1、INTERNATIONAL STANDARD ISO 1134 Second edition 1993-1 O-I 5 Pears - Cold storage Poires - En treposage r6frigM Reference number ISO 1134:1993(E) ISO 1134:1993(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national Standards bodies (ISO member bodie
2、s). The work of preparing International Standards is normally carried out through ISO technical committees. Esch member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations? governmental and n
3、on-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodie
4、s for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO 1134 was prepared by Technical Committee lSO/TC 34, AgriculturaI food products, Sub-Committee SC 14, Fresh fruits and vegetables. This second edit
5、ion cancels and replaces the first edition (ISO 1134:1980), which has been technically revised. Annexes A and B of this International Standard are for information only. 0 ISO 1993 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronie o
6、r mechanical, including photocopying and microfilm, without per- mission in writing from the publisher. International Organization for Standardization Case Postale 56 l CH-l Zl 1 Geneve 20 l Switzerland Printed in Switzerland ii ISO 1134:1993(E) Introduction This International Standard provides guid
7、ance of a very general nature only. Because of the variability of the fruit according to the time and place of cultivation, local circumstances may make it necessary to specify other conditions of harvesting or other physical conditions in the store. This International Standard does not apply unrese
8、rvedly, therefore, to all varieties in all climates, and each specialist will decide on any modifi- cations to be made. Moreover, it does not take into account the role played by horticultural factors, and wastage during storage is not dealt with. The importante of these two subjects has not been fo
9、rgotten, but the influential factors (i.e. ecological or agrotechnical factors) are not very well known; moreover, the origin of many of the most frequent physiological disorders of pears is still uncertain, as are often the appropriate means of combating them. lt was therefore considered difficult
10、to prepare recommendations on these two Points. Nevertheless, it was considered useful to give, in annex B, a few rec- ommendations which appear sufficiently well founded in the present state of knowledge. Subject to all possible restrictions arising from the fact that fruits are living material and
11、 may vary considerably, the application of the guidance con- tained in this International Standard should enable much wastage in cold storage to be avoided and long-term storage to be achieved in most cases. . . . Ill This page intentionally left blank INTERNATIONAL STANDARD ISO 1134:1993(E) Pears -
12、 Cold storage 1 Scope This International Standard gives guidance on con- ditions for the successful cold storage of varieties of pears (Pyrus communis Linnaeus) up to their use in the fresh state. 2 Normative references The following Standards contain provisions which, through reference in this text
13、, constitute provisions of this International Standard. At the time of publi- cation, the editions indicated were valid. All Standards are subject to revision, and Parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most re- cent e
14、ditions of the Standards indicated below. Members of IEC and ISO maintain registers of cur- rently valid International Standards. ISO 2169:1981, Fruits and vegetables - Physical conditions in cold stores - Definitions and measure- ment. AGRI/WP.l/EUR.STAN.l, Apples and pears? 3 Conditions for harves
15、ting and storage 3.1 Harvesting The practical criteria of ripeness most frequently used for defining the best time for harvesting2) are the fol- lowing. a) Basic colour of the outer skin:3) judged with the aid of a Standard table. b) Firmness of the flesh: estimated by means of a spring penetrometer
16、. c) The total soluble solids content of the fruit, which should be at least 10 % at harvest: determined by a refractometer. d) Ease of Separation. e) Presence of starch in the flesh of the fruits: checked by treating a Cross-section of the fruit with an iodine/potassium iodide Solution. The values
17、obtained from these criteria are not uni- versally valid; for a given variety they vary from one region to another and it is for the grower to decide on his own criteria for picking, on the basis of experi- ence. Determination of the Optimum harvest time is more important for early varieties (for ex
18、ample, Coscia) than for late varieties. The fixing of the time of harvesting has greater im- portance for controlled-atmosphere storage than for storage in air. 3.2 Characteristics for storage Fruit put into store should be of quality “extra” and II II I , the characteristics of which are defined in
