proceedings of the workshop on chemical aspects of rice grain quality

PROCEEDINGS OF THE WORKSHOP ON CHEMICAL ASPECTS OF RICE GRAIN QUALITY 1979 INTERNATIONAL RICE RESEARCH INSTITUTE LOS BAÑOS, LAGUNA, PHILIPPINES P.O BOX 933, MANILA, PHILIPPINES Correct citation: International Rice Research Institute 1979 Proceedings of the Workshop on Chemical Aspects of Rice Grain Quality Los Baños, Laguna, Philippines The International Rice Research Institute receives support from a number of donors including the Ford Foundation, the Rockefeller Foundation, the European Economic Community, the United Nations Development Programme, the United Nations Environment Programme, the Asian Development Bank, the International Development Research Centre, the World Bank, and the international aid agencies of the following governments: United States, Canada, Japan, United Kingdom, Netherlands, Australia, Federal Republic of Germany, Iran, Saudi Arabia, New Zealand, Belgium, Denmark, and Sweden The responsibility for all aspects of this publication rests with the International Rice Research Institute FOREWORD The characteristics of the rice plant covered by the term grain quality to a large extent determine market price and acceptance by consumers Next to yield, grain quality is the most important factor considered by plant breeders If consumers not care for the taste, texture, aroma, or appearance of a newly developed rice variety, any other outstanding characteristic may be worthless And grain quality takes on even greater importance as developing nations become more prosperous and as producing countries achieve self-sufficiency in rice, for both of these conditions produce discriminating consumers All of this notwithstanding, the subject of grain quality has not been discussed in detail at any of the annual International Rice Research Conferences and symposia held at IRRI since 1960 Reviews of current knowledge and methodology on rice grain quality are published in various periodicals in different countries The Workshop on the Chemical Aspects of Rice Grain Quality was convened at IRRI (October 23-25, 1978) (a) to critically review the present state of knowledge on the subject, (b) to review the status of rice quality evaluation in breeding programs in selected countries, (c) to examine existing methodology for estimating quality, (d) to recommend priorities for research in grain quality, and (e) to organize cooperative studies The 3-day workshop was attended by 28 breeders and chemists from 11 countries and IRRI The proceedings of this Workshop give evidence that the Workshop accomplished its objectives It is likely to be the basic reference on the subject of the grain quality of rice for years to come Cooperative studies of tests for grain quality are already being scheduled by the workshop participants We wish to express our thanks to the workshop committee, which consisted of W R Coffman, G S Khush, B O Juliano (chairman), J S Nanda, and M D Pathak N.C BRADY Director General February 1979 Contents Foreword v Opening remarks RICE GRAIN RESEARCH The Genetic Evaluation and Utilization program of the International Rice Research Institute M D PATHAK Rice grain quality evaluation and improvement at IRRI 21 IRRI’s efforts to improve the protein content of rice 33 Genetic studies on the grain quality of rice 49 Effect of environment on protein and amylose content of rice 59 The chemical basis of rice grain Quality 69 The nutritional value of rice in comparison with other cereals 91 G S KHUSH, C M PAULE, and N M DE LA CRUZ J S NANDA and W R COFFMAN T T CHANG and B SOMRITH K A GOMEZ B O JULIANO B O EGGUM COUNTRY REPORTS Rice grain quality evaluation in Australia 115 Studies on quality of rice in Bangladesh 123 Rice breeding for grain quality in France 129 Status of rice breeding for grain quality in India 135 Rice grain quality evaluation in Japan 149 Rice grain quality evaluation in the Philippines 161 Rice grain quality evaluation in Spain 167 Rice grain evaluation in Sri Lanka 175 Physicochemical properties of Thai rice varieties and methodology used in quality improvement 183 Components of rice quality: their identification, methodology, and stage of application in United States breeding programs 191 A B BLAKENEY N H CHOUDHURY P FEILLET and R MARIE K R BHATTACHARYA H.SUZUKI, H IKEHASHI, and K KUSHlBUCHl F E MERCA, T M MASAJO, and A, D BUSTRILLOS S BARBER and E TORTOSA C BRECKENRIDGE N KONGSEREE B D WEBB, C N BOLLICH, T H JOHNSTON, and W O MCILRATH REVIEW OF METHODOLOGY Outlook for rice milling quality evaluation systems 209 Methodology of assessing appearance of the rice grain, including chalkiness and whiteness 223 Gelatinization temperature of rice starch and its determination 231 Amylose analysis in rice – a review 251 Amylography and alkali viscography of rice 261 Assessing parboil-canning stability of rice in varietal improvement programs 283 Gel consistency and viscosity of rice 293 Quality tests for waxy (glutinous) rice 303 Sensory assessment of cooked milled rice 313 Use of the Texturometer for measuring the texture of cooked rice 321 Instron measurement of cooked-rice texture 343 Use of the Viscoelastograph for measuring the texture of cooked rice 355 Tests for parboiled rice 363 S BARBER and C BENEDITO DE BARBER H IKEHASHI and G S KHUSH K R BHATTACHARYA B O JULIANO H SUZUKI B D WEBB C M PEREZ N KONGSEREE A M DEL MUNDO H SUZUKI A B BLAKENEY B LAIGNELET and P FEILLET K R BHATTACHARYA WORKSHOP REPORTS Priority research problem areas for assessment of grain quality in rice-breeding programs – workshop committee report 377 Collaborative testing – report of the workshop chairmen 381 Appendix A – Participants and authors Appendix B – Abbreviations 385 B D WEBB and A B BLAKENEY 390 OPENING REMARKS N C BRADY It gives me great pleasure to welcome participants in this Workshop on Chemical Aspects of Grain Quality to the International Rice Research Institute I am pleased to see the interdisciplinary focus on rice grain quality which this Workshop will foster In 1960, when IRRI was first established, primary attention was given to increasing rice yields The productive potential of tropical rices had not yet been determined, and many feared that the tropics were permanently saddled with lower yields than could be achieved in the temperate zones Consequently, increasing yields was the primary focus, not only of IRRI scientists, but of those in national programs as well Even as late as the 1970s, when widespread drought and floods drastically reduced food grain levels, the world's primary emphasis was on the quantity of food produced and not on its quality Once again the worry was how the food could be produced and not so much its acceptability as a food product In spite of this continued emphasis on yields, those who best understand food consumption patterns have encouraged attention to grain quality As soon as IR8, the first of the modem varieties released by IRRI, became widely grown, its grain weaknesses were as conspicuous as its high yield capabilities The "white belly", chalky appearance, short grain and hardness after cooking were negative quality characteristics that prevented IR8 from being a choice quality rice A counterpart release of the University of the Philippines College of Agriculture, C4 (C4-63G), while it lacked IR8's yield vigor, was much more acceptable to Filipino consumers because of its "quality" characteristics At IRRI banquets and luncheons we sometimes serve C4 rather than our own varieties Plant breeders have an acute awareness of consumer quality preferences A survey of the genetic traits sought by breeders in India in their new rice varieties showed grain quality to be exceeded only by yield potential as a desired characteristic of N C Brady, director general, International Rice Research Institute Los Baños, Laguna, Philippines Chemical aspects of rice grain quality the new rices they develop The generally accepted practice by breeders of crossing the high-yielding modern lines and varieties with lower yielding local varieties having known desirable quality characteristics is added evidence of the significance given to grain quality in modern rice-improvement programs But grain quality is not always easy to describe and identify And research on grain quality is no simple activity In the first place, it is not always easy to identify and quantify the characteristics or combinations of characteristics that are responsible for human preferences which are popularly equated with grain quality Second, there is uncertainty about the relationship between nutritional quality and human preferences A food is not nutritionally superior just because people prefer it At the same time, the nutritional quality of a food that humans not accept may not be too important Thus human preferences and nutritional value must both be considered The third complicating factor influencing grain quality research is the lack of tools or methods for measuring grain quality It is especially difficult to reduce to quantitative chemical and physical terms the parameters that characterize good grain quality, whether it be in terms of human preference or nutritional value Even the taste panel approach to obtain an integrated estimate of consumer preference has some weaknesses In spite of these difficulties, it would be incorrect to leave the impression that no progress has been made in combining in modern rice varieties good grain quality and high yield potential Scientists in national research programs and at IRRI have been successful in producing high-yielding rices with good grain quality, high consumer acceptability, and resistance to six or more major insect pests and diseases Furthermore, chemical and physical methods for quantifying at least some elements of grain quality have been developed Several such methods are now routinely used here at IRRI, permitting us to evaluate thousands of experimental lines annually And research is underway to develop practical techniques for evaluating the protein level and quantity of new rices as well as the ability of humans to fully utilize the nutritional potential of the These research efforts are supplemented more protein-rich rices with biochemical studies which are adding to our knowledge about how grain constituents, such as starch and protein, are interrelated in the rice grain Studies of rice grain quality continue to point toward the need for interdisciplinary inputs for effectively improving and evaluating this grain quality The chemist, biochemist, nutritionist, and food scientist must work together to better identify those characteristics which make for good grain quality Opening remarks They can then turn to the plant breeder with clear specifications for what characteristics must be bred into modern rices The plant breeder, in turn, must couple his activities with those of the agronomist, the entomologist, the plant pathologist, and the engineer, each of whom is concerned with cultural and/or pest management activities that may have a bearing on grain food quality Workshops such as the one you are attending permit an effective interchange among scientists from different disciplines Research accomplishments on the chemical aspects of grain quality will be exchanged at this workshop We hope there will also be time to give some attention to the future We at IRRI are especially seeking your advice about research priorities in relation to not only our own activities but to the collaborative research we should with you or with scientists elsewhere in the world Our manpower and financial resources are limited, but the nature and scope of the research to be accomplished may make it possible for us to attract the interest of others, thereby multiplying the work that can be done We thank you sincerely for taking time to participate in this workshop and wish you success in your presentations and discussions IN PRIORITY RESEARCH PROBLEM AREAS FOR ASSESSMENT OF GRAIN QUALITY RICE-BREEDING PROGRAMS – WORKSHOP COMMITTEE The report was prepared by a committeea the participants REPORT and was approved by The quality of rice can be defined as the composite of those characteristics that differentiate individual lots and have significance in determining the degree of consumer acceptability of each one The overall quality of rice to be evaluated must be analyzed for its component attributes and each measured independently Since consumer preference for rice varies widely and rice is used for diverse purposes, its quality attributes vary in number and significance and must be identified and evaluated in each particular case Only then can a "complete quality evaluation system" satisfying all concerned breeders, producers, processors, dealers, and consumers be established The participants to the Workshop recognized that, although much knowledge of the rice grain has been accumulated in the last 20 years, the "component quality attributes" of rice are not sufficiently known In summary, in the opinion of the Committee, the research priorities can be defined as follows: AREA CHARACTERS