Characterisation of pulse protein ingredients produced using different protein sources and processing technology, and potential for application in milk alternatives
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Date
2022-02-25
Authors
Vogelsang-O'Dwyer, Martin
Journal Title
Journal ISSN
Volume Title
Publisher
University College Cork
Published Version
Abstract
In the face of the growing global population along with climate and food security
concerns, there is currently much interest in developing plant protein ingredients from
sustainable sources. Pulses are a valuable source of protein which could play an
increased role in reducing our reliance on animal protein. Pulse protein ingredients can
potentially provide the required functional properties (e.g., solubility, emulsifying,
gelling, foaming) for a range of food applications. However, further development is
necessary in order to increase our understanding and maximise the utility of pulse
proteins as demand increases. This thesis addresses how protein source and processing
can impact various properties of ingredients, including functional, nutritional and
environmental aspects. In addition, the application of pulse proteins in high protein
milk alternatives is examined. Furthermore, the impact of enzymatic hydrolysis on
physicochemical and functional properties is explored. Protein isolates from blue lupin
(Lupinus angustifolius) and white lupin (L. albus) were compared to assess the
influence of protein source on various properties. Electrophoresis revealed major
differences in molecular weight distribution. Solubility and foaming properties were
similar for both isolates, while major differences in thermal gelling behaviour were
found, with white lupin protein gelling at a lower concentration (7%) compared to blue
lupin (23%). Both isolates were low in FODMAPs (fermentable mono-, di,
oligosaccharides and polyols). In addition, the life cycle assessment (LCA) showed
generally lower environmental impacts for the lupin isolates compared to milk powder
per kg protein. Faba bean protein-rich flour (FPR) produced using dry fractionation
was compared to faba bean protein isolate (FPI) produced using wet fractionation.
Protein content of dry matter was lower for FPR (64.1%) compared to FPI (90.1%)
Overall, superior functionality was found for FPR, including solubility and foaming
properties. Wet processing (FPI) was found to be effective for removal of vicine, and
trypsin inhibitors and FODMAPs. In the LCA, lower environmental impacts were
found for FPR than FPI; however, both FPR and FPI had much lower impacts
compared to milk powder. Milk alternatives were produced with blue lupin (BL) or
white lupin (WL) protein isolate, with similar protein and fat content to low-fat cow’s
milk. Both BL and WL milk alternatives had good colloidal stability and were suitable
for low FODMAP diets. Increased homogenisation pressure (780 bar vs 180 bar)
resulted in smaller particle size and increased stability for both BL and WL milk
alternatives. WL milk alternative homogenised at 780 bar had the lowest separation
rate, comparable to low fat cow’s milk, indicating good resistance to creaming. The
effects of enzymatic hydrolysis on the physicochemical and functional properties of
lentil protein isolate were assessed, in a comparison of three proteases. Hydrolysis with
Alcalase or Novozym 11028 resulted in considerably higher solubility from pH 4–6,
where the control showed poor solubility. Hydrolysis with Flavourzyme resulted in
moderately increased solubility in this pH range, but slightly decreased solubility at
neutral pH. Foaming properties were not impacted significantly by hydrolysis.
Hydrolysis with Alcalase resulted in larger particle size and higher viscosity compared
to the control. Overall, these studies provide useful insight into the properties of pulse
protein ingredients which depend on pulse type and ingredient processing,
modification with enzymatic hydrolysis, as well as their suitability for high protein
milk alternatives.
Description
Keywords
Pulse protein , Functional properties , Lupin , Faba , Lentil , Processing , Milk alternative
Citation
Vogelsang-O'Dwyer, M. 2022. Characterisation of pulse protein ingredients produced using different protein sources and processing technology, and potential for application in milk alternatives. PhD Thesis, University College Cork.