Closing the fibre gap in refined cereal product – quality and health

This thesis explores the incorporation of refined and chemically modified dietary fibres (DF) into widely consumed cereal products—pasta, cake, and bread—as a strategy to help close the fibre intake gap. Despite recommendations of 25–38 g/day, actual intake remains low, partly due to the dominance of refined cereals with reduced fibre content. Whole grain alternatives are more nutritious but often poorly accepted due to their texture and taste. Reformulating familiar refined products to enhance fibre content presents a practical strategy to help close the fibre gap and support public health. Current literature shows that most research targets the incorporation of individual fibre ingredients into food products, while human intervention trials typically evaluate these fibres in their isolated form, not as part of a food matrix. To address this gap, this thesis employed two complementary approaches. Firstly, fibre blends were optimised using Response Surface Methodology. In pasta, enrichment with cellulose, pectin, and resistant starch (RS) type IV improved sensory and techno-functional properties while reducing starch digestibility. The optimised pasta is high in fibre, with a 125% increase in DF compared to the control pasta. A similar strategy was applied to cake using a broader mix of fibres (arabinoxylan, β-glucan, cellulose, pectin, and RS-IV) which extended shelf life, enhanced nutritional quality, and improved the sensory profile. The optimised cake qualifies as a high-fibre product according to the AOAC 991.43 method, or as a source of fibre based on the AOAC 2017.16 method. By employing both traditional and updated analytical approaches, these findings enable direct comparisons with previous research, effectively bridging methodological gaps between older and more recent studies in the field. Bread enriched with arabinoxylan, cellulose, and RS-IV showed greater structural impact than other products, with a 12.4% reduction in gluten strength and 24.4% longer development time, yet still delivered significant nutritional gains. Overall, the dietary fibre content of the white bread was increased by 128%. Secondly, the effects of different RS types (RS-II, RS-III, RS-IV) on bread quality and nutritional profile were compared, alongside two fibre analysis methods. All RS-enriched breads met the 'high in fibre' claim under AOAC 991.43, providing 17–31.5% of daily fibre per 50g, but only RS-II and RS-III met this threshold under AOAC 2017.16, with RS-IV classified as a 'source of fibre'. Overall, this research supports fibre-rich reformulation of refined staples as a feasible route to improving public health. Future research will incorporate these foods as part of a high-fibre diet in a human intervention study to evaluate their impact on health outcomes such as glycemia, energy intake, satiety, and gut microbiome composition and function.

Grantor dc:publisher

University College Cork

Year dc:date.issued

2025

Author dc:creator

• Sempio, Rebecca

Advisors dc:contributor.advisor

• Arendt, Elke K.
• Sahin, Aylin

• Dietary fibre
• Cereal products
• Response Surface Methodology
• Starch digestion
• Sensory analyses

Statement dc:rights

• © 2025, Rebecca Sempio.

Licence dc:rights.uri

• https://creativecommons.org/licenses/by/4.0/

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/10468/18468

OAI identifier oai:identifier

oai:cora.ucc.ie:10468/18468