Karim Jiménez-Aliaga

The growing demand for sustainable nutraceutical ingredients has driven the exploration of underutilized plant proteins such as the Andean legume Erythrina edulis. The study aimed to recover and characterize an enriched albumin fraction (AF) and optimize its enzymatic hydrolysis to produce multifunctional protein hydrolysates. The AF was recovered using tangential flow filtration (TFF), achieving a 7.4-fold concentration, 73.5% recovery, and 57.3% protein content, with proteins predominantly between 15 ̶ 20 kDa. The AF showed a high essential amino acid content (45.0%), including Met (0.97%), Cys (1.97%), Lys (6.00%), antioxidant capacity (up to 0.62 ± 0.03 µmol TE/mg protein) but limited in vitro protein digestibility (45.80%) and trypsin-inhibitor activity (49.12%). Proteomic analysis further revealed a balanced annotated distribution across Gene Ontology categories, including cellular component (33.11%), molecular function (33.23%), and biological process (33.65%). AF was hydrolyzed using Alcalase under optimized conditions (E/S 7000 U/mg, 50 °C, 120 min). The resulting hydrolysate (AHA) exhibited a predominance of low-molecular-weight peptides (< 10 kDa), enhanced antioxidant capacity (up to 4.37-fold), IVPD (94.6%), and in vitro α-glucosidase (IC₅₀ of 1.29 ± 0.53 mg protein/mL) and DPP-IV (IC₅₀ of 0.17 ± 0.04 mg protein/mL) inhibitory activities, along with increased AChE inhibition. Fourier-transform infrared (FTIR) spectroscopy showed protein conformation rearrangements in AF and AHA. These findings highlight an integrated approach combining TFF-based recovery, enzymatic hydrolysis and multifunctional profiling for the revalorization of E. edulis and the development of functional ingredients, with potential for scale-up. Future studies should focus on cellular and in vivo validation approaches.

Exopolysaccharides (EPS) are polymers of high industrial value due to their wide range of uses, and their profitable and sustainable production is a constant challenge. The objective of this work was to conduct EPS production by Leuconostoc sp. LU1 using sweet potato (Ipomoea batatas) waste as a substrate, as well as its physicochemical and functional characterization. Leuconostoc sp. LU1, isolated from the gherkin fruit, was phenotypically characterized and phylogenetically analyzed. The effect of different pH levels, yeast extract, and sweet potato waste on biomass and EPS production was evaluated by simple factor analysis. The physicochemical characterization was performed using FTIR, TGA, NMR and HPLC techniques, while the functional properties determined were the water solubility index, water and oil retention capacity, and antioxidant capacity. Regarding the evaluated parameters, cultivation at pH 5, with 1.0 g L^- 1 yeast extract and 100% (v/v) sweet potato residue, resulted in a production of 5.86 ± 0.04 g L^- 1 of EPS with a yield of 0.49 g g^- 1 and a productivity of 0.06 g L^- 1 h^- 1. Analysis of the monosaccharide composition by HPLC indicated that the EPS corresponds to a homopolymer composed of glucose units; in addition, it showed a degradation temperature of 205 °C. NMR spectroscopy indicated anomeric proton signals corresponding to α-glucopyranosid, consistent with the structure of dextran. Likewise, the biopolymer exhibited high water solubility and a water retention capacity of 127.60 ± 0.41% (w/w). Additionally, the EPS presented an ABTS•+ free radical scavenging capacity of 92 ± 0.03%. The study highlights the production of an exopolysaccharide by a native strain, which promotes the development of a sustainable and profitable bioprocess by taking advantage of agroindustrial waste.

The growing demand for functional foods has driven the search for bioactive compounds derived from plant proteins. Lupinus mutabilis “Tarwi”, a legume native to the Peruvian Andes, stands out for its high protein content and potential as a source of bioactive peptides (BPs). In this study, the functionality of the proteins contained in the albumin fraction (AF) isolated by tangential ultrafiltration (TFF) was investigated by using the OmicsBox software. The identified proteins were functionally classified into three groups: cellular component (35.57%), molecular function (33.45%), and biological process (30.97%). The isolated AF was hydrolysed with the native protease PC7 (HAP), optimizing the E/S ratio and time parameters. Additionally, sequential hydrolysis of the PC7 protease and alcalase (HAPA) was performed. In vitro multifunctionality assays, HAP and HAPA demonstrated the ability to scavenge radicals (ABTS and ORAC) and inhibit angiotensin-converting enzyme (ACE)-I and dipeptidyl peptidase IV (DPP-IV). The findings of this study highlight the potential of L. mutabilis albumin hydrolysate as a multifunctional ingredient for functional foods aimed at managing chronic conditions associated with oxidative stress, hypertension, and/or metabolic disorders.

