Browsing by Subject "antioxidant"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Antioxidant, color and sensory properties of sorghum bran in pre-cooked ground beef patties varying in fat and iron content(2009-05-15) Shin, Dae KeunThe effect of currently used antioxidants and sorghum bran in pre-cooked beef patties was evaluated at two different fat levels (10 and 27%, w/w). Pre-formulated ground beef was purchased at a retail store on three different processing days. Within each fat level, ground beef portions were weighed and randomly assigned to control, butylated hydroxanisole (BHA) and butylated hydroxytoluene (BHT) (0.001%), rosemary (0.25%) or sorghum bran (0.25, 0.5 or 1.0%). After mixing in the appropriate antioxidant, 200-g patties were formed, and pH and objective color measurements for each raw patty were performed. Patties were cooked to an internal temperature of 73oC. Cooked patties were packaged and stored at 4oC. Two patties per treatment were sampled after 0, 1, 3 and 5 d of storage and analyzed for 2-thiobarbituric acid reactive substances (TBARS), non-heme iron, pH, instrumental color and trained flavor and texture descriptive attributes. The addition of BHA/BHT and rosemary extract to patties reduced non-heme iron, TBARS values, and cooked beef fat flavor attributes, but increased beef/brothy flavor attributes relative to control patties (P<0.05). As sorghum bran level increased, cooked beef patties were darker (P<0.05), less yellow (P<0.05), had higher non-heme iron (P<0.05), lower TBARS (P<0.05) and higher sandy/gritty (P<0.05) sensory texture. Cooked patties containing antioxidants did not differ in other sensory attributes (P>0.05). Fat mouthfeel of control patties were higher than treated patties (P<0.05). Sorghum bran delayed lipid oxidation by reducing TBARS values and cooked beef fat flavors, and when used at 0.25 and 0.5%, minimal effects on color and sensory attributes were observed. Our results suggested that sorghum bran can be a desirable natural antioxidant in pre-cooked ground beef.Item Chemical Characterization, Bioactive Properties, and Pigment Stability of Polyphenolics in A?ai (Euterpe oleracea Mart.)(2010-07-14) Pacheco Palencia, Lisbeth A.Phytochemical composition, antioxidant activity, pigment stability, bioactive properties, and in-vitro absorption of polyphenolics in acai fruit (Euterpe oleracea Mart.) were investigated. Detailed characterization of phenolic compounds present in acai fruit, acai fruit pulp, and a polyphenolic-enriched acai oil were conducted by HPLCESI- MSn analyses and their stability and influence on antioxidant capacity determined. Anthocyanins were predominant in acai fruits, which also contained several flavone and flavonol glycosides, flavanol derivatives, and phenolic acids. In-vitro absorption and antiproliferative effects of phytochemical extracts from acai pulp and acai oil were determined as a function of chemical composition. Polyphenolic mixtures from both acai pulp and acai oil extracts significantly inhibited HT-29 colon cancer cell proliferation, also inducing the generation of reactive oxygen species. In-vitro intestinal absorption using Caco-2 cell models demonstrated that phenolic acids and monomeric flavanol derivatives are readily transported through cell monolayers in-vitro. The influence of polyphenolic cofactors on the stability of anthocyanins in acai fruit under varying conditions of temperature and pH was evaluated. Significant time, temperature, and pH-dependent anthocyanin losses were observed in all models, yet the presence of phenolic acids, procyanidins, and flavone-C-glycosides had a positive influence on anthocyanin stability. External addition of flavone-C-glycosides significantly enhanced visual color, increased anthocyanin stability during exposures to high pH or storage temperatures, and had comparable effects to those of a commercial anthocyanin enhancer. Anthocyanin polymerization reactions occurring during storage of acai fruit juice models were investigated and potential mechanisms and reaction products identified. Polymeric anthocyanin fractions contained several anthocyanin-flavanol adducts based on cyanidin or pelargonidin aglycones and their presence was related to increased anthocyanin sulfite bleaching resistance and to the appearance of large, unresolved peaks in HPLC chromatograms. A reaction mechanism involving the nucleophilic addition of anthocyanins in their hydrated form to flavanol carbocations resulting from cleavage of interflavanic bonds was proposed for the formation of flavanol-anthocyanin adducts in acai fruit juices. Antiproliferative activity and in-vitro absorption of monomeric and polymeric anthocyanin fractions were also evaluated. Both fractions inhibited HT-29 colon cancer cell growth in a similar, concentration-dependent manner, yet in-vitro absorption trials using Caco-2 intestinal cell monolayers indicated the presence of anthocyanin polymers may influence anthocyanin absorption in acai fruit products.Item The role of reactive oxygen species as mediators of respiratory syncytial virus induced pulmonary inflammation(2008-06-27) Shawn Monique Castro; Roberto Garofalo M.D.; Xiaodong Cheng; Mary Treinen-Moslen; Kent Pinkerton Ph.D.; Istvan BoldoghRespiratory Syncytial Virus (RSV) is the leading cause of epidemic respiratory tract illness in children worldwide. Although the mechanisms of RSV-induced airway disease are unknown, experimental evidence suggests that early local inflammatory processes serve as major initiating events in the pathogenesis of RSV-induced lung disease. RSV induced inflammation is mediated in part by small inflammatory chemokines. We investigated the mechanism of RSV-induced chemokine RANTES gene expression in epithelial cells and identified reactive oxygen species as critical signaling molecules involved in STAT and IRF transcription factor activation and the IKK-epsilon pathway, two activated pathways involved in the regulation of pro-inflammatory gene expression. We showed that RSV induced oxidative stress in vivo and that antioxidant therapy with butylated hydroxyanisole (BHA) attenuated RSV induced oxidative stress, pulmonary inflammation and airway hyper-responsiveness. The one caveat to anti-inflammatory antioxidant therapy was the slight increase in RSV viral load observed following antioxidant administration. To eliminate the undesired outcome of increased viral load, a combination therapy approach was utilized employing BHA and the potent anti-viral IFN-alpha. Combination therapy yielded similar results of diminishing RSV-induced pulmonary inflammation while also decreasing RSV viral load in the lungs. Another key mediator regulated by oxidative stress and involved in inflammation is Poly (ADP)-Ribose Polymerase (PARP). We demonstrated that RSV is a potent inducer of PARP activity and that pharmacological inhibition of PARP with INO-1001 abolished RSV-induced PARP activity. INO-1001 also significantly reduced RSV-induced release of inflammation and lung pathology. Of environmental significance, cigarette smoke is also a potent oxidant mixture and important risk factor for the severity of RSV-induced disease. The mechanism(s) causing a worsening of RSV-induced lung disease by environmental tobacco exposure are unclear. Therefore, we investigated the effect of co-exposure of airway epithelial cells to cigarette smoke condensate (CSC) and RSV on inflammatory chemokine gene expression. We demonstrated that CSC and RSV synergistically increased MCP-1 and IL-8 chemokine expression through NF-kappaB and IRF transcription activation. Overall, the modulation of RSV-induced oxidative processes, either by dampening ROS production through pharmacological intervention or by heightening it by toxicant exposure, identify ROS as major signaling molecules involved in regulating RSV-induced inflammation.