POMÁCEAS TECHNICAL BULLETIN CONTENIDOS SUPERFICIAL SCALD ON APPLES: NEW CHALLENGES EDITORIAL

Transcription

1 POMÁCEAS TECHNICAL BULLETIN Volume 12, Number 1 January 2012 ISSN SUPERFICIAL SCALD ON APPLES: NEW CHALLENGES (Carolina Torres, Omar Hernández & Mauricio Fuentes) Superficial scald is one of the most detrimental physiological disorders of long-term apple and pear storage. The most affected apple cultivars are Granny Smith, Fuji and Red Delicious and the pears Packham s Triumph, Anjou and Bartlett. Without doubt, Granny Smith is the most susceptible cultivar in Chile. At commercial level it shows the highest incidence. The oxidative damage is superficial, generally does not affect the flesh of the fruit and appears as brown stains on the skin (Photo 2 & 3). Symptoms develop after cold storage during the the shelf life period. EDITORIAL During 2012, a number of training seminars were held as part of Centro Pomaceas activities in the O Higgins and La Araucanía regions. On 13 January the O Higgins PDTE Project held a workshop Methodology, use and fertiliser rates based on fruitlet analysis: focusing on fruit quality at Rosario. This was followed up with a field-day at Chumaquito Farm - Requinoa (Photo 1). Continuing on 19 and 20 January with the workshop Job training and labour incentives: focusing on personnel training of harvest tasks by the middle management following up with a field-day Tambo Fruit Farms Ltd - Malloa. On 26 January a seminar with emphasises on planning strategies and personnel management was held at Angol as part of the Araucaría PDTE Project (Photo 1). Photo 2. Superficial scald of apples cv. Granny Smith (A and B) and Red Delicious (C). CONTENIDOS Superficial Scald of Apples: New Challanges Editorial Climatic Update Research Summary Miscellaneous Photo 1. Field-day at Chumaquito Farm - Requinoa (above); attendants at the harvest planning seminar at Angol. 1

2 The damage is caused by the oxidation of alphafarnesene, a volatile compound in apple waxes. During cold storage the compound accumulates, during the induction phase of the disorder, and then it oxidizes and forms conjugated trienes (CT), toxic substances responsible for superficial scald symptoms. In pears, there are two types of scald: superficial and senescent. Senescent scald symptoms are similar to superficial scald. However, it may affect the flesh, and appears after more than 6 month of cold storage. Contrary to apples, harvest time does not have an effect on superficial scald incidence. Other post-harvest techniques to reduce scald are: Controlled Atmosphere (CA) and ULO (Ultra Low Oxygen), Dynamic Controlled Atmosphere (DCA), application of 1-MCP (depending on certain maturity conditions), storage temperature control. All these control the disorder to a certain degree with, in some cases, at higher costs or undesired side effects. CA delays the appearance of scald symptoms, due to the high CO 2 and low O 2 levels that reduce the oxidation of alpha-farnesene. Consequently, the efficiency is only partial and, therefore, in addition, producers are forced to use antioxidants, such as DPA. Storing at very low O 2 concentrations, for instance DCA, provide higher efficiency, not only due to a decrease in alpha-farnesene oxidation, but also reduction of ethylene synthesis. The latter affects synthesis and accumulation of CT. It has to be mentioned that these techniques, due to the low O 2 levels, might lead to internal disorders of the fruit. Photo 3. Superficial scald of pears cv. P. Triumph (D and E). Control To date, control of superficial scald of both apples and pears, is based almost exclusively on the use of synthetic antioxidants such as, diphenylamine and ethoxiquin, which are very effective. Diphenylamine (DPA) is registered for use in the majority of the apples and pears producing countries. In the USA, it has been registered for the use in apples since On the other hand, pears, and depending on the market, are treated with either DPA or ethoxyquin (the latter being less phyto-toxic, and not registered in Chile). DPA inhibits oxidation of alpha-farnesene to CT preventing the damage to appear during and after storage. Various investigations have shown 1-MCP s efficiency to control superficial scald. This is due to the close correlation between ethylene and the synthesis/accumulation of alpha-farnesene. However, the efficiency to control scald can be affected by the physiological condition of the fruit at the time application. Many studies have tested the effect of various natural antioxidants, such as vitamins C and E. to reduce superficial scald expression. Though, effectiveness has been variable and less than needed to replace DPA commercially. Future of DPA use of in apples and pears World-wide, for some years now, there have been concerns regarding the use of DPA because of its synthetic nature and possible negative effects on human health. On 30 November 2009 the European Union (EU) eliminated DPA from the Annexe I of the Product Guide for Plant Protection (91/414/EEC). This, due to the presence of unidentified metabolites in 2

