Polishing and parboiling effect on the nutritional and technological properties of pigmented rice

• Published in: Food chemistry Vol. 191; pp. 105 - 112
• Main Authors: Paiva, Flávia Fernandes, Vanier, Nathan Levien, Berrios, Jose De J., Pinto, Vânia Zanella, Wood, Delilah, Williams, Tina, Pan, James, Elias, Moacir Cardoso
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15.01.2016
• Subjects: Black rice; Color; Cooking; Cooking quality; Free and bound phenolics; Genotype; Hardness; Hot Temperature; Oryza - chemistry; Oryza - genetics; Phenols - analysis; Proximate composition; Red rice; Starch - chemistry; Structure; Proximate composition; Red rice; Free and bound phenolics; Cooking quality; Structure; Black rice
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2015.02.047

•Red rice presented higher protein migration during parboiling than black rice.•Parboiling reduced the ash content of red rice.•Parboiling allowed the partial preservation of free phenolics in black and red rice.•Black and red rice presented lower relative crystallinity after parboiling.•Cooking time of black rice decreased as a consequence of polishing and parboiling. This study aims to evaluate the effects of polishing and parboiling on proximate composition, structure, phenolic compounds, antioxidant activity, cooking time and hardness of IAC-600 black rice cultivar and MPB-10 red rice lineage. Proximate analysis and light micrographs revealed higher migration of red rice proteins than black rice proteins to the endosperm as a result of parboiling. Parboiling reduced the ash content of red rice while no difference was determined in black rice. Gelatinized starch granules from both genotypes showed similar appearance. There was a decrease in relative crystallinity on both black and red rice subjected to parboiling, which was an indicative of crystallites disruption. Polishing removed more than 90% of free phenolics for both genotypes, while parboiling allowed the partial preservation of free phenolics content in polished rice. Parboiling induced an increase in the cooking time of red rice, but a decrease in the cooking time of black rice.