared against a control without irradiation. The harvest maturity status was established as a blocking factor. The evaluation was carried out for 20 days after the application of the treatments, emulating conditions of refrigerated transport at 7 °C. The variables firmness, exocarp and mesocarp color, soluble solids, dry mass, respiration, and weight loss were analyzed longitudinally at five evaluation points, where time acted as an intrasubject factor in the analysis of longitudinal multivariate variance. The variables lipid peroxidation and ethylene production rate were evaluated only once at the end of the test. We found that the highest radiation treatment affected the color of the exocarp and the content of total soluble solids, while all treatments affected the respiratory intensity, increased lipid peroxidation, altering the color of the mesocarp, which is the tissue of greater commercial interest for fresh fruits. All the treatments affected the visual quality of the fruits independent of the point of harvest maturity. The Hass avocado is a crop with significant growth potential for Colombia as an export product; however, the country has reported quarantine-type pest insect species that limit its export. The objective of this research was to evaluate gamma radiation treatments of fruit in order to study its use as a post-harvest treatment. Gamma radiation levels were evaluated at 100, 200, 400 and 800 Gy and compared against a control without irradiation. The harvest maturity status was established as a blocking factor. The evaluation was carried out for 20 days after the application of the treatments, emulating conditions of refrigerated transport at 7 °C. The variables firmness, exocarp and mesocarp color, soluble solids, dry mass, respiration, and weight loss were analyzed longitudinally at five evaluation points, where time acted as an intrasubject factor in the analysis of longitudinal multivariate variance. The variables lipid peroxidation and ethylene production rate were evaluated only once at the end of the test. We found that the highest radiation treatment affected the color of the exocarp and the content of total soluble solids, while all treatments affected the respiratory intensity, increased lipid peroxidation, altering the color of the mesocarp, which is the tissue of greater commercial interest for fresh fruits. All the treatments affected the visual quality of the fruits independent of the point of harvest maturity.

In an active packaging system, the control of moisture condensation can significantly reduce deterioration and loss of shelf life for fresh produce. In this study, an integrated mathematical model is proposed to represent the transport of water in an active packaging system with a moisture adsorber. For this, suitable equations were used to represent the different processes involved: a first-order kinetics and a Freundlich equilibrium equation were used to represent the adsorption from the active element. The product transpiration was represented by considering its heat of respiration and the difference in water concentration between the product and the packaging headspace surrounding it. Likewise, the differential equations of mass balance for O2, CO2, N2 and water vapor were established for the active packaging. For the moisture adsorption, a mixture of sodium polyacrylate (SPA) and cotton in ‘sachets’ of porous vegetable paper (70% SPA w/w) was used as adsorber determining its capacity and rate of adsorption as a function of relative humidity and temperature. To validate the proposed model, ‘Hass’ avocado samples were stored in rigid perforated polyethylene terephthalate (PET) packages for 12 days at 12 °C. With the model it was possible to satisfactorily represent the accumulation of moisture in the package, the amount of water adsorbed by the adsorber and the weight loss of the packaged avocado fruits (R2 = 0.97–0.99 for the different tests).

In Peru, approximately 20% of the production of avocado var. Hass is discarded due to its low quality, and sold at low prices in local markets. The aim of this study was to optimize the blanching time and temperature to produce avocado pulp, using low quality discarded fruits as the raw material. The process was optimized using Response Surface Methodology with a 22 central composite rotational design (R2 ≥ 0.75; p < 0.05). The independent variables studied were the blanching time (0, 1.5, 5, 8.5, 10 min) and temperature (65, 68, 75, 82, 85 °C), where the avocados were blanched by immersion (with peel), and the pulp extracted, processed, vacuum sealed (0.035 MPa) and stored under refrigeration at 5 °C for 49 days. The low quality discarded avocados were shown to be ideal for pulping, since 98% of the fruits had an oil content below 15% with an average pulp yield of 79.23%. The results indicated that longer blanching times and higher temperatures of above 5 min and 75 °C, respectively, retained the green colour and increased the brightness of the pulp, avoiding enzymatic browning. In addition, the increase in both contributed to the stability of the product acidity and pH level, extending its shelf life. However, in the sensory analysis, the pulp submitted to temperatures above 82 °C obtained the lowest scores for taste, odour and general acceptance due to the presence of a bitter taste and unpleasant odours in the pulp. The central point trials (5 min; 75 °C) presented the best scores for the independent variables such as colour, taste, odour and sensory texture, also showing good physicochemical stability with a shelf life of 37 days. Resumo No Peru, aproximadamente 20% da produção de abacate var. Hass é descartada pelo baixo calibre, sendo vendida a preços baixos nos mercados locais. O propósito do trabalho foi otimizar o tempo e a temperatura de branqueamento para a produção de polpa de abacate, utilizando como matéria-prima frutos de descarte por baixo calibre. A otimização foi realizada utilizando a Metodologia de Superfície de Resposta com delineamento rotacional composto central 22 (R2 ≥ 0,75; p < 0,05). As variáveis independentes estudadas foram o tempo (0; 1,5; 5; 8,5; 10 min) e a temperatura (65, 68, 75, 82, 85 °C) de branqueamento, em que os abacates foram branqueados por imersão (com casca), a polpa foi extraída, processada, selada a vácuo (0,035 MPa) e armazenada em refrigeração a 5 °C durante 49 dias. Os abacates de baixo calibre mostram-se ideais para a produção de polpa, pois 98% dos frutos apresentaram um teor de óleo inferior a 15%, com um rendimento médio em polpa de 79,23%. Os resultados indicaram que tempos longos e temperaturas altas de branqueamento acima de 5 min e 75 °C, respectivamente, retêm a cor verde e aumentam o brilho na polpa, evitando o escurecimento enzimático; além disso, o aumento de ambos contribui na estabilidade da acidez e do nível de pH do produto, estendendo sua vida útil. No entanto, na análise sensorial, a polpa submetida a temperaturas acima de 82 °C obteve as menores pontuações em sabor, odor e aceitação geral, devido à presença de sabores amargos e odores desagradáveis na polpa. Os testes do ponto central (5 min; 75 °C) apresentaram as melhores pontuações para as variáveis independentes, como cor, sabor, odor e textura sensorial, além de apresentar boa estabilidade físico-química com uma vida útil de 37 dias.

