Search results for " biotechnology"
showing 10 items of 3723 documents
Involvement of an Alkane Hydroxylase System of Gordonia sp. Strain SoCg in Degradation of Solid n-Alkanes▿
2010
ABSTRACT Enzymes involved in oxidation of long-chain n -alkanes are still not well known, especially those in Gram-positive bacteria. This work describes the alkane degradation system of the n -alkane degrader actinobacterium Gordonia sp. strain SoCg, which is able to grow on n -alkanes from dodecane (C 12 ) to hexatriacontane (C 36 ) as the sole C source. SoCg harbors in its chromosome a single alk locus carrying six open reading frames (ORFs), which shows 78 to 79% identity with the alkane hydroxylase (AH)-encoding systems of other alkane-degrading actinobacteria. Quantitative reverse transcription-PCR showed that the genes encoding AlkB (alkane 1-monooxygenase), RubA3 (rubredoxin), RubA4…
The influence of Opuntia ficus-indica mucilage edible coating on the quality of ‘Hayward’ kiwifruit slices
2016
Abstract The aim of this work was to study the effect of mucilage edible coating extracted from Opuntia ficus-indica (OFI) on the quality and shelf life maintenance of packaged kiwifruit slices. OFI mucilage alone or added with TWEEN ® 20 were applied on kiwifruit fresh cut surfaces. After treatments, kiwifruit samples were stored under passive atmosphere at 5 ± 1 °C for 3, 5, 7 and 12 days. At each storage period, visual quality and flavor score, pectin content, ascorbic acid and the microbiological characteristics were measured together with CO 2 and O 2 content in the packages. Kiwifruit slices coated only with mucilage or with mucilage plus Tween 20, showed a significant higher firmness…
Influence of flavour transfer between different gel phases on perceived aroma
2007
International audience; Multiphasic models of stirred fruit yoghurts made from a bilayer that consisted of a pectin and a dairy gel were developed in order to study the transfer of strawberry flavour compounds between the two phases. Several parameters (i.e., the flavour concentration, the fat content of the dairy gel and the storage temperature) affecting flavour compound transfer, using an experimental design, together with their effect on sensory perception were investigated. Strawberry flavour transfer between the two gels was high enough to affect the sensory perception of the dairy gels. The parameters that modified the partitioning of ethyl esters between the pectin and dairy gel (i.…
An overview of the traditional and innovative approaches for pectin extraction from plant food wastes and by-products: Ultrasound-, microwaves-, and …
2018
Abstract Background A large amount of food wastes and by-products are produced from farm to plate. They represent valuable sources for the production of high-added value compounds such as pectin. Pectin is the methylated ester of polygalacturonic acid and presents a wide range of applications in pharmaceutical and cosmetic products as well as in food industry such as gelling agent in fruit-based products, stabilizer in fruit and milk beverages and fruit filling for bakery and confectionary products, among others. Therefore, pectin recovery is of great importance. Scope and Approach The commercially available pectin is almost exclusively derived from citrus peels or apple pomace, by-products…
Retention/release equilibrium of aroma compounds in fat-free dairy gels
2010
BACKGROUND: The replacement of fat by thickeners in fat-free yoghurts leads to an important modification of aroma compound partitioning, with an impact on aroma perception. Investigation of retention/release equilibria allows a good understanding of aroma compound behaviour depending on food composition. RESULTS: Vapour/liquid equilibria of ten aroma compounds (two esters, two ketones, three aldehydes and three alcohols) in several media were studied to investigate the influence of pectin addition to fat-free dairy gel on the retention/release equilibrium. The partition coefficient of each aroma compound was measured by headspace analysis at equilibrium in six media (pure water, low-methoxy…
Inorganic phosphate is a trigger factor for Microbispora sp. ATCC-PTA-5024 growth and NAI-107 production
2014
Background NAI-107, produced by the actinomycete Microbispora sp. ATCC-PTA-5024, is a promising lantibiotic active against Gram-positive bacteria and currently in late preclinical-phase. Lantibiotics (lanthionine-containing antibiotics) are ribosomally synthesized and post-translationally modified peptides (RiPPs), encoded by structural genes as precursor peptides. The biosynthesis of biologically active compounds is developmentally controlled and it depends upon a variety of environmental stimuli and conditions. Inorganic phosphate (Pi) usually negatively regulates biologically-active molecule production in Actinomycetes, while it has been reported to have a positive control on lantibiotic…
Isolation of Gram-positive n-alkane degraders from a hydrocarbon-contaminated Mediterranean shoreline.
2007
Aims: To investigate the petroleum hydrocarbon (HC)-degrading potential of indigenous micro-organisms in a sandy Mediterranean coast, accidentally contaminated with petroleum-derived HCs. Methods and Results: Using culturable methods, a population of Gram-positive n-alkane degraders was detected in the contaminated soil. Five isolates, identified as one Nocardia, two Rhodococcus and two Gordonia strains, were able to degrade medium- and long-chain n-alkanes up to C36 as assessed by growth assays and gas chromatography-mass spectrometry analysis. Diverging alkane hydroxylase-encoding genes (alkB) were detected by PCR, using degenerated primers, in all the strains; multiple sequences were obt…
Effect of electric currents on antibacterial effect of chlorhexidine against Entrococcus faecalis biofilm : An in vitro study
2018
Background This in vitro study was mainly aimed to evaluate the effect of high-frequency alternating currents (AC) applied by an electronic apex locator (EAL) on the antibacterial properties of chlorhexidine (CHX) on E. faecalis biofilm. Material and Methods The root canals of 120 extracted human single-rooted teeth were prepared using Gates-Glidden drills and hand K-files. After contaminating the root canals with E. faecalis, they were incubated for 60 days. Then, the teeth were randomly divided into six experimental groups (n=20). Group 1, 2% CHX; group 2, normal saline (NS) with direct current (DC); group 3, normal saline (NS) with high-frequency alternating current (AC); group 4, 2% CHX…
Reuse of Food Waste and Wastewater as a Source of Polyphenolic Compounds to Use as Food Additives
2020
Abstract The problem of waste and byproducts generated from agro-industrial activities worldwide is an increasing concern in terms of environmental sustainability. In this ambit, the quantity of food wastes—produced in all steps of the whole food chain—is enormous, and it may be forecasted that food waste could amount to more than 120 billion tonnes by 2020. The reuse of food waste and wastewater as source of polyphenolic compounds could be an interesting discussion in this ambit. In fact, polyphenols obtained in this way might be used for food and non-food purposes by means of new, improved, and safe extraction methods. In light of the opportunity represented by the treatment of agro-indus…
Transfers of small analytes in a multiphasic stirred fruit yoghurt model
2007
International audience; The transfer of small analytes in a multiphasic stirred fruit yoghurt model, made of a pectin gel aimed to mimic fruit pieces and of a dairy gel done with milk acidified by glucono-δ-lactone hydrolysis, have been studied. The concentration gradients between the pectin gel and the dairy gel were the driving force for the migration of small analytes (i.e. water, protons and colorants). Water migrated from the dairy to the pectin gel, causing modifications in the water content of both gels and an equilibration of their water activity at 0.938±0.003. Inversely, protons migrated from the pectin to the dairy gel. These changes in composition of both gels being likely to ha…