OF COOKED RICE In considering need for further research, it was recognized that the characteristics of raw rice are much better known than those of the cooked rice grain and that more emphasis should be put on the latter to identify and evaluate its essential component quality attributes Assessment of grain quality in rice-breeding programs could thus be based on additional tools supplying direct information on the product as it must be consumed Identify, define, and evaluate: 1.1 sensory characters, that is the attributes that are perceived by the human senses when a cooked sample of rice is consumed The sensory characteristics that consumers the world over use in evaluating a Composed of S Barber (chairman), K R Bhattacharya, P Feillet, H Ikehashi, A M del Mundo, V V S Murty, and V Sivasubramanian 378 Chemical aspects of rice grain quality rice should be tested, and a tentative scoring of those more significant to local preferences prepared 1.2 Physical characteristics, particularly the component attributes of appearance (color is considered of secondary importance) and texture Determine correlations between individual sensory and physical characters (1.1 and 1.2) and between procedures within each Obtain more information on the physical and chemical basis of cooked rice characteristics: 2.1 physical structure; 2.2 chemical components Remarks The Committee emphasized the need for standardizing the degree of milling and the procedure for cooking the milled sample to evaluate the above-mentioned parameters, since the degree of milling has a great influence on the measured or perceived characteristics of cooked rice AREA INHERITANCE STUDIES INFLUENCING GRAIN ON CHARACTERISTICS QUALITY The importance of identifying and evaluating the grain quality attributes that are primarily genetically controlled, in contrast with those that are primarily affected by environment, was recognized, and research urgently recommended Identify those physical and chemical characters of the rice grain that are related to grain quality and are genetically controlled Undertake studies on the inheritance of amylose content, since amylose has a profound influence on cooked rice characteristics Pay attention to other grain characteristics (such as gelatinization temperature) which are genetically controlled and have an influence on the quality of cooked rice Study the inheritance of hull percentage in rough rice, since this greatly influences rough-rice utilization and exhibits a wide variation among varieties Many other subjects were discussed Of these, two relevant examples are the need for further research on 1) processing quality of rough rice for parboiled rice and other processed rice products, and 2) mechanism(s) of aging or storage changes in rice, as these are very important areas The Priority research problem areas 379 nutritional value of rice was recognized as important Some participants considered that breeding for raw rice quality will already take care of breeding for parboiled rice quality There was a felt need to gather and disseminate information on traditional processed rice products other than parboiled rice to include details of the processes and specific indigenous varieties suitable for these products Often, the new varieties are less suited for these products than the traditional varieties they replace It was suggested as a Master's thesis for a food science student in each country Methodology for the study of aging is not sensitive enough to show changes in the properties of starch granules and protein bodies The workshop recognized the important role of rice as the major source of dietary protein in tropical Asia Breeding programs should ensure that the new varieties have at least the same protein content as the varieties they replace The workshop also recognized the significance of losses of vitamins and minerals during processing Another problem discussed was the bran in the grooves of brown rice, which is not readily removed on ordinary milling and requires overmilling for its complete removal Information about varietal variation in the depth of the grooves and its relation to genetic factors is needed However, the need for concentration of research efforts into selected areas to ensure more rapid progress, rather than spread them over a wide area, dictated that these subjects not be included