Trypsin Inhibitor Activity Research Articles

Phenolic, antioxidant capacity and antinutritional compounds in different Australian acacia seeds

Abstract The polyphenols, antioxidant activities and antinutrients in Acacia seeds of different species, growing locations and harvest years were characterised in this study. The main phenolic compounds were 6-hydroxy-2-methylindole and 2,2′-methylenebis(6-tert-butyl-methylphenol). The total phenolic and total flavonoid contents of the free polyphenol fractions were positively correlated, while the total phenolic content and ABTS, DPPH and ORAC of the bound fractions were negatively correlated. There were no differences in trypsin and chymotrypsin inhibition activities across all seed batches. The lowest phytate (11.1038 ± 0.006 mg/g) and tannin contents (2.0323 ± 0.7462%) were found in Acacia retinodes Amphitheatre 2020 and A. retinodes Firgrove 2022, respectively. The highest saponin (45.4578 ± 12.2990%) and oxalate contents (4.2396 ± 0.7949%) were found in A. retinodes Grampians 2020 and A. retinodes Firgrove 2020, respectively. The results of this study showed differences in antioxidant activities and antinutrients content which implies that compositional values should not be extrapolated between different species and harvest years.

Analysis of Protein Inhibitors of Trypsin in Quinoa, Amaranth and Lupine Seeds. Selection and Deep Structure–Function Characterization of the Amaranthus caudatus Species

Protease inhibitors are biomolecules with growing biotechnological and biomedical relevance, including those derived from plants. This study investigated strong trypsin inhibitors in quinoa, amaranth, and lupine seeds, plant grains traditionally used in Andean South America. Amaranth seeds displayed the highest trypsin inhibitory activity, despite having the lowest content of aqueous soluble and thermostable protein material. This activity, directly identified by enzymatic assay, HPLC, intensity-fading mass spectrometry (IF-MS), and MS/MS, was attributed to a single protein of 7889.1 Da, identified as identical in Amaranthus caudatus and A. hybridus, with a Ki of 1.2 nM for the canonical bovine trypsin. This form of the inhibitor, which is highly homogeneous and scalable, was selected, purified, and structurally–functionally characterized due to the high nutritional quality of amaranth seeds as well as its promising agriculture–biotech–biomed applicability. The protein was crystallized in complex with bovine trypsin, and its 3D crystal structure resolved at 2.85 Å, revealing a substrate-like transition state interaction. This verified its classification within the potato I inhibitor family. It also evidenced that the single disulfide bond of the inhibitor constrains its binding loop, which is a key feature. Cell culture assays showed that the inhibitor did not affect the growth of distinct plant microbial pathogen models, including diverse bacteria, fungi, and parasite models, such as Mycoplasma genitalium and Plasmodium falciparum. These findings disfavour the notion that the inhibitor plays an antimicrobial role, favouring its potential as an agricultural insect deterrent and prompting a redirection of its functional research.

Effects of Substituting Soybean Meal With Winged Bean on Growth, Physiological Function and Flesh Quality of Indian Butter Catfish (Ompok bimaculatus).

Soybean meal (SBM) remains a primary protein source in aquafeeds. This study investigated the potential of winged bean (Psophocarpus tetragonolobus) meal as a SBM replacement in diets for butter catfish (Ompok bimaculatus) juveniles (mean weight: 1.24 ± 0.23 g). A response surface methodology (RSM) optimized processing conditions to minimize antinutritional factors (ANFs) in winged bean meal (WBM), resulting in minimized tannin (4.14 ± 0.018 mg/g at 40 min, 110°C), phytate (0.414 ± 0.0009 mg/g at 31.67 min, 104.5°C) and trypsin inhibitor activity (70.8 ± 0.06% inhibition at 20 min, 90°C). Experimental diets containing 30% crude protein and varying levels of WBM substitution (0%, 25%, 50%, 75% and 100%) were fed for 70 days. Growth performance, measured by weight gain, was significantly higher in the 25% substitution group (p < 0.05) but not significantly different from the control at 50% substitution. Quadratic regression analysis predicted an optimal inclusion level of 15.10% for maximizing weight gain. Survival rates did not differ significantly among treatments (p > 0.05). Feed utilization was most efficient in the 25% substitution group. Haematological and immunological parameters indicated improved fish health at the 25% substitution level. Flesh quality attributes, including texture profile analysis, pH and antioxidant activity, were superior in the 25% group compared to other treatments. However, colour enhancement was more pronounced at higher inclusion levels (≥50%). While flesh pH and antioxidant activity suggested potential stress at higher winged bean inclusion levels, the 25% group showed improved values compared to the control. These findings suggest that WBM can potentially replace up to 50% of SBM in butter catfish diets, offering a promising alternative protein source. This study provides preliminary data on the feasibility and prospects of utilizing WBM in O. bimaculatus diets.

