Biochemical Properties of α-Amylase from Peel of Citrus sinensis cv. Abosora

Abstract

alpha-Amylase activity was screened in the peel, as waste fruit, of 13 species and cultivars of Egyptian citrus. The species Citrus sinensis cv. Abosora had the highest activity. alpha-Amylase AI from Abosora peel was purified to homogeneity using anion and cation-exchange, and gel filtration chromatographies. Molecular weight of alpha-amylase AI was found to be 42 kDa. The hydrolysis properties of alpha-amylase AI toward different substrates indicated that corn starch is the best substrate. The alpha-amylase had the highest activity toward glycogen compared with amylopectin and dextrin. Potato starch had low affinity toward alpha-amylase AI but it did not hydrolyze beta-cyclodextrin and dextran. Apparent Km for alpha-amylase AI was 5 mg (0.5%) starch/ml. alpha-Amylase AI showed optimum activity at pH 5.6 and 40 degrees C. The enzyme was thermally stable up to 40 degrees C and inactivated at 70 degrees C. The effect of mono and divalent metal ions were tested for the alpha-amylase AI. Ba2+ was found to have activating effect, where as Li+ had negligible effect on activity. The other metals caused inhibition effect. Activity of the alpha-amylase AI was increased one and half in the presence of 4 mM Ca2+ and was found to be partially inactivated at 10 mM Ca2+. The reduction of starch viscosity indicated that the enzyme is endoamylase. The results suggested that, in addition to citrus peel is a rich source of pectins and flavanoids, alpha-amylase AI from orange peel could be involved in the development and ripening of citrus fruit and may be used for juice processing.

Optimised amylases extraction from oat seeds and its impact on bread properties

“…2C showed that amylolytic activity of germinated seeds from oat (A. sativa) preserve more than 70% of its maximum activity in the range of pH of 5-7 with an optimum observed at pH 5.6. In the other hand, the same optimum pH was described for amylase extracted from the peel of Citrus sinensis [39].…”

“…␣-Amylases are generally active in the pH range from 5.5 to 8, but exceptions exist on both sides, mainly for enzymes of microbial origin [11,39]. In this study, the amylase activity was measured at different pHs ranged from 3.6 to 10.5.…”

Raw agro-industrial orange peel waste as a low cost effective inducer for alkaline polygalacturonase production from Bacillus licheniformis SHG10

“…Citrus fruit is one of the commercial crops in the Egyptian market (Mohamed et al 2010). Orange juice is one of the most consumed beverages today (Martin et al 2010).…”

Purification and characterization of an amylase from Opuntiaficus‐indica seeds

“…The optimum temperature and thermal stability of amylase from O. ficus‐indica seeds were higher than any other plant amylase reported so far except the α‐amylase of Korean pine seeds . The optimum temperature of α‐amylase from finger millet, wheat and peel of Citrus sinensis were reported to be 45–50, 40 and 40–50 °C, respectively …”