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  • Changes in fatty acid composition and electrolyte leakage of 'Hayward' kiwifruit during storage at different temperatures
    Publication . Antunes, Maria Dulce; Sfakiotakis, E. M.
    Exposure to low storage temperature induces changes in electrolyte leakage and fatty acids composition, in a way depending on the plant tissue. Those changes alter the response of the fruit to storage conditions. The influence of storage temperature on ripening, fatty acids composition and electrolyte leakage of 'Hayward' kiwifruit were investigated. Harvested fruit were stored at 0, 5, 10,15 and 20 degrees C for 5, 12 and 17 days. Measurements of SSC, firmness, flesh colour, fatty acid composition and electrolyte leakage were performed during the experiment. Kiwifruit did not fully ripen during the 17 days storage at any temperature. The major fatty acid component in 'Hayward' kiwifruit consisted of linolenic, followed by oleic, palmitic, linoleic and stearic acid. Membrane permeability and unsaturated/saturated fatty acid ratio increased during storage in all treatments. The highest increase was during the first 5 days and at the lowest temperatures. The increase in unsaturated/saturated fatty acid ratio was caused mainly by a decrease in palmitic and an increase in oleic acids. Stearic, linoleic and linolenic acids had insignificant changes during storage. The main increase in electrolyte leakage and unsaturated/saturated fatty acid ratio occurred during the first storage days and at lower temperatures, probably as a response of the tissue to an adaptation to the new stress storage conditions. (C) 2008 Elsevier Ltd. All rights reserved.
  • Effect of 1-Methylcyclopropene application prior to storage on fresh-cut kiwifruit quality
    Publication . Antunes, Maria Dulce; Miguel, Maria Graça; Metelo, S.; Dandlen, S. A.; Cavaco, A. M.
    Kiwifruit is commercially important as fresh-cut. The purpose of this work was to study the effect of 1-methylcyclopropene (1-MCP) applied after harvest, before storage, on the posterior behaviour of ripe fruit prepared as fresh-cut. Harvested fruit where treated with 1 mu l L(-1) 1-MCP for 20 hours at room temperature, then stored at 0 C. After 3 months, fruit were removed from storage, peeled and cut longitudinally in quarters, then stored at 2 C for 8 days. Measurements of flesh colour, firmness, soluble solids content (SSC), electrolyte leakage and ascorbic acid were performed after 0, 4 and 8 days. Kiwifruit treated with 1-MCP showed higher firmness and lower a* value, electrolyte leakage and SSC than the control, after 3 months storage. Values of a* and electrolyte leakage increased through fresh-cut storage and after 8 days differences between treatments become almost nil. SSC did not change in fruit treated with 1-MCP, while it increased after 4 days and decreased on 8(th) day in the control. Firmness decreased through fresh-cut storage, being higher in 1-MCP treated fruit than control except on 8(th) day. Ascorbic acid which was higher in control, showed a higher decrease on those fruit and after 8 days was similar in both treatments. Panellists did not find significant differences between treatments, except that 1-MCP treated fruit had better appearance. The application of 1-MCP immediately after harvest showed beneficial effects in keeping kiwifruit quality during 3 months storage, and its effect lasted through shelf-life of those fruit when used as fresh-cut.
  • Innovative postharvest techniques for sustainable handling of horticultural products
    Publication . Antunes, Maria Dulce; Miguel, Maria Graça; Neves, Alcinda
    Fresh fruits and vegetables are important components of human food. However, horticultural products are highly perishable and losses can be of great importance if postharvest correct measures are not provided. There is a worldwide trend to explore new alternatives to increase storage life, giving priority to methods that reduce horticultural product decay avoiding negative effects to human heath and environment. The objective of our research was to apply environmental and human health friendly techniques to preserve fresh fruit quality through storage. Figs, apricots, oranges, pomegranates and kiwifruits were treated with sodium bicarbonate, calcium chloride, acetic acid or subjected to modified atmosphere packaging to increase their storage life with minimal quality loss, as well as damage to human health and environment. The use of these treatments and techniques gave a great performance in the reduction of fruit losses, weight loss and fruit softening. Postharvest techniques such as modified atmosphere and calcium, sodium bicarbonate and acetic acid treatments, when applied in adequate concentrations, help to keep fruit quality through storage, without damaging the environment and human health. The benefit of each treatment depends on the type of fruit.
  • Ethylene biosynthesis and ripening behaviour of 'Hayward' kiwifruit subjected to some controlled atmospheres
    Publication . Antunes, Maria Dulce; Sfakiotakis, E. M.