Ethyl formate (EF) is a Generally Recognised As Safe (GRAS) alternative to methyl bromide, with potential to control surface pests on New Zealand avocados before export. "Hass" avocados, two-spotted spider mites (TSM) and oleander scale (OS) insects were fumigated with 1.2% EF (240 g VAPORMATE™/m3) at 6 °C for 1, 2 or 4 h. Fruit were then stored at 5 °C for 3 weeks before external and internal fruit quality assessment. Survival of pest species was assessed 1 or 7 days later. Fumigation with 1.2% EF + 10% CO2 for 2 or 4 h controlled all life stages of non-diapausing TSM and all life stages of OS, apart from crawlers (0.3-0.7% survivorship). Diapausing TSM were harder to control (17% ± 4.8% mortality; 4-h treatment). Ethyl formate treatment resulted in damage to avocado skins (41% ± 5.3% – 91% ± 2.0%), and an increase in vascular browning and rots. The EF fumigations of avocado fruit at doses used here have potential to control non-diapausing mites and scale insects, but treated fruit were of unacceptable quality. Future studies could examine whether prior cool storage could reduce fruit damage.

Resumen En la comunidad de la Fortuna, municipio de Tepic, Nayarit. México, ubicada en las coordenadas 21° 33’ N y 104° 57’ O, con una precipitación promedio anual, de 1300 - 1450 mm se evaluó el efecto de la aplicación de nitrógeno (N) y Potasio (K), utilizando nitrato de potasio (KNO3) en la producción de fruto y el volumen de copa en el cultivo de aguacate (Persea americana Mill.) variedad Hass. La evaluación se realizó durante 1 año a partir de septiembre de 2014. Los tratamientos fueron dispuestos en bloques al azar con diez repeticiones y arreglo factorial 4 x 2, donde el factor A consistió en las dosis de KNO3: 230, 460 y 690 g por árbol más un testigo sin aplicación. El factor B consistió en la aplicación y no aplicación de riego, durante la época sin lluvia en la región. Las concentraciones foliares de N y K fueron determinadas en las diferentes etapas fenológicas del cultivo. La producción de frutos, la extracción de N y K en fruto (g), y el volumen de copa (m3) del árbol fueron determinadas en el momento de cosecha. Estas variables presentaron diferencias significativas (P < 0.05) tanto en condiciones de temporal como de riego, siendo la dosis de KNO3 de 690 g/árbol la que presentó los valores más altos. El incremento en producción fue de 59% y 73%, respectivamente, en comparación con el testigo; el efecto fue mayor en el sistema de riego lo cual indica que el nitrógeno y el potasio son más dinámicos en el sistema suelo-planta cuando hay disponibilidad de humedad. En este sistema se observó una correlación positiva entre la concentración foliar de N y K y la mayor producción. Abstract The aim was to quantify the effect of potassium nitrate (KNO3) on fruit production and canopy volume in Hass avocado (Persea americana Mill.). In Tepic (21° 33’ N y 104° 57’ O), Nayarit. México, from September 2014 to September 2015, a randomized block experiment with ten replicates and 3x2 factorial treatments was established, where factor A was three doses of KNO3: 0, 230, 460 and 690 g per tree; the factor B consisted of the humidity conditions (irrigation and temporal). In different phenological stages the foliar concentration of N and K was quantified and both were correlated; nutrient extraction of K and N in fruit (g), and canopy volume (m3) were quantified. The variables of fruit production, canopy volume and nutrient extraction by fruit showed statistically significant differences under irrigation conditions, being the dose of 690 g of KNO3 which showed higher values. It is concluded that fertilization with KNO3 had a positive effect on fruit production per tree (kg), both under the condition of rainy and irrigation, the increase production was 59 % and 73 % respectively, compared to the control; the effect was greater under irrigation condition which indicates that nitrogen and potassium are more dynamic in the soil-plant system when moisture is available. In the system with irrigation, a positive correlation was observed between the foliar concentration of N and K, which finally favored a higher production.

