Differential responses of chicory ecotypes exposed to drought stress in relation to enzymatic and non-enzymatic antioxidants as well as ABA concentration

Drought stress causes various physiological and biochemical effects in plants. Chicory (Cichorium intybus L.), of the Asteraceae, is a medicinal herbal that is found in most parts of Iran. This study was taken as a factorial experiment based on a completely randomized design? with four replications, to evaluate the effect of water deficit on changes in antioxidant enzyme activity, proline content, and ABA accumulation of four ecotypes of chicory (Sefid Shiraz, Siyah Shiraz, Sefid Isfahan, Siyah Isfahan). To conduct this research, greenhouse cultivation at four different irrigation levels, 100% (as a control), 80, 60 and 40% of field capacity (FC), was conducted and after 60 days of tension under specific treatment, the plants were harvested and the indicators were investigated. The results of the present study indicate that Siyah Shiraz performs better than the others under water deficit conditions, as indicated by higher antioxidant enzyme (superoxide dismutase, catalase, and peroxidase) activity, proline content (as non-enzymatic anti oxidant) and abscisic acid accumulation in leaves. Since activation of the antioxidant system helps the plants with stress-induced damages, our results indicate that Siyah Shiraz has a better defense system against oxidative damage. These data are useful for better understanding of the physiological basis of changes in drought resistance as well as crop breeding projects.     

Solubilization of type I and V collagens in Japanese flounder muscle during chilled storage

ABSTRACT:   The post-mortem changes of type I and V collagens in Japanese flounder muscle during chilled storage were examined. The muscle softened significantly within 12 h under chilled storage. Both type I and V collagens isolated by ion-exchange chromatographies showed no remarkable changes in band patterns even after 24 h of storage, suggesting that degraded collagen molecules may be removed from the collagen fraction by a conventional preparation method. In contrast, type I and V collagen molecules were detected by Western blotting with each specific antibody in a saline extract and gradually increased during chilled storage. These results suggest that both type I and V collagens may participate in the post-mortem softening of fish muscle.     

Prevention of thaw-rigor during frozen storage of bigeye tuna Thunnus obesus and meat quality evaluation

Thaw-rigor is often found in frozen meat of bigeye tuna Thunnus obesus. Excessive amounts of drip loss and stiffness greatly lower the commercial value of tuna meat. In order to prevent thaw-rigor in meat stored at −60°C post-capture, we adapted a temperature shift technique that stores the meat at −7°C for 1 day or −10°C for 7 days before thawing. Biochemical changes in muscle of bigeye tuna before and after the temperature shift to −7 or −10°C were characterized. Contents of ATP, NAD⁺, glycogen, and creatine phosphate decreased after the temperature shift. NAD⁺ levels decreased faster than ATP levels and were highly correlated with the rigor index. Thaw-rigor occurred in muscle containing NAD⁺ at 1 μmol/g and ATP at 7 μmol/g. On the other hand, the meat color of tuna during frozen storage changed to brown depending on the storage temperature and reflected the rate of metmyoglobin (met-Mb) formation. Met-Mb formation increase was dependent on the decrease in NADH levels during the frozen storage. A temperature shift technique with storage at −7°C for 1 day or −10°C for 7 days before thawing prevented thaw-rigor and met-Mb formation.     

Relationships between quality parameters and content of glycerol galactoside and porphyra-334 in dried laver nori <Emphasis Type="Italic">Porphyra yezoensis</Emphasis>

ABSTRACT:   Glycerol galactoside (GG; floridoside + isofloridoside) and porphyra-334 (P-334) are contained in nori (Susabinori Porphyra yezoensis and Asakusanori Porphyra tenera ). Glycerol galactoside has been found to have bifidogenic growth stimulator activity and P-334 is known to have ultraviolet-absorbing activity in the UVA region of sunlight. These substances have, respectively, potential for application to pre-biotic foods and in cosmetics as a sunscreen. In the present study, to investigate the relationships between GG and P-334 contents and the quality of nori, we measured the GG and P-334 contents with other components (total protein, chlorophyll-a, β-carotene and phycobillins) that are related to the quality of nori samples produced from different production areas and with different qualities. We found that the GG content was closely negatively correlated with the contents of other components, whereas P-334 was positively correlated with the other components. From these results, it is suggested that low-quality nori is a potential source of GG, and as a source for P-334, scraps of nori produced during nori processing should be suitable.     

Inhibitory effects of edible marine algae extracts on degranulation of RBL-2H3 cells and mouse eosinophils

Inhibitory effects on degranulation of rat basophilic leukemia (RBL-2H3) cells and mouse eosinophils by marine algae extracts were examined. More than 50% of the degranulation of RBL-2H3 cells was inhibited by water extracts of Ecklonia cava and Chrysymenia wrightii at a concentration of 100 μg/mL. More than 50% of the degranulation of RBL-2H3 cells was inhibited by methanol extracts of Petalonia binghamiae, Scytosiphon lomentaria, Undaria pinnatifida, Porphyra dentata, Codium fragile and Ulva japonica at a concentration of 200 μg/mL. Most inhibitory substances in the methanol extracts were partitioned into ethyl acetate and hexane layers. The ethyl acetate-partitioned layer of methanol extract of Petalonia binghamiae had higher inhibitory effects than the hexane-partitioned layer on the degranulation of RBL-2H3 cells. By contrast, the hexanepartitioned layer of the same extract had a higher inhibitory effect than the ethyl acetate-partitioned layer on the degranulation of mouse eosinophils. The ethyl acetate-partitioned layer of methanol extract of Petalonia binghamiae was further separated into eight fractions by silica gel column chromatography. Most inhibited the degranulation of RBL-2H3 cells, but not that of mouse eosinophils significantly. These results suggest methanol extract of Petalonia binghamiae contains materials that inhibit the degranulation of basophils and eosinophils differentially.