## 5 Pasting Properties of Pigmented Rice
### Dehulling, Parboiling, and Milling
[51] compared parboiling of black and red rice genotypes, and reported that red rice had higher protein migration compared to black rice during the process but there was reduced ash content. Parboiling resulted in partial preservation of free phenolics and lower relative crystallinity (crystallites disruption). In addition, parboiling affected the levels of bioactive compounds in black (Venere brown and Violet brown) and red (Ermes brown and Orange brown) Italian pigmented rice varieties; however, they still retained higher antioxidant activity in the final product compared to non-pigmented rice [52]. [PERSON] et al. [49] described that germination and parboiling treatments significantly increased the viscosity and thermal properties of germinated red rice and decreased heat enthalpy. Germination alone decreased viscosity profiles of red rice while parboiling improved the pasting profile of germinated red rice. All viscosity parameters (except breakdown value) increased with 0 to 2 min parboiling. The authors argued that during the parboiling process, gelatinization, and re-crystallization of starch take place in a starch-water mixture, where dispersed amylose chains create double-helical structures consisting of 40-70 glucose units through hydrogen bonding. Thus, retrogradation of the outermost branches of starch granules can result in increased pasting viscosity of germinated rice. This could be attributed to disruption of hydrogen bonds or breaking of covalent linkages of the double helices. The authors concluded that a short time parboiling can improve the viscosity characteristics of germinated red rice. Germination and parboiling increased thermal properties (T\({}_{0}\), T\({}_{\rm P}\), and T\({}_{\rm c}\)), while change in enthalpy decreased, which further indicated that the rice granule structure was destroyed by parboiling. Parboiling (rice paddy, 24 h soaking, 1 h steaming, sundried, and oven dried, 12-14% moisture) increased the resistant starch (five-fold) of intermediate and high amylose pigmented rice. The linear helical chains of amylose can form tightly packed structures with high crystallinity, which restricts enzymatic access [53]. On the other hand, [PERSON] et al. [54] concluded that extrusion cooking promoted cooked pasta firmness when applied to parboiled white rice flour. They reported that pasta using parboiled white rice showed the lowest starch enzymatic susceptibility, indicating that the pasta-making process for parboiled rice flours resulted in significant rearrangement of starch macromolecules, effectively reducing cooking losses. High extrusion cooking temperaturesled to greater starch gelatinization and increased retrogradation and further decreased enzymatic susceptibility. Innovative Processing to Improve Nutritional Quality of Wholegrain Pigmented Rice (Micronisation, Microfluidisation, and Fractionation--Air Classification)  
Micronisation is an advanced technique used to valorise bran of cereal grains. It is a process that applies mechanical high shear force to reduce solid materials to the microscale. Mechanical grinder, supercritical fluid technologies and homogenizers can be used for micronisation [55]. On the other hand, microfluidisation--a modified version of micronisation--is a high-pressure homogenization that creates very fine emulsions. By reducing the particle size and microstructure, these processes improve the functional and nutritional properties of rice brass [56]. Reducing the particle size to micron level enhances functional and physicochemical properties such as water-holding capacity, swelling capacity, solubility, and antioxidant activity. It also aids in food preservation by exposing antimicrobial compounds, inactivating microbes, or inhibiting enzymes, thereby increasing food stability. Micronisation delays retrogradation, promotes gelatinization, reduces synessis, shortens fermentation time, creates stable products, and improves dissolution rates.