A compound responsible for metallic flavour in dairy products: II. Theoretical consideration of the mechanism of formation of oct-1-en-3-one

1967 ◽  
Vol 34 (1) ◽  
pp. 89-102 ◽  
Author(s):  
R. A. Wilkinson ◽  
W. Stark
Keyword(s):  
Dairy Products ◽  
Atmospheric Oxygen ◽  
Free Access ◽  
Mechanism Of Formation ◽  
Significant Extent ◽  
Ionic Intermediates ◽  
Arachidonic Acids ◽  
Flavour Component

SummaryPossible mechanisms are considered for the formation of a metallic flavour component, oct-1-en-3-one, in a vacuum-packed butterfat-antioxidant-synergist mixture, and in washed cream and butter with free access to atmospheric oxygen. The oct-1-en-3-one is likely to be derived from linoleic or arachidonic acids, or both. A complex of reactions linking oxygen, catalysts, substrate, radicals, and antioxidants is discussed. Pathways for the production of intermediates giving rise to oct-1-en-3-one are suggested for systems with free and with limited access to oxygen. These mechanisms would involve secondary oxidations with formation of polyfunctional monomers and would be competing for oxygen with those giving rise to polymers. The reasons why they compete to a significant extent are discussed in relation to the detailed environmental conditions including lipid reactivity, effective oxygen pressure in situ, steric effects at phase boundaries and the role of acidity and of ionic intermediates.

SRET Visualisation of Pyrite Corrosion and its Inhibition in Aerated Solution

2008 ◽  
Vol 587-588 ◽  
pp. 1008-1013
Author(s):  
L.P.S. Araújo ◽  
Diogo M.F. Santos ◽  
César A.C. Sequeira
Keyword(s):  
Atmospheric Oxygen ◽  
Reference Electrode ◽  
Industrial Wastes ◽  
Inhibiting Effect ◽  
Electrode Technique

In this work, the Scanning Reference Electrode Technique (SRET) was used to visualise the pyrite corrosion by atmospheric oxygen and its inhibition by a thymol derivative. SRET has the advantage over the potentiostatic and galvanostatic techniques of enabling in situ operation without imposing any potential or current to the sample under study. SRET revealed that the inhibiting effect is effective only if the sample is oxidised beforehand. It also revealed that pyrite corrosion by oxygen is a localised process whereas that by Fe(III) is not local, thus the oxidation of pyrite by atmospheric oxygen is not only due to the oxidative role of Fe(III). Adsorption of oxygen plays probably a determining role. Studies are now carried on to evidence the intervention of galvanic processes or catalysis phenomena occurring during the corrosion of natural conducting minerals and industrial wastes. Their aim is to better understand the mechanisms and to propose remediation processes.

Dispersal in pond snails: potential role of waterfowl

1986 ◽  
Vol 64 (4) ◽  
pp. 904-909 ◽  
Author(s):  
D. A. Boag
Keyword(s):  
Potential Role ◽  
Lymnaea Stagnalis ◽  
Free Access ◽  
Snail Population ◽  
Air Stream ◽  
Air Speed ◽  
Pond Snails ◽  
Better Than

Young pond snails of three species (Lymnaea stagnalis, Stagnicola elodes, and Helisoma trivolvis) were allowed free access to waterfowl feathers floating on the surface of shallow containers. Snails adhering to the feathers were subjected to simulated flight conditions by placing them in an air stream. The size of these snails, the length of time they adhered to the feathers while in the air stream, and their survivability for various lengths of time under these conditions were recorded. Those snails that adhered to the feathers were mainly small individuals (< 2.5 mm long in all three species). The proportion that remained clinging to the feathers declined sharply with time; after 15 min of exposure only 6% of L. stagnalis, 18% of S. elodes, and 15% of H. trivolvis remained. Survivability also declined with time exposed to the simulated flight conditions; after 15 min only 50% of L. stagnalis, 23% of S. elodes, and 15% of H. trivolvis were still alive. Larger individuals tended to survive better than smaller ones for any given exposure time, but they also tended to fall off the feathers sooner than smaller ones; no snail more than 3 mm long was recorded adhering to the feathers for more than 4 min under the test conditions of simulated flight (air speed of 41 km/h). These results suggest that despite a low proportion of the snail population adhering to the feathers (< 1% of those available at any given time) and the relatively high rates of loss, either by falling off the feathers or dying in situ after adhering, the probability of successful dispersal for distances up to 10 km remains high (a mallard flying for 15 min at 41 km/h was deemed capable of carrying at least three surviving individuals of any of the species tested over a distance of about 10 km). Of the three species tested, S. elodes had the greatest probability of successful dispersal, which may explain its almost ubiquitous distribution in the water bodies of central Alberta.

scholarly journals Role of mammals on seed dispersal and predation processes of Mauritia flexuosa (Arecaceae) in the Colombian Amazon

2016 ◽  
Vol 64 (1) ◽  
pp. 5 ◽  
Author(s):  
Juan Fernando Acevedo Quintero ◽  
Joan Gastón Zamora-Abrego
Keyword(s):  
Seed Dispersal ◽  
Camera Traps ◽  
The Other ◽  
Free Access ◽  
Relative Importance ◽  
Mauritia Flexuosa ◽  
Open Treatment ◽  
Palm Fruits

Mammals and palms are important elements of fauna and flora in the Neotropics, and their interactions, such as fruit consumption and seed dispersal, are one of the most important ecological relationships in these ecosystems. The main objective of this study was to identify the relative importance of mammals in the dispersal and predation of Mauritia flexuosa palm fruits. We installed camera-traps in front of palm fallen seeds and clusters with fruits. A catalog of species was prepared with the recorded videos and the foraging behaviors exhibited were classified and identified. In addition, two exclusion treatments with three repetitions each were used. In the semi-open treatment, a plot was fenced with metal mesh leaving four openings in order to allow access only to small and medium sized mammals, while in the open treatment, the small, medium and large sized mammals had free access. In both cases, seed removal was evaluated. We recorded a total of 19 species of mammals, nine of which fed on palm fruits and the other five were seed dispersers. We reported for the first time the consumption of Mauritia flexuosa fruits by Atelocynus microtis. The species with the highest relative importance was Dasyprocta fuliginosa, which showed the highest percentage of seed dispersal (63.5%) compared to the other species. Tayassu peccary was identified as an in situ consumer, eating 45.3% of seeds without dispersing them. The number of seeds consumed in situ in the open treatment showed significant differences regarding the semi-open treatment, suggesting greater involvement of large mammals in this process. In conclusion, the fruits of M. flexuosa are an important food source for the local mammal community. Additionally, the consumption of seeds under the canopy of the mother palm is proportionally greater than their dispersion. Generally, the pressure of frugivorous species over seeds may determine the reproductive strategies of plants. However, research on effective dispersion, dispersal distances and demographic impact should be conducted to determine the specific role of medium and large sized mammals in the ecology of this palm.

Health of the child and the role of dairy products

2016 ◽  
Vol 77 (5) ◽  
pp. 83-88
Author(s):  
I.N. Matvienko ◽  
Keyword(s):  
Dairy Products

Estimation of Aflatoxin M1 Levels in Some Dairy Products Manufactured from Raw Milk Experimentally Inoculated with Toxin

2019 ◽  
Vol 43 (1) ◽  
pp. 50-58
Author(s):  
H. S. Alnaemi
Keyword(s):  
Dairy Products ◽  
Raw Milk ◽  
Aflatoxin M1 ◽  
Consumer Health ◽  
Goat’S Milk ◽  
White Cheese ◽  
Elisa Technique ◽  
Permissible Levels ◽  
Goat's Milk

     Fate of AflatoxinM1 in soft white cheese and its by-product (whey) and in yogurt locally made from raw sheep's and goat's milk experimentally inoculated with 0.05 and 0.5 µg/l AflatoxinM1 were investigated using ELISA technique. Results reported that AflatoxinM1 was concentrated in cheese at levels significantly higher than that recorded in the raw milk that used for its processing, with a significant decrease in AflatoxinM1 levels in its by-product (whey) comparable to the raw milk used in manufacturing at both inoculated levels. Yogurt produced from raw sheep's milk at second inoculated level exerted AflatoxinM1concentration significantly lower than that present in the milk. Significant differences in AflatoxinM1distribution in cheese and whey produced from sheep's milk comparable to their counterparts produced from goat's milk were recorded. Finally, results revealed the efficacious role of the various dairy manufacturing processes in AflatoxinM1 distribution and the necessity to issue of local legislations concerning the maximum permissible limits for AflatoxinM1 in milk in order to stay within the universal permissible levels for AflatoxinM1 in dairy products to provide greater protection for consumer health. 

{10-12} Twinning Mechanism During In Situ Micro-Tensile Loading of Pure Mg: Role of Basal Slip and Twin-Twin Boundary Interaction

2020 ◽  
Author(s):  
Nicolò Maria della Ventura ◽  
Szilvia Kalácska ◽  
Daniele Casari ◽  
Thomas Edward James Edwards ◽  
Johann Michler ◽  
...  
Keyword(s):  
Twin Boundary ◽  
Basal Slip ◽  
Tensile Loading ◽  
Boundary Interaction

The role of (bio)surfactant sorption in promoting the bioavailability of nutrients localized at the solid-water interface

1999 ◽  
Vol 39 (7) ◽  
pp. 91-98 ◽  
Author(s):  
Ryan N. Jordan ◽  
Eric P. Nichols ◽  
Alfred B. Cunningham
Keyword(s):  
Mass Transfer ◽  
Cell Membrane ◽  
Substrate Concentration ◽  
Water Interface ◽  
Industrial Systems ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Surfactant Sorption

Bioavailability is herein defined as the accessibility of a substrate by a microorganism. Further, bioavailability is governed by (1) the substrate concentration that the cell membrane “sees,” (i.e., the “directly bioavailable” pool) as well as (2) the rate of mass transfer from potentially bioavailable (e.g., nonaqueous) phases to the directly bioavailable (e.g., aqueous) phase. Mechanisms by which sorbed (bio)surfactants influence these two processes are discussed. We propose the hypothesis that the sorption of (bio)surfactants at the solid-liquid interface is partially responsible for the increased bioavailability of surface-bound nutrients, and offer this as a basis for suggesting the development of engineered in-situ bioremediation technologies that take advantage of low (bio)surfactant concentrations. In addition, other industrial systems where bioavailability phenomena should be considered are addressed.

THE ROLE OF BACTERIAL COMMUNITIES ON IN-SITU ARSENIC AND IRON CYCLING IN RIVERBANKS ALONG THE MEGHNA RIVER, BANGLADESH

2020 ◽  
Author(s):  
Kimberly D. Myers ◽  
◽  
Katrina Lee Jewell ◽  
P.S.K. Knappett ◽  
Mehtaz M. Lipsi ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Iron Cycling
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