Avocados (Persea americana Mill.) are often held for short periods after harvest at relatively high temperatures both in the field, in storage during preconditioning (ethylene ripening), or prior to ripening with unknown effects on subsequent quality. To better understand the quality effects of short-term high temperature exposure, avocados were harvested at five different times during the first commercial season and held at 20, 25, 30 or 35 °C for 24 h or 48 h, with and without ethylene. During the subsequent season (2) the experiment was repeated, but without the 30 and 35 °C treatments. In both seasons, following the short-term temperature treatment, fruit were either immediately ripened at 20 °C or stored for 14 d at 5 °C and then ripened to determine the influence of storage. After final ripening to eating firmness (4.4–6.7 N) the fruit were evaluated for quality parameters. Results from the first two seasons showed that even a 24 h exposure to 25 °C and above was sufficient to inhibit subsequent ripening and enhance the occurrence of postharvest disorders such as stem end rot and body rot. Application of ethylene during the short-term temperature exposure was ineffective in preventing the disorders. In the third season of the study the effect of prolonged temperature exposure on final ripening was examined. Although there had been research done in the past on this subject, prior work had not examined the effect of different ripening temperatures on flavor. Avocados were harvested at seven harvest dates, stored for either 4 d or 14 d at 5 °C and then ripened to eating firmness at temperatures ranging from 15 to 25 °C. Increasing temperatures up to 20 °C decreased ripening time, beyond which there was no further change. Avocados ripened at temperatures above 20 °C had an increased incidence of the development of pink discoloration in the mesocarp. Ripening temperature had no effect on overall likeability, or ratings of grassy or rich flavor. This correlated with a lack of clear effect of ripening temperature on aroma volatile content of the fruit. Panelists found fruit ripened at 15 °C to have a different texture that those ripened at 20 °C but this had no influence on likeability. This study strongly indicated the importance of maintaining the ripening temperature of avocados at or near 20 °C both when the fruit is ripened soon after harvest or after storage to optimize postharvest quality.

Avocatin B, an avocado-derived compound mixture, was demonstrated recently to possess potent anticancer activity by selectively targeting and eliminating leukemia stem cells. Avocatin B is a mixture of avocadene and avocadyne, two 17-carbon polyhydroxylated fatty alcohols (PFAs), first discovered in avocado seeds; their quantities in avocado pulp are unknown. Analytical methods to detect avocado seed PFAs have utilized NMR spectroscopy and GC-MS; both of these lack quantitative capacity and accuracy. Herein, we report a sensitive LC-MS method for the quantitation of avocadene and avocadyne in avocado seed and pulp. The method has a reliable and linear response range of 0.1–50 μM (0.03–17.2 ng/μL) for both avocadene and avocadyne (r2 > 0.990) with a lower limit of quantitation (LLOQ) of 0.1 μM. The intra- and interassay accuracy and precision of the quality control (QC) samples at LLOQ showed ≤18.2% percentage error and ≤14.4% coefficient of variation (CV). The intra- and interassay accuracy and precision ...

Temperature and exogenous ethylene are two important factors that determine the rate of quality change in ‘Hass’ avocado. The aim of this study was to quantify this effect and to build a mathematical model that will assist in predicting the effect of temperature, exogenous ethylene, and time on quality outcomes of ‘Hass’ avocado. A mathematical model was developed to describe autocatalytic ethylene production, and coupled to models describing softening and colour changes via ethylene. The effect of exogenous ethylene was incorporated by addition of a diffusion term, while temperature effect was modelled by expressing rate constants as a function of temperature using the Arrhenius equation. The model was calibrated using data on ethylene efflux rate, firmness and skin hue collected on ‘Hass’ avocado fruit stored at 5, 10, or 20 °C, in atmospheres containing −1 (air), 1 μL L −1 or 10 μL L −1 ethylene in air. Effect of ethylene on softening was greater than on colour change, with clear firmness separation of the different ethylene treated fruit evident even during ripening at 20 °C. The high dependency of softening on ethylene was revealed in the Michaelis-Menten constant for the regulation of the softening enzyme by ethylene, which was about 15 times larger than that for the colour degrading enzymes. The model was successfully validated on a sub-dataset.

Avocado is a fruit with great nutritional value; however, it is highly perishable, reaching in Colombia around 40% postharvest losses. The evaluation of using non-conventional technologies to process fruits and vegetables, like ultraviolet light irradiation, use of antioxidant solutions, and packaging in modified atmospheres constitute an alternative to lengthen the shelf life of perishable foods. This research evaluated irradiation at three times, reaching up different irradiation levels, all of them below the maximum permitted for fruits and vegetables. The pH and total soluble solids content of the samples showed variations due to storage at 4 °C, without being affected by the application of ultraviolet light. The chromatic characteristics showed important variations due to maturation and senescence processes in fruits. Application of the highest dose evaluated (20.32 kJ * m−2) in combination with antioxidant solution had the best results on texture and color. Likewise, greater reduction was observed in the fruit's initial microbial load and inhibition of its development during the storage time. Samples with UV treatment and packaged in modified atmosphere had the best behavior in chromatic parameters (L*, a*, b*) and soluble solid content (°Brix). Using combined mechanisms contributes to extending the shelf life of perishable foods, representing an alternative to generate added value to the crop and diminish losses in its postharvest.