Recovery of Proteases and Protease Inhibitors from Ganoderma spp. Cultivated in Amazonian Lignocellulose Wastes.

Ganoderma spp. are a great source of bioactive molecules. The production and recovery of bioactive molecules vary according to strain, growth substrate, and extraction solution. Variations in protease and their inhibitors in basidiomata from a commercial strain (G. lingzhi) and an Amazonian isolate (Ganoderma sp.) cultivated in Amazonian lignocellulosic wastes and extracted with different solutions are plausible and were investigated in our study. Basidiomata from cultivation in substrates based on açaí seed, guaruba-cedro sawdust and three lots of marupá sawdust were submitted to extraction in water, Tris-HCl, and sodium phosphate. Protein content, proteases, and protease inhibitors were estimated through different assays. The samples were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR). Tris-HCl provided higher protein extraction from Ganoderma sp. and higher caseinolytic, gelatinolytic, and fibrinolytic activity for G. lingzhi cultivated in açaí. Water extracts of Ganoderma sp., in general, exhibited higher trypsin and papain inhibitor activities compared to G. lingzhi. Extracts in Tris-HCl and sodium phosphate showed more intense protein bands in SDS-- PAGE, highlighting bands of molecular weights around 100, 50, and 30 kDa. FTIR spectra showed patterns for proteins in all extracts, with variation in transmittance according to substrate and extractor. Water extract from Amazonian Ganoderma sp. cultivated in marupá wastes are promising as a source of protease inhibitors, while the Tris-HCL extract of G. lingzhi from açaí cultivation stands out as a source of proteases with fibrinolytic, caseinolytic, and gelatinolytic activities.

Interactions between protein Z and lycopene: A win-win scenario for both security and stability.

Malt protein Z (PZ), the main albumin in malt endosperm, exhibits trypsin inhibitory activity and has the ability to bind fat-soluble active molecules. However, its potential utilization as a food ingredient necessitates an evaluation of its allergenicity. Lycopene has many functional activities, such as antioxidant and treatment or alleviation of various diseases, but its tendency to degrade easily hinders its effective utilization. Therefore, this paper investigates the allergenicity of PZ and provides a win-win scenario that PZ interacts with lycopene. PZ interacts with lycopene through non-covalent interactions with a ratio of 4.07±0.20, leading to the formation of homogenous particles with an increased absolute zeta potential, from -7.3±0.2 to -20.0±0.6. Unsurprisingly, the presence of lycopene alleviates the allergenicity of PZ by decreasing the IgE, mMcp-1 and vascular permeability, such as the plasma mMcp-1 decreased from 245.0±5.2ng/mL for the PZ group to 217.8±4.1ng/mL for the PZ-LYC group. To uncover the potential mechanism, the linear antigenic epitopes of PZ by ABCpred were predicted, which are almost the potential binding site of lycopene at PZ. On the other hand, PZ improved the storage stability of lycopene. The addition of PZ increased lycopene retention in solution from 14.9±2.7% to 65.5±2.8% over 10days at room temperature with light exposure. These results provide foundations for PZ utilization concerning security, and give ways to protect bioactive molecules.

An industry survey of the composition and variability of soybean gums and soapstocks across US soybean processing plants.