The high content and quality of protein in Andean legumes make them valuable for producing protein hydrolysates using proteases from bacteria isolated from extreme environments. This study aimed to carry out a single-step purification of a haloprotease from Micrococcus sp. PC7 isolated from Peru salterns. In addition, characterize and apply the enzyme for the production of bioactive protein hydrolysates from underutilized Andean legumes. The PC7 protease was fully purified using only tangential flow filtration (TFF) and exhibited maximum activity at pH 7.5 and 40 °C. It was characterized as a serine protease with an estimated molecular weight of 130 kDa. PC7 activity was enhanced by Cu²⁺ (1.7-fold) and remained active in the presence of most surfactants and acetonitrile. Furthermore, it stayed completely active up to 6% NaCl and kept ̴ 60% of its activity up to 8%. The protease maintained over 50% of its activity at 25 °C and 40 °C and over 70% at pH from 6 to 10 for up to 24 h. The determined K_m and V_max were 0.1098 mg mL⁻¹ and 273.7 U mL⁻¹, respectively. PC7 protease hydrolyzed 43%, 22% and 11% of the Lupinus mutabilis, Phaseolus lunatus and Erythrina edulis protein concentrates, respectively. Likewise, the hydrolysates from Lupinus mutabilis and Erythrina edulis presented the maximum antioxidant and antihypertensive activities, respectively. Our results demonstrated the feasibility of a simple purification step for the PC7 protease and its potential to be applied in industrial and biotechnological processes. Bioactive protein hydrolysates produced from Andean legumes may lead to the development of nutraceuticals and functional foods contributing to address some United Nations Sustainable Development Goals (SDGs).

El objetivo del estudio fue realizar la caracterización bioinformática, así como optimizar la producción de L-asparaginasa extracelular de Bacillus sp. M62 aislada de las salinas de Maras (Cusco). Para ello, se verificó la producción de L-asparaginasa mediante el viraje del medio M9 modificado con azul de bromofenol 0.0075%, pH 7.4 a 37 °C por 72 h. A la vez, se extrajo el ADN genómico para amplificar los genes ribosómicos 16S y el gen ansA3. La secuencia aminoacídica codificada por el gen ansA3 se predijo mediante análisis bioinformático. La producción de L-asparaginasa intracelular y extracelular se evaluó a diferentes niveles de glucosa, L-asparagina, NaCl y pH en el medio M9 modificado. Adicionalmente, las actividades enzimáticas de L-asparaginasa y L-glutaminasa se determinaron mediante cuantificación del amonio liberado por el método de Nessler. Así, Bacillus sp. M62 produjo el viraje del medio M9 modificado, obtuvo alta similitud y cercanía evolutiva con Bacillus licheniformis, se encontró que el gen ansA3 amplificado codificaba para 319 aa, dentro de la cual se predijo una secuencia patrón del sitio activo (GFVITHGTDTM ) y 15 sitios inmunogénicos. La producción de L-asparaginasa extracelular fue superior a la intracelular, la que se optimizó de 0.37 U/mL (0.24 U/mg) a 2.15 ± 0.39 U/mL (0.63 U/mg). Finalmente, se encontró que Bacillus sp. M62 presenta L-asparaginasa extracelular con mínima actividad de L-glutaminasa.

Quercetin has been studied extensively for its anti-Alzheimer’s disease (AD) and anti-aging effects. Our previous studies have found that quercetin and in its glycoside form, rutin, can modulate the proteasome function in neuroblastoma cells. We aimed to explore the effects of quercetin and rutin on intracellular redox homeostasis of the brain (reduced glutathione/oxidized glutathione, GSH/GSSG), its correlation with β-site APP cleaving enzyme 1 (BACE1) activity, and amyloid precursor protein (APP) expression in transgenic TgAPP mice (bearing human Swedish mutation APP transgene, APPswe). On the basis that BACE1 protein and APP processing are regulated by the ubiquitin–proteasome pathway and that supplementation with GSH protects neurons from proteasome inhibition, we investigated whether a diet containing quercetin or rutin (30 mg/kg/day, 4 weeks) diminishes several early signs of AD. Genotyping analyses of animals were carried out by PCR. In order to determine intracellular redox homeostasis, spectrofluorometric methods were adopted to quantify GSH and GSSG levels using o-phthalaldehyde and the GSH/GSSG ratio was ascertained. Levels of TBARS were determined as a marker of lipid peroxidation. Enzyme activities of SOD, CAT, GR, and GPx were determined in the cortex and hippocampus. ΒACE1 activity was measured by a secretase-specific substrate conjugated to two reporter molecules (EDANS and DABCYL). Gene expression of the main antioxidant enzymes: APP, BACE1, a Disintegrin and metalloproteinase domain-containing protein 10 (ADAM10), caspase-3, caspase-6, and inflammatory cytokines were determined by RT-PCR. First, overexpression of APPswe in TgAPP mice decreased GSH/GSSG ratio, increased malonaldehyde (MDA) levels, and, overall, decreased the main antioxidant enzyme activities in comparison to wild-type (WT) mice. Treatment of TgAPP mice with quercetin or rutin increased GSH/GSSG, diminished MDA levels, and favored the enzyme antioxidant capacity, particularly with rutin. Secondly, both APP expression and BACE1 activity were diminished with quercetin or rutin in TgAPP mice. Regarding ADAM10, it tended to increase in TgAPP mice with rutin treatment. As for caspase-3 expression, TgAPP displayed an increase which was the opposite with rutin. Finally, the increase in expression of the inflammatory markers IL-1β and IFN-γ in TgAPP mice was lowered by both quercetin and rutin. Collectively, these findings suggest that, of the two flavonoids, rutin may be included in a day-to-day diet as a form of adjuvant therapy in AD.

