Peptídeo do hidrolisado protéico de RuBisCO e sua aplicação na preservação de carne bovina

The objective of this work was to purify the small (705 Da) and hydrophilic antimicrobial Arg-Asp-Arg-Phe-Leu peptide from RuBisCO protein hydrolysate and to evaluate its effect on the microbiological and oxidative stability of beef mince during refrigeration. RuBisCO was obtained from alfafa green juice. The peptide extract was fractionated using RP-HPLC, and the active fractions were analyzed by liquid chromatography, electrospray ionization, and tandem mass spectrometry (LC-ESI-MS). Beef mince was analyzed in the following treatments: negative control, meat with two different BHT concentrations of 0.1 and 0.5% (w/w), and meat with two different Arg-Asp-Arg-Phe-Leu peptide concentrations of 0.1 and 0.5% (w/w). Lipid oxidation using the thio-barbituric acid-reactive substance (TBARS) values were significantly affected by the storage period and the concentration of bioactive peptide. Arg-Asp-Arg-Phe-Leu, a small antibacterial peptide from RuBisCO, can be isolated and purified by HPLC from alfafa green juice with retention time between 10 and 50 min, which corresponds to antimicrobial peptides. RuBisCO peptide Arg-Asp-Arg-Phe-Leu 0.5% increases oxidative stability of beef mince during refrigeration. RuBisCO peptide Arg-Asp-Arg-Phe-Leu inhibit microbial growth under refrigeration for 11 days.O objetivo deste trabalho foi purificar peptídeo antimicrobiano pequeno (705 Da) e hidrofílico Arg-Asp-Arg-Phe-Leu a partir do hidrolisado proteico RuBisCO e avaliar seu efeito na estabilidade microbiológica e oxidativa de carne bovina moída durante refrigeração. RuBisCO foi obtida a partir do suco verde de alfafa. O extrato peptídico foi fracionado utilizando RP-HPLC, e as frações ativas foram analisadas por cromatografia líquida, ionização por eletrospray e espectrometria de massa em tandem (LC-ESI-MS). A carne bovina moída foi analisada nos seguintes tratamentos: controle negativo, carne com duas concentrações diferentes de BHT de 0,1 e 0,5% (p/p) e duas concentrações de peptideo Arg-Asp-Arg-Phe-Leu de 0,1 e 0,5% (p/p). Os valores de oxidação lipídica utilizando a substância reativa ao ácido tiobarbitúrico (TBARS) foram significativamente afetados pelo período de armazenamento e pela concentração do peptídeo bioativo. Arg-Asp-Arg-Phe-Leu, um pequeno peptídeo de RuBisCO, pode ser isolado e purificado por HPLC de suco verde de alfafa com tempos de retenção de 10 e 50 min, o que corresponde ao peptídeo antimicrobiano. O peptídeo Arg-Asp-Arg-Phe-Leu 0,5% aumenta a estabilidade de oxidação da carne moída durante a refrigeração. O peptídeo Arg-Asp-Arg-Phe-Leu de RuBisCO inibe o crescimento microbiano sob refrigeração durante 11 dias

Peptide from RuBisCO protein hydrolysate and its application in beef meat preservation

Abstract The objective of this work was to purify the small (705 Da) and hydrophilic antimicrobial Arg-Asp-Arg-Phe-Leu peptide from RuBisCO protein hydrolysate and to evaluate its effect on the microbiological and oxidative stability of beef mince during refrigeration. RuBisCO was obtained from alfafa green juice. The peptide extract was fractionated using RP-HPLC, and the active fractions were analyzed by liquid chromatography, electrospray ionization, and tandem mass spectrometry (LC-ESI-MS). Beef mince was analyzed in the following treatments: negative control, meat with two different BHT concentrations of 0.1 and 0.5% (w/w), and meat with two different Arg-Asp-Arg-Phe-Leu peptide concentrations of 0.1 and 0.5% (w/w). Lipid oxidation using the thio-barbituric acid-reactive substance (TBARS) values were significantly affected by the storage period and the concentration of bioactive peptide. Arg-Asp-Arg-Phe-Leu, a small antibacterial peptide from RuBisCO, can be isolated and purified by HPLC from alfafa green juice with retention time between 10 and 50 min, which corresponds to antimicrobial peptides. RuBisCO peptide Arg-Asp-Arg-Phe-Leu 0.5% increases oxidative stability of beef mince during refrigeration. RuBisCO peptide Arg-Asp-Arg-Phe-Leu inhibit microbial growth under refrigeration for 11 days

Identification of ACE I-Inhibitory Peptides Released by the Hydrolysis of Tub Gurnard (<i>Chelidonichthys lucerna</i>) Skin Proteins and the Impact of Their In Silico Gastrointestinal Digestion

Tub gurnard is a highly abundant fishery species caught as a discard in the Mediterranean Sea. This work proposes its valorisation through the release of potential antihypertensive peptides and glycosaminoglycans (GAGs) through the controlled hydrolysis of tub gurnard skin proteins. Four proteases (Esperase, Alcalase, Trypsin and Pronase E) were used to obtain potent angiotensin converting enzyme I (ACE)-inhibitory hydrolysates. Peptides and GAGs were separated and evaluated for their antihypertensive potential by fluorometry. The peptide-rich fractions derived from the Esperase and Alcalase hydrolysates showed very low IC50 values (47 and 68 μg/mL, respectively). Only the GAGs from the Trypsin and Esperase hydrolysates were relevant ACE inhibitors (63 and 52% at 1 mg/mL, respectively). The peptide composition of the most potent ACE-inhibitory fractions derived from the Esperase and Alcalase hydrolysates (IC50 values of 33 and 29 μg/mL, respectively) was analysed by RP-LC-ESI-MS/MS. The analysis suggests that the ACE-inhibitory activity is related to the peptide hydrophobicity, as well as to the presence of specific residues at any of the last four C-terminal positions. The in silico gastrointestinal digestion of these fractions yielded small peptides with antihypertensive potential

