Abstract
This study investigated the effects of partially substituting wheat flour (WF) with tiger nut flour (TNF) on the physical and sensory properties of different bread types. The substitution was performed at a WF:TNF ratio of 100:0, 90:10, 85:15, 80:20, 75:25 and 70:30 for butter bread (Bb), tea bread (Tb) and sugar bread (Sb). Substituting WF with TNF increased bread brownness, increased colour saturation and decreased lightness, showing the highest impact on Sb, followed by Tb and Bb. Additionally, bread-specific volume decreased significantly after 20 % (Bb), 25 % (Tb) and 30 % (Sb) TNF substitutions. Furthermore, substituting using 30 % TNF increased crumb hardness from approx. 1.87 N to 3.64 N (Bb), 3.46 N to 8.14 N (Tb) and 6.71 N to 11.39 N (Sb), and caused significant increases after 3 d storage to 17.80 N (Tb) and 21.08 N (Sb). Only a minimal effect on hardness of Bb (4.32N) was observed after storage. Substituting WF with 10 % TNF for Bb or 25 % TNF for Tb led to significantly higher consumer (N = 56) scores for all attributes and overall acceptability, but no significant effects on the overall acceptability of Sb were observed. Flash profiling showed frequently used descriptors for Bb as firm, moist, buttery, smooth and astringent. After 10% TNF substitution, descriptors were chewy, firm, sweet, porous, dry, caramel, whilst that of 30 % TNF were grainy, chocolate, brown, nutty and flaky. Substituting WF with TNF increased the lipids, fibre and minerals but decreased the protein and carbohydrate contents of bread. TNF substitution led to different physical and sensory changes depending on bread type, showing higher consumer acceptability for Bb, followed by Tb and Sb. The study is relevant for utilizing tiger nuts as an ingredient in bakery products.
Supplementary Materials
The following are available online at https://www.mdpi.com/article/10.3390/Foods2022-12955/s1.
Author Contributions
Conceptualization, E.E.A., N.K.-H., J.A. and J.A.-A.; methodology, J.A., J.A.-A. and N.K.-H.; software, N.K.-H. and E.E.A.; validation, J.A.-A. and E.E.A.; formal analysis, J.A.-A.; investigation, J.A. and N.K.-H.; resources, E.E.A. and N.K.-H.; data curation, J.A.-A.; writing—original draft preparation, N.K.-H.; writing—review and editing, J.A.-A. and E.E.A.; visualization, J.A.-A. and J.A.; supervision, E.E.A. and N.K.-H.; project administration, E.E.A., J.A.-A., N.K.-H. and J.A. All authors have read and agreed to the published version of the manuscript.
Funding
This research was partly funded by the Directorate for Research, Innovation and Consultancy (DRIC), University of Cape Coast (Grant no. UCC-IRB/EXT/2022/37).
Institutional Review Board Statement
The study was conducted in accordance with the Declaration of Helsinki, and approved by the Institutional Review Board of The University of Cape Coast, Ghana (protocol code 0MB No. 0990-0279, 25 August 2022) for studies involving humans.
Informed Consent Statement
Not applicable.
Data Availability Statement
Not applicable.
Conflicts of Interest
The authors declare no conflict of interest.
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