3 formulated DPA, and the formation of nitrosamines (chemical compound potentially carcinogenic) during its manufacture, which could afterwards be carried into the apples. Furthermore, no data are available for possible degradation products or the reaction of DPA residues in processed products. This led to the conclusion that no DPA could be used in the EU, and had to be withdrawn, at the latest by 30 May 2010 (Table 2). Officially, DPA cannot be used after May However, to continue applications European producers applied for emergency use. Thus, Spain, France, Italy, Ireland and the United Kingdom producers can use DPA formulations until 30 May Facing the concern of restriction of DPA use, a group of DPA formulations manufactureres (Pace International, Decco and Xeda) formed a Task- Force to provide the metabolic information required by the EU with the intention to have DPA readmitted on the authorized pesticides list for use on fruit. At the same time maintaining the existing maximum residue limit (MRL) (Table 1). A new complete metabolic report will be presented at the European Food Security Authority (EFSA) during January/February In the case that the permit is denied, no DPA treated fruit can be exported to the EU after December Table 1. DPA - Maximum Residue Limits (LMR, ppm) superficial for apples and pears in USA and EU. Manzanas Peras USA EU USA EU Actual Proposed Source: Data collected from various sources. Table 2. Dates and actions involved to add DPA to Annexe I. 20/06/07 Ireland presents information of effects of DPA on both human health, as well as, the environment to EFSA 30/09/08 EFSA warns the EU commission about the dangers of the active ingredient DPA. 26/02/09 The EU concludes not to add the active ingredient DPA in the Annexe I of the directive 91/414/EEC and determines that the phytosanitary product authorisation of products that contain DPA has to be withdrawn of the market not later than 30/05/10. EU member states authorize to 30/09/09 withdraw phytosanitary products containing DPA in Europe. 30/05/10 Through the Emergency Use finalize area the use of DPA by EU producers 30/05/11 Task-Force presents complete methabolic report to the EU. January/Febru ary Hand in final request for the use of DPA (European summer) July 2012 Source: Data collected from various sources. In order to face the DPA situation and to continue searching for DPA alternatives, the Centro de Pomáceas was recipient of a grant from the Fundación para la Innovación Agraria (FIA; Foundation for Agricultural Innovation), to fund the 36 months project called Development of new commercial products, based on oils and natural industrial residues, to control of superficial scald in apples and pears (PI: Carolina Torres). The project not only looks at chemical alternatives for DPA applied at harvest, but also at alternatives for pre-harvest applications intended to improve resistance to chilling injury. 3

