Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 Page 14 Page 15 Page 16 Page 17 Page 18 Page 19 Page 20 Page 21 Page 22 Page 23 Page 24 Page 25 Page 26 Page 27 Page 28 Page 29 Page 30 Page 31 Page 32 Page 33 Page 34 Page 35 Page 36 Page 37 Page 38 Page 39 Page 40 Page 41 Page 42 Page 43 Page 44 Page 45 Page 46 Page 47 Page 48 Page 49 Page 50 Page 51 Page 52 Page 53 Page 54 Page 55 Page 56 Page 57 Page 58 Page 59 Page 60 Page 61 Page 62 Page 63 Page 64 Page 65 Page 66 Page 67 Page 68 Page 69 Page 70 Page 71 Page 72 Page 73 Page 74 Page 75 Page 7668 IREC Farmers' Newsletter No. 195 ­ – Rice R&D 2016 Daniel Waters Southern Cross Plant Science, Southern Cross University, Lismore S TARCH, the dominant component of the rice grain, is made of only one type of building block — glucose. Research that has taken place over many years has found these glucose building blocks form chains that differ in length and amount of branching, and these differences affect rice grain quality. Although the rice grain is mostly starch, experiments that have removed and replaced proteins from rice flour have shown proteins also affect the way the rice flour behaves. This suggests rice grain proteins affect rice grain quality, but we know very little about varietal differences in rice grain proteins and how these differences affect rice grain quality. All cereal grain proteins, including rice, were not created equal. While starch is made of one building block (glucose), protein is made of twenty different building blocks, collectively called amino acids. These amino acids join together in different combinations and create a vast array of different molecules and structures within all living things, including cereal grains. Proteins are remarkably variable in their properties, for example, protein is the dominant biological molecule in both fingernails and egg white, yet fingernail and egg white proteins have very different properties and water solubilities. There are four main types of cereal grain proteins: albumin, globulin, glutelin and prolamin. The globulins, glutelins and prolamins are storage proteins that are pulled apart to build the developing seedling and are found in structures called protein bodies that lie between the starch granules. Solubility differences Cereal grain proteins, including those of rice, have very different solubility properties: l  albumins dissolve in water l  globulins dissolve in salt solutions l  glutelins dissolve in weak acid or base l  prolamins dissolve in alcohol solutions. Rice is cooked in water so the way the components of the rice grain interact with QUICK TAKE l  A new method has been developed to analyse protein in rice grain and it shows clear differences in the protein profiles of long and medium grains, with the basmati types having the most distinctive profile. l  The levels of the protein prolamin and the prolamin/ glutelin ratio plays an important role in medium grain rice quality, particularly hardness. l Broken and unbroken grains have characteristic differences in protein composition. l  Better understanding of rice grain proteins will allow for more accurate selection of high quality and better milling rice lines. Rice grains are packages of energy and nutrients put in place by the rice plant to support the next generation of plants until they become self-sufficient. l Protein bodies are visible with an electron microscope and appear like round balls that lie between the angular starch granules. RICE PROTEINS