Commercial avocado orchards typically consist of composite trees. Avocado is salt-sensitive, suffering from substantial growth and production depreciation when exposed to high sodium and chloride levels. Salt ions penetrate the roots and are subsequently transferred to the foliage. Hence, understanding distinct physiological responses of grafted avocado plant organs to salinity is of great interest. We compared the ion, metabolite and lipid profiles of leaves, roots and trunk drillings of mature 'Hass' scion grafted onto two different rootstocks during gradual exposure to salinity. We found that one rootstock, VC840, did not restrict the transport of irrigation solution components to the scion, leading to salt accumulation in the trunk and leaves. The other rootstock, VC152, functioned selectively, moderating the movement of toxic ions to the scion organs by accumulating them in the roots. The leaves of the scion grafted on the selective rootstock acquired the standard level of essential minerals without being exposed to excessive salt concentrations. However, this came with an energetic cost as the leaves transferred carbohydrates and storage lipids downward to the rootstock organs, which became a strong sink. We conclude that mutual scion-rootstock relationships enable marked tolerance to salt stress through selective ion transport and metabolic modifications.

Hass avocado ripening heterogeneity generates logistics problems to importers and ripeners due to higher labour costs, inconsistent quality delivery and postharvest losses. The main aims of this research were: (i) to evaluate two postharvest pre-treatments (nitrogen shock N 2 and heat shock) prior controlled atmosphere (CA) on reduction of ripening heterogeneity of Hass avocado without being detrimental to fatty acid profile and (ii) to study the potential metabolic processes implicated in such ripening synchronization with focus on cell wall remodelling and ethylene biosynthetic pathways. Results showed that heat shock prior to CA storage significantly reduced ripening heterogeneity in early and middle season fruit while N 2 + CA did not. Pectin methyl esterase (PME) and polygalacturonase (PG) activity did not display significant differences among treatments. Additionally, none of the treatments altered the fatty acid profile. ACS transcript for early and middle season fruit kept constant during storage for heat + CA, CA and N 2 + CA. ACO instead displayed less abundance after 21 d storage for all treatments of early season fruit. These results point to ripening synchronization in Hass avocado subjected to heat to be related to induction of metabolic processes related to ethylene (biosynthesis), possibly at the action level (receptors) but the efficiency of the heat treatment was related to the maturity stage of the batch.

Hass avocado postharvest ripening heterogeneity creates several logistics problems at destination markets. Although several approaches mainly based on targeted analysis have been undertaken to broaden our understanding of the potential causes of this postharvest ripening heterogeneity, still the secret is not yet unveiled. In this study biopsies from individual fruit displaying contrasting ripening behavior (slow vs fast) and subjected to different storage conditions (immediately after harvest, 30 d regular air at 5 °C and 30 d at 5 °C and 4 kPa O 2 and 6 kPa CO 2 ) were analyzed for targeted fatty acid analysis and cell wall enzyme activity combined with a more integrative approach based on gel free proteomics LC–MS/MS. The high throughput proteomics was capable of discriminating between slow and fast ripening avocado fruit. Proteins that were mainly less abundant in the slow ripening phenotype were annotated to correct protein folding, translation and de novo synthesis and higher abundant proteins were annotated to amino sugar and nucleotide metabolism, detoxification and stress response and proteolysis. Our study opens new insights into the causes of heterogeneous ripening and may provide new markers for avocado ripening at harvest and after prolonged storage.

A study was conducted to compare the physicochemical properties of Hass avocado oil from different geographical locations (Mexico, Australia, United States and New Zealand). Regardless of geographical origins, Hass avocado pulp was characterized by high lipid content (61.27–62.66%). Among Hass avocados of different origins examined, avocado oil of New Zealand origin exhibited the lowest saponification value. The L*, a* and b* values for avocados of New Zealand origin were higher than others, translating into the oil being the lightest in color and containing more red and yellow pigments. The predominant fatty acids in the Hass avocado oil were oleic (42.59–50.97%) and palmitic (20.61–25.63%) acids, whereas the predominant triacylglycerols (TAGs) were OOO (21.41–34.69%) and POO (19.65–24.68%), where O and P denote oleic and palmitic acids, respectively. The melting curves of Hass avocado oil displayed three endothermic peaks, whereas the crystallization curves displayed two endothermic peaks. Hass avocado oil of New Zealand origin contained a significant amount of natural pigments and unsaturated compounds (unsaturated fatty acids and tri-unsaturated TAGs) than Mexico, Australia and United States origins.

In plants, secondary metabolites (SMs) have functions of both defense and adaptation to the environment in which they develop. In Mexico, ‘Hass’ avocado is cultivated in different climate types, so during its development, the fruit is exposed to extreme climatic factors, especially temperature and solar radiation. A recent study showed that the thickness and roughness of ‘Hass’ skin increased in the hottest climate. It is unknown how these factors affect the presence of SMs and lignin in the skin. The aim of this research was to quantify the concentration of total phenolic compounds (TPCs), chlorophylls, total carotenoids (TCARs), and lignin in the skin of ‘Hass’ avocado fruit over five developmental stages (S), based on fruit diameter [Olive (20–30 mm ø), S-I (35–45 mm ø), S-II (50–60 mm ø), S-III (60–70 mm ø) and Harvest (mesocarp dry matter ≥21.5%)], in three producing regions of Mexico: Nayarit (warm subhumid climate, elevation 1151 m), Jalisco (semiwarm, subhumid climate, elevation 2180 m), and Michoacán (temperate climate, elevation 1579 m). Both fruit developmental stage and producing region had a significant influence on the concentrations of SMs and lignin in the skin. During fruit development, the skin showed a decrease in the concentration of phenolic compounds (PCs) and an increase in the presence of chlorophylls, carotenoids, and lignin. The skin of fruit produced in regions with a semiwarm and temperate climate had higher production of lignin and PCs, as well as a lower concentration of chlorophylls.

