title: Status of free radicals in Indian monsooned coffee beans gamma-irradiated for disinfestation.
abstract: Free radicals in two cultivars of Indian monsooned coffee beans, gamma-irradiated for hygienic and quarantine purposes, were examined by entrapping the small amount of samples in potassium chloride powder in ESR quartz tubes. In contrast to a prominent free radical signal at g = 2.002, observed in spermoderm (silver skin) and cotyledon (whole seed without skin) parts of normal coffee beans, the same was not discernible in monsooned coffee bean parts of both cultivars. The ESR signal was found to be more prominent in the spermoderm than in the whole seed portion of the normal coffee beans. Common practices of roasting and powdering were found to generate quantitatively more free radicals in coffee beans than gamma-irradiation alone. Phenols, contributing maximally to observed free radical signals in coffee beans, were significantly different in normal and monsooned coffee beans. These observations on insignificant free radical population in irradiated monsooned coffee beans may be attributed to their inherent possession of high water activity, favoring decay of free radicals produced. Textural studies with monsooned coffee beans, before and after mild heat treatments, supported these findings.
authors.affiliation: Food Technology Division, Bhabha Atomic Research Centre, Mumbai, India. bbhushan@apsara.barc.ernet.in
authors.forename: Brij
authors.initials: B
authors.lastname: Bhushan
authors.forename: Rajeev
authors.initials: R
authors.lastname: Bhat
authors.forename: Arun
authors.initials: A
authors.lastname: Sharma
mesh_terms: D002726:Chlorogenic Acid / Q000032:analysis; D040503:Coffea / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D005514:Food Irradiation; D005609:Free Radicals / Q000032:analysis*; D005720:Gamma Rays; D007194:India; D010636:Phenols / Q000032:analysis; D012639:Seeds / Q000737:chemistry*
chemical_list: D005609:Free Radicals; D010636:Phenols; D002726:Chlorogenic Acid