Isolation, Characterization And Identification Of Anti-Amylase Peptides From Cumin Seeds (Cuminum Cyminum)
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Date
2018-05
Authors
Siow, Hwee Leng
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Publisher
Universiti Sains Malaysia
Abstract
The main objective of this thesis was to discover novel anti-amylase peptides from cumin (Cuminum cyminum) seeds. This spice seed is high in protein and has a long history of use in traditional medicine, especially in treating diabetes, making it potential precursor proteins for producing peptides with potent bioactivities that can impart health-promoting effects beyond their nutritional values. The first phase of this study comprises fundamental studies on the extraction and characterization of soluble protein from cumin seeds. Through response surface methodology (RSM), a maximum yield of 44.98 mg soluble protein/g defatted sample was obtained under a condition of 0.6 h, 26.3 ˚C, and buffer-to-sample ratio of 10 mL/g. Based on its amino acid composition, the hydrophobic (37.4%) and hydrophilic (62.6%) characters of the protein suggest a high potential for causing inhibitory interactions with α-amylase. However, the soluble proteins only gave an approximately 6.7% inhibitory activity against α-amylase. The lack of inhibition was likely related to the structural constraints of the protein tertiary structure, and thus, Protamex®-assisted hydrolysis was applied to liberate bioactive peptide sequences from the protein chain where they are encrypted. Again, RSM was adopted to optimize the hydrolysis process. The optimum condition was 42.6 ˚C, 1.83 h, and enzyme-to-substrate ratio of 70 (U/mg), resulting in a 2.5-fold higher inhibitory activity compared to the intact proteins. The optimized protein hydrolysates were subsequently subjected to fractionation, followed by peptide sequence identification. The smallest peptide fraction (< 15 kDa) was the only fraction to display α-amylase inhibitory activity, and in this fraction, 56 peptide sequences (ALC > 80%) were identified using tandem mass spectrometry LTQ-Orbitrap.
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Keywords
Discover novel anti-amylase peptides from cumin , long history of use in traditional medicine