Influences of combined enzyme-ultrasonic extraction on the physicochemical characteristics and properties of okra polysaccharides

This study obtained two novel polysaccharides from okra by enzyme-assisted and combined enzyme-ultrasonic methods while comparing with previously established hot-water, ultrasonic methods, for their food application potentials. Structural characteristics and physicochemical properties were evaluated and their relationships with functional properties and biological activities including viscosity, emulsifying abilities, antioxidant and antimicrobial activities were observed. All okra polysaccharides (OKPs) showed similar structural features as revealed by 1H NMR, in accordance with FT-IR spectroscopy. The result of monosaccharide composition confirmed isolated OKPs as acidic heteropolysaccharides consisting of galactose, glucose, rhamnose, arabinose, galacturonic and glucuronic acid, in the varying molar percentages of 33.8–38.6%, 12.4–17.9%, 13.7–17.5%, 3.0–9.9%, 19.0–21.2%, and 6.7–8.3%, respectively. All OKPs were broadly polydispersed with molecular weights (Mw) ranging between 129 and 193 × 103 g mol−1, polysaccharide content ranging from 43.95 to 70.75%, a high degree of acetylation (20.81–37.88%) and low methyl-esterification (26.9–38.95%). Combined enzyme-ultrasonic extracted polysaccharide (CEUP) exhibited superior properties such as solubility, emulsifying capacity, high antioxidant activity and showed more potency in Escherichia coli and Listeria monocytogenes inhibition, extending its versatility in...
Source: Food Hydrocolloids - Category: Food Science Source Type: research

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oacute;n MC Abstract The present paper describes the generation of derivatives from the hybrid peptide called Ent35-MccV, active against Gram-positive and Gram-negative bacteria. This peptide has a triple glycine hinge region between enterocin CRL35 and microcin V. In order to obtain variants of Ent35-MccV with greater biotechnological potential, a saturation mutagenesis was carried out in the hinge region. As a result, we obtained a bank of E. coli strains expressing different mutated hybrid bacteriocins in the central position of the hinge region. From all these variants, we found that the one bearing a tyrosine...
Source: Applied Microbiology and Biotechnology - Category: Microbiology Authors: Tags: Appl Microbiol Biotechnol Source Type: research
koh Disease outbreaks caused by the ingestion of contaminated vegetables and fruits pose a significant problem to human health. The sources of contamination of these food products at the preharvest level of agricultural production, most importantly, agricultural soil and irrigation water, serve as potential reservoirs of some clinically significant foodborne pathogenic bacteria. These clinically important bacteria include: Klebsiella spp., Salmonella spp., Citrobacter spp., Shigella spp., Enterobacter spp., Listeria monocytogenes and pathogenic E. coli (and E. coli O157:H7) all of which have the potential to cause dise...
Source: International Journal of Environmental Research and Public Health - Category: Environmental Health Authors: Tags: Review Source Type: research
Publication date: 2019Source: Materials Today: Proceedings, Volume 19, Part 1Author(s): Α. Ntolia, N. Matisioudis, E. Triantafillou, G. Evangelopoulou, V. Karachristou, E. Rizos, T. Karamanidou, A. Tsouknidas, D. Papadopoulos, D. Tsipas, N. Michailidis, A. AggeliAbstractSilver nanoparticles (AgNPs) constitute a promising approach for the development of new antimicrobial systems. The major global concern about the emergence of bacterial strains resistant to widely used therapeutic agents for human infections has increased research for the discovery of new antimicrobial compounds as therapeutic alternatives. The aim of...
Source: Materials Today: Proceedings - Category: Materials Science Source Type: research
(BfR Federal Institute for Risk Assessment) To make food even safer for humans, experts from scientific institutions, food regulatory authorities and the business community will discuss current developments and strategies at the 'Zoonoses and Food Safety' Symposium at the German Federal Institute for Risk Assessment (BfR) on 4 and 5 November 2019, in Berlin-Marienfelde. Because some micro-organisms in food can cause health problems. Campylobacter in raw milk, salmonella in eggs or listeria in ready-to-eat foods often lead to outbreaks affecting numerous patients.
