Massey Documents by Type

Permanent URI for this communityhttps://mro.massey.ac.nz/handle/10179/294

Browse

Filters

1995 - 199912020 - 20251

Settings

Subject: search.filters.subject.Fava bean

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Fabrication, characterisation, and application of functional protein aggregates derived from faba bean protein isolates : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, Auckland, New Zealand
    (Massey University, 2025-07-14) Hu, Yinxuan
    This thesis explores the preparation, characterisation, and applications of plant protein aggregates, derived from faba bean protein isolate (FPI). The formation of FPI aggregates was accomplished by various methods, including pH adjustments, salt addition, heat treatment, sonication, and thermosonication (TS). The physico-chemical properties and technofunctional characteristics of FPI aggregates formed by different treatments, such as ζ-potential, solubility, emulsification capability, and particle sizes, were also characterised in this study. Furthermore, the microstructure of the FPI aggregates in solutions was examined using various techniques, including light scattering, microscopies (TEM and SEM), and small angle neutron scattering. Additionally, this project further developed the TS method for formation of FPI fibrillar aggregates at pH 2 and amorphous aggregates at pH 7. The characteristics of FPI aggregates formed by TS and conventional heat treatment (CH) were analysed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and liquid chromatography linked to tandem mass spectrometry (LC-MS/MS). In addition, Thioflavin T (ThT) fluorescence, Fourier-transform infrared spectroscopy (FTIR) and circular dichroism (CD) were applied to investigate the differences in secondary structure between CH-treated FPI and TS-treated FPI, indicating that TS effectively converted FPI structures to be enriched in β-sheets. The gelation behaviours of different FPI aggregates at 10 wt% were studied by examining their rheological properties and observing the microstructure using scanning electron microscopy (SEM), indicating that TS-treatment of FPI at pH 7 facilitated the formation of stronger protein hydrogels. The functionality of FPI aggregates fabricated from various treatments at the oil-water and oil-air-water interfaces was also characterised. Emulsions (O/W) with various oil factions (ϕ) ranging from 0.2 (dilute emulsions) to 0.75 (high internal phase emulsions, HIPEs), were stabilised by suitable FPI aggregates selected based on their different physico-chemical properties. The findings indicate that higher FPI concentrations (~5 wt%) and pH values (~pH 9) result in better emulsification capabilities. Among all FPI aggregates studied in this project, fibrillar aggregates exhibited the best emulsification performance as they could stabilise emulsions with oil content up to 75% (v/v). However, emulsions stabilised by FPI aggregates induced from TS at pH 7 had the greatest application potential due to their long-term stability (up to 28 days) and compatibility with a neutral pH environment. Therefore, another study in this thesis was to investigate the application of FPI aggregates in stabilising vegetable oil-based whipped creams. TS-treated FPI at pH 7 exhibited superior functional properties compared to other treatments, such as CH and ultrasonication (US), in terms of visual appearance, overrun, and stability of whipped cream. Overall, this project provides fundamental insights into the physical-chemical and techno-functional properties of FPI aggregates, including their ability to stabilise and form emulsions, gels, and foams, with an emphasis on their potential applications in innovative food products such as 3D-printed emulsion gels and plant based whipped cream. The enhanced physicochemical and techno-functional properties of FPI aggregates fabricated in this study showed a great application potential as novel food ingredients for formulation of plant-based food products.
  • Thumbnail Image
    Item
    The structural and functional effects of electromagnetic fields on the plasma membrane of Vicia faba, the broad bean : a thesis dissertation presented in partial fulfilment of the requirements for the degree of Master of Science, Plant Biology at Massey University
    (Massey University, 1995) Stange, Bernadette Cathy
    Vicia faba (broad bean) root-tip cells were exposed to electromagnetic fields at 50 and 60 Hz, square and sine waveforms and 0.1, 1, and 10 gauss. Levels of [³H]-alanine uptake and ion efflux were measured at these parameters and compared to unexposed control seedlings. The ultrastructure of cortical cells from the zone of elongation exposed to a 1 gauss, 50 hertz, squarewave field was studied under the electron microscope. In the first uptake trials alanine uptake via ATP dependant membrane carriers was stimulated by square waveform fields, but inhibited by 50 Hz fields. In the replicate trials alanine uptake was inhibited by both 50 and 60 hertz, square and sine waveform fields. The different response between trials was attributed to aging of the seeds used, owing to a six month chemical supply delay. This apparent aging of the seeds appeared to increase seedling susceptibility to modification by electromagnetic fields. The ion efflux trials saw no significant change in the pattern of ion efflux (as measured by conductivity) from exposed cells, although there was a significant decrease in hydrogen ion efflux at 0.1 and 1 gauss. A secondary inhibition effect on hydrogen ion efflux occurred with exposure to sine and square waveforms, but only in the presence of 0.1 and 1 gauss field amplitudes. The reduction in hydrogen efflux was most probably due to the inhibition of an active ATP dependent membrane carrier responsible for maintaining the transmembrane electrochemical gradient. Under the electron microscope exposed cortex cells from the zone of elongation had significantly more pinocytotic vesicles than the controls. These vesicles were believed to be involved in bulk uptake of extracellular media, which may permit exposed cells to expand more rapidly than the controls. Thus the functioning of three separate membrane transport systems were shown to be susceptible to functional modification, at least in the short term, by extremely low frequency electromagnetic fields. This introduces the potential for an enormous array of downstream effects to echo through-out the organism via signal transduction pathways.