From grain to feed – process development concerning production of high protein fractions from grain and legum products to be used in extruded fish feed pellets

The Danish project “Organic Aquaculture” the link between sustainable production and superior products” is examining the availability of relevant organically produced crops with a high protein content to be used as raw materials for fish feed. Fish meal is the main source of protein for fish feed. On a global scale the production of fish meal will not increase. There is a demand for developing sustainable protein sources as a substitution for fish meal. Protein from crops and legumes is an obvious solution, however, the crops and legumes need to be processed into fractions with a higher protein content in order to compete with fish meal. The process development was carried out at The Danish Technological Institute’s pilot plant located in Sdr. Stenderup, Denmark. Sweet lupine seeds were processed among other grains and legumes. A dehulling process was developed based on three process steps: knife mill grinding, vibration sifting and zig zag air classifying. The protein content was concentrated from 34 % to 43 % protein on dry matter and fat free basis. 90,5 % of the hull was removed. The dehulled lupines were grinded so that 84 % of the fraction was below 250 µm. The grinding was carried out using a hammer mill with a 2.0 mm and a 1.0 mm sieve at 2950 rpm and finally using an Alpine 160 Z pine mill at 18.900 rpm. The grinded product was air classified by using a MP 400 Alpine Air Classifier. A protein fraction of 62 % protein on dry matter and fat free basis was reached. The relation between the particle size of the protein product and the protein content in the fraction was investigated. A linear relation was found and demonstrated; when the protein content in the product was increased the amount of particles in the fraction below 70 µm also increased linearly. The lupine protein was incorporated into a recipe for fish feed and extruded into pellets on a Werner Pfleider Continua 37 Twin Screwed Extruder

A general extrudate bulk density model for both twin-screw and single-screw extruder extrusion cooking processes

Effects of extrusion parameters and raw materials on extrudate expansion are respectively investigated in a twin-screw extruder and a single-screw extruder extrusion cooking experiments for fish feed, wheat, and oat & wheat mixture processing. A new phenomenological model is proposed to correlated extrudate bulk density, extrusion parameters and raw material changes based on the experimental results. The average absolute deviation (AAD) of the correlation is 2.2% for fish feed extrusion in the twin-screw extrusion process. For the single-screw extrusion process, the correlation AAD is respectively 3.03%, 5.14% for wheat and oat & wheat mixture extrusion; and the correlation AAD is 6.6% for raw material change effects. The correlation results demonstrate that the proposed equation can be used to calculate extrudate bulk density for both the twin-screw extruder and the single-screw extruder extrusion cooking processes

Surface water temperature, salinity, and density changes in the northeast Atlantic during the last 45,000 years: Heinrich events, deep water formation, and climatic rebounds

We developed a new method to calculate sea surface salinities (SSS) and densities (SSD) from planktonic foraminiferal delta(18)O and sea surface temperatures (SST) as determined from planktonic foraminiferal species abundances. SST, SSS, and SSD records were calculated for the last 45,000 years for Biogeochemical Oceanic Flux Study (BOFS) cores 5K and 8K recovered from the northeast Atlantic. The strongest feature is the dramatic drop in all three parameters during the Heinrich ''ice-rafting'' events. We modelled the possibility of deepwater formation in the northeast Atlantic from the SSD records, by assuming that the surface waters at our sites cooled as they flowed further north. Comparison with modelled North Atlantic deepwater densities indicates that there could have been periods of deepwater formation between 45,000 and 30,000 C-14 years B.P. (interrupted by iceberg meltwater input of Heinrich event 3 and 4, at 27,000 and 38,000 C-14 years B.P.) and during the Holocene. No amount of cooling in the northeast Atlantic between 30,000 and 13,000 years could cause deep water to form, because of the low salinities resulting from the high meltwater inputs from icebergs. Our records indicate that after each Heinrich event there were periods of climatic rebound, with milder conditions persisting for up to 2000 years, as indicated by the presence of warmer and more saline water masses. After these warm periods conditions returned to average glacial levels. These short term cold and warm episodes in the northeast Atlantic ate superimposed on the general trend towards colder conditions of the Last Glacial Maximum (LGM). Heinrich event 1 appears to be unique as it occurs as insolation rose and was coeval with the initial melting of the Fennoscandian ice sheet. We propose that meltwater input of Heinrich event 1 significantly reduced North Atlantic Deep Water formation reducing the heat exchange between the low and high latitudes, thus delaying deglaciation by about 1500 radiocarbon years (2000 calendar years)

Merging late Holocene molecular organic and foraminiferal-based geochemical records of sea surface temperature in the Gulf of Mexico

Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 26 (2011): PA1209, doi:10.1029/2010PA002000.A molecular organic geochemical proxy (TEX86) for sea surface temperature (SST) is compared with a foraminifera-based SST proxy (Mg/Ca) in a decadal-resolution marine sedimentary record spanning the last 1000 years from the Gulf of Mexico. We assess the relative strengths of the organic and inorganic paleoceanographic techniques for reconstructing high-resolution SST variability during recent climate events, including the Little Ice Age (LIA) and the Medieval Warm Period (MWP). SST estimates based on the molecular organic proxy TEX86 show a similar magnitude and pattern of SST variability to foraminiferal Mg/Ca-SST estimates but with some important differences. For instance, both proxies show a cooling (1°C–2°C) of Gulf of Mexico SSTs during the LIA. During the MWP, however, Mg/Ca-SSTs are similar to near-modern SSTs, while TEX86 indicates SSTs that were cooler than modern. Using the respective SST calibrations for each proxy results in TEX86-SST estimates that are 2°C–4°C warmer than Mg/Ca-SST throughout the 1000 year record. We interpret the TEX86-SST as a summer-weighted SST signal from the upper mixed layer, whereas the Mg/Ca-SST better reflects the mean annual SST. Downcore differences in the SST estimates between the two proxies (ΔT = TEX86 − Mg/Ca) are interpreted in the context of varying seasonality and/or changing water column temperature gradients.This work was supported, in part, by the National Science Foundation under grants OCE‐0318361 and OCE‐0903017

Rapid switches in subpolar North Atlantic hydrography and climate during the Last Interglacial (MIