In this study, amidrazone acrylic fabric was applied as an immobilising support for α-amylase. The immobilised α-amylase was characterised by Fourier transform infrared spectroscopy and scanning electron microscopy. Furthermore, the optimum conditions for immobilisation efficiency, immobilisation time, reusability, kinetic parameters and pH, for the immobilisation process were examined. The study demonstrated that with 4% cyanuric chloride, and a pH of 7.0, the highest immobilization efficiency of 81% was obtained. Around 65% of the initial activity was maintained after storage at 4 °C for 8 weeks. The immobilised enzyme retained 53% of its original activity after being reused 15 times and exhibited improved stability compared with the free enzyme in relation to heavy metal ions, pH, temperature and inhibitors. The immobilised enzyme presented kinetic parameters of 2.6 mg starch and 0.65 µmol maltose/mL for K m and V max respectively, compared with 3.7 mg starch and 0.83 µmol maltose/ mL for the free enzyme. The improvements in the enzyme’s catalytic properties, stability and reusability obtained from immobilisation make amidrazone acrylic fabric support a good promising candidate for bio-industrial applications.

The aim of this study was to develop a chemical method for demythylation of curcumin. The methoxy groups reduced solubility and low bioavailability of curcumin. The treatment of curcumin with hydrogen bromide or choline chloride increased cucumin water solubility from 1 mg/mL to 30 or 25 mg/mL, respectively. 1 HNMR spectra showed that the chemical shift of O-methoxy groups at 3.9 ppm disappeared upon chemical treatment of curcumin, and indicated that these groups were removed especially after hydrogen bromide treatment. The antioxidant activity of treated curcumin and untreated curcumin was measured using different in vitro assays (i.e., 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azinobis (3-ethylbenzo-thiazoline-6-sulfonic acid) radical scavenging, and phosphomolybdenum complex formation). A remarkable increase in 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azino-bis (3-ethylbenzo-thiazoline-6-sulfonic acid) radical scavenging was observed as curcumin-hydrogen bromide > curcumin-Choline chloride > curcumin. The formation of phosphomolybdenum complex was found to increase in the order of curcumin-choline cloride > curcumin-hydrogen bromide > curcumin with EC 50 30, 41, and 114 µg/mL, respectively. In conclusion, hydrogen bromide-treated curcumin could be used as potential antioxidant in new functional foods.

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