Purification, crystallization and preliminary X-ray analysis of recombinant betaine aldehyde dehydrogenase 2 (OsBADH2), a protein involved in jasmine aroma, from Thai fragrant rice (Oryza sativa L.)

Effects of milling on aromatics, lipophilic phytonutrients, and fatty acids in unprocessed white rice of scented rice 'Cheonjihyang-1-se

To understand effects of milling, scented rice 'Cheonjihyang-1-se' was milled from 10 to 140 s and changes in volatiles, phytonutrients, and fatty acids were evaluated. Among 43 identified odor-active compounds, four volatiles, including hexan-3-one, exhibited decreases of up to 78%, while four others including (E)-non-2-enal, increased following milling. Levels of 2-acetyl-1-pyrroline, the most distinctive popcorn-flavoring compound in scented rice, were not affected by the degree of milling (DM). Partial least squares discriminant analyses of volatiles were able to differentiate white rice according to the DM. Benzene and 2-pentylfuran showed the highest variable importance in projection scores, which could be applied in estimating the DM of rice. Milling significantly decreased tocopherols, tocotrienols, squalene, phytosterols contents and oleic acid composition, while palmitic acid composition was increased. These results suggest milling-dependent variations in phytonutrient levels and lipid composition, as well as changes in aroma and subsequent market quality, in 'Cheonjihyang-1-se' rice.

Thai Hom Mali Rice: Origin and Breeding for Subsistence Rainfed Lowland Rice System

The world-renowned Thai Hom Mali Rice has been the most important aromatic rice originating in Thailand. The aromatic variety was collected from Chachoengsao, a central province, and after pure-line selection, it was officially named as Khao Dawk Mali 105, (KDML105). Because of its superb fragrance and cooking quality, KDML105 has been a model variety for studying genes controlling grain quality and aroma. The aromatic gene was cloned in KDML105, as an amino aldehyde dehydrogenase (AMADH) or better known as BADH2 located on chromosome 8. Later on, all other aromatic rice genes were discovered as allelic to the AMADH. As a selection of local landrace variety found in rainfed areas, the Thai Jasmine rice showed adaptive advantages over improved irrigated rice in less fertile lowland rainfed conditions. Because KDML105 was susceptible to most diseases and insect pests, marker-assisted backcross selection (MABC) was used for the genetic improvement since 2000. After nearly 17 years of MABC for integrating new traits into KDML105, a new generation of KDML105, designated HM84, was developed which maintains the cooking quality and fragrance, and has gained advantages during flash flooding, disease, and insect outbreak.