19、 AGRI/WP.l/EUR.STAN.l. Fruit put into cold store should be Sound, free from bruises or physiological disorders, and free from any visible sign of fungal or bacterial attack. lt should be clean and free from any trace of water in the liquid state. 1) Revised European Standard, recommended by the Work
20、ing Party on Standardization of Perishable Produce and Quality Development of the Economic Commission for Europe. 2) The number of days after flowering is also used sometimes as a criterion for harvesting. 3) The basic colour should be distinguished from the red anthocyanin Pigmentation, the intensi
21、ty and extent of which vary according to the variety and, to some extent, with exposure to sunlight. ISO 1134:1993(E) 3.3 Putting into store The fruit should be put into the cold store as soon as possible after harvesting, the temperature being low- ered to a value suitable for the variety. Rapid re
22、moval of field heat and precooling of har- vested pears are essential for long storage. 3.4 Method of storage The fruit should be handled with care. The packages should allow free circulation of air. Storage densities of about 250 kg per cubic metre of usable space are recommended for a Stack of pal
23、lets. The use of box pallets provides an increase of 10 % to 20 % in storage density. 4 Optimum storage conditions 4.1 Temperature The pears should be kept at as low a temperature as possible, subject only to avoiding the risk of freezing. In general, the best results are obtained at - 1 “C to + 0,5
24、 “C. A differente of 1 “C in storage temperature has a profound effect on the time for which the pears tan be kept. lt has been shown that, during cold storage, the freezing-Point of the fruit falls slightly; it is on this account that, for Williams Bon Chretien pears, it has been possible to recomm
25、end a method of storage based on progressive lowering of the temperature (0 “C; - 0,3 “C; - 0,8 “C; - 1,5 “C). This procedure has enabled the storage life to be appreciably prolonged, but it is difficult to carry out since it is not possible to maintain a large bulk of fruit at a sufficiently unifor
26、m temperature in a cold store. The course of development of the fruit during storage depends on the choice of storage temperature. When the temperature of the cold store is low (0 “C to - 1 “C) the Change in ripening characteristics of the pears is very slow during cold storage and it is necessary t
27、o submit them to a complementary ripening process at a higher temperature when they are removed from the cold store. On the other hand, from a certain temperature (+3 “C for Doyenne du Comice pears, +4 “C for Passe Crassane), ripening is slow but tan be completed in storage. Some varieties ripen com
28、pletely at higher tempera- tures only if the storage period at low temperature has not been too long (for example, Comtesse de Paris, Doyenne du Comice, Kaiser, Abbe Fetel, Louise Bonne dAvranches and Williams Bon Chretien). An accidental rise in storage temperature tan initiate ripening, which cont
29、inues when the fruit is again ex- posed to the cold. Table 1 gives the storage temperature and duration recommended for a number of varieties. 4.2 Relative humidity Pears may generally be stored at a relative humidity of between 90 % and 95 %. 4.3 Air circulation An air circulation ratio of 20 to 30
30、 (see ISO 2169) or Ventilation of 80 m3/h to 100 m3/h per tonne of fruit is recommended. 4.4 Storage life Table 1 gives the expected storage life under the conditions mentioned above, for a number of var- ieties. Storage should not be prolonged beyond limits compatible with the maintenance of good q
31、uality. Samples of fruit should be taken in such a way as to detect the appearance of any wastage. 4.5 Operations at the end of storage The recommended ripening temperature for pears af- ter storage is 15 “C to 18 “C. The ripening may be accelerated by ethylene treat- ment. The gas is generally used
32、 at concentrations of 1 % to 2 %, the treatment being carried out at a temperature of + 18 “C and at approximately 90 % relative humidity. Table 1 gives the varieties which should undergo a complementary ripening after cold storage. 5 Adjuncts and other keeping processes 5.1 Controlled-atmosphere st
33、orage The following ommended: gas mixtures are most frequently rec- carbon dioxide l,o % to 3,0 % Oxygen 2,0 % to 5,0 % These compositions are given only as a guide, and it is for the experts in each country to give any necess- ary advice on other kinds of compositions according to the particular re
34、quirements of each variety, as re- gards the content of carbon dioxide or of Oxygen in the atmosphere or on account of particular local con- ditions. Annex A gives an example of this. ISO 1134:1993(E) It should be noted that the storage disorders called “brown heart” and “hard heart” result from the
