Date of Award
Spring 5-2021
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Food Science
First Advisor
Dr. Lilian Were
Second Advisor
Dr. Anuradha Prakash
Third Advisor
Dr. Aftab Ahmed
Fourth Advisor
Gemma Velayos
Abstract
Sunflower protein can be extracted at alkaline pH with sulfites or organic solvent de-phenolization of sunflower seed meals if greening is unwanted. This greening is promoted at alkaline pH when chlorogenic acid (CGA) oxidizes and reacts with free amine groups from amino acids, such as lysine. Thiol-containing dough conditioners: L-cysteine hydrochloride and reduced glutathione (GSH) were investigated as an alternative de-greening strategy to de-phenolization. Varying pH from 7 to 11 and concentration of 0.82 to 5.6 mM were randomly assigned by Response Surface Methodology (RSM) to evaluate the combined and additive greening inhibition effect of thiol and extraction pH. The powders with the highest greening were control (pH 8.93-9.3 and no added thiols) and pH 10.41 with 0.82 mM with thiols added. The powders with cysteine however had more browning than GSH. From RSM, the maximum greening inhibition was achieved with pH 8.71 and 4.23 mM cysteine and pH 8.51 and 3.78 mM GSH. Furthermore, fluorescence spectroscopy revealed that cysteine had a protective effect against alkaline denaturation, whereas GSH quenched fluorescence. Overall, the incorporation of thiol ingredients can be an alternative de-greening strategy for sunflower protein. These results could lead to extensive use of sunflower protein applications in non-allergenic and non-GMO plant-based meat alternatives or bakery products where greening is unwanted.
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Recommended Citation
Ishii, A.K. (2021). Color and structural modifications of alkaline extracted sunflower protein concentrates and isolates using L-cysteine and glutathione. Master's thesis, Chapman University. https://doi.org/10.36837/chapman.000228