Depending on the soybean processing plant, gums and soapstocks may be added back to soybean meal during soybean processing. Despite potential effects on soybean meal quality, there is limited information available on the composition and variation in soybean by-products and the resulting soybean meal if by-products are added back during processing. A total of 36 soybean by-product samples from 14 plants across 8 different companies were examined in an industry survey evaluating the composition and variation of soybean gums and soapstocks across the US. All soybean processing plants in the study produced at least one of two by-products: soybean gums or soybean soapstocks. Soybean by-product and soybean meal samples were collected within two different timeframes: May to July 2023 and October to November 2023. The individual plants surveyed constitute approximately 30% of total US soybean meal production, with 8 participating companies representing 80% of the total US soybean meal production. By-products were analyzed for lipid quality criteria including moisture, fat by acid hydrolysis, fatty acid analysis, and oxidation markers. Soybean meal samples were submitted for analysis of proximate composition, neutral detergent fiber, Ca, P, and trypsin inhibitor activity. Soybean gums had a greater (P ≤ 0.05) percentage of acid hydrolyzed fat and p-Anisidine value compared to soybean soapstocks. Soybean soapstocks tended to have a greater (P = 0.085) percentage of moisture and volatile matter as well as an increased (P = 0.052) concentration of insoluble impurities compared with soybean gums. Most notably, there was considerable variation in the composition of by-product samples among processing plants indicating differences in processing procedures or incoming soybean quality. Soybean meal containing added soybean by-products had 61% greater (P < 0.05) ether extract than soybean meal samples without added soybean by-products on a dry matter basis, but there was no difference (P > 0.10) in crude protein. Furthermore, trypsin inhibitor units varied considerably among plants with values ranging from 1.45 to 9.26 TIU/mg of seed powder, regardless of by-product inclusion. These results provide information on the composition and variation in soybean by-products across various processing plants; however, further information is still needed to evaluate their subsequent effects on livestock diets.

Fungal endophytes enhanced insect resistance by improving the defenses of Achnatherum sibiricum before locust feeding.

Epichloë endophytes provide many benefits to host plants, including enhanced insect resistance. Fungal alkaloids are usually thought to be responsible for the endophyte-conferred herbivore resistance. Nonetheless, the fungal alkaloid profiles and concentrations may vary considerably among grass-endophyte systems. This indicates that apart from fungal alkaloids, additional mechanisms such as endophyte-mediated host defense are likely contributed to endophyte-grass-insect interactions. In this study, we addressed this issue by investigating the effect of Epichloë on the defense responses of Achnatherum sibiricum against locusts. The results showed that Epichloë endophytes increased locust resistance of A. sibiricum in both choice and non-choice feeding experiments. In no feeding groups, endophyte infection increased the content of jasmonic acid (JA) and ethylene (ET), chitinase activity, and the biosynthetic gene expression of the relevant pathways. Endophyte infection also increased the content of total phenolics and condensed tannins. These indicators were negatively correlated with leaf consumption. In locust feeding groups, endophyte infection increased trypsin inhibitor activity. Exogenous application of phytohormones further proved that JA and ET reduced the consumption of A. sibiricum by locusts. The present study showed that endophyte-conferred host defense was mainly constitutive, that is, the defense characteristics of host plants were mainly manifested in no feeding groups. Endophyte presence enhanced locust resistance of the host by activating the JA/ET signaling pathway, elevating chitinase activity and phenolic compounds content, thereby improving the defense ability of host plants. © 2024 Society of Chemical Industry.

Screening Study on Serine Protease Inhibitory Activity of 10 Plant Species.

In this research, in vitro serine protease inhibitory activity of 10 plant species was evaluated, and extracts that showed strong activity were analyzed through high-performance liquid chromatography (HPLC). Rhododendron caucasicum Pall. (leaf) and Potentilla reptans L. were found to have the highest chymotrypsin inhibitory activities (83.77% and 82.01% inhibition). The highest trypsin inhibitory activity was observed in R. caucasicum (flower) (82.86% inhibition), followed by Cruciata laevipes Opiz (82.22% inhibition). Extracts showing potent enzyme inhibition were fractioned and subjected to activity tests. The highest chymotrypsin inhibitory activity was observed in the n-hexane fraction of P. reptans (92.90% inhibition). In comparison, the highest trypsin inhibitory activity was found in the ethyl acetate fraction of Lythrum salicaria L. (89.81% inhibition). HPLC studies determined that the 80% ethanol extract of P. reptans contained chlorogenic acid. The screened plants were generally rich in phenol and flavonoid content and showed strong antioxidant activity.