In this study, nanostructured edible coatings based on chitosan nanoparticles (CSNPs) and chitosan-thyme essential oil nanoparticles (CSTEO-NPs) were characterized and evaluated on in vitro growth of Colletotrichum gloeosporioides and on inoculated avocado fruit cv. Hass, to evaluate their fungicidal activity and the effect on fruit quality. From TEM and particle size distribution characterization, the size of nanoparticles increased after thyme essential oil incorporation. Overall a synergistic effect between the chitosan and thyme essential oil (TEO) was observed. For in vitro evaluation, incorporation of this essential oil to CSNPs improved the control of C. gloeosporioides as there was a complete growth inhibition. CSNPs with concentrations of TEO at 3 and 5% had a fungicidal effect. The coating formulation with 55% CSTEO-NPs notably reduced the incidence of C. gloeosporioides on avocado cv. Hass by up to 60%. Also, at the end of the 8-day storage period, CSTEO-NPs incorporation into the coating did not affect the quality of avocado; moreover, fruit firmness was better maintained than untreated fruit.

A convective drying process was optimized as strategy to produce dehydrated ingredients with high antioxidant capacity; using Hass avocado byproducts (peels and seeds). Studied processing variables were: temperature (45 °C–75 °C), air-flow (0.8 m/s to 1.8 m/s) and loading density (1 kg/m2 to 3 kg/m2). The response variables were Total Phenol Content (TPC) and Antioxidant Capacity (DPPH). Drying kinetic analysis revealed that seeds had higher water diffusivity than peels, but the latter showed shorter drying times. Multiple optimization routines allowed maximizing simultaneously DPPH and TPC. Thus, 62.82% and 54.81% of the initial TPC was retained in dehydrated peels and seeds, respectively. Sorption isotherms for both dehydrated byproducts showed that avocado seeds were more hygroscopic than peels, which was attributed to differences on their composition. This research has outlined a useful tool for the transformation of avocado wastes into storable commodities with high antioxidant properties which may have different food uses.

High standards regarding Listeria monocytogenes control and consumer demands for food products without synthetic additives represent a challenge to food industry. We determined the antilisterial properties of an enriched acetogenin extract (EAE) from avocado seed, compared it to two commercial antimicrobials (one enriched in avocado acetogenins), and tested purified molecules. Acetogenin composition in pulp and seed of Hass avocado was quantified. EAE were obtained by two sequential centrifuge partition chromatography separations and molecules purified by preparative chromatography and quantified by HPLC-MS-TOF and HPLC-PDA. Avocado seed extracts which are the following two: 1) EAE and 2) the commercially available antimicrobial Avosafe®, presented similar inhibition zones and chemical profiles. Minimum inhibitory concentration (MIC) values of extracts and two isolated acetogenins varied between 7.8 and 15.6 mg/L, were effective at 37 and 4 °C, and showed a bactericidal effect probably caused by increased membrane permeability and lytic effects, evidenced by flow cytometry at 10 and 100× MIC. Activity was comparable to Mirenat®. Most potent acetogenins were Persenone C (5) and A (6), and AcO-avocadenyne (1), the latter exclusively present in seed. Common features of bioactive molecules were the acetyl moiety and multiple unsaturations (2 to 3) in the aliphatic chain, some persenones also featured a trans-enone group. Seeds contained 1.6 times higher levels of acetogenins than pulp (5048.1 ± 575.5 and 3107.0 ± 207.2 mg/kg fresh weight, respectively), and total content in pulp was 199 to 398 times higher than MIC values. Therefore, acetogenin levels potentially consumed by humans are higher than inhibitory concentrations. Results document properties of avocado seed acetogenins as natural antilisterial food additives.

The seed of Hass avocado (Persea Americana Mill.), which is about 13% of the total weight of the fresh fruit, is considered as an agricultural waste and discarded with no proper applications. The current research article presents a study focused on the mathematical modelling of the drying kinetics of Hass avocado seeds. The drying experiments of the non-pretreated and pretreated (sliced and crushed) Hass avocado seeds were performed in a heating furnace where the influence of five different air temperatures (313, 323, 333, 343, and 353 K) on the rate of moisture evaporation was systematically studied. It was observed that the pretreatment process stimulated the drying progression of Hass avocado seeds. Four different semi-theoretical drying mathematical models were compared based on their coefficient of determination, reduced mean square error, root mean square error, mean bias error, and mean absolute error of the deviation to characterize the drying curves at previous mentioned conditions. The rise in the air temperature resulted in steeper decline in the curve shape of moisture ratio. The obtained scientific findings suggested that a newly proposed Avhad and Marchetti model provided superior simulation of the drying kinetics of Hass avocado seeds than the Lewis model, the Henderson and Pabis model, and the Page model over the experimental temperature range.