    The effects of storage in air (AS), controlled atmosphere (CA) or ultra low oxygen (ULO) on ethylene biosynthesis and ripening of 'Hayward' kiwifruit during storage at 0 degreesC and post-storage at 20 degreesC, were investigated. Fruit were stored for 60, 120 and 180 days at 0 degreesC in AS, CA (2%O(2) + 5%CO(2)) and ULO (0.7%O(2) + 0.7%CO(2) and 1%O(2) + 1%CO(2)). Freshly harvested fruit and fruit removed from storage were treated with 130 mul/l propylene or propylene-free air for 9 days at 20 degreesC. Fruit treated with propylene at 20 degreesC at harvest produced ethylene with a tag period of 3 days, had concomitant 1-aminocyclopropane-1-carboxylic acid (ACC) production, 1-aminocyclopropane-1-carboxylate synthase (ACC synthase) and 1-aminocyclopropane-1-carboxylate oxidase (ACC oxidase) activities, and were ripe after 3-5 days while fruit not treated with propylene were not able to produce ethylene and ripen during the 9 days experiment. AS fruit softened faster during the first 60 days of storage. This effect was reduced in CA and ULO treatments. The soluble solids content (SSC) increased markedly during the first 60 days of storage and remained almost constant thereafter in all treatments. After 9 days shelf life, only AS and CA stored fruit were ripe. Fruit from ULO storage required propylene treatment to ripen fully. When kiwifruit were placed at 20 degreesC, after 60, 120 or 180 days storage at 0 degreesC, there was an induction of ethylene production with no tag period in fruit from AS or CA, with or without propylene. There was some ACC content and ACC synthase activity after 60 days storage for all treatments, while ACC oxidase activity increased only upon rewarming of the fruit in AS or CA. Kiwifruit removed from ULO-storage showed drastically reduced capacity to produce ethylene mainly due to low ACC oxidase activity rather than reduced ACC production or ACC synthase activity. Respiration increased upon rewarming of the fruit in all treatments. With storage time, there was a decrease in the capacity of the warmed fruit to produce ethylene and CO(2) as well as in the activities of ACC synthase and ACC oxidase, mostly after 60 days storage. (C) 2002 Elsevier Science B.V. All rights reserved.
  • Mapping orchard fruit quality characteristics of apricot (Prunus armeniaca L.) cultivars 'Beliana' and 'Lindo'
    Publication . Panagopoulos, Thomas; Baltasar, O.; Antunes, Maria Dulce
    The market has become increasingly more demanding about information on product origin, production inputs, environment impacts and quality. Frequently, information required by the post-harvest and marketing components must be sourced from the producer. Also, the information sought from the producer needs to be based on complex data collected under a wide range of field conditions. The objective of this work was to use tools such as geographic information systems and geostatistics to generate information that can be used to optimise physical and financial aspects of apricot production systems. Apricot fruits from geo-referenced groups of trees were analysed at harvest for soluble solids content (degrees Brix), firmness, dry matter and colour (a* value). From these data were elaborated quality maps for cultivars 'Beliana' and 'Lindo' of the studied apricot orchard. Fruits of 'Belianal were firmer and had lower degrees Brix, dry matter and a* values than 'Lindol. For 'Beliana', the degrees Brix was lower in the Eastern and Western orchard borders and for 'Lindo' in the North. Dry matter and firmness were lower in the central part and in the East, respectively, for 'Beliana'. For 'Lindo', dry matter was higher in the North-East, where the firmness was lower. Higher a* values appeared in two central orchard spots for 'Lindo' and in the inside part of the orchard for 'Beliana'. These maps can help the producer to make decisions about harvesting time or localised correction of production factors.
  • Effects of post-harvest treatment and storage time on the organic acid content in Assaria and Mollar pomegranate (Punica granatum L.) fruit
    Publication . Miguel, Maria Graça; Fontes, C.; Martins, D.; Neves, Alcinda; Antunes, Maria Dulce
    The effects of postharvest treatment and storage at 5 degrees C on changes in the organic acid content in the juice of 'Assaria' and 'Mollar' pomegranate were monitored. The fruit was chill stored after the following treatments: covering boxes with a 25-mu thick low-density polyethylene film and spraying with 1.5% CaCl2; untreated fruit was used as the control. The results showed that citric acid is the main organic acid in the 'Mollar' cultivar, followed by tartaric acid, whereas three organic acids were present at similar levels in 'Assaria' pomegranate: citric, oxalic and tartaric acids. Differences in the main organic acid contents were detected when fruit was submitted to different treatments prior to cold storage. The different pretreatments did not significantly interfere with the accumulation of organic acids in either cultivar. There were two exceptions. The ascorbic acid content was significantly higher in the 'Mollar' cultivar when the fruit was treated with calcium, while the pyruvic acid content was significantly higher in the 'Assaria' cultivar in the untreated fruit.