Insights of the trypsin inhibitory activity and ultrasound effect of ovomucoid based on molecular docking and spectroscopic

Ovomucoid (OVM) is the most abundant trypsin inhibitor in egg white, considered as one of the anti-nutritional factors in egg processing. In this study, the molecular mechanism of the interaction between OVM and trypsin was explored. Besides, the effect of food processing methods on the activity of OVM and structural change of OVM was analyzed. The results showed that OVM mainly inhibited trypsin activity through hydrogen bonding in its first domain and it was a non-competitive inhibitor. Surprisingly, ultrasound treatment could reduce trypsin inhibitory activity of OVM to 30%. The hydrolytic resistance to digestive enzymes and the thermal stability of the OVM was also significantly reduced. The spectroscopic results indicated ultrasound treatment affected the trypsin inhibitory activity of OVM by reducing β-sheet content and increasing hydrophobicity. In conclusion, this study reveals the molecular mechanism by which OVM inhibits trypsin activity, and provides an ultrasound treatment method to effectively reduce this activity of OVM.

Kunitz-type trypsin inhibitor from durian (Durio zibethinus) employs a distinct loop for trypsin inhibition.

Kunitz-type trypsin inhibitors are ubiquitous in plants. They have been proposed to be a part of a defense mechanism against herbivores. Trypsin inhibitors also have potential applications in the biotechnology industry, such as in mammalian cell culture. We discovered that durian (Durio zibethinus) seed contains Kunitz-type trypsin inhibitors as identified by N-terminal sequencing and mass spectrometry. Eleven new trypsin inhibitors were cloned. The D. zibethinus trypsin inhibitors (DzTIs) that are likely expressed in the seed were produced as recombinant proteins and tested for trypsin inhibitory activity. Their inhibitory activity and crystal structures are similar to the soybean trypsin inhibitor. Surprisingly, a crystal structure of the complex between DzTI-4, the DzTI with the lowest inhibitory constant, and bovine trypsin revealed that DzTI-4 utilized a novel tryptophan-containing β1-β2 loop to bind trypsin. Site-direct mutagenesis confirmed the inhibitory role of this loop. DzTI-4 was not toxic to the HEK293 cells and could be used in place of the soybean trypsin inhibitor for culturing the cells under serum-free conditions. DzTI-4 was not toxic to mealworms. However, a mixture of DzTIs extracted from durian seed prevented weight gain in mealworms, suggesting that multiple trypsin inhibitors are required to achieve the antinutritional effect. This study highlights the biochemical diversity of the inhibitory mechanism of Kunitz-type trypsin inhibitors and provides clues for further application of these inhibitors.

Characterization and effects of heat treatments on antinutritional components and enzyme activities in sainfoin (Onobrychis viciifolia L.) seeds: A high-protein alternative plant-based food source

The aim of this study was to characterize and explore the food potential of sainfoin seeds, which are primarily used in their green plant form to feed livestock. A detailed assessment of the seed’s proximate composition, enzyme activity levels, and antinutrient content was performed. The seeds were then subjected to infrared, hot air, and blanching treatments to examine how these processing methods affect enzyme activities and antinutrients. In addition, optimization of processing conditions was carried out using the response surface method and central composite design to ensure low antinutrient levels, minimal color change, and total enzyme inactivation. Sainfoin seeds have a crude protein content of 42 % in dry matter, making them a promising alternative plant-based protein source. They also contain 45 % dietary fiber, 9 % crude fat, and significant levels of potassium and magnesium. The unprocessed seeds exhibited 2.01 U/g lipase activity and 10.51 U/g lipoxygenase activity, which were inactivated with infrared treatment at 2000 W IR power in 75 s. In terms of antinutrients, sainfoin seeds contain 247 mg/100 g phytic acid, 2582 TIU/g trypsin inhibitor activity, 7.9 mg catechin equivalents of tannin /100 g, and 24.97 mg/100 g hydrocyanic acid. The optimal process conditions were 2000 W IR power and 105 s for IR treatment, 150 °C and 103 min for hot air treatment, and 81 °C and 16 min for blanching. The antinutrient levels and enzyme activities in unprocessed sainfoin seeds are comparable to those found in conventional legumes, although sainfoin seeds contain a higher amount of tannins. While infrared treatment was most effective for enzyme inactivation, the impact of the different processing methods varied across the parameters studied.

