Effects of High Pressure Processing on the Quality of Vacuum Packed Fish Patties

2014 ◽  
Vol 644-650 ◽  
pp. 4671-4676
Author(s):  
Ying Chun Zhu ◽  
Li Zhen Ma ◽  
Yu Jing Tian ◽  
Hua Yang ◽  
Yao Hua Guo ◽  
...  
Keyword(s):  
High Pressure ◽  
Bacterial Growth ◽  
Reduction Potential ◽  
Meat Products ◽  
High Pressure Processing ◽  
Control Group ◽  
Oxidation Reduction ◽  
Preservation Method ◽  
Oxidation Reduction Potential

The objective of this study was to evaluate the use of high pressure processing (HPP) as a preservation method of meat products. Vacuum-packaged fish patties were subjected to HPP (300 MPa for 30 min 15°C or 500 Mpa for 10 min at 15°C). Untreated samples represented the control group. The three groups were stored at 4°C for 0–5 weeks. Color parameters, pH, thiobarbituric (TBARS), bacterial growth, and Oxidation-Reduction Potential (ORP) were determined. The results revealed that the 500-MPa treatment inhibited bacterial growth and extended the shelf-life of fish patties to four weeks with insignificant effects on the physicochemical attributes.

Physico-chemical Characterization of “Bone Taint” in Spanish Dry-cured Hams

1997 ◽  
Vol 60 (6) ◽  
pp. 667-672 ◽  
Author(s):  
DOMINGO BLANCO ◽  
AGUSTIN ARIÑO ◽  
PILAR CONCHELLO ◽  
CONSUELO PEREZ ◽  
JAVIER YANGÜELA ◽  
...  
Keyword(s):  
Moisture Content ◽  
Reduction Potential ◽  
Chemical Characterization ◽  
Control Group ◽  
Chemical Parameters ◽  
General Terms ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Physico Chemical

Samples of Spanish dry-cured hams were analyzed using several physico-chemical parameters (moisture content, chlorides, water activity, nitrate, nitrite, total volatile basic nitrogen [TVBN], pH, and oxidation-reduction potential [Eh]). The samples (n = 76) were taken from three basic types of dry-cured hams produced in Spain: slow-cured hams from white pigs (n = 39), fast-cured hams from white pigs (n = 15), and hams from black-skinned Iberian pigs (n = 22). Overall, 56 samples (73.7%) showed the “bone taint” condition, and the remaining 20 hams (26.3%) were normal, and therefore considered as a control group. The objective of this research was to establish the possible circumstances that determine the alteration by means of the differences found in the values of the analyzed measurements in both groups of samples (altered versus normal ones). The hams with “bone taint” were, in general terms, those with a higher TVBN content, a greater pH, and a lower Eh, attributable to an anomalous development of the proteolytic phenomena. The conjunction of a lower concentration of chlorides, greater moisture content, and a higher aw in the affected hams may have created the conditions favorable for tissue enzyme and/or microbial activity.

scholarly journals Unravelling the Molecular Mechanisms Underlying the Protective Effect of Lactate on the High-Pressure Resistance of Listeria monocytogenes

Biomolecules ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 677
Author(s):  
Cristina Serra-Castelló ◽  
Ilario Ferrocino ◽  
Anna Jofré ◽  
Luca Cocolin ◽  
Sara Bover-Cid ◽  
...  
Keyword(s):  
High Pressure ◽  
Protective Effect ◽  
Molecular Mechanisms ◽  
Rna Extraction ◽  
Meat Products ◽  
High Pressure Processing ◽  
Membrane Properties ◽  
Short Exposure ◽  
Cooked Ham ◽  
Pressure Resistance

Formulations with lactate as an antimicrobial and high-pressure processing (HPP) as a lethal treatment are combined strategies used to control L. monocytogenes in cooked meat products. Previous studies have shown that when HPP is applied in products with lactate, the inactivation of L. monocytogenes is lower than that without lactate. The purpose of the present work was to identify the molecular mechanisms underlying the piezo-protection effect of lactate. Two L. monocytogenes strains (CTC1034 and EGDe) were independently inoculated in a cooked ham model medium without and with 2.8% potassium lactate. Samples were pressurized at 400 MPa for 10 min at 10 °C. Samples were subjected to RNA extraction, and a shotgun transcriptome sequencing was performed. The short exposure of L. monocytogenes cells to lactate through its inoculation in a cooked ham model with lactate 1h before HPP promoted a shift in the pathogen’s central metabolism, favoring the metabolism of propanediol and ethanolamine together with the synthesis of the B12 cofactor. Moreover, the results suggest an activated methyl cycle that would promote modifications in membrane properties resulting in an enhanced resistance of the pathogen to HPP. This study provides insights on the mechanisms developed by L. monocytogenes in response to lactate and/or HPP and sheds light on the understanding of the piezo-protective effect of lactate.