Fruit quality is largely determined before harvest. Postharvest treatments mainly seek tonmaintain this quality. A better understanding of the interaction between preharvest factorsnand postharvest fruit quality is required in order to find the best practices to optimize qualitynand reduce variability in quality. This thesis studied (1) the extent of variability in thenpostharvest performance of 'Hass' avocado fruit caused by production locality, harvest datenand fruit canopy position; (2) the underlying causes of quality variation such as mineralnnutrition; and (3) cultural practices such as irrigation, nitrogen fertilization and the use of thengrowth retardant paclobutrazol to manipulate fruit quality.Significant variation in fruit quality was noted between 6 production localities in south-eastnQueensland, where fruit were harvested at 3 stages of maturity (estimated at 24, 29 and 34%ndry matter, DM), and ripened immediately at 22oC or following 7oC storage for 3 weeks.nFruit from the warmer climates were smaller and less elongated than fruit from the coolernclimates. The days to eating soft and fruit Ca and Mg concentrations declined with laternharvests in fruit from most, but not all locations, while fruit mass and skin colour at harvestnincreased with later harvests. Anthracnose severity was either not affected by harvest stage,nor increased with later harvests in seasons with higher severity in fruit from the warmnenvironments.Long-term storage potential of fruit was influenced by production locality, harvest date andnmineral concentrations. Fruit from the sub-tropical (Childers) and semi-temperaten(Toowoomba) environments were stored at 7, 2 or 1oC for 3 or 5 weeks before ripening.nFruit stored at 7oC did not develop skin discolouration during storage, but developed fleshndisorders, especially in less mature fruit. Storage at 1 or 2oC significantly reduced thenseverity of mesocarp discolouration, but increased the severity of skin discolouration.nEarly harvested fruit from Childers had 40% of fruit skin affected by discolouration and latenharvested fruit from Toowoomba had 25% of skin discolouration. Vascular browning wasnonly found in fruit from the Toowoomba district following 7oC storage.Canopy height and depth had significant effects on finit size, shape and % DM, but not onnpostharvest finit quality in the Maleny orchard (representing cool sub-tropicalnenvironments). However, canopy aspects had effects on postharvest quality and mineralnconcentrations in fruit from the Toowoomba orchard. Fruit harvested from the lowerncanopy took 1.3 days longer to soften than those from the upper canopy when they werenripened immediately at 22oC. The variation in quality of fruit between these canopy factorsnwas related to the different irradiance received.n n n n

Objectives Excess adiposity increases risk for cognitive impairment. Consumption of avocado, a highly bioavailable source of the xanthophyll lutein, has been shown to improve retinal lutein accumulation and cognitive function. Thus, we evaluated the influence of avocado consumption on cognitive function and lutein status among adults with overweight and obesity using a randomized-controlled trial with matching design for pertinent study outcomes. Methods A cohort of 84 adults (25–45 years, 31 males) were randomized to a treatment group (N = 47) that received a 12-week daily meal with fresh Hass avocado or a control group (N = 37) that received an isocaloric meal ( clinicaltrials.gov , NCT02740439 ). Serum lutein and macular pigment optical density (MPOD) were used to assess xanthophyll status. Attention and inhibition were assessed using the Flanker, Oddball and Nogo tasks with accompanying electroencephalographic (EEG) recording. Results Participants in the treatment group exhibited improvements in serum lutein and accuracy in the Flanker task. However, there were no relationships between performance and changes in lutein status, nor neuroelectric variables. No significant changes in MPOD were observed. Conclusion Daily avocado intake over 12 weeks, after controlling for covariates, improved attentional inhibition and increased serum lutein concentrations among adults with overweight and obesity. However, the cognitive benefits were independent of changes in lutein concentrations. Additional work is necessary to determine non-carotenoid, or carotenoid interactive, mechanisms by which avocados may influence cognitive function.

Avocado (Persea americana Mill) is rich in a variety of essential nutrients and phytochemicals; thus, consumption has drastically increased in the last 10 years. Avocado unlike other fruit is characterized by oil accumulation during growth and development and presents a unique carbohydrate pattern. There are few previous and current studies related to primary metabolism. The fruit is also quite unique since it contains large amounts of C7 sugars (mannoheptulose and perseitol) acting as transportable and storage sugars and as potential regulators of fruit ripening. These C7 sugars play a central role during fruit growth and development, but still confirmation is needed regarding the biosynthetic routes and the physiological function during growth and development of avocado fruit. Relatively recent transcriptome studies on avocado mesocarp during development and ripening have revealed that most of the oil is synthesized during early stages of development and that oil synthesis is halted when the fruit is harvested (pre-climacteric stage). Most of the oil is accumulated in the form of triacylglycerol (TAG) representing 60-70% in dry basis of the mesocarp tissue. During early stages of fruit development, high expression of transcripts related to fatty acid and TAG biosynthesis has been reported and downregulation of same genes in more advanced stages but without cessation of the process until harvest. The increased expression of fatty acid key genes and regulators such as PaWRI1, PaACP4-2, and PapPK-β-1 has also been reported to be consistent with the total fatty acid increase and fatty acid composition during avocado fruit development. During postharvest, there is minimal change in the fatty acid composition of the fruit. Almost inexistent information regarding the role of organic acid and amino acid metabolism during growth, development, and ripening of avocado is available. Cell wall metabolism understanding in avocado, even though crucial in terms of fruit quality, still presents severe gaps regarding the interactions between cell wall remodeling, fruit development, and postharvest modifications.