among the first-priority problem areas The subject of rice byproducts was not considered, as it was extensively covered in 1974 in an international conference in Valencia, Spain, and its proceedings have been circulated However, the importance of varieties with high-oil-content bran and low hull proportion was recognized COLLABORATIVE TESTING – REPORT OF THE WORKSHOP CHAIRMEN B D WEBB AND A B BLAKENEY It was agreed that international collaborative tesing would be carried out on the following methods for assessing grain quality in rice: Degree of milling Collaborators: S K A P B N C B Barber, Organizer R Bhattacharya B Blakeney Feillet O Juliano Kongseree Paule D Webb Alkali test Collaborators: B O Juliano, Organizer K R Bhattacharya A B Blakeney Insone Butta c/o N Kongseree N Kongseree V V S Murty C Paule B D Webb T Iwasaki Amylose content Collaborators: B K A P N V C B O Juliano, Organizer R Bhattacharya B Blakeney Feillet Kongseree V S Murty Daule D Webb 382 Chemical aspects of rice grain quality Gel consistency Collaborators : B A P N C B O Juliano, Organizer B Blakeney Feillet Kongseree Paule D Webb Instrument methods for texture of cooked rice Collaborators : B O Juliano , Organizer S Barber K R Bhattacharya A B Blakeney 5-6 P Feillet (and B Launay) 7-8 B D Webb (and K K Keneaster) H Suzuki 10 T Iwasaki METHODOLOGY Degree of milling Two methods are to be used 1) May-Grunwald staining test for measuring percentage of the kernel surface still covered by bran 2) Alkali pigment test for measuring the percentage of alkali-extractable pigment remaining on milled rice It was further agreed that data on the percentage of weight lost from milling and the reduction in 1000-grain weight be included Four rice varieties are to be tested initially: two japonicas, one long-slender indica, and one medium-slender indica IRRI will supply indica rough rice In the samples to be used, a brown rice sample and samples representing several degrees of milling selected by the organizer should be included A written copy of the staining technique proposed by Dr Barber and one of the alkali pigment methods proposed by Dr Bhattacharya detailing the method of testing is to be circulated (by the organizer) with the test samples Collaborative testing 383 Alkali test It was agreed that collaborative testing would be conducted on two waxy varieties (high and low gel temp.) and three nonwaxy varieties (low-intermediate-high gel temp.) The following test conditions were agreed upon: 1) Concentration of KOH, 1.1%, 1.4%, and 1.7% Percentage of alkali concentration to be determined by titration with standard acid (method to be given) 2) Test to be conducted at room temp for 18-24 hr Collaborators are to report their room temperature 3) In all tests, the grains must still be covered by alkali at completion of the test An attempt is to be made to maintain a ratio of six grains to 10 ml KOH solution 4) All tests to be in triplicate, and on a minimum total of 18 grains 5) Collaborators will provide all raw score data 6) Scorecard proposed by Little, Hilder, and Dawson for alkali spreading values will be used Additional scoring using a modified scorecard and classification system proposed by and to be provided by Dr K R Bhattacharya will be made 7) The organizer will provide a precise written method and BEPT and Amylograph gelatinization temperature data when circulating the 5-g test samples Amylose test It was agreed that collaborative testing would be conducted on five samples representing waxy, very low, low, intermediate and high amylose types Milled rice (5 g), rice flour (5 g), and defatted rice starch (5 g) will be circulated A one-gram sample of potato amylose will also be provided Collaborators will (where facilities permit) determine iodine binding capacity of the defatted starch samples The simplified method of IRRI will be followed except that 1) digestion in 1.0 N NaOH will be for 15 hr at room temperature without shaking, and 2) all readings are to be made at 620 nm A written copy of the modified procedure will be provided by the organizer when the samples are circulated He will also provide IBC data on the defatted rice starches Solvent extraction step ex K R Bhattacharya was considered optional 384 Chemical aspects of rice grain quality Gel consistency test It was agreed that the organizer would provide the method