Hybrid levan–Ag/AgCl nanoparticles produced by UV-irradiation: properties, antibacterial efficiency and application in bioactive poly(vinyl alcohol) films

International audienceFoodborne diseases caused by resistance of microorganisms to multiple antimicrobial agents haveemerged as a major public health concern around the world. The search for potential antimicrobials hasresulted in the emergence of metal nanoparticles for protection against these infections. In this study aneco-friendly and green approach was used to biosynthesize hybrid Ag/AgCl nanoparticles (NPs), usinglevan from Bacillus mojavensis as a stabilizing/reducing agent, with a high efficiency against a broadspectrum of foodborne bacteria as well as biofilm formations. The morphology and physicochemicalcharacteristics of levan–Ag/AgCl NPs were investigated by transmission electron microscopy (TEM), Xraydiffraction (XRD), UV-vis spectroscopy (UV), dynamic light scattering (DLS) and thermogravimetricanalysis (TGA). The hybrid levan–Ag/AgCl was evaluated for antibacterial activity against foodbornepathogenic bacteria (Escherichia coli, Klebsiella pneumoniae, Salmonella enterica, Pseudomonasaeruginosa, Staphylococcus aureus, Micrococcus luteus, Listeria monocytogenes, Enterococcus faecalis,Bacillus subtilis and Bacillus thuringiensis). The study demonstrated the strong efficiency of hybrid levan–Ag/AgCl NPs as a potent inhibitor against all tested strains, with much higher activity against Gramnegativethan Gram-positive bacteria. Furthermore, bacterial strains were found to be highly sensitive tohybrid levan–Ag/AgCl NPs in comparison to the tested antibiotics. As a possible application of levan–Ag/AgCl NPs as an additive in packaging, PVA films with different amounts of hybrid levan–Ag/AgCl NPswere prepared by casting and their antibacterial, mechanical, and optical properties and ability to expandthe shelf life of beef meat were explored. Interestingly, the amount of Ag leached out from films wasbelow the permissible limit. This work demonstrates the strong antibacterial action of hybrid levan–Ag/AgCl NPs and their potential use in bioactive packaging material

Purification, identification and structural modelling of DPP-IV inhibiting peptides from barbel protein hydrolysate

Inhibition of DPP-IV may improve glycemic control in diabetics by preventing the rapid breakdown and there by prolonging the physiological action of incretin hormones. Barbel muscle protein hydrolysate (BMPH) was noted to exhibit DPP-IV inhibitory activity, with an IC value of 1.94mg/mL. It was fractionated into five major fractions (F-F) by size exclusion chromatography using a Superdex peptide. The F fraction was noted to display the highest inhibitory activity, with an IC value of 1.23mg/mL, and was, therefore, further fractionated by RP-HPLC. Four major peptide sub-fractions were selected. The results revealed that the SF sub-fraction showed the highest DPP-IV inhibitory activity, with an IC value of 0.21mg/mL. This sub-fraction was submitted to RP-HPLC, ESI-MS, and ESI-MS/MS analyses. The findings indicated that SF4 consisted of two peptides (IC=96μg/mL), namely PP1 and PP2, whose structures were identified as Trp-Ser-Gly (330Da) and Phe-Ser-Asp (349Da), respectively. This is the first report of these sequences from barbel proteins.The structural modelling through docking simulations results with DPP-IV showed that the Trp-Ser-Gly peptide bound to DPP-IV with high affinity. Overall, the results suggested that BMPH can be considered as a promising natural source of DPP-IV inhibitory peptides.This work was funded by the Ministry of Higher Education and Scientific Research, by the Spanish Ministry of ForeignPeer Reviewe

Isolation and identification of an arabinogalactan extracted from pistachio external hull: assessment of immunostimulatory activity

This work studies the extraction and purification of a novel arabinogalactan from pistachio external hull. It was extracted with a simple method from pistachio hull which is considered as unexploited waste. Based on the results of sugar analysis by GC-FID, glycosidic linkage by GC-MS, NMR spectroscopy, and molecular weight by Size Exclusion Chromatography, pistachio hull water soluble polysaccharides (PHWSP) were identified as a type II arabinogalactan (AG), with characteristic terminally linked α-Araf, (α1 → 5)-Araf, (α1 → 3,5)-Araf, terminally linked β-Galp, (β1 → 6)-Galp, and (β1 → 3,6)-Galp. DEPT-135, HSQC, HMBC and COSY NMR data suggested the presence of (β1 → 3)-Galp mainly branched at O-6 with (β1 → 6)-Galp chains, α-Araf chains, and terminally linked α-Araf. These AG from pistachio external hulls showed in vitro stimulatory activity for B cells, suggesting their possible use as an immunological stimulant in nutraceutical and biomedical applications.publishe