## 1 Introduction  
Traditional Cultivars Influence on Physical and Engineering Properties of Rice from the Cauvery Deltaic Region of Tamil Nadu  
[PERSON] 1, [PERSON] 2,*(c), [PERSON] 3,*(c),  
[PERSON] 4, [PERSON] 5, [PERSON] 6, [PERSON] 7,  
[PERSON] 1, [PERSON] 1(c), [PERSON] 6(c) and [PERSON] 9,*(c)  
Footnote 1: [[https://www.mdpi.com/journal/applsci](https://www.mdpi.com/journal/applsci)]([https://www.mdpi.com/journal/applsci](https://www.mdpi.com/journal/applsci))  
Footnote 2: [[https://www.mdpi.com/journal/applsci](https://www.mdpi.com/journal/applsci)]([https://www.mdpi.com/journal/applsci](https://www.mdpi.com/journal/applsci))  
Footnote 3: [[https://www.mdpi.com/journal/applsci](https://www.mdpi.com/journal/applsci)]([https://www.mdpi.com/journal/applsci](https://www.mdpi.com/journal/applsci))  
Footnote 4: [[https://www.mdpi.com/journal/applsci](https://www.mdpi.com/journal/applsci)]([https://www.mdpi.com/journal/applsci](https://www.mdpi.com/journal/applsci))  
Footnote 5: [[https://www.mdpi.com/journal/applsci](https://www.mdpi.com/journal/applsci)]([https://www.mdpi.com/journal/applsci](https://www.mdpi.com/journal/applsci))  
Footnote 6: [[https://www.mdpi.com/journal/applsci](https://www.mdpi.com/journal/applsci)]([https://www.mdpi.com/journal/applsci](https://www.mdpi.com/journal/applsci))  
**Keywords: traditional rice cultivars; physical; gravimetric and engineering properties; Pearson correlation coefficient; principal component analysis**  
## 1 Introduction  
Rice is the second-most important staple food, behind wheat, and is widely consumed around the world [1]. India has witnessed a drastic boost in its rice production, which accounts for 1/4 th of the global total. Rice is the second most cultivated crop in India, after sugarcane, and has significantly influenced the nation's agricultural output [2]. Rice is grown in the Cauvery Deltaic parts of Tamil Nadu, where it is the region's major food crop; this region is a homeland for more than 400 traditional rice varieties. Major areas of the Cauvery Deltaic region have been farming traditional rice types and eating them since time immemorial, and some of the landraces show promise in terms of output. The green revolution has brought about a surge in the production of high-yielding varieties, resulting in traditional cultivars being pushed to the background. Several old rice varieties have resurfaced in recent years as part of the process of rediscovering traditional agricultural knowledge. After COVID, the eating habits of people have changed, and they are showing interest in traditional cultivars, which are rich in biochemical compounds that enhance immunity. Rice varieties with whitish kernels are the most prevalent form of rice in Tamil Nadu. However, the Cauvery Deltaic region of Tamil Nadu is also reported to have pigmented varieties that possess high medicinal values through the presence of higher total phenol, flavonoids, and anthocyanin content. Rice grain characteristics distinguish its market worth and influence milling and cooking quality, which has a direct impact on consumer acceptability [3; 4]. Quality assessment of food products involves several factors, such as physical looks, sensory properties, texture, and nutrition. All of these characteristics are crucial in determining the overall quality. Investigation of the physical properties of rice is fundamental for designing rice processing equipment and setting up standard unit procedures that would be useful in wiping out losses that happen during the milling process. Additionally, information on density parameters could, besides influencing heat and mass exchange of moisture during air circulation and drying processes, help in choosing appropriate sizes for storage bins [5]. Bulk density, tapped density, real density, Hausner ratio, and Carr's index are important gravimetric qualities that must be taken into consideration in designing processing machines for the drying, transportation, and storage of grains.