Antioxidant and Angiotensin-Converting Enzyme Inhibitory Activity of Faba Bean-Derived Peptides After In Vitro Gastrointestinal Digestion: Insight into Their Mechanism of Action.

Faba bean flour, after in vitro gastrointestinal digestion, showed important antioxidant and angiotensin-converting enzyme (ACE) inhibitory activities. In the present study, 11 faba bean- derived peptides were synthesized to confirm their bioactivities and provide a deeper understanding of their mechanisms of action. The results revealed that 7 peptides were potent antioxidants, namely, NYDEGSEPR, TETWNPNHPEL, TETWNPNHPE, VIPTEPPH, VIPTEPPHA, VVIPTEPPHA, and VVIPTEPPH. Among them, TETWNPNHPEL had the highest activity in the ABTS (EC50 = 0.5 ± 0.2 mM) and DPPH (EC50 = 2.1 ± 0.1 mM) assays (p < 0.05), whereas TETWNPNHPE had the highest activity (p < 0.05) in the ORAC assay (2.84 ± 0.08 mM Trolox equivalent/mM). Synergistic and/or additive effects were found when selected peptides (TETWNPNHPEL, NYDEGSEPR, and VVIPTEPPHA) were combined. Four peptides were potent ACE inhibitors, where VVIPTEPPH (IC50 = 43 ± 1 µM) and VVIPTEPPHA (IC50 = 50 ± 5 µM) had the highest activity (p < 0.05), followed by VIPTEPPH (IC50 = 90 ± 10 µM) and then VIPTEPPHA (IC50 = 123 ± 5 µM) (p < 0.05). These peptides were noncompetitive inhibitors, as supported by kinetic studies and a molecular docking investigation. This study demonstrated that peptides derived from faba beans have multifunctional bioactivities, making them a promising food-functional and nutraceutical ingredient.

Improved in vitro gastrointestinal digestion protocol mimicking brush border digestion for the determination of the Digestible Indispensable Amino Acid Score (DIAAS) of different food matrices.

The Digestible Indispensable Amino Acid Score (DIAAS) is the new gold standard method for the assessment of protein nutritional quality. The DIAAS is evaluated with in vivo models, that are complex, constraining and costly. There is still no established method to assess it in vitro. In this study, we proposed to add a jejunal-ileal digestion phase to the standardized in vitro gastrointestinal digestion protocol developed by the International Network of Excellence on the Fate of Food in the Gastrointestinal Tract (INFOGEST protocol) to mimic brush border digestion and to enable DIAAS assessment in vitro in a more physiologically relevant manner. This jejunal-ileal digestion phase was performed with a porcine intestinal aminopeptidase as an alternative to brush border membrane extract, which is more difficult to obtain in a standardized way. This modified INFOGEST protocol was applied to various food matrices (faba bean, pea and soy flours, whey protein isolate and caseins) and the results were compared to published in vivo data to assess the model's physiological relevance. The addition of the jejunal-ileal digestion phase lead to a significant (p < 0.05) increase of 31 and 29 % in free and total amino acid digestibility, respectively, and of 83 % on average for the in vitro DIAAS values for all food matrices. Although the in vitro DIAAS remained underestimated compared to the in vivo ones, a strong correlation between them was observed (r = 0.879, p = 0.009), stating the relevance of this last digestion phase. This improved digestion protocol is proposed as a suitable alternative to evaluate the DIAAS in vitro when in vivo assays are not applicable.

Investigation of the nutritional quality of raw and processed Canadian faba bean (Vicia faba L.) flours in comparison to pea and soy using a human in vitro gastrointestinal digestion model.

Faba bean is an ancient legume that is regaining interest due to its environmental and nutritional benefits. Very little is known on the protein quality of the new faba bean varieties. In this study, the digestibility and the Digestible Indispensable Amino Acid Score (DIAAS) of the protein quality of three Canadian faba bean varieties (Fabelle, Malik and Snowbird) were compared to pea and soy using the harmonized in vitro digestion procedure developed by the International Network of Excellence on the Fate of Food in the Gastrointestinal Tract (INFOGEST). The impact of boiling on the nutritional quality of faba bean flours was also ascertained. Protein content in faba bean (28.7-32.5%) was lower than defatted soy (56.6%) but higher than pea (24.2%). Total phenolics and phytate content were higher (p < 0.05) in faba bean (2.1-2.4 mg/g and 11.5-16.4 mg/g respectively) and soy (2.4 mg/g and 19.8 mg/g respectively) comparatively to pea (1.3 mg/g and 8.9 mg/g). Trypsin inhibitor activity was significantly higher (p < 0.05) in soy (15.4 mg/g) comparatively to pea (0.7 mg/g) and faba bean (0.8-1.1 mg/g). The digestibility of free amino acids of raw faba bean flours ranged from 31 to 39% while the digestibility of total amino acids ranged from 38 to 39%. The in vitro Digestible Indispensable Amino Acid Score (IV-DIAAS) of raw faba bean flours ranged from 13 to 16 (when calculated based on free amino acid digestibility) to 32-38 (when calculated based on total amino acid digestibility) and was in a similar range to pea (13-31) and soy (11-40). Boiling modified the protein electrophoretic profile and decreased trypsin inhibitor activity (30-86% reduction), while total phenolics and phytate content were unaffected. The IV-DIAAS significantly decreased in all boiled legumes, possibly due to an increased protein aggregation leading into a lower protein digestibility (18-32% reduction). After boiling, the nutritional quality of faba bean was significantly lower (p < 0.05) than soy, but higher than pea. Our results demonstrate that faba bean has a comparable protein quality than other legumes and could be used in similar food applications.