4 Literature consulted - Achard, M Moderador en modulo Postcosecha del seminario de peras verde, rojas y asiáticas. Almacenamiento en atmosfera controlada en manzanas y peras. p Ben-Arie, R., Levin, A., Zutkhi, Y Elevated CO2 for control of superficial scald on CA-Stored apples. Washington State University Tree Fruit Postharvest Journal. Vol 4 (2): Calvo, G. Inta EEA Alto Valle, Junio Situación actual de antiescaldantes y alternativas de control de escaldadura superficial en manzanas y peras. 17 p. - Diario Oficial de la Unión Europea, Decisión de la comisión relativa a la no inclusión de la etoxiquina en el Anexo I, de la Directiva 91/414/EEC del consejo y por la que se modifica la decisión 2008/941/CE de la comisión. 2 p. - Diario Oficial de la Unión Europea, Decisión de la comisión relativa a la no inclusión de la difenilamina en el Anexo I, de la Directiva 91/414/EEC del consejo y a la retirada de las autorizaciones de los productos fitosanitarios que contengan dicha sustancia. 2 p. - Jung, S. Watkins, C Superficial Scald control after delayed treatment of apple fruit with diphenylamine (DPA) and 1-Methylcyclopropene (1- MCP). - Lurie, S. Watkins, C Superficial scald, its etiology and control. Postharvest Biology and Technology 65: Huelin, F.E., Coggiola, I.M., Superficial scald a functional disorder of stored apples. IV. Effect of variety, maturity, oiled wraps and diphenylamine on the concentration of alfa-farnesene in fruit. Journal Science Food Agricultural. 19, Manseka, V.S., Vasilakakis, M Effect of stage of maturity, postharvest treatments and storage conditions on superficial scald and quality of apples. Acta Horticulturae. 326: Moggia, C Escaldado en Manzanas. Boletín Técnico. 2: Sistema de calidad SmartFresh, Recomendaciones para uso en manzanas en Chile. - Soria, Y. Tesis Doctoral El escaldado superficial en manzana Granny Smith. Fisiología de la alteración y estudio de métodos de control alternativos a la difenilamina. 114 p. - Tecnopera Congreso nacional de la pera. Previsiones de cosecha y control de escaldado. Asociación empresarial de la fruta de Cataluña. (Disponible en 17-tecnopera-2011-previsiones-de-cosecha-y-controldel-escaldado.html) - Watkins, C.B., Bramlage, W.J., Cregoe, B.A., Superficial scald of Granny Smith apples is expressed as a typical chilling injury. Jorunal American Society Horticultural Science. 120: Whitaker, B.D., Solomos, T., Harrison, D.J., Quantification of farnesene and its conjugated trienol oxidation products from apple peel by C-18-HPLC with UV detection. Journal Agricultural Food Chemistry. 45, Whitaker, B.D., Nock, J.F., Watkins, C.B., Peel tissue farnesene and conjugated trienol concentrations during storage of White Angel x Rome Beauty hybrid apple selections susceptible and resistant to superficial scald. Postharvest Biology and Technology. 20,

5 CLIMATIC UPDATE During the first stage (cell division), fruit growth rate depends heavily on ambient temperature (T ). Later on the increase in size is due to cell elongation. The cell division stage is completed when the fruit passes T-stage, between 30 and 50 days after full bloom (DAFB). High T during this period favour potential size at harvest, but may advance fruit maturity and consequently change storage life. During the present season. Average T during the cell division period (1 October - 15 November) was slightly higher or similar to the previous season. (Table 3). Temperature accumulation is higher than last season. With an early blossom of Gala types one may expect a very advanced harvest date compared to the previous season. During the summer not only will fruit growth be limited by water and nutrient supply, high T during this period can cause negative effects on both fruit (physiological disorders, lack of colour, etc.) and tree. Table 3. Average temperatures ( C) from 1 October to 15 November. Accumulation base 10 and GDH between 1 October and 15 January. Incidents conducive to sunburn (number of days with more than 5 days with T above 27 and 29 C). Stress units between 1 October and 15 January. Location Average T 1 Oct-15 Nov GD 1 Oct-15 Jan GDH 1 Oct-15 Jan Days 5 hr. T >27 C 1 Oct-15 Jan Days 5 hr. T >29 C 1 Oct-15 Jan Stress (thousands) 1 Oct-15 Jan 10/11 11/12 10/11 11/12 10/11 11/12 10/11 11/12 10/11 11/12 10/11 11/12 Graneros ,873 30, Morza ,763 27, Río Claro ,045 26, San Clemente ,954 30, El Colorado ,057 27, Colbún ,312 28, Angol ,904 29, Freire ,950 23, The effect of high summer temperatures (with low relative humidity) in pome fruit, are: Stomata close and lower assimilate production. Increased sunburn. More physiological disorders related to Cadeficiency. Reduced fruit size. Less colour. Harvest date advanced. A 1 increase in the average T during summer is estimated to advance harvest by 3.5 days. Organoleptic quality in relation to physiological maturity delayed. Post-harvest life reduced. Softer fruit. Increased susceptibility to water core. Accumulation of tree reserves reduced. SUNBURN Days with 5 continuous hours with T above 29 C serve as an indicator for sunburn. As the fruit develops T criteria drops to 27 C. Table 1 shows a comparison between the last two seasons. Although, during 2011/12 more incidences conducive to sunburn than before have been registered, the majority of these occurred in December when the fruit was small and without high exposure. The number of incidents occurred specifically in high, cold areas (South and foothills). At 15 January the season was hotter than before. No delay in harvest is expected, however, neither a high sunburn incidence. 5

