This study was conducted to investigate the effect of drying in antioxidant activity and to compare the changes of ascorbic acid and colour by drying and storage in Korean red pepper. The antioxidant activity of red pepper dried by modified method (MM, dried at 70°C/6 h in cut pods) was about threefold higher than those dried by conventional method (CM, dried at 80°C/5 h followed by 60°C/18 h in whole pods) in the ([2,2¢-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid)] (ABTS) and (2,2-diphenyl-1-picrylhydrazyl) (DPPH) radical-scavenging assays, respectively. The ascorbic acid contents in MM and CM drying were 12.41 ± 2.15 mg g )1 and 3.05 ± 0.39 mg g )1 , and were not changed for 3 months at 0°C in red pepper dried by MM. The ASTA colour values of red pepper dried by MM and CM were 114.0 and 107.4, respectively. For 6-month storage, 72-85% of the colour was retained regardless of drying and storage conditions.

Multiple lines of evidence suggest that natural compounds can prevent skin ageing induced by ultraviolet light. Luteolin, a bioactive compound found in chilli, onion, broccoli, celery and carrot, has been reported to exhibit anti-photoageing effects in vitro. However, the molecular targets and mechanisms of luteolin are still poorly understood. In this study, we sought to investigate the effects of luteolin on UVB-induced photoageing and the molecular mechanisms involved, using HaCaT human keratinocytes and SKH-1 hairless mice. Luteolin was found to inhibit UVB-induced MMP-1 expression in HaCaT cells, as well as UVB-induced activation of AP-1, a well-known transcription factor targeting the MMP-1 promoter region, as well as c-Fos and c-Jun, which comprise the AP-1 complex. In contrast, Western blot data showed that UVB-induced phosphorylation of JNK, ERK and p90RSK was not inhibited by luteolin. In vitro kinase assay data revealed that luteolin significantly suppressed JNK1 and p90RSK activity, but not that of JNK2 and ERK2. Pull-down assays showed that luteolin binds JNK1 in an ATP-competitive manner and p90RSK2 in an ATP-independent manner. Luteolin also inhibited UVB-induced wrinkle formation and MMP-13 expression, a rodent interstitial collagenase in mouse skin, in vivo. Taken together, our observations suggest that luteolin exhibits anti-photoageing effects in vitro and in vivo and may have potential as a treatment for the prevention of skin ageing.

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This article proposes a finite element analysis–based inverse approach to estimate the friction coefficient in hot bar rolling. The focus is to minimize the difference between the spread of material measured from the pilot hot bar rolling test and that computed from finite element analysis. The recursive response surface method was used with a changed observation range to minimize the difference. The pilot hot bar rolling test was conducted at temperatures ranging from 850 °C to 1150 °C and reduction ratios from 20% to 40%. Finite-element simulation of the pilot hot bar rolling test was carried out. A fast running model that can rapidly determine the friction coefficient at the arbitrary reduction ratios and temperatures in the ranges mentioned above was also presented. The estimated friction coefficient was approximately 10%–17% higher than the friction coefficient typically used in hot strip rolling. The effect of temperature variation on the friction coefficient was greater at higher reduction ratios (30%–40%) than at a lower reduction ratio (20%).