Assessment of Protein Nutritional Quality of Novel Hairless Canary Seed in Comparison to Wheat and Oat Using In Vitro Static Digestion Models.

Hairless canary seed (Phalaris canariensis L.) is a novel true cereal that is now approved for human consumption in Canada and the United States. This true cereal grain has higher protein content (22%) than oat (13%) and wheat (16%) and represents a valuable source of plant proteins. Assessment of canary seed protein quality is therefore essential to evaluate its digestibility and ability to provide sufficient amounts of essential amino acids for human requirements. In this study, the protein nutritional quality of four hairless canary seed varieties (two brown and two yellow) were evaluated in comparison to oat and wheat. The assessment of anti-nutrients contents (phytate, trypsin inhibitor activity, and polyphenols) showed that brown canary seed varieties had the highest content in phytate and oat the highest in polyphenols. Trypsin inhibitor level was comparable among studied cereals, but slightly higher in the brown canary seed Calvi variety. In regard to protein quality, canary seed had a well-balanced amino acid profile and was particularly high in tryptophan, an essential amino acid normally lacking in cereals. The in vitro protein digestibility of canary seeds as determined by both the pH-drop and INFOGEST (international network of excellence on the fate of food in the gastrointestinal tract) protocols appears slightly lower than wheat and higher than oat. The yellow canary seed varieties showed better overall digestibility than the brown ones. For all studied cereal flours, the limiting amino acid was lysine. The calculated in vitro PDCAAS (protein digestibility corrected amino acid score) and DIAAS (digestible indispensable amino acid score) were higher for the yellow C05041 cultivar than the brown Bastia, similar to those of wheat, but lower than those of oat proteins. This study demonstrates the feasibility and utility of in vitro human digestion models for the assessment of protein quality for comparison purpose.

Health Beneficial Bioactivities of Faba Bean Gastrointestinal (In Vitro) Digestate in Comparison to Soybean and Pea.

Faba beans are a promising emerging plant-based protein source to be used as a quality alternative to peas and soy. In this study, the potential health beneficial activities of three Canadian faba bean varieties (Fabelle, Malik and Snowbird) were investigated after in vitro gastrointestinal digestion and compared to two commonly used legumes (peas and soy). The results revealed that the faba beans had a higher antioxidant activity than peas when assessed with the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assays, except for the Fabelle variety. In the oxygen radical absorbance capacity (ORAC) and the iron chelating assays, the faba beans had a lower antioxidant activity than soy. Interestingly, Fabelle and Snowbird showed a higher antioxidant effect than the peas and soy at the cellular level. The antihypertensive properties of Fabelle and Malik varieties were significantly higher than peas but lower than soy. The in vitro antidiabetic activity was higher for soy, but no differences were found at the cellular level. The faba bean peptides were further fractionated and sequenced by mass spectrometry. Eleven peptides with in silico predicted bioactivities were successfully identified in the faba bean digestate and support validating the health-promoting properties of peptides. The results demonstrate the bioactive potential of faba beans as a health-promoting food ingredient against non-communicable diseases.

Faba Bean: An Untapped Source of Quality Plant Proteins and Bioactives.

Faba beans are emerging as sustainable quality plant protein sources, with the potential to help meet the growing global demand for more nutritious and healthy foods. The faba bean, in addition to its high protein content and well-balanced amino acid profile, contains bioactive constituents with health-enhancing properties, including bioactive peptides, phenolic compounds, GABA, and L-DOPA. Faba bean peptides released after gastrointestinal digestion have shown antioxidant, antidiabetic, antihypertensive, cholesterol-lowering, and anti-inflammatory effects, indicating a strong potential for this legume crop to be used as a functional food to help face the increasing incidences of non-communicable diseases. This paper provides a comprehensive review of the current body of knowledge on the nutritional and biofunctional qualities of faba beans, with a particular focus on protein-derived bioactive peptides and how they are affected by food processing. It further covers the adverse health effects of faba beans associated with the presence of anti-nutrients and potential allergens, and it outlines research gaps and needs.

Scale up fractionation of components from novel glabrous brown and yellow canary seeds (Phalaris canariensis L.) and techno-functional properties of the resulting protein isolates.

Glabrous canary seed (Phalaris canariensis L.) is a novel true cereal grain produced primarily in Western Canada which has been approved for human consumption by the U.S. Food and Drug Administration and Health Canada in 2016. Due to its high protein content (22%), this new edible grain is emerging as an alternative source of plant proteins. In the present work, protein extractability from four novel glabrous (2 yellow and 2 brown) canary seeds varieties was improved based on the selection of optimal pH of protein solubilisation and precipitation. Solubilisation at pH 12 followed by acid precipitation at pH 5 were retained as optimal conditions. Scale up of the protein optimized wet fractionation process resulted in highly purified canary seed protein isolates (purity of 91 to 93%) with protein recovery yield of 65 to 69%. In parallel, for the others canary seed components, a good recovery yields were obtained for the oil fraction (6.1-6.7 g/100 g flour), starch fraction (48.1-54 g/100 g flour), and crude fiber fraction (15.1-19.7 g/100 g flour). The study of the functional properties of the obtained canary protein isolates revealed, higher solubility at acidic than alkaline region; enhanced fat and water holding capacities and notably higher foaming and emulsifying capacities than control soy protein isolate. With growing global demand for protein, glabrous canary seed has high potential in the food industry, particularly as a good source of functional gluten free cereal proteins.