scholarly journals In situ measurements of oxidation–reduction potential and hydrogen peroxide concentration as tools for revealing LPMO inactivation during enzymatic saccharification of cellulose

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Adnan Kadić ◽  
Anikó Várnai ◽  
Vincent G. H. Eijsink ◽  
Svein Jarle Horn ◽  
Gunnar Lidén
Keyword(s):  
Reduction Potential ◽  
Enzymatic Saccharification ◽  
The State ◽  
Enzyme Inactivation ◽  
Ex Situ ◽  
Process Economics ◽  
Complete Inactivation ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential

Abstract Background Biochemical conversion of lignocellulosic biomass to simple sugars at commercial scale is hampered by the high cost of saccharifying enzymes. Lytic polysaccharide monooxygenases (LPMOs) may hold the key to overcome economic barriers. Recent studies have shown that controlled activation of LPMOs by a continuous H2O2 supply can boost saccharification yields, while overdosing H2O2 may lead to enzyme inactivation and reduce overall sugar yields. While following LPMO action by ex situ analysis of LPMO products confirms enzyme inactivation, currently no preventive measures are available to intervene before complete inactivation. Results Here, we carried out enzymatic saccharification of the model cellulose Avicel with an LPMO-containing enzyme preparation (Cellic CTec3) and H2O2 feed at 1 L bioreactor scale and followed the oxidation–reduction potential and H2O2 concentration in situ with corresponding electrode probes. The rate of oxidation of the reductant as well as the estimation of the amount of H2O2 consumed by LPMOs indicate that, in addition to oxidative depolymerization of cellulose, LPMOs consume H2O2 in a futile non-catalytic cycle, and that inactivation of LPMOs happens gradually and starts long before the accumulation of LPMO-generated oxidative products comes to a halt. Conclusion Our results indicate that, in this model system, the collapse of the LPMO-catalyzed reaction may be predicted by the rate of oxidation of the reductant, the accumulation of H2O2 in the reactor or, indirectly, by a clear increase in the oxidation–reduction potential. Being able to monitor the state of the LPMO activity in situ may help maximizing the benefit of LPMO action during saccharification. Overcoming enzyme inactivation could allow improving overall saccharification yields beyond the state of the art while lowering LPMO and, potentially, cellulase loads, both of which would have beneficial consequences on process economics.

scholarly journals The Negative Impact of Varicocele on Basic Semen Parameters, Sperm Nuclear DNA Dispersion and Oxidation-Reduction Potential in Semen

2021 ◽  
Vol 18 (11) ◽  
pp. 5977
Author(s):  
Kamil Gill ◽  
Michal Kups ◽  
Patryk Harasny ◽  
Tomasz Machalowski ◽  
Marta Grabowska ◽  
...  
Keyword(s):  
Reduction Potential ◽  
Nuclear Dna ◽  
Study Groups ◽  
Semen Parameters ◽  
Sperm Dna Fragmentation ◽  
Control Groups ◽  
Infertile Men ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Sperm Dna

Since varicocele is so common in infertile men, this study intends to analyse the relationships between varicocele and conventional semen characteristics, sperm nuclear DNA dispersion and oxidation-reduction potential (ORP) in semen. Varicocele-positive and varicocele-negative infertile men (study groups) showed significantly lower standard sperm parameters and higher sperm DNA fragmentation (SDF) and ORP in semen than healthy volunteers and subjects with proven fertility (control groups). A lower proportion of low SDF levels (0–15% SDF) and higher incidence of high SDF levels (>30% SDF), as well as a higher prevalence of high ORP values (>1.37 mV/106 sperm/mL), were found in the study groups vs. the control groups. Moreover, infertile men had significantly lower odds ratios (ORs) for low SDF levels and significantly higher ORs for high SDF levels and high ORP. SDF and ORP were negatively correlated with sperm number, morphology, motility and vitality. Furthermore, a significant positive correlation was found between SDF and ORP. The obtained results suggest that disorders of spermatogenesis may occur in varicocele-related infertility. These abnormalities are manifested not only by reduced standard semen parameters but also by decreased sperm DNA integrity and simultaneously increased oxidative stress in semen.

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