Lactobacillus fermented chickpeas: Improving dough process quality and biscuit nutritional value

This study aimed to examine the impact of lactobacillus fermented chickpeas (LFC) on dough quality and assess their application potential in biscuits. The results of rheological properties showed that LFC significantly increased the storage modulus (G′) and loss modulus (G″) of the dough, with a greater increase in G'. The textural analysis showed that the LFC significantly increased the hardness of the dough before and after fermentation. In the low-field NMR analysis, LFC enhanced the bound water content of the dough and reduced the mobility of the water molecules. Furthermore, the network structure of gluten proteins was weakened by LFC, resulting in more exposed starch. In vitro protein digestibility increased by 28.01% at the gastric end and 11.76% at the intestinal end of LFC-biscuits as compared to chickpea biscuits. It was associated with lactobacilli fermentation reducing phytic acid and trypsin inhibitor activity in chickpeas. Moreover, the protein content of the biscuits has been increased (33.26%) and their free amino acid composition has been optimized. The hardness, brittleness, and specific volume of biscuits were significantly enhanced by LFC, with well sensory acceptance. These findings will enrich the theory of lactobacilli fermentation of legumes and inspire its application in baked foods.

Effect of the microwave treatment on anti-nutrients of soybeans

BACKGROUND: Soybeans contain anti-nutrients that have to be inactivated before being used as feed for livestock and poultry. AIM: Obtaining the new data on the effect of the heat treatment on soybeans. MATERIALS AND METHODS: Soybeans of the Dongsheng 22 and SK Alta varieties were processed with micronization, autoclaving and microwaves in the developed microwave unit. RESULTS: After micronization, the decrease in total starch was 10–16%, after autoclaving and microwave treatment — 15–17%. The three kinds of treatment did not have a significant effect on total phenolic content. The content of flavonoids increased by 7–9% after autoclaving and micronization and by 16% after microwave treatment. When micronizing and autoclaving soybeans, no changes in antioxidant activity were observed, but with microwave treatment, it increased by 3–5%. The decrease in trypsin inhibitor activity was 80% after microwave treatment and 73–79% after micronization and autoclaving. The tannin content was reduced by 10% with microwave treatment and by 7–9% after micronization and autoclaving. The decrease in phytic acid content was 43–45% and repeated for all kinds of treatment. CONCLUSION: The reduction of antinutrients after micronization, autoclaving and microwave processing ensures the use of soybeans for feed. Milder temperature conditions and cyclic processes of heating and cooling during microwave processing increase the safety of soybeans. The higher heating rate and low energy costs of microwave processing ensure economic feasibility.

The impact of milling degree on physicochemical, nutritional, rheological, textural properties, and in vitro digestibility of rice: From brown rice to white rice

The objective of this study was to characterize the rice milling fractions acquired at each stage of a commercial milling system. This characterization included an analysis of color, ash content, dietary fiber, mineral composition, as well as antinutritional compounds like phytic acid, trypsin inhibitor activity, and saponin. Additionally, we investigated in vitro starch and in vitro protein digestibility, along with pasting, cooking, and textural properties.Our findings revealed that milling improved the visual appeal of rice (e.g., volume expansion, weight gain, whiteness) and notably enhanced its starch digestibility. However, milling reduced dietary fiber, mineral content, antinutrients, cooking time, and texture characteristics such as hardness, chewiness, gumminess, springiness, and cohesiveness to varying degrees. Certain parameters, such as dietary fiber, exhibited a gradual change with the duration of milling, while others, such as mineral content and texture, showed significant variation at the initial stage of milling, particularly at the first mill.

