Kinetic modelling of vitamin C loss in frozen green vegetables under variable storage conditions.

Abstract A systematic kinetic study of l-ascorbic acid loss of four green vegetables was conducted in the temperature range of freezing storage. The temperature-dependence of vitamin C loss in the À3 to À20 C range was adequately modelled by the Arrhenius equation and activation energy ranged from 98 to 112 kJ/mol for the four frozen green vegetables. The developed models were validated in fluctuating time-temperature conditions, in order to establish their applicability in the real marketing path of the commercial products. Based on the models, the nutritional level can be estimated, at any point of the freezing chain, when the full time-temperature history is available. Comparison among different green vegetables showed that the type of plant tissue significantly affects the rate of vitamin C loss. Frozen spinach was found to be the most susceptible to vitamin C degradation, peas and green beans demonstrated a moderate retention, whereas okra exhibited a substantially lower loss rate.

A MSFD complementary approach for the assessment of pressures, knowledge and data gaps in Southern European Seas : the PERSEUS experience

PERSEUS project aims to identify the most relevant pressures exerted on the ecosystems of the Southern European Seas (SES), highlighting knowledge and data gaps that endanger the achievement of SES Good Environmental Status (GES) as mandated by the Marine Strategy Framework Directive (MSFD). A complementary approach has been adopted, by a meta-analysis of existing literature on pressure/impact/knowledge gaps summarized in tables related to the MSFD descriptors, discriminating open waters from coastal areas. A comparative assessment of the Initial Assessments (IAs) for five SES countries has been also independently performed. The comparison between meta-analysis results and IAs shows similarities for coastal areas only. Major knowledge gaps have been detected for the biodiversity, marine food web, marine litter and underwater noise descriptors. The meta-analysis also allowed the identification of additional research themes targeting research topics that are requested to the achievement of GES. 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license.peer-reviewe

Chemical properties and fluorescence of DOM in relation to biodegradation in the interconnected Marmara-North Aegean Seas during August 2008

The dynamics of dissolved organic matter (DOM) in the Marmara Sea-Dardanelles Straits-North Aegean Sea were investigated using measurements of dissolved organic carbon and nitrogen (DOC, DON), PARAFAC modeling of 3-D excitation-emission fluorescence spectra and bacterial production (BP) and respiration (BR) rates. In the surface brackish waters, chemical parameters showed an increase from the Aegean to the Marmara (DOC: 65-217μmolL-1; DON: 3.08-9.34μmolL-1; Dissolved Inorganic Nitrogen (DIN): 0.044-1.38), followed by an increase in BP rates (7.2-195nmolL-1d-1). In the subsurface waters, DIN also showed an increase in the Marmara basin (0.085-9.79μmolL-1) followed by an increase in BP rates (3.3-17.4nmolL-1d-1). PARAFAC modeling revealed three fluorescent components: λex/λem: <260(330)/464nm, humic-like; λex/λem: <(260) 285/364nm, quinone-like; λex/λem: 270/308nm, tyrosine-like. DOC:DON ratios were found similar for the Marmara (21±3) and the N. Aegean Sea (19±2). The slopes δDOC:δDON suggested that in the Marmara Sea mineralization processes require more carbon relative to nitrogen (22.3), whereas in the N. Aegean there is preferential removal of nitrogen over carbon (5.66). The lack of significant correlation between DOC and AOU (apparent oxygen utilization) in the deep Marmara waters indicates that particulate organic matter is important in deep mineralization processes. © 2013 Elsevier B.V

Chemical properties and fluorescence of DOM in relation to biodegradation in the interconnected Marmara-North Aegean Seas during August 2008

The dynamics of dissolved organic matter (DOM) in the Marmara Sea-Dardanelles Straits-North Aegean Sea were investigated using measurements of dissolved organic carbon and nitrogen (DOC, DON), PARAFAC modeling of 3-D excitation-emission fluorescence spectra and bacterial production (BP) and respiration (BR) rates. In the surface brackish waters, chemical parameters showed an increase from the Aegean to the Marmara (DOC: 65-217μmolL-1; DON: 3.08-9.34μmolL-1; Dissolved Inorganic Nitrogen (DIN): 0.044-1.38), followed by an increase in BP rates (7.2-195nmolL-1d-1). In the subsurface waters, DIN also showed an increase in the Marmara basin (0.085-9.79μmolL-1) followed by an increase in BP rates (3.3-17.4nmolL-1d-1). PARAFAC modeling revealed three fluorescent components: λex/λem: <260(330)/464nm, humic-like; λex/λem: <(260) 285/364nm, quinone-like; λex/λem: 270/308nm, tyrosine-like. DOC:DON ratios were found similar for the Marmara (21±3) and the N. Aegean Sea (19±2). The slopes δDOC:δDON suggested that in the Marmara Sea mineralization processes require more carbon relative to nitrogen (22.3), whereas in the N. Aegean there is preferential removal of nitrogen over carbon (5.66). The lack of significant correlation between DOC and AOU (apparent oxygen utilization) in the deep Marmara waters indicates that particulate organic matter is important in deep mineralization processes. © 2013 Elsevier B.V