34 research outputs found
DETERMINATION OF VITAMIN E CONTENT IN SUNFLOWER OILS AVAILABLE ON THE ROMANIAN MARKET
Vitamin E is soluble in fat and alcohol, withstands temperatures up to 250ºC, but is sensitive to light and oxygen. Very high or very low temperature values reduce the amount of tocopherol in food by up to two-thirds. 12 samples of different types of sunflower oil were analyzed using HPLC with fluorescent detector. The total tocopherols amount was between 150-930 mg/l. The highest concentration was found in cold press sunflower oil, stored in dark glass bottles and the lowest in store bought sunflower oil, in PET packaging. α-Tocopherol had the highest concentration from all the other tocopherols, analyzed (β-Tocopherol, γ-Tocopherol, δ-Tocopherol). In some samples of sunflower oil, in PET packaging β-Tocopherol, γ-Tocopherol, δ-Tocopherol were under the detection limit. Sunflower oil no matter the technology used for it’s production it’s a an important source of α-Tocopherol
Liquid chromatographic method for the determination of beta-carotene from milk and cheese
The beta-carotene content in milk and cheese is an accurate indicator for the feeding method used for cows. It can also be sued as an indicator of adulteration of goat and other types of milk with cow milk. A high accuracy HPLC-UV method for the determination of beta-carotene from milk and cheese has been developed. After saponification with an alcoholic solution of potassium hydroxide the samples where extracted with a mixture of hexane: ethyl acetate (70:30) was used. The concentrated extract was analyzed using Perkin Elmer 200 Series High Performance Liquid Chromatograph (HPLC) with UV detector for the determination of beta-carotene content. The calibration was done in 4 points from 1-20 ng/ml. The recovery yield was between 73,8-89,7 %. The method was tested on 3 milk samples and 5 cheese samples. The highest concentration of beta-carotene was found in cheddar cheese produced with milk from pasture raised cows.
The mineralogical composition of calcium and calcium-magnesium carbonate pedofeatures of calcareous soils in the European prairie ecodivision in Hungary
Abstract
There is little data on the mineralogy of carbonate pedofeatures in the calcareous soils in Hungary which belong to the European prairie ecodivision. The aim of the present study is to enrich these data.
The mineralogical composition of the carbonate pedofeatures from characteristic profiles of the calcareous soils in Hungary was studied by X-ray diffractometry, thermal analysis, SEM combined with microanalysis, and stable isotope determination.
Regarding carbonate minerals only aragonite, calcite (+ magnesian calcite) and dolomite (+proto-dolomite) were identified in carbonate grains, skeletons and pedofeatures.
The values relating, respectively, to stable isotope compositions (C13, O18) of carbonates in chernozems and in salt-affected soils were in the same range as those for recent soils (latter data reported earlier). There were no considerable differences between the values for the carbonate nodules and tubules from the same horizons, nor were there significant variations between the values of the same pedofeatures from different horizons (BC-C) of the same profile. Thus it can be assumed that there were no considerable changes in conditions of formation.
Tendencies were recognized in the changes of (i) carbonate mineral associations, (ii) the MgCO3 content of calcites, (iii) the corrected decomposition temperatures, and (iv) the activation energies of carbonate thermal decompositions among the various substance-regimes of soils.
Differences were found in substance-regimes types of soils rather than in soil types
Differentiation of plant derived organic matter in soil, loess and rhizoliths based on n-alkane molecular proxies
Persistent Place-Making in Prehistory: the Creation, Maintenance, and Transformation of an Epipalaeolithic Landscape
Most archaeological projects today integrate, at least to some degree, how past people engaged with their surroundings, including both how they strategized resource use, organized technological production, or scheduled movements within a physical environment, as well as how they constructed cosmologies around or created symbolic connections to places in the landscape. However, there are a multitude of ways in which archaeologists approach the creation, maintenance, and transformation of human-landscape interrelationships. This paper explores some of these approaches for reconstructing the Epipalaeolithic (ca. 23,000–11,500 years BP) landscape of Southwest Asia, using macro- and microscale geoarchaeological approaches to examine how everyday practices leave traces of human-landscape interactions in northern and eastern Jordan. The case studies presented here demonstrate that these Epipalaeolithic groups engaged in complex and far-reaching social landscapes. Examination of the Early and Middle Epipalaeolithic (EP) highlights that the notion of “Neolithization” is somewhat misleading as many of the features we use to define this transition were already well-established patterns of behavior by the Neolithic. Instead, these features and practices were enacted within a hunter-gatherer world and worldview
The mineralogical composition of calcium and calcium-magnesium carbonate pedofeatures of calcareous soils in the European prairie ecodivision in Hungary
Anaerobiosis revisited: growth of Saccharomyces cerevisiae under extremely low oxygen availability
The budding yeast Saccharomyces cerevisiae plays an important role in biotechnological applications, ranging from fuel ethanol to recombinant protein production. It is also a model organism for studies on cell physiology and genetic regulation. Its ability to grow under anaerobic conditions is of interest in many industrial applications. Unlike industrial bioreactors with their low surface area relative to volume, ensuring a complete anaerobic atmosphere during microbial cultivations in the laboratory is rather difficult. Tiny amounts of O2 that enter the system can vastly influence product yields and microbial physiology. A common procedure in the laboratory is to sparge the culture vessel with ultrapure N2 gas; together with the use of butyl rubber stoppers and norprene tubing, O2 diffusion into the system can be strongly minimized. With insights from some studies conducted in our laboratory, we explore the question ‘how anaerobic is anaerobiosis?’. We briefly discuss the role of O2 in non-respiratory pathways in S. cerevisiae and provide a systematic survey of the attempts made thus far to cultivate yeast under anaerobic conditions. We conclude that very few data exist on the physiology of S. cerevisiae under anaerobiosis in the absence of the anaerobic growth factors ergosterol and unsaturated fatty acids. Anaerobicity should be treated as a relative condition since complete anaerobiosis is hardly achievable in the laboratory. Ideally, researchers should provide all the details of their anaerobic set-up, to ensure reproducibility of results among different laboratories.
A correction to this article is available online at http://eprints.whiterose.ac.uk/131930/
https://doi.org/10.1007/s00253-018-9036-