Novel Ag(I)‐based 1,2,4‐Oxadiazole Complexes: Synthesis, X‐Ray Crystal Structure, and Biological Evaluation as Anticancer Candidates

ABSTRACTThe 3,5‐diaryl‐1,2,4‐oxadiazole scaffolds 2 and 3 were synthesized and used as ligands to obtain three novel Ag(I) complexes 4–6. The structure of the Ag(I) complexes 4–6 has been confirmed by single crystal X‐ray diffraction. Complex 4 has the dinuclear formula [Ag(2)(NO3)]2. 5 and 6 are monomeric complexes having the formula [Ag(3)2(NO3)] and [Ag(3)2]ClO4, respectively. In vitro, trypsin, ALDH2, and iNOS inhibition activities were assessed for the free ligands and their Ag(I) complexes. Interestingly, Ag(I) complexes 4–6 revealed more prominent trypsin inhibitory activity than the ligands 2 and 3. The oxadiazole derivative 3 and its Ag(I) complex (6) showed significant ALDH2 inhibition (45% and 55%, respectively). Complex 6 (IC50 = 35.61 μM) surpassed its 1,2,4‐oxadiazole ligand 3 (IC50 = 88 μM) and evidenced the most prominent ALDH2 inhibitory activity. The oxadiazole derivative 3 and its corresponding Ag(I) complexes 5 and 6 showed significant iNOS inhibition (77.77%, 84.12%, and 84.15%, respectively). With IC50 values of 18.13, 18.15, and 13.96 μM, respectively, complex 6 is the most potent against iNOS, surpassing the reference standard.

Comparison of rice bran characteristics fermented by mono- or di-strain probiotics based on omics technology

Rice bran is a premium agricultural byproduct rich in nutrients and bioactive substances. The aim of this study was to compare the effects of fermentation with Bacillus subtilis, Lactobacillus plantarum, and a mixture of both on the bacterial communities and metabolic functions of rice bran based on omics techniques. The results showed that probiotic fermentation decreased crude fiber (CF) content, phytic acid, and trypsin inhibitor activity (TIA), and increased trichloroacetic acid soluble protein (TCA-SP), reducing sugar (RS), and total phenol (TP) in rice bran. Ten dominant genera with relative abundances greater than 1% were successfully identified, and probiotic fermentation significantly reduced the relative abundances of Enterobacter, Kasakonia, and Pantoea. A total of 63 differentially expressed metabolites (DEMs) were identified and further analysis revealed that probiotic fermentation increased essential amino acids, phenolic compounds, and organic acids in rice bran. Additionally, the di-strain probiotic fermentation of Bacillus subtilis and Lactobacillus plantarum facilitated the growth of beneficial microbiota (Limosilactobacillus, Prevotella and Dialister) and the production of bioactive substances (lactic acid, catechol, beta-tyrosine, etc.). In conclusion, co-fermentation of di-strain probiotics is a valuable method to produce functional compounds and enhance the health-promoting properties of rice bran.

Credible and Facile Fluorometric Detection of Soybean Trypsin Inhibitor Activity with a Water-Soluble Poly(diphenylacetylene) Derivative

Credible and Facile Fluorometric Detection of Soybean Trypsin Inhibitor Activity with a Water-Soluble Poly(diphenylacetylene) Derivative

CHEMICAL COMPOSITION OF ACID AND ALKALINE SOAKED DEHULLED AFRICAN YAM BEAN SEEDS (Sphenostylis stenocarpa) SEEDS

African yam bean (AYB) (Sphenostylis stenocarpa) is an indigenous food legume crop in the tropics, but it is not as popular as food when compared with other major legumes. It is high in protein but it is under - utilized due to the presence of tannin, trypsin inhibitors, haemaglutinins, oxalates, phytates and saponins.. To improve its nutritional value as a protein source, AYB was subjected to dehulling, dehulled soaking in ogi liquor (acidic media) and dehulled soaking in wood ash (alkaline media) and its anti-nutritional contents analyzed. There were no significant (P&gt;0.05) difference in tannin, phytate, saponin, and oxalate across the dietary treatments. However trypsin inhibitor and haemagglutinin showed significant (p&lt;0.05) difference across the treatments. Raw AYB had the highest value for tannin (0.09/mg/g), phytate (0.67/mg/g), trypsin inhibitors (31.26/TIU/g), saponin (0.32mg/kg), haemaglutinnins (58.24HIU/g) and oxalates (0.25mg/g) followed by the dehulled seed with tannin (0.07/mg/g), phytate (0.49mg/g), trypsin inhibitor (11.34/TIU/mg), saponin (0.26/mg/kg) and haemmaglutinins (49.15/HIU/g). African yam bean soaked in alkaline media (pH 10) recorded the least value for tannin (0.05mg/g), phytates (0.05/mg/g), trypsin inhibitor (0.06/TIU/g), haemmaglutinins (6.35/HIU/g). The lowest value of oxalate was for AYB soaked in acidic medium (0.20mg/g). Soaking in alkaline medium (pH 10) was found to be more effective in reducing the levels of trypsin inhibitors activity and haemaglutinins by 99.8% and 89.1% respectively. However, soaking of AYB in (pH 3.9) resulted in 63.7% and 15.6% reduction in trypsin inhibitor activity and haemaglutinins respectively. It could be concluded that anti-nutritional factors present in African yam bean could easily be reduced when soaked in alkaline solution.

