## 5 Pasting Properties of Pigmented Rice  
Determining the pasting properties is crucial in product development, especially for rice-based products, as they influence the texture, consistency, and overall sensory quality. These properties describe how starch behaves when heat is applied in the presence of water. It shows how the starch swells, gelatinizes, breaks down, and retrogrades upon cooling. These behaviours are correlated with key qualities of food products such as stickiness, firmness, viscosity, and cohesiveness. The composition of rice grain and the processes involved also directly influence the pasting properties of rice flour. The pasting properties determine the functional properties of starch and are greatly affected by the amylose/amylopectin ratio, lipid content, varieties, and cropping environment [35]. A comparison between brown and polished white rice from five traditional Sri Lankan rice grains showed that brown rice flour had lower swelling power, lower RVA viscoamylograph profile, lower gel hardness, and lower gelatinization enthalpy, but higher gelatinization peak temperature, as compared to polished counterparts [36]. Amylase activity in brown rice also results in reduced peak, setback, and final viscosities, as amylase breaks down starch before it fully gelatinizes. In pigmented rice, variation in amylose content exists. Ten Indonesian pigmented rice varieties exhibited no significant differences in functional and proximate properties, except for crude fibre content [19]. The water absorption index ranged from 4.22-7.63 g/g, water solubility index from 3.62-7.40%, oil absorption index from 0.88-1.36 g/g, and swelling power between 5.31-8.42 g/g. The gelatinization enthalpy ranged from 0.82-1.33 J/g, and the sample with the lowest amylose had the highest peak, trough, and final viscosities. The protein, lipid, and dietary fibre content of rice grains are negatively correlated with the hardness of rice flour paste and cooked rice, but positively correlated with stickiness [36; 37]. Protein and dietary fibre specifically compete with starch for water absorption, lowering swelling power, water binding capacity, and peak viscosity, and hindering retrogradation (a process during which amylose reorganizes and retrogrades through hydrogen bond formation). On the other hand, lipid-amylose complexes restrict starch swelling (low peak viscosity) but improve hot paste viscosity (low breakdown viscosity). Protein, lipid, and dietary fibre interfere with amylose reassociation during cooling preventing retrogradation [36]. If the same amount of water is used for cooking, rice with high protein, lipid, and dietary fibre will result in a harder and more rigid cooked rice or gel [38]. Phenolic compounds are characterized by the presence of hydroxyl and carboxyl groups. Polyhydroxy compounds compete with starch granules for water, thereby inhibiting their hydration and swelling, which results in a reduction of peak viscosity [39]. [PERSON] et al. [40] reported that polyphenols form complexes with starch via hydrogen bonding, with the interaction influenced by the polyphenols' structure, molecular weight, and the number of hydroxyl and methoxy groups. These factors contribute to the varying physicochemical properties of polyphenol-starch complexes. Additionally, the ratio of amylose to amylopectin significantly affects the binding affinity of polyphenols, with higher amylose content promoting the formation of more ordered polyphenol-amylose crystallites, resulting in a higher degree of crystallinity. The presence of polyphenols such as ferulic acid has been shown to enhance the water-holding capacity of rice starch, leading to the formation of a more porous gel matrix upon gelatinization [41]. Thermal processing plays a crucial role in facilitating starch-polyphenyl interactions by disrupting the double-helix structure of starch, thereby exposing more binding sites for polyphenols and promoting complex formation.