Source: EurekAlert! - Infectious and Emerging Diseases - Category: Infectious Diseases Source Type: news
This study was performed to analyze perinatal prognosis and related factors of maternal bacterial sepsis in west China. We conducted a cross-sectional study of pregnant women with bacterial sepsis who were admitted into a tertiary care center in western China between 2011and 2015. Data from these cases were collected and analyzed. Eighty six women were identified with bacterial sepsis in our hospital, and the incidence of maternal bacterial sepsis was 1.7 per 1000 maternities, the incidence of septic shock was 1.8 per 10,000 maternities, and 1 maternal death occurred. Among the 86 pregnant women with bacterial sepsis, ge...
Source: Medicine - Category: Internal Medicine Tags: Research Article: Observational Study Source Type: research
Many bacteria and some archaea produce the second messenger cyclic diadenosine monophosphate (c-di-AMP). c-di-AMP controls the uptake of osmolytes in Firmicutes, including the human pathogen Listeria monocytogenes, making it essential for growth. c-di-AMP is known to directly regulate several potassium channels involved in osmolyte transport in species such as Bacillus subtilis and Streptococcus pneumoniae, but whether this same mechanism is involved in L. monocytogenes, or even whether similar ion channels were present, was not known. Here, we have identified and characterized the putative L. monocytogenes' potassium tran...
Source: Journal of Biological Chemistry - Category: Chemistry Authors: Tags: Microbiology Source Type: research
Publication date: December 2019Source: Food Packaging and Shelf Life, Volume 22Author(s): Shiv Shankar, Yeong-Ju Bang, Jong-Whan RhimAbstractLow-density polyethylene (LDPE) based nanocomposite film incorporated with grapefruit seed extract (GSE), melanin nanoparticle (Mel), and zinc oxide nanoparticles (ZnONP) was prepared by the extrusion-blowing method. The UV–vis spectra of LDPE/GSE/Mel/ ZnONP film exhibited the characteristic absorption peak of ZnONP at 370 nm. The UV-barrier, thickness, elongation at break, and thermal stability of LDPE film increased after the incorporation of GSE, Mel, and ZnONP, but transpa...
Source: Food Packaging and Shelf Life - Category: Food Science Source Type: research
In conclusion, SCLP was a potential natural antimicrobial substance with strong antimicrobial activity, which may reduce the use of antibiotics or combat drug-resistant bacteria through synergistic combination with antibiotics. PMID: 31637496 [PubMed - as supplied by publisher]
Source: Applied Microbiology and Biotechnology - Category: Microbiology Authors: Tags: Appl Microbiol Biotechnol Source Type: research
Abstract Recently, oxo-biodegradable polymers have attracted much attention due to taking less time to break down after disposal in comparison to ordinary polymers. Polyvinyl alcohol/gelatin (PVA/G) nanocomposite films, containing ZnO, TiO2 or ZnO/TiO2 nanoparticles supported on 4A zeolite (4A z), are novel active packaging that can control the release of antimicrobial compounds. The present study assessed the efficacy of PVA/G nanocomposite films with 1.5% (w/w) ZnO/4A z (treatment 1), 1.5% (w/w) TiO2/4A z (treatment 2), or 1% (w/w) ZnO, TiO2/4A z (treatment 3) in controlling the microbial load and maintaining th...
Source: International Journal of Food Microbiology - Category: Food Science Authors: Tags: Int J Food Microbiol Source Type: research
During infection, bacterial pathogens successfully sense, respond and adapt to a myriad of harsh environments presented by the mammalian host. This exquisite level of adaptation requires a robust modulation of their physiological and metabolic features. Additionally, virulence determinants, which include host invasion, colonization and survival despite the host's immune responses and antimicrobial therapy, must be optimally orchestrated by the pathogen at all times during infection. This can only be achieved by tight coordination of gene expression. A large body of evidence implicate the prolific roles played by bacterial ...
Source: Frontiers in cellular and infection microbiology - Category: Microbiology Source Type: research
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