and a series of prepared samples for the collaborative tests Instrument method for cooked rice texture The objective of this collaboration is to compare the wide rar?ge of instrument methods currently used to measure cooked rice texture It was considered that at least 10 varieties (at least months from harvest) be tested in duplicate by each collaborator (100-200 g head rice per variety) The individual methods of testing usually followed by collaborators are to be used However, the following standard cooking method is to be used in preparing the samples for instrument analysis 1) Distilled water is to be used for cooking 2) Samples are to be cooked in a large excess of boiling water without stirring Report if stirring was done 3) Degree of cooking will be determined by the glass platewhite core method Boil the rice for more minutes after minimum cooking time 4) Following cooking, samples will be drained on a screen for 10 minutes, placed in a sealed container, and allowed to cool for hr at room temperature before testing without stirring Report if stirring was done The organizer will provide a precise written cooking method with the samples Collaborators will be requested to provide all of their raw data to allow statistical analysis of the instrument method K R Bhattacharya requested determination of moisture content of cooked rice APPENDIX A — PARTICIPANTS AND AUTHORS PARTICIPANTS Salvador Barber, Director, Instituto de Agroquimica y de Alimentos, Jaime Roig 11, Valencia 10, Spain Tecnologia Kshirod R Bhattacharya, Scientist, Discipline of Rice and Pulse Technology, Central Food Technological Research Institute, Mysore 570013, India Anthony B Blakeney, Cereal Chemist (Rice), Agricultural Research Centre, New South Wales Department of Agriculture, Yanco, New South Wales 2703, Australia Nyle C Brady, Director General, International Rice Research Institute (IRRI) ,* Los Baños , Laguna, Philippines Chandra Breckenridge, Research Officer (Cereal Chemistry), Division of Food Technology, Central Agricultural Research Institute, Gannoruwa-Peradeniya, Sri Lanka Aguinaldo J Bueno, Rice Horticulture Department, Center, Bureau of Plant Muñoz, Nueva Ecija 2311 , Research Coordinator and Head, AgronomyMaligaya Rice Research and Training Industry, Ministry of Agriculture, Philippines Te-Tzu Chang, Geneticist, Plant Breeding Department, IRRI* Nurul H Choudhury, Senior Scientific Officer, Rice Technology Division, Bangladesh Rice Research Institute (BRRI) , P.O Box 911, Dacca, Bangladesh, and Predoctorate Fellow, IRRI* Tohar Danakusuma, Plant Breeder, Sukamandi Branch, Central Research Institute for Agriculture, Department of Agriculture, Sukamandi, Region Subang, Indonesia Bjorn O, Eggum, Senior Research Officer, Department of Animal Physiology and Chemistry, National Institute of Animal Science, Rolighedsvej 25, 1958 Copenhagen V, Denmark Pedro B Escuro, Plant Breeder, Plant Breeding Department, IRRI* Present address: CIDE-IRRI-Burma Project, c/o Agricultural Corporation, 74 Shwedagon, Pagoda Road, Rangoon, Rurma *Mail address: P.O Box 933, Manila, Philippines 386 Chemical aspects of rice grain quality Pierre Feillet, Director, Laboratoire de Technologie des Blés Durs et du Riz, Institut National de la Recherche Agronomique, 34060 Montpellier, Cedex, France Kwanchai A Gomez, Statistician, Statistics Department, IRRI* Hiroshi Ikehashi, Plant Breeder, Plant Breeding Department, IRRI* Bienvenido O IRRI* Juliano, Chemist and Head, Chemistry Department, Gurdev S Khush, Plant Breeder and Head, Plant Breeding Department, IRRI* Ngamchuen Kongseree, Agricultural Researcher, Seed Standard and Quality Branch, Rice Division, Department of Agriculture, Bangkhen, Bangkok 9, Thailand Tomas M Masajo, Plant Breeder, Plant Breeding Section, Department of Agronomy, College of Agriculture, University of the Philippines at Los Baños (UPLB), College, Laguna, Philippines Florinia E Merca, Instructor, Department of Chemistry, College of Arts and Sciences, UPLB Nur Mohammad Miah, Rice Breeder, BRRI H K Mohanty, Professor and Rice Breeder, Department of Plant Breeding and Genetics, College of Agriculture, Orissa University of Agriculture and Technology, Bhubaneswar 751003, India Angelita M del Mundo, Assistant Professor, Institute of Human Ecology, UPLB V V S Murty, Rice Breeder, All-India Coordinated Rice Improvement Project, Rajendranagar, Hyderabad 