  • Taste panel quality evaluation of 'Hayward' kiwifruit of different origins
    Publication . Franco, J.; Melo, F.; Guilherme, R.; Neves, N.; Curado, F.; Antunes, Maria Dulce
    In Portugal, the regions of Entre-Douro e Minho and Beira Litoral have exceptional conditions for the production of good quality kiwifruit. However, demand exceeds local supply resulting in importation of kiwifruit from Italy, Chile and New Zealand. Taste panels were run in December, May and June to study the preferences of Portuguese consumers for 'Hayward' kiwifruit. In December, a comparison was made between kiwifruit from Portugal and Italy, in May between kiwifruit from Portugal and Chile and in June between kiwifruit from Portugal, Chile and New Zealand. Attributes assessed by panellists were: appearance, texture, flavour, sweetness and acidity. The same samples were analyzed for: weight, equatorial and longitudinal diameter, firmness, soluble solids (as measured by refractometer) and titratable acidity. In May, panellists preferred Portuguese kiwifruit, but in December and June the preference was not so clear. In December, Portuguese kiwifruit were not at the eating ripe stage and in June they were at the end of their storage life (bad appearance but better flavour, sweetness and texture).
  • Anthocyanin concentration of "Assaria" pomegranate fruits during different cold storage conditions
    Publication . Miguel, Maria Graça; Fontes, C.; Antunes, Maria Dulce; Neves, Alcinda; Martins, D.
    The concentration of anthocyanins in fruits of "Assaria" pomegranate, a sweet Portuguese cultivar typically grown in Algarve (south Portugal), was monitored during storage under different conditions. The fruits were exposed to cold storage (5 degrees C) after the following treatments: spraying with wax; spraying with 1.5% CaCl2; spraying with wax and 1.5% CaCl2; covering boxes with 25 mu c thickness low-density polyethylene film. Untreated fruits were used as a control. The anthocyanin levels were quantified by either comparison with an external standard of cyanidin 3-rutinoside (based on the peak area) or individual calculation from the peak areas based on standard curves of each anthocyanin type. The storage time as well as the fruit treatment prior to storage influenced total anthocyanin content. The highest levels were observed at the end of the first month of storage, except for the fruits treated with CaCl2, where the maximal values were achieved at the end of the second month. The anthocyanin quantification method influenced the final result. When total anthocyanin was calculated as a sum of individual pigments quantified based on standard curves of each anthocyanin type, lower values were obtained.
  • The effect of calcium applications on kiwifruit quality preservation during storage
    Publication . Antunes, Maria Dulce; Neves, N.; Curado, F.; Rodrigues, S.; Franco, J.; Panagopoulos, Thomas
    It is well known that calcium increases storage life of many fruits. This study investigated the effect of vine calcium application, as well as postharvest application on storage behaviour of 'Hayward' kiwifruit. Three applications of 0.03% CaCl2 or CaO were made in June, July and September. After harvest half of the fruit from sprayed vines were dipped in a solution of 2% CaCl2; the other fruit were untreated. All fruit were then stored at 0 degrees C and relative humidity of about 90-95%. Results for fruit of the size range 85-105 g are discussed. Kiwifruit dipped in 2% CaCl2 postharvest maintained higher firmness through storage than undipped fruit, but soluble solids content was only slightly lower after storage. This suggests that postharvest dipping of kiwifruit in 2% CaCl2 benefits storage life. The concentrations of 0.03% CaCl2 (Antistip) or 0.03% CaO (Chelal) used in vine applications seem to be too low and higher concentrations should be tried.
  • Preliminary Results on the Non-Destructive Determination of Pear (Pyrus communis L.) cv. Rocha Ripeness by Visible/Near Infrared Reflectance Spectroscopy
    Publication . Cavaco, A. M.; Antunes, Maria Dulce; da Silva, J. M.; Guerra, Rui Manuel Farinha das Neves
    Pear (Pyrus communis L.), cv. Rocha was rapidly adopted by consumers due to its inherent quality and currently has great acceptance in both national and international markets, being mainly produced in the west region of Portugal. We report here a first approach to the use of the non-intrusive method of Visible/Near Infrared Reflectance Spectroscopy (Vis/NIRS) to estimate the ripeness of pear cv. Rocha. Mature unripe pears obtained from Frutoeste (Mafra, Portugal) after a six-month cold-storage, were maintained in a dark room at circa 20 degrees C during three weeks. They were followed using the Vis/NIRS in the wavelength band between 400 and 950 nm with two different configurations for the spectra acquisition, namely the Integrating Sphere (IS) and the Partial Transmittance (PT). The diffuse reflectance spectra obtained by the two configurations were compared with the respective fruit ripening parameters (colour, firmness, soluble solids content and % dry matter), determined through the standard techniques. Concerning the rough estimation of ripening parameters, data suggested an increase in both the intensity in the green to red band and pulp %dry matter, but a decreasing firmness. All other parameters remained constant. Relatively to the optical results, we have observed that the PT spectra exhibited clearer features than the IS spectra, especially from 700 nm onwards. This is probably due to the fact that the PT configuration probes more deeply into the fruit pulp. Three peaks at 600 (circa 30%), 725 and 812 nm (both at circa 50%) and a minimum at 675 nm, were identified in both IS and PT spectra. The values of reflectance peaks were approximately constant during ripening, but they moved to slightly lower wavelengths in the second week. A significant increase (circa 3-fold) in the minimal diffuse reflectance was observed in the second week, most probably associated partially, to a decrease in the fruit peel chlorophyll content.