Background Avocados contain fiber, lutein, and vitamin E, and they are a rich source of MUFAs. The effect of including an avocado daily as part of a hypocaloric weight-loss diet on weight loss is not known. Objective The aim of this study was to determine the effect of daily avocado consumption as part of a hypocaloric diet on weight loss, body composition, satiety, biomarkers of inflammation, and intestinal microbiota composition. Methods In this randomized, parallel-controlled, open-label, 2-arm intervention study, 51 healthy overweight/obese women and men were assigned to a hypocaloric diet with 1 Hass avocado daily (AVO; n = 24) or a hypocaloric diet (CTRL; n = 27) without daily avocado for 12 wk. Serum markers and intestinal microbiota were analyzed at baseline and week 12. Results Both groups experienced significant weight loss, decrease in BMI (in kg/m2), total body fat, and visceral adipose tissue, respectively (AVO: -2.3 ± 2 kg, -0.8 ± 0.8, -1.1% ± 2%, and -81.2 ± 118 g; CTRL: -2.6 ± 3.6 kg, -0.9 ± 1, -1.5% ± 2%, and -87.4 ± 216 g). We observed a significant decrease in serum glucose over time in the control group compared with the AVO group. There was no change between the groups in serum triglyceride, but a significant decrease from baseline to 12 wk was observed in the AVO group. Serum hepatic growth factor (HGF) and relative proportion of bacterial phyla (Firmicutes and Bacteroidetes), family (Bacteroidaceae and Erysipelotrichaceae), and genus (Bacteroides, Clostridium, Methanosphaera, and Candidatus Soleaferrea) were significantly altered in the AVO group compared with the CTRL group. A trend to decrease in serum inflammatory factors IL-1β (P = 0.07) and C-reactive protein (P = 0.074) was observed in the AVO group compared with CTRL. Conclusions Daily Hass avocado consumption as part of a hypocaloric diet supported weight loss, a decrease in serum HGF, and an increase in the abundance of bacteria involved in plant polysaccharide fermentation. This trial was registered at clinicaltrials.gov as NCT02953158.

A proper description of the respiration and ethylene generation is important in the development of package systems for the preservation of fresh fruits and vegetables. In this work, a model based on both Michaelis-Menten and chemical kinetics equations was developed and assessed in order to describe the respiration and ethylene generation of avocado (Persea americana cv. Hass) and feijoa fruits (Acca sellowiana Berg) from experimental data obtained at different temperatures by a closed system method. The temperature effect in both processes was described using Arrhenius-type relationships. After this, avocadoes and feijoas were packed in perforated low-density polyethylene (LDPE) and polypropylene (PP) bags for 8 days at 12°C and 80% RH to validate the usefulness of the model to describe the gas evolution in modified atmosphere packaging (MAP). For avocado fruits, respiration rates of 2680-3030 cm3 kg-1 d-1 were obtained at 24 °C and normal atmosphere, and 3650-4230 cm3 kg-1 d-1 for feijoa fruits....

Effects of nitrogen (N) fertilizer application times and rates on ‘Hass’ avocado (Persea americana) yield and fruit size were determined to resolve whether a single dose of soil-applied N [1x N (25 lb/acre)] at each of the five key stages of tree phenology (January, April, July, August, and November) (control) was as efficacious as soil-applied 2x N (50 lb/acre) at one or two key stages or soil- or foliar-applied 3x N (75 lb/acre) at only one stage. All trees received soil-applied N at 125 lb/acre as ammonium nitrate (NH4NO3) annually; trees receiving 2x or 3x N received the remaining N divided evenly at the same phenological stages (months) as trees receiving five 1x N applications. The importance of supplying N during the summer, when June drop, exponential fruit growth, vegetative shoot growth, and floral initiation occur, was determined by testing soil-applied 0.8x N in July plus August only (40 lb/acre N as NH4NO3 annually). Application time proved an important determinant of total yield. Yield of commercially valuable size (CVS) fruit was correlated with total yield (r = 0.80, P < 0.0001). Four-year cumulative total yields were equal for trees receiving soil-applied 1x N at five key phenological stages and trees receiving soil-applied 2x N in April and 18.75 lb/acre N at the four other stages (months). However, trees receiving soil-applied 2x N in April plus November and only 8.3 lb/acre N in the three other months, in particular July and August, had significantly lower 4-year cumulative total yields (P = 0.0362). Additional evidence of the importance of meeting avocado tree N demand in the summer is that trees receiving only 40 lb/acre N split in July plus August produced 4-year cumulative total yields equal to trees receiving 25 lb/acre N at the five key phenological stages; lower annual N would reduce fertilizer expense and protect the environment.