Evaluation of the Effective Cowpea [Vigna unguiculata (L.) Walp] Sprouting or Roasting for Pig Feeding

Background: The study investigated the effective roasting or sprouting of cowpeas (Vigna unguiculata) based on effects on in vitro digestibility (IVDMD), supported by measurement of key chemical components and trypsin inhibitor activity (TIA). Methods: The in vitro dry matter digestibility (IVDMD) of raw and all processed cowpeas were evaluated using standard, 3-step (gastric-ileal-colon) simulation of porcine digestion, modified for micro (0.5 g) sample digestion. Standard methods were employed to track processing effects on Ash, CP, Fat, ADF, NDF and trypsin inhibitor activity (TIA) at key processing points. Result: Sprouting for 2 and 3 days significantly decreased (p less than 0.05) gastric-ileal IVDMD while increasing (p less than 0.05) colon IVDMD. Total (steps 1-3) IVDMD increased (p less than 0.05) in 2-day (0.911) and 4-day (0.902) sprouts. The 20-minute cowpea roasting to 105°C terminal grain temperature resulted in high (p less than 0.05) step 3 and total IVDMD coefficients. The lowest (p greater than 0.05) total IVDMD was recorded in 15-minute (0.883) (95°C terminal grain temperature) roasts. In both experiments 1 and 2, quantitative changes in IVDMD were consistent with the changes in the chemical components (ADF, NDF, fat, CP, minerals) and trypsin inhibitor activity. In conclusion, the compartmental and total IVDMD and quantitative change in chemical components and TIA indicated 4 days sprouting and 20-minute (105°C) roasting were respectively most effective for cowpea processing.

Reduction of antinutrients and off-flavour in kidney bean flour by acidic and alkaline reactive extrusion

The presence of antinutrients and undesirable flavours in kidney bean flour poses challenges to consumer acceptance. Although extrusion can mitigate antinutrients to some extent, its impact on reducing beany flavour in bean flour remains underexplored. This study investigated the effects of injecting acetic acid or sodium carbonate solutions at three concentration levels (0.05, 0.1, 0.15 mol/L), in conjunction with three temperature profiles (40/60/80/80/90, 40/60/80/90/110, 50/70/90/110/130 °C) and two feed moisture levels (25, 30 %), on the removal of antinutrients (condensed tannins, trypsin inhibitor activity, phytic acid, raffinose family oligosaccharides) and reduction of volatile compounds that contribute to beany flavour in whole kidney bean flour. The results showed that all concentrations of acetic acid and sodium carbonate solutions effectively reduced condensed tannins compared to water, especially at 130 °C extrusion temperature. Introducing acetic acid and sodium carbonate solutions at a concentration of 0.15 mol/L led to 72 and 90 % reduction of total raffinose family oligosaccharide content, respectively, in contrast to the 17 % reduction observed with water alone. The incorporation of sodium carbonate solution reduced the total volatile compounds by 45–58 % as compared with water (23–33 %) and acetic acid (11–27 %). This reduction was primarily due to the reduction of aldehydes, alcohols, and aromatic hydrocarbons. These results indicate that injecting sodium carbonate solution during extrusion can effectively reduce antinutrients and beany flavour compounds in kidney bean flour.