Title

Dual enzyme-assisted extraction of total carotenoids from lemon (citrus limo) peels using xylanase and pectinase

Date of Completion

2018

Document Type

Thesis

Degree Name

Bachelor of Science in Biochemistry

Keywords

Carotenoids.

Abstract

Effects of varying enzyme proportions coupled with different incubation periods on the levels and antioxidant capacity of lemon peels carotenoids obtained through dual-enzyme-assited extraction significantly improved the recovery of total carotenoids in comparison with solvent-only extraction. Increase in incubation time slightly improved the recovery of total carotenoids for 25:75 and 50:50 ratios of xylanase-to-pectinase. Highest total carotenoid content (TC) was noted for the extract obtained from 50:50 xylanase-to-pectinase. Highest total carotenoid content (TC) was noted for the exctract obtained from 50:50 xylanse: pectinase treatment at 90 min incubation yielding 36.16 ug phytofluence equivalent/g lemon peel sample. UV-Visible absorption spectra showed consistently the presence of a major peak at around 330 nm similar to that of phytofluence but a small shoulder was observed at around 290 nm at certain conditions (i.e. certain ratio and incubation time) worthy of further investigations. Considering antioxidant activity of the carotenoid extracts, shorter incubation time gave the highest scavenging activity, though low TC. The use of 75:25 xylanase:pectinase ratio and incubation period of 30 min gave statistically comparable TC (35.84 ug/g) with that of 50:50 xylanae:petinase at 90 min (36.16 ug/g) while the antioxidant activity acity radical scavenging tended to be higher at the shorter incubation time. Fourier-Transform Infrared (FTIR) spectra confirmed the presence of hyroxyl-containg carotenoids as well as aromatic ring containing ones, indicating that majority of the recovered carotenoids from lemon peels using enzyme-assisted protocols were oxocarotenoids in nature.

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