The ability of multifunctional food-derived peptides to act on different body targets make them promising alternatives in the prevention/management of chronic disorders. The potential of Erythrina edulis (pajuro) protein as a source of multifunctional peptides was proven. Fourteen selected synthetic peptides identified in an alcalase hydrolyzate from pajuro protein showed in vitro antioxidant, anti-hypertensive, anti-diabetic, and/or anti-obesity effects. The radical scavenging properties of the peptides could be responsible for the potent protective effects observed against the oxidative damage caused by FeSO₄ in neuroblastoma cells. Moreover, their affinity towards the binding cavity of angiotensin-converting enzyme (ACE) and dipeptidyl peptidase IV (DPP-IV) were predicted by molecular modeling. The results demonstrated that some peptides such as YPSY exhibited promising binding at both enzymes, supporting the role of pajuro protein as a novel ingredient of functional foods or nutraceuticals for prevention/management of oxidative stress, hypertension, and metabolic-alteration-associated chronic diseases.

Multifunctional peptides, capable of acting on different body systems through multiple mechanisms of action, offer many advantages over monofunctional peptides, including lower adverse side effects and costs. Erythrina edulis (pajuro) is a legume with a large number of high-quality proteins, of which their potential as a source of antioxidant peptides has been recently reported. In this study, the behavior of these proteins under a sequential enzymatic hydrolysis with digestive and microbial enzymes was investigated by evaluating the multi-functionality of the hydrolyzates. The albumin hydrolyzates obtained after the action of pepsin, pancreatin, and Alcalase showed antioxidant, angiotensin-converting enzyme (ACE), α-amylase, α-glucosidase, and dipeptidyl peptidase (DPP)-IV inhibitory activities. The radical scavenging properties of the hydrolyzate could be responsible for the potent protective effects observed in FeSO₄-induced neuroblastoma cells. The findings support the role of pajuro protein as an ingredient of functional foods or nutraceuticals for health promotion and the prevention of oxidative stress, hypertension, and metabolic alteration-associated chronic diseases.

BACKGROUND: Oxidative reactions are responsible for the changes in quality during food processing and storage. Oxidative stress is also involved in multiple chronic diseases, such as cardiovascular and neurodegenerative disorders, diabetes, cancer, and aging. The consumption of dietary antioxidants has been demonstrated to help to reduce the oxidative damage in both the human body and food systems. In this study, the potential of Erythrina edulis (pajuro) protein as source of antioxidant peptides was evaluated.RESULTS: Pajuro protein concentrate hydrolyzed by alcalase for 120 min showed potent ABTS^·+ and peroxyl radical scavenging activity with Trolox equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC) values of 1.37 ± 0.09 µmol TE mg⁻¹ peptide and 2.83 ± 0.07 µmol TE mg⁻¹ peptide, respectively. Fractionation of the hydrolyzate to small peptides resulted in increased antioxidant activity. De novo sequencing of most active fractions collected by chromatographic analysis enabled 30 novel peptides to be identified. Of these, ten were synthesized and their radical activity evaluated, demonstrating their relevant contribution to the antioxidant effects observed for pajuro protein hydrolyzate.CONCLUSIONS: The sequences identified represent an important advance in the molecular characterization of the pajuro protein, demonstrating its potential as a source of antioxidant peptides for food and nutraceutical applications. © 2018 Society of Chemical Industry

Lupinus mutabilis (tarwi) is a cultivated legume used principally as a protein source in human and animal nutrition. In this study, protein concentrate was obtained from debittered and defatted tarwi seed flour. SDS-PAGE analysis revealed the presence of highly intense bands ranged between 35 and 60 kDa. Tarwi protein concentrate was subjected to the action of alcalase to produce hydrolyzates with antioxidant activity. A central composite design was employed to study the effect of the experimental variables, enzyme/substrate ratio and incubation time, on the degree of hydrolysis and the radical scavenging capacity. The influence of both variables on the variable responses was demonstrated. The optimal conditions to obtain the highest degree of hydrolysis were enzyme/substrate ratio of 1.72% and 133 min of incubation. The highest radical scavenging activity (TEAC value of 2.7 ± 0.1 μmol Trolox equivalents/mg protein and ORAC value of 3.8 ± 0.1 μmol Trolox equivalents/mg protein) was found in hydrolyzates with alcalase after 138 min and an enzyme/substrate ratio of 1.87%. Peptides released by the action of alcalase and containing hydrophobic and aromatic amino acids could contribute to the antioxidant effects observed. Tarwi proteins could be a new alternative as a food additive with antioxidant properties or as an ingredient of functional foods for health promotion and prevention of free radical-induced chronic diseases.