Effect of protein concentration and N2 gas injection on expansion dynamics and physical properties of extruded puffed snacks produced with corn starch and pea protein blends

Simple item page
dc.contributor.authorLuo, Siwen
dc.contributor.examiningcommitteeScanlon, Martin (Food and Human Nutritional Sciences)
dc.contributor.examiningcommitteeBandara, Nandika (Food and Human Nutritional Sciences)
dc.contributor.examiningcommitteePaliwal, Jitendra (Biosystems Engineering)
dc.contributor.examiningcommitteeJoye, Iris (University of Guelph)
dc.contributor.supervisorKoksel, Filiz
dc.date.accessioned2025-03-19T20:27:16Z
dc.date.available2025-03-19T20:27:16Z
dc.date.issued2025-03-18
dc.date.submitted2025-03-18T19:06:20Zen_US
dc.degree.disciplineFood and Human Nutritional Sciences
dc.degree.levelDoctor of Philosophy (Ph.D.)
dc.description.abstractThe rising demand for nutritious, high-protein snacks has sparked interest in developing alternatives to traditional starch-based puffed snacks, which are often low in protein. However, incorporating high protein levels into puffed snacks poses challenges, as protein can negatively impact expansion and texture during extrusion. Traditional extrusion methods struggle to balance high protein content with acceptable snack quality. Nitrogen gas-assisted extrusion, a relatively new approach, introduces nitrogen gas as an additional blowing agent during extrusion. Despite its promise, a comprehensive understanding of how nitrogen gas affects expansion dynamics and the physical properties of high-protein extrudates is still limited. This study comprehensively examined the effect of nitrogen gas injection pressure (0, 150, and 300 kPa) and feed protein content (0, 10, 20, 30, 40, and 50%) on extrudate expansion dynamics, expansion indices, density, microstructure, mechanical properties, and texture. In addition, the employment of high-speed thermal imaging and X-ray microtomography provided detailed and novel insights into nitrogen gas’s effects on expansion behavior and microstructural characteristics. Results showed that the effects of nitrogen gas injection on extrudate properties are a function of feed protein content. Due to this significant interaction, it was challenging to isolate the impact of individual factors on specific extrudate properties. In general, high radial expansion, characterized by larger cell sizes, was desirable for enhancing extrudate crispness and crunchiness. However, this increase in radial expansion could possibly lead to greater extrudate hardness, which is typically considered unfavorable. Most prominently, nitrogen gas significantly improved longitudinal expansion, microstructure uniformity, and reduced cell wall thickness, particularly at the highest protein level (50%). At this protein level, nitrogen gas injection also led to lower extrudate density, reduced hardness, and improved crispness, mitigating the negative textural impacts typically associated with high protein levels. This research filled a critical gap in literature by demonstrating the potential of nitrogen gas-assisted extrusion to enhance the quality of high-protein snacks, offering a viable solution for overcoming the challenges of protein incorporation in snack formulas. The findings provided a foundation for optimizing extrusion conditions in the production of healthier, protein-rich snacks that meet growing consumer demand for nutrition and sensory appeal.
dc.description.noteMay 2025
dc.identifier.urihttp://hdl.handle.net/1993/38937
dc.language.isoeng
dc.subjectHigh-protein snacks
dc.subjectPhysical blowing agents
dc.subjectGas-assisted extrusion
dc.subjectExpansion dynamics
dc.subjectBubble growth
dc.subjectBubble shrinkage
dc.subjectTexture
dc.subjectMechanical properties
dc.subjectMicrostructure
dc.titleEffect of protein concentration and N2 gas injection on expansion dynamics and physical properties of extruded puffed snacks produced with corn starch and pea protein blends
local.subject.manitobano
oaire.awardTitleDiscovery Grants and Create Grants programs
project.funder.nameNatural Sciences and Engineering Research Council of Canada
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
Luo_Siwen.pdf
Size:
3.72 MB
Format:
Adobe Portable Document Format
Description:
A portion of the research is currently under submission for publication in a peer-reviewed journal.
Download
License bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
license.txt
Size:
770 B
Format:
Item-specific license agreed to upon submission
Description:
Download
Collections
FGS - Electronic Theses and Practica