35、 presence of an excess of carbon dioxide (above 5 %) in the atmosphere. lt is necessary to avoid the use of mixtures with a high carbon dioxide content for storing varieties known to be susceptible to these disorders (for example, Doyenne du Comice, Beurre Bosc, Williams Bon Chretien). 5.2 Storage i
36、n plastic packages The use of certain types of plastic film which are known to be suitable for contact with food products permits losses in mass during storage to be reduced considerably and, in certain cases, the storage life in the cold is prolonged. Plastic films should be perfor- ated with small
37、 holes to prevent a build-up of CO,. Table 2 summarizes, for certain varieties, the gas The level of CO, should not be above 3 % within the mixtures which have given the best results, and also liners, or core and flesh browning may develop. Film the recommended temperature and the expected liners wi
38、ll extend the storage life of several cultivars storage life. of pears by 4 to 8 weeks. ISO 1134:1993(E) Variety Docteur Guyot Williams Bon Chretien Beurre Bosc Beurre Clairgeau Table 1 - Storage in air Recommended temperature Expected storage life General remarks “C (weeks) Oto+l 3 to 4 Complementa
39、ry ripening necessary Complementary ripening necessary -ltoO 9 to 11 Susceptible to scald Ripens between + IO “C and + 24 “C only -1 14 to 28 Susceptible to brown heart Complementary ripening necessary - 1 to - 0,5 18 to 20 Susceptible to scald Susceptible to brown heart Beurre Diel Cure Louise Bonn
40、e dAvranches Doyenne du Comice Oto+1 8to 12 Oto+l 16 to 20 Oto+l 6 -1 too Oto 12 -ltoO 8to 12 5 months maximum Tendency to shrivelling Complementary ripening necessary Does not ripen further after 2 1/2 months at + 1 “C In certain areas, does not ripen normally af- ter 2 to 3 months at 0 “C ipine du
41、 Mas Beurre Hardy Passe Crassane Comtesse de Paris + 2 to + 3 6 Oto+l 12 to 16 0 12 to 20 0 20 to 22 -4 about 17 0 20 to 22 Ripens at this temperature Susceptible to scald Complementary ripening necessary Does not ripen normally in some areas un- less previously stored in cold conditions (1 1 weeks
42、at 0 “C) Does not ripen normally after too prolonged storage in the cold Packharn Conference Comtesse de Charnoux Abbe Fete1 + 2 to + 3 -lt00 Oto+l - 0,5 0 8 18 to 20 24 to 28 8 to 20 10 to 12 Susceptible to warming Susceptible to warming Complementary ripening necessary Does not ripen normally afte
43、r 3 months of storage Ankara 0 20 Complementary ripening necessary Bitterness occurs after too prolonged stor- age in the cold Rocha - 0,5 to 0 28 to 32 ISO 1134:1993(E) Table 2 - Controlled-atmosphere storage Recommended mixtures Variety Temperature Expected Carbon Oxygen Reference storage life dio
44、xide “C OO / OO / weeks 0 4 2 France 24 -lt00 4,5 3 Italy, Germany Villiams Bon Chretienl) -1 2 to 3 2 to 3 Australia 16 to 20 - 0,6 to 1 - 0,8 to 1,O 2,5 to 3,0 USA 0 2 2 Switzerland 2 to 3 2 to 3 Australia leurre Bosc -1 0,6 to 1,O 2,5 to 3,0 USA 22 lackharn 0 5 16 Australia Iocha*) Portugal 5 3 I
45、taly 0 2 2 Switzerland )oyenne du Comice - 0,6 to - 1 1 2 USA Not very satis- factory - 0,6 to 0 2 16 Netherlands 0 5 2 to 3 United Kingdom 5 5 5 France asse Crassane 28 to 32 0 5 3 Italy IOTE - Data taken from Ryall L.A. and Pentzer W.T. Handling, Transportation and Storage of Fruits and Vegetables
46、. Vol. 2, Fruits and Tree Juts. Westport, Connecticut: AVI Co., 2nd edn., 1982. 1) The controlled-atmosphere storage of Williams pears is delicately balanced, as it entails the need to harvest fruit in- ended for this kind of cold storage at exactly the right time. n some countries, such as the Unit
47、ed Kingdom, controlled-atmosphere storage is no longer recommended for this variety. ?) Transportation is not in a controlled atmosphere. 5 ISO 1134:1993(E) Annex A (informative) Example of storage conditions for varieties of pears See table A. 1. Cultivar Table A.1 - Storage conditions in a control
48、led atmosphere Temperature Relative humidity Mixture “C % (32 02 % % Storage life months Abbe Fete1 Asian pear Anjou Conference (yeIlow)l) Conference (green) Doyenne du Comice Doyenne dhiver General Leclerc Hardy Kaiser or Bosc Louise Bonne dAvranches Max Red Bartlett Packharn Triumph Passe Crassane
49、 (green) Passe Crassane (yellow) Pierre Corneille Spodona William or Bartlett 1) Remove ethylene. -ltoO 90 7 to 8 0 to 1 4 to 5 -1toO 90 1 to 4 3 to 5 3 to 4 - 0,5 to 0 92 1 to 2 0,5 to 2 6 to 7 - 1 to - 0,5 95 6 to 7 1 to 1,5 6 to 7 - 1,5 to - 0,5 95 2 to 3 1 to 1,5 7 to 8 - 1 to - 0,5 95 3 to 4 3 to 4 4 to 6 - 1 to - 0,5 90 3 3 to 4 6 to 7 - 0,5 to 0 92 2 to 3 2 to 3 4 to 5 - 1 to 0 95 3 to 4 3 to 5 3 to 5 - 1 to - 0,5 95 4 to 5 1 to 1,5 5 to 6 - 0,5 to 0 90 2 to 3 2 to 3 4 to 5 - 1 to - 0,5 90 2 to 3 3 to 4 3 to 4 - 1 to 0 90 2 to 3 3 to
