## 4 Discussion
However, they can still move around by sliding on their flat sides. With knowledge of the curvature of each grain variety, it is possible to design hoppers efficiently for the milling process [1]. The drying behavior of grain is greatly influenced by grain volume and surface area [29]. The information about the volume to the surface area of rice is significant in the planning of grain cleaners, suction tools, pneumatic separators, and dryers, since it decides the extended region of the grains suspended in a tempestuous air stream [30]. Drying of grains requires both energy and time, which can be accurately measured from the surface area to volume ratio. This is because heat and mass transfer rates are directly proportional to it [31]. In addition to this, several researchers [32; 33] highlighted the importance of the surface area in the cooking process, as it is important for the diffusion of water and thereby decides the optimum cooking time. Grain volume estimations find significance for the development of appropriate drying, warming, and cooling devices that are used during rice processing [18]. Grains that have higher volumes will consume extra space during transportation. In the global market, when rice is exported in volume, grains with the highest volume will be helpful to the vendor since they will consume more space. However, cost-wise, grains with less volume will have lower transportation costs since they will consume less space in the transporting hub than those of high volume [34]. Aspect ratio is considered to be a major factor in rice quality for post-harvest machine designing. It also can have a considerable impact on the market price [4]. In addition, the aspect ratio determines the rolling or sliding behavior of grain in a hopper for developing storage and sorting equipment. The current study agrees with the literature that the majority of the rice varieties have a lower aspect ratio (0.26-1.00), which aids in rolling on the surface of the hopper rather than sliding [17; 35]. Thousand-grain weight is a significant parameter for assessing grain yield. From the study, it was found that the pigmented rice had the highest 1000-grain weight among the 30 rice varieties, which will have more yield [30]. Hence, the cultivation of such pigmented rice is urged to increase productivity and profitability. The primary determinant of the cooking, pasting, nutritional, and eating properties of rice is its amylose content [36]. One of the best single predictors of the texture, in particular the hardness, of samples of rice is thought to be the amylose content [37]. In this study, we found that twenty-eight varieties (nearly 94%) have high amylose content, whereas two belong to the intermediate range, with a content in the range of 22.9-37.1%. The Glycemic Index (GI) value of the rice is influenced by the amylose content of the grain; amylose-rich rice often has a lower GI value. This might be one of the factors contributing to the relative popularity of some traditional rice among local consumers, who are willing to pay a higher price for it. Rice with a high AC is often preferred by Indian and Bangladesh consumers [38]. Rice with greater amylose content expands more when it is cooked because it tends to absorb more water. After cooking, the texture becomes dry and fluffy, and the grains are simple to separate [39].