Full-fat soybean origin and thermal processing affect protein secondary structure, in vitro digestion kinetics, and predicted standardized ileal amino acid digestibility in broiler chickens.
4 affiliations
- 1Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada.
- 2Department of Animal Sciences, Pwani University, Kilifi, Kenya.
- 3Department of Animal Production, University of Nairobi, Nairobi, Kenya.
- 4Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada. [email protected].
Abstract
Background
This study evaluated the chemical composition, protein secondary structure, crude protein (CP) solubilization, and in-vitro amino acid (AA) digestibility of three Kenyan full-fat soybean (FFSB) samples (S1, S2, S3) with unknown processing histories and compared with Canadian samples: raw FFSB, extruded FFSB at 160.0 °C, and FFSB roasted at 136.7 °C, 151.7 °C, or 154.4 °C. Protein structure was characterized using attenuated total reflectance-Fourier transform infrared spectroscopy. A two-phase in-vitro digestion model was used to determine CP solubilization and AA digestibility. Observed in-vivo standardized ileal digestibility (SID) values from a study using FFSB roasted at 136.7 °C were regressed on corresponding in-vitro AA digestibility values to generate predicted SID values.Results
Thermal processing reduced trypsin inhibitor activity (TIA) in Canadian FFSB from 17.42 TIU/mg in raw FFSB to 3.85 TIU/mg in extruded FFSB and to 4.77, 4.59, and 2.30 TIU/mg in samples roasted at 136.7, 151.7, and 154.4 °C, respectively. In contrast, Kenyan Samples 1, 2, and 3 had residual TIA values of 8.00, 6.00, and 12.00 TIU/mg, respectively. Protein secondary structure differed among samples (P < 0.001), with the 136.7 °C-roasted sample having greater aggregated β-sheet and β-turn contents and lower random coil content than most samples. CP solubilization differed among samples at each digestion time point (P < 0.001). At the end of the intestinal phase, processed Canadian samples had greater CP solubilization than raw FFSB but did not differ from one another, whereas Kenyan Samples 2 and 3 were comparable to Canadian raw FFSB. In-vitro AA digestibility differed among samples for all AA (P ≤ 0.001). For mean total AA digestibility, the 154.4 °C and 151.7 °C-roasted sample had the highest digestibility; Kenyan Sample 1 was greater than Samples 2 and 3, and Sample 3 did not differ from raw FFSB. The regression model showed agreement at the mean level but larger prediction errors for lysine, aspartic acid, and proline, indicating AA-specific limitations.Conclusions
Overall, processing conditions and ingredient origin influenced FFSB quality, with roasting at 151.7-154.4 °C producing favorable structural and digestibility responses. The variability observed among Kenyan samples highlights the need for routine quality assessment of commercial FFSB before feed formulation.
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BibTeX
@article{njeri2026fullfat,
title = {{Full-fat soybean origin and thermal processing affect protein secondary structure, in vitro digestion kinetics, and predicted standardized ileal amino acid digestibility in broiler chickens.}},
author = {Felix M Njeri and Adriana Leticia Ciola and Lonita A Manoa and Munene Kithama and Joyce G Maina and Charles K Gachuiri and Lee-Anne Huber and Elijah G Kiarie},
journal = {Journal of animal science and biotechnology},
year = {2026},
month = nov,
doi = {10.1186/s40104-026-01512-w},
url = {https://europepmc.org/article/MED/42968187},
note = {CC BY},
}
RIS
TY - JOUR
TI - Full-fat soybean origin and thermal processing affect protein secondary structure, in vitro digestion kinetics, and predicted standardized ileal amino acid digestibility in broiler chickens.
AU - Felix M Njeri
AU - Adriana Leticia Ciola
AU - Lonita A Manoa
AU - Munene Kithama
AU - Joyce G Maina
AU - Charles K Gachuiri
AU - Lee-Anne Huber
AU - Elijah G Kiarie
PY - 2026
DA - 2026/11/02
JO - Journal of animal science and biotechnology
DO - 10.1186/s40104-026-01512-w
UR - https://europepmc.org/article/MED/42968187
AB - Background This study evaluated the chemical composition, protein secondary structure, crude protein (CP) solubilization, and in-vitro amino acid (AA) digestibility of three Kenyan full-fat soybean (FFSB) samples (S1, S2, S3) with unknown processing histories and compared with Canadian samples: raw FFSB, extruded FFSB at 160.0 °C, and FFSB roasted at 136.7 °C, 151.7 °C, or 154.4 °C. Protein structure was characterized using attenuated total reflectance-Fourier transform infrared spectroscopy. A two-phase in-vitro digestion model was used to determine CP solubilization and AA digestibility. Observed in-vivo standardized ileal digestibility (SID) values from a study using FFSB roasted at 136.7 °C were regressed on corresponding in-vitro AA digestibility values to generate predicted SID values.Results Thermal processing reduced trypsin inhibitor activity (TIA) in Canadian FFSB from 17.42 TIU/mg in raw FFSB to 3.85 TIU/mg in extruded FFSB and to 4.77, 4.59, and 2.30 TIU/mg in samples roasted at 136.7, 151.7, and 154.4 °C, respectively. In contrast, Kenyan Samples 1, 2, and 3 had residual TIA values of 8.00, 6.00, and 12.00 TIU/mg, respectively. Protein secondary structure differed among samples (P < 0.001), with the 136.7 °C-roasted sample having greater aggregated β-sheet and β-turn contents and lower random coil content than most samples. CP solubilization differed among samples at each digestion time point (P < 0.001). At the end of the intestinal phase, processed Canadian samples had greater CP solubilization than raw FFSB but did not differ from one another, whereas Kenyan Samples 2 and 3 were comparable to Canadian raw FFSB. In-vitro AA digestibility differed among samples for all AA (P ≤ 0.001). For mean total AA digestibility, the 154.4 °C and 151.7 °C-roasted sample had the highest digestibility; Kenyan Sample 1 was greater than Samples 2 and 3, and Sample 3 did not differ from raw FFSB. The regression model showed agreement at the mean level but larger prediction errors for lysine, aspartic acid, and proline, indicating AA-specific limitations.Conclusions Overall, processing conditions and ingredient origin influenced FFSB quality, with roasting at 151.7-154.4 °C producing favorable structural and digestibility responses. The variability observed among Kenyan samples highlights the need for routine quality assessment of commercial FFSB before feed formulation.
SN - 1674-9782
SN - 2049-1891
ER -