Rice is one of the most important cereals in human nutrition, consumed by about 75% of the global population. Among the cereals, rice share equal importance as leading food sources for humankind. Rice is a staple food for nearly one-half of the world’s population and provides 60% of the food intake in Southeast Asia (Muthayya et al., 2014). During the processing operation of rice, prevention of fractures in rice kernels is uncontrollable even with the care and precision in treatment in order to obtain the maximum HRY. It has been found that there is still a considerable breakage in milled rice for some varieties of paddy. In such cases the inherent poor milling quality is the main cause of breakage. Such a breakage may be eliminated by gelatinizing the starch which will fill the voids and cement the fissures and cracks (Ituen Ukpakha, 2011). According to the three-point bending test, the researchers concluded a significant relationship between the mechanical properties of paddy and HRY and also a strong relationship between HRY and the percentage of paddy rice that could withstand the certain breakage force (Wani et al., 2012). In order to determine the quality properties of rice grain, checking the starch varieties is important as one of the key parameters in determining of cooking quality (Wani et al., 2012). Endosperm of cereals is largely starch grains made of Gonal. The spaces between grains are filled with air and moisture. The seeds are so opaque appearance. During the seeds production, it may arise fractures or cracks in the grains (Danbaba et al., 2011). Parboiled rice is prepared from paddy processed with thermal energy and water before drying and milling process (Bhattacharya, 2011). In fact, the parboiled rice is nothing but rice precooked in paddy form and then dried back before being milled (Bhattacharya, 2011). Rice is included starch granules that are gelatinized during parboiling and open molecules of starch and protein fill the empty space between the grains in the endosperm. The color of rice grain becomes fainter and more rigid mode which can reduce percent of the broken kernels of rice during processing due to prevent rice crunch (Agrawal et al., 2014). The hydrogel of starch is subjected to wet heat, which get a product having greater rigidity (Chun et al., 2015). As a result of gelatinized starch, several important physical changes occur in rice which play an important role in the next processing operations of rice. For example, it would be effective storage, milling, and cooking quality (Bhattacharya, 2011; Hu et al., 2017; Roy et al., 2011; Siriphollakul et al., 2015; Yu et al., 2017). Depending on the variety of rice, water temperature and duration of soaking, steaming time, temperature and pressure, drying time and temperature and other factors related to the rice parboiling, show different physical properties and so several quality. It takes the longer time to cook at the same temperature for parboiled rice than raw rice (no parboiling) at the same variety. As well as, the loss of protein and starch in the parboiled rice is less during cooking (Agrawal et al., 2014). Parboiling of paddy is carried out in three steps. Soaking, steaming and drying. In the soaking process void spaces in the hull and rice kernel are filled with water. Starch granules absorb water and swell causing an increasing in the volume of paddy. This makes the starch granules swell enough to gelatinization and those fill the empty spaces of kernel (Bello et al., 2015). Soaking in water is a result of molecular absorption, capillary absorption and hydration. At the beginning of soaking, the water enters into the grain due to capillary force and fills the spaces between the granules in the grain. Then, some water molecules absorbed by starch molecules enter into its molecular networks, and so remain as hydrated water (Mohsenin, 1996). Steaming process is done to enhance the moisture content of paddy. During steaming process, paddy is already soaked to be exposed to hot steam for a period of time (Ituen Ukpakha, 2011). Steaming is completed gelatinization of starch and it is the most important part of parboiling process. Steaming process depends on factors such as: steaming conditions, the pressure of the steam and steaming time (Bhattacharya, 1985; Yu et al., 2017). After two rounds, the rice becomes dry. Paddy must be harvested at high-moisture content, ranging from 20 to 28%. This high moisture content is conducive to rapid deterioration in quality such as discoloration, yellowing, germination and damage to milling quality. Drying method is a key factor affecting the milling quality of parboiled rice (Bhattacharya, 2011). Parboiled paddy may be dried in shade, sun or with hot air. Drying of high moisture paddy is important to prevent the grain quality deterioration. The conventional method for drying process as sun drying, is inadequate to guarantee the quality and quantity of the produce, so there is a high demand for mechanical drying facilities. Several methods have been used for drying of parboiled rice, such as sun drying, hot air drying, vacuum drying and superheated steam drying (Bhattacharya, 2011; Soponronnarit et al., 2006; Taechapairoj et al., 2004). Rice, including products that depending on the variety and relative humidity is picked with a humidity of 16 to 28 (% w.b.). The thermal drying systems was used for drying the product, especially in areas with high relative humidity. For this purpose, a warm air stream is passed in the bed in order to more quickly reach the desired level of humidity. In the drying, air transport is used to displace the evaporate moisture as well as the heat to evaporate the moisture content. In the continuous drying, breakage of kernels started in the humidity of approximately 18% and it increases with the gradual reduction of humidity. Therefore, it is recommended that this is done at about 20% moisture content (Bello et al., 2006). Drying, should be done as continuous and multistage and also includes a tempering step in the process. After that, seeds can be dried easily and with the lowest percentage of breakage. Many studies have been done in order to optimize the drying and tempering conditions to reduce waste and improve the HRY during the conversion of rice (Aquerreta et al., 2007; Dong et al., 2010; Ghasemi et al., 2018; Siebenmorgen et al., 2004; Wang et al., 2017). Grain varieties those are long and thin were used more for parboiling, because of the amount of fragmentation on them, more than short or medium grain. In addition, some varieties of rice that are more likely crunch, are preferred (Bello et al., 2006). The aim of this study was to investigate the effects of drying methods and steaming time on some physical and mechanical properties such as HRY, crack percentage and breakage resistance in parboiled rice of long grain of Hashemi variety which dried by two drying methods of mixed- mode solar dryer and continuous dryer.