Factors Affecting Oxidative Stability of Pork, Beef, and Chicken Meat

2-Thiobarbituric acid-reactive substances (TBARS) values of raw pork, and chicken breast and thigh meats did not change during a 7-d storage period. Low free iron content and high ferric ion reducing capacity (FRC) were responsible for the low TBARS values in those meats during storage. TBARS values of raw beef loin, however, significantly increased during 7-d storage because of high free iron content and high lipoxygenase-like activities by ferrylmyoglobin. The TBARS values of cooked meat increased significantly with storage. Heat-stable FRC was detected in all cooked meat and was responsible for the increase of TBARS in cooked meat during storage. The rate of TBARS increases and the amounts of nonheme iron and heat-stable FRC in cooked beef loin were higher than those in cooked pork loin and chicken breast. In spite of lower amounts of nonheme iron and heat-stable FRC, cooked chicken thigh showed similar levels of TBARS to cooked beef loin after 7-d storage because of its high PUFA content. The total amount of PUFA in meat, most of which were present in triglycerides, influenced the development of lipid peroxidation only in the presence of sufficient amounts of free irons in cooked meat. This indicated that the content of free ionic iron, myoglobin, and ferric ion reducing capacity (FRC) were the primary determinants for the different susceptibility of raw meats to lipid peroxidation. In cooked meat, the contents of free ionic iron and heat-stable FRC played a key role on the development of lipid peroxidation. PUFA was important for lipid oxidation in cooked meat only when sufficient amount of free iron was present

Packaging Determines Color and Odor of Irradiated Ground Beef

Irradiation of ground beef under aerobic conditions oxidized myoglobin and drastically reduced color a*-values. Under vacuum or non-oxygen conditions, however, irradiation did not influence the redness of ground beef. Also, the red color of ground beef was maintained even after the irradiated beef was exposed to aerobic conditions. Vacuum-packaged irradiated ground beef had lower metmyoglobin content and lower oxidation-reduction potential than the aerobically packaged ones. Irradiating ground beef under vacuum-packaging conditions was also advantageous in preventing lipid oxidation and aldehydes production. Vacuum-packaged irradiated beef, however, produced high levels of sulfur volatiles during irradiation and maintained their levels during storage, which resulted in the production of characteristic irradiation off-odor. Double-packaging (V3/A3: vacuum-packaging during irradiation and the first 3 days of storage and then aerobic-packaging for the remaining 3 days) was an effective alternative in maintaining original beef color (red), and minimizing lipid oxidation and irradiation off-odor. The levels of off-odor volatiles in double-packaged irradiated ground beef were comparable to that of aerobically packaged ones, and the degree of lipid oxidation and color changes were close to those of vacuum-packaged ones. Ascorbic acid at 200 ppm level was not effective in preventing color changes and lipid oxidation in irradiated ground beef under aerobic conditions, but was helpful in minimizing quality changes in doublepackaged irradiated ground beef. This suggested that preventing oxygen contact from meat during irradiation and early storage period (V3/A3 double-packaging) and doublepackaging+ascorbic acid combination are excellent strategies to prevent off-odor production and color changes in irradiated ground beef. Developing methods that can prevent quality changes of irradiated beef is important for the implication of irradiation, which will improve the safety of beef

Recent Application of Bio-Alcohol: Bio-Jet Fuel

Recently, the biomass-based energy production has been actively studied as a research and development area for reducing carbon emissions as a solution to global warming caused by the increase of carbon dioxide emissions. Especially, as the energy consumption in the air transportation field increases, the carbon dioxide emissions increase simultaneously. Therefore, the bio-jet fuel production technology is being actively developed to solve this problem. The bio-jet fuel manufacturing process is a process of manufacturing biomass-derived jet fuel that can replace the existing petroleum-based jet fuel. It includes an alcohol-to-jet (ATJ) process using bio-alcohol such as bio-butanol and bio-ethanol, oil-to-jet (OTJ) process using vegetable oil, and an F-T process using syngas obtained from gasification of biomass-based raw materials

Discrimination of cultivation ages and cultivars of ginseng leaves using Fourier transform infrared spectroscopy combined with multivariate analysis

AbstractTo determine whether Fourier transform (FT)-IR spectral analysis combined with multivariate analysis of whole-cell extracts from ginseng leaves can be applied as a high-throughput discrimination system of cultivation ages and cultivars, a total of total 480 leaf samples belonging to 12 categories corresponding to four different cultivars (Yunpung, Kumpung, Chunpung, and an open-pollinated variety) and three different cultivation ages (1 yr, 2 yr, and 3 yr) were subjected to FT-IR. The spectral data were analyzed by principal component analysis and partial least squares-discriminant analysis. A dendrogram based on hierarchical clustering analysis of the FT-IR spectral data on ginseng leaves showed that leaf samples were initially segregated into three groups in a cultivation age-dependent manner. Then, within the same cultivation age group, leaf samples were clustered into four subgroups in a cultivar-dependent manner. The overall prediction accuracy for discrimination of cultivars and cultivation ages was 94.8% in a cross-validation test. These results clearly show that the FT-IR spectra combined with multivariate analysis from ginseng leaves can be applied as an alternative tool for discriminating of ginseng cultivars and cultivation ages. Therefore, we suggest that this result could be used as a rapid and reliable F1 hybrid seed-screening tool for accelerating the conventional breeding of ginseng

Highly Monodispersed PbS Quantum Dots for Outstanding Cascaded-Junction Solar Cells.

High-performance cascaded-junction quantum dot solar cells (CJQDSCs) are fabricated from as-prepared highly monodispersed lead sulfide QDs. The cells have a high power conversion of 9.05% and a short-circuit current density of 32.51 mA cm-2. A reliable and effective stratagem for fabricating high-quality lead sulfide quantum dots (QD) is explored through a "monomer" concentration-controlled experiment. Robust QDSC performances with different band gaps are demonstrated from the as-proposed synthesis and processing stratagems. Various potential CJQDSCs can be envisioned from the band edge evolution of the QDs as a function of size and ligands reported here