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 7659 IREC Farmers' Newsletter No. 195 ­ – Rice R&D 2016 How is cracking measured? The extent of cracking is usually measured on dry grains after milling and can be used to determine the likelihood of grains breaking in storage. However, there are different types of cracks and not all cracks will result in a broken grain during cooking. Most research into cracking has been done on dry grains and determining the extent of cracking relies on specialised equipment. However, the ‘Hanasaki’ method is a better indicator of how grain cracking affects the quality of cooked rice using the absorption method commonly used in sushi production. ‘Hanasaki’ is a Japanese term for ‘fissures, fractures or cracks’ that occur in rice during submersion in water, and is determined by soaking grains in water for a defined time period and determining the percentage of cracked grains. If the rice cracks during this period of soaking, it will likely crack during the cooking process (SunRice, pers. comm.). Assessment of the Hanasaki procedure has found that it is a good measure of predicting cooking performance in milled grain (SunRice, pers. comm.) with a threshold of less than 35% generally deemed acceptable. Hanasaki measurement The Hanasaki measurement was used on grain harvested from nitrogen trials in 2014 to assess the method and investigate the effects of nitrogen regimes on crack formation. Opus and Koshihikari were the subset of varieties used to compare different forms of nitrogen fertiliser (urea and sulfate of ammonia at 150 kg N/ha), split applications (two-thirds upfront and one-third at panicle initiation) and four sowing dates (YRNA, YRNB, YRNC, YRND). Staggered sowing dates were instigated at the one location to ensure the full range of temperature extremes were encountered during grain formation and ripening (summer/autumn). Method Hanasaki was determined by submerging approximately 100 milled rice grains in tap water at room temperature (22 ± 1°C) for one hour. Images were captured with a digital SLR camera and assessed visually and by automatic image analysis. Up to 30 minutes soaking time has been used in the past (SunRice, pers. comm.), however one hour was chosen since after this time it is easier to identify cracks and it is in alignment with commercial practices in which rice is left in rice-cookers overnight on timers. l Figure 1. Average cracking percentage utilising the Hanasaki method for Opus and Koshihikari under different forms and rates of nitrogen over four sowing dates in CY2014 (l.s.d. (P