6 . RESEARCH SUMMARY CHARACTERISTICS OF STAIN AND INTERNAL BROWNING ON APPLES CV. FUJI. (ACOSTA, J BACHELOR OF AGRICULTURAL THESIS. U. DE TALCA, 33 PAGES. GUIDING PROF.: C. TORRES). During 2009/2010 season a study was carried out to understand stain and internal browning development on Fuji apples, as well as to test different treatments to prevent their appearance postharvest. To characterize fruit staining, fruit with different sunburn levels (mild, moderate, and severe) were harvested and stored in low temperature storage for 150 days. Internal browning was induced storing the fruit in in controlled atmosphere (3 % CO % O 2 ). fluorescence was evaluated on the same fruit. The following chemical treatments were assessed: T1: DPA, T2: ascorbic acid (Vit. C, 2 %) + delayed cooling, T3: DPA + Vit. C (2 %), T5: Control. None of the treatments tested decreased staining incidence on the fruit. However, sunburn levels and storage period showed to be highly correlated with stain appearance. In the case of internal browning, Vit. C application resulted in a significant reduction of the disorder appereance. Quality variables, such as fruit firmness, soluble solids, ethylene, as well as disorder s incidences were evaluated monthly. Furthermore, chlorophyll MISCELLANEOUS Mr. Luis Chadwick, President of Agrícola San Clemente Ltda. visited the Centro de Pomáceas, 29 December (Photo 4) to accede a pre- and postharvest management project on Pink Lady apples. Prior to that (14 December) as part of the Fondef Project Juice production from fresh apples a workshop took place with Mr. Andrés Pérez de Arce, manager of Nabios Company (Photo 4). Led by Aldo Segatori a group of INTA Alto Valle - Argentina extension officers visited us on 13 December (Photo 5). Followed by a Korean delegation headed Dr. Tae Kyu Ahn who expounded on fluorescence in vegetation (Photo 5). Photo 5. INTA Alto Valle delegation (left); Korean researchers (right). Photo 4. Luis Chadwick (left), Andrés Pérez de Arce (right). Programmer Technical Meetings 2012 Tuesday 27 March Tuesday 29 May Tuesday 31 July Tuesday 25 September Tuesday 27 November POMÁCEAS, Technical Bulletin published by the Centro de Pomáceas at the University of Talca. Periodical and free distribution. Legal Representative: Dr. Álvaro Rojas Marín, Rector Director: Dr. José Antonio Yuri, Director of Centro de Pomáceas Editors: José Antonio Yuri & Valeria Lepe Avenida Lircay s/n Talca Tel Fax [email protected] Web site: utalca.cl 6