500030, India Jata S Nanda, Visiting Plant Breeder, Plant Breeding Department, IRRI* Mano D Pathak, Director, Research and Training Coordination, IRRI* Consuelo M Perez, Assistant Scientist, Chemistry Department, IRRI* V Sivasubramaniam, Rice Breeder, Agricultural College and Research Institute, Tamil Nadu Agricultural University, Coimbatore 641003, Tamil Nadu, India *Mail address: P.O Box 933 Manila, Philippines Participants and authors 387 Bernard Siwi, Plant Breeder, Central Research Institute for Agriculture, Department of Agriculture, Jalan Merdeka 99 Bogor, Indonesia Hiroshi Suzuki, Professor, Department of Agricultural Chemistry, Faculty of Agriculture, Kagawa University, Ikenobe, Miki-cho, Kagawa-ken, Japan 761-07 Bill D Webb, Research Chemist, Rice Research, Federal Research, Southern Region, Science and Education Administration, U.S Department of Agriculture, Route 5, Box 784, Beaumont, Texas 77706, U.S.A Praphas Weerapat, Rice Breeder, Rice Division, Department of Agriculture, Bangkhen, Bangkok-9, Thailand Front row left to right: Salvador Barber, H K Mohanty, Angelita M del Mundo, Florinia E Merca, Consuelo M Perez, T T Chang, V Sivasubramaniam, V V S Murty, Gurdev S Khush, Carmen M Paule, and Ngamchuen Kongseree Second row left to right: Nurul H Choudhury, Pedro B Escuro, Bienvenido O Juliano, Praphas Weerapat, Aguinaldo J Bueno, Jata S Nanda, Nur Md Miah, Hiroshi Ikehashi, Hiroshi Suruki, and Mano D Pathak Third row left to right: Bill D Webb, Bjørn O Eggum, Kshirod R Bhattacharya, Tomas M Masajo, C H Mishra, Anthony B Blakeney, and Pierre Feillet 388 Chemical aspects of rice grain quality OTHER AUTHORS Carmen Benedito de Barber, Investigador Cientifico, Laboratorio de Cereales y Proteaginosas, Instituto de Agroquimica y Tecnologia de Alimentos, Calle Jaime Roig 11, Valencia-10, Spain C N Bollich, Research Agronomist, Science and Education Administration, U.S Department of Agriculture, Federal Research, Southern Region, Texas A & M University Agricultural Research, and Extension Center, Rt 5, Box 784, Beaumont, Texas 77706, U.S.A Antonio D Bustrillos, Associate Professor, Department of Chemistry, College of Arts and Sciences, University of the Philippines at Los Baños, College, Laguna, Philippines W R Coffman, Plant Breeder, Plant Breeding Department, IRRI* Normita M de la Cruz, Research Assistant, Plant Breeding Department , IRRI* T H Johnston, Research Agronomist, Science and Education Administration, U.S Department of Agriculture, Federal Research, Southern Region, P.O Box 287, Stuttgart, Arkansas 72160, U.S.A Kinya Kushibuchi, Research Coordinating Officer, Agriculture, Forestry and Fisheries Research Council, Ministry of Agriculture, Forestry and Fisheries, 1-2-1 Kasumigaseki, Chiyoda-ku, Tokyo, Japan B Laignelet, Chargé de Recherches l'INRA, Laboratoire de Technologie des Blés Durs et du Riz, Institut National de la Recherche Agronomique, 34060 Montpellier, Cedex, France R Marie, Maitre de Recherches l'INRA, Station d'Amelioration des Plates, Institut National de la Recherche Agronomique, Place Viala, 34060 Montpellier, Cedex, France W O McIlrath, Research Agronomist, Science and Education Administration, U.S Department of Agriculture, Federal Research, Southern Region, P.O Box 1429, Crowley, Louisiana 70529, U.S.A Carmen M Paule, senior Research Assistant, Plant Breeding Department , IRRI *Mail address: P.O Box 933, Manila, Philippines Participants and authors 389 Boriboon Somrith, Rice Breeder, Khon Kaen Rice Experiment Station, Khon Kaen, Thailand Enrique Tortosa, Investigador Cientifico, Laboratorio de Cereales y Proteaginosas, Instituto de Agroquimica y Tecnologia de Alimentos, Calle Jaime big 11, Valencia-10, Spain 390 Chemical aspects of rice grain quality APPENDIX B – ABBREVIATIONS B.U °C cc cm d.b g h.p hr kcal kg l LSD mg ml mm ppm psig or psi rpm T U.S wt ug µm * ** List Brabender units degrees Celsius cubic centimeters centimeter dry basis gram horse power hour kilocalories kilogram liter least significant difference milligram milliliter millimeter parts per million pounds per square inch gauge pressure revolutions per minute Transmittance United States weight microgram micrometer significant at 5% level significant at 1% level Abbreviations of periodicals follows the 1961 Chemical Abstracts of Periodicals published by the American Chemical Society