https://search.dev.ndltd.org/etd/massey/oai:mro.massey.ac.nz:10179/17960
type: CreativeWork
name: Effects of non-thermal food processing technologies on physicochemical properties of quinoa protein isolate dispersions : a thesis presented in partial fulfilment of the requirement for the degree of Master of Food Technology at Massey University, Auckland, New Zealand
description: The effects of high-pressure homogenisation (HPH) (0-50 MPa for 1 pass), sonication (14.4 W, 10 mL for 0-15 min), high hydrostatic pressure (HHP) (0-600 MPa for 15 min) and heat treatment (81 ± 2 °C for 30 min) on structural and physicochemical properties changes of quinoa protein isolate (QPI) dispersions were investigated in this thesis. Firstly, the impacts of HPH on the physicochemical, microstructural, and rheological properties of QPI suspensions were studied. Individual protein bands were kept unchanged with HPH treatment up to 50 MPa, as revealed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). After HPH treatment at 50 MPa, large protein aggregates were disrupted, and particle size was substantially reduced from ~8.2–0.5 µm. Concurrently, water solubility, emulsifying, and foaming capability were significantly enhanced. QPI molecules after HPH treatment became more flexible with increased surface hydrophobicity and adsorbed at the air-water and oil-water interfaces faster, resulting in a more rapid decrease of surface tension and interfacial tension. The secondary structure of QPI proteins was not significantly altered after HPH treatment as probed by Fourier transform infrared spectroscopy (FTIR). All QPI suspensions formed weak gels after thermal treatment (85 °C, 30 min), and HPH-treated QPI suspensions resulted in a stronger gel strength with a more compact and homogeneous protein network microstructure. Secondly, 1% w/w QPI was exposed to sonication or HHP treatments at pH 5, pH 7, and pH 9. As revealed by SDS-PAGE, substantial amounts of 11S globulin participated in the formation of aggregates via the disulfide (S-S) bond under HHP, particularly at pH 7 and pH 9. Free sulfhydryl (SH) groups and surface hydrophobicity were increased after the sonication treatment, while an opposite trend was observed in HHP-treated samples. Finally, the sonication treatment induced a significant improvement in the solubility and a reduction in p…
abstract: The effects of high-pressure homogenisation (HPH) (0-50 MPa for 1 pass), sonication (14.4 W, 10 mL for 0-15 min), high hydrostatic pressure (HHP) (0-600 MPa for 15 min) and heat treatment (81 ± 2 °C for 30 min) on structural and physicochemical properties changes of quinoa protein isolate (QPI) dispersions were investigated in this thesis. Firstly, the impacts of HPH on the physicochemical, microstructural, and rheological properties of QPI suspensions were studied. Individual protein bands were kept unchanged with HPH treatment up to 50 MPa, as revealed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). After HPH treatment at 50 MPa, large protein aggregates were disrupted, and particle size was substantially reduced from ~8.2–0.5 µm. Concurrently, water solubility, emulsifying, and foaming capability were significantly enhanced. QPI molecules after HPH treatment became more flexible with increased surface hydrophobicity and adsorbed at the air-water and oil-water interfaces faster, resulting in a more rapid decrease of surface tension and interfacial tension. The secondary structure of QPI proteins was not significantly altered after HPH treatment as probed by Fourier transform infrared spectroscopy (FTIR). All QPI suspensions formed weak gels after thermal treatment (85 °C, 30 min), and HPH-treated QPI suspensions resulted in a stronger gel strength with a more compact and homogeneous protein network microstructure. Secondly, 1% w/w QPI was exposed to sonication or HHP treatments at pH 5, pH 7, and pH 9. As revealed by SDS-PAGE, substantial amounts of 11S globulin participated in the formation of aggregates via the disulfide (S-S) bond under HHP, particularly at pH 7 and pH 9. Free sulfhydryl (SH) groups and surface hydrophobicity were increased after the sonication treatment, while an opposite trend was observed in HHP-treated samples. Finally, the sonication treatment induced a significant improvement in the solubility and a reduction in p…
author: Luo, Lan
date published: 2022
date modified: 2026-07-27T20:17:28Z
provider: Massey University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Massey University