CAPTURING ANTHOCYANIN IMMOBILIZATION ON RICE THROUGH THE ULTRA-HIGH RESOLUTION ELECTRON LENSES
Abstract
Coating parboiled rice grains (PRG) with pigment-immobilized nanometer thickness cells abbreviated "pinacell" offered rice grains with more uniform Clitoria ternatea (flower) pigment distribution. The resultant blue pinacell, predominantly of delphinidin anthocyanin, was then examined for its penetration into the rice grain using an ultra-high resolution Field Emission Scanning Electron Microscopy (FESEM) and soft peeling from polystyrene surface. Pinacell-polystyrene surface tension occurring at 40oC facilitated delamination, signaling another prospectus commercialization candidate and the possibility of a zero-waste process. Analysis of the coated grain cross-section via XHR FESEM shows pigment penetration to the core of the grain plausibly delivered first, by the nanofibrils slipping into the inter-granular gaps, IGS. Next, the anthocyanin adhered to the PRG core, driven by its biochemical affinity for starch and proteinaceous structures of the PRG. The thermal canopy effects arising from the muffling web of pinacell and the thermo-pockets forming at PRG surface IGS during the 40oC drying, coupled with the antimicrobial characteristic of Clitoria ternatea pigment rendered profound preservation measures. The identified coating and penetration mechanisms account for better grain longevity, color uniformity, and an enhanced shelf-life placing the coated parboiled rice closer to market readiness.