The aroma in avocados (Persea americana Mill. cv. ‘Hass’) is mainly defined by fatty acids-derived volatile compounds that change according to the fruit maturity stage which is modulated by ethylene. In order to understand the changes in fatty acid substrates and gene expression involved in the synthesis of the key aroma-volatile compounds in avocado after harvest, we performed two trials using avocados harvested with 11% oil content. In the first trial avocados were ripened immediately after harvest at 20 °C until reaching the ready-to-eat stage, and in the second trial, fruit were stored at 5 °C for 30 days and then ripened at 20 °C. In addition, to assess the ethylene effect in the volatile compounds and transcript levels measured, a 100 μl L−1 ethylene application was carried out, at harvest or after storage for trial 1 and 2, respectively. The concentration of the key volatile compounds and fatty acids were performed by gas chromatography, and the changes in the expression of genes related to lipoxygenase derived compounds were measured by q-PCR. The results obtained indicated that ethylene modulated the production of linolenic acid and hexanal, whereas at the gene expression level, only PamLOX transcript changes responded to ethylene application, although its changes were maturity/ripening dependent. The cold storage did not generate significant changes in fatty acids and gene expression levels, but a decreased in the concentration of hexanal during the ripening was observed.

Persea americana Mill. cv ‘Hass’ is a subtropical fruit highly appreciated as a rich source of fatty acids mostly of the monounsaturated type. Commonly commercially applied postharvest ripening strategies for the ready to eat market based on high temperature (15 and 20 °C) and external ethylene (0 or 100 ppm applied for 24 h) application did not have a detrimental effect on the fatty acid profile or composition and total amount of oil recovered at edible ripeness. The results of this study have important implications for the fresh fruit and avocado oil industry. The composition of the fatty acid profile in ‘Hass’ avocados was mostly influenced by growing and environmental conditions. Commercially applied postharvest ripening strategies based on temperature and ethylene did not affect negatively the fatty acid composition of the fruit.

To reduce cold damage (CD) and loss of quality during cold storage of early season Hass avocados (22.9–26.3% dry matter), a pre-conditioning treatment that consisted on pulp hydrocooling to 6 °C in a 0.3% CaCl 2 solution was effective in comparison to a control group of fruit pre-conditioned at 6 °C for 3 days in a cold room. Half of the fruit from both pre-conditioning treatments were waxed and stored at 3 ± 1 °C for 1, 23 and 46 days. After each storage time, quality parameters such as: epidermis and pulp damage, fruit firmness, % weight variation, colour, respiration, ethylene production, ethanol and acetaldehyde were assessed. Results demonstrated that the hydrocooling pre-treatment alone does not completely reduce lenticelosis but in combination with waxing resulted in a three fold reduction of internal damage and retarded fruit colour break. The use of waxing, independently of the initial pre-conditioning treatment, retarded fruit colour break, minimized quality loss, reduced metabolism and ethylene production and allowed to extend the commercialization period of the fruit at room temperature after storage at 3 °C for 46 days.

Avocado trees ( Persea americana Mill.) invest heavily in flowering but fruit set percentage is unusually low, even after hand pollination. Our hypothesis was that the carbohydrate and boron content of avocado flowers at anthesis affected the potential of these flowers to set fruit. We hand pollinated ‘Hass’ avocado flowers in orchards in New Zealand and Spain, then 24 h later, after pollen tube growth had occurred, collected the styles from these flowers leaving the ovary intact. The excised styles were then analysed for starch, total and individual sugars and boron content. These data were later compared with the fate of the flower from which the style had been collected. Starch and all individual sugars were higher in the styles from flowers that went on to successful fruit set. Boron content was significantly higher in the styles from flowers that successfully set fruit in New Zealand but no significant difference was observed in the boron content of styles from Spain. These data support previous findings that suggest sink strength of flowers is predetermined at anthesis and influences the probability of fruit set for that flower.

This study investigated how the quality of avocado oil is affected by the fruit ripening stage and peeling, and the drying process used. Expeller pressed avocado oils were obtained from unripe or ripe pitted avocados after drying peeled or unpeeled pulps by convection oven, microwave or freeze-drying. Oils from the unpeeled microwave dried pulp (from unripe or ripe avocados) showed the highest induction period (54.2–83.6 h) and antioxidant capacity (4.07–5.26 mmol TE/kg), and high amounts (mg/100 g) of α-tocopherol (11.6–21.0), β-carotene (0.49–0.65) and chlorophyll (44.3–54.0), and unsaponifiable matter (2.48–2.99 g/100 g). Pulp drying process and avocado (un)peeling were the major contributors to the induction period (R2 = 0.61; p = 0.0139) and antioxidant capacity (R2 = 0.62; p = 0.011), and the oils from microwave dried unpeeled pulp were those that presented the best performance. The phenolic composition of these oils improved with ripening and keeping the peel during the pressing process.

The objective of this work was to evaluate the effect of different gibberellin biosynthesis inhibitors on shoot growth above the panicle, as well as on fruit yield, size, and shape of nonirrigated 'Hass' avocado (Persea americana) trees. The experiment was carried out in a randomized complete block design, with five treatments, four replicates, and 40 trees. From 2013 to 2015, the following treatments were applied at full bloom, as foliar sprayings: water (control), 250 mg L-1 prohexadione-calcium, 2,500 mg L-1 trinexapac-ethyl, 1,750 mg L-1 paclobutrazol, and 350 mg L-1 uniconazole; the first two are acylcyclohexanediones and the last two, triazoles. Fruit yield, yield efficiency, and alternate bearing were not affected by the application of plant growth regulators. However, the gibberellin inhibitors increased fruit size and modified the fruit shape of nonirrigated 'Hass' avocado. Uniconazole reduces shoot growth above the panicle, and this effect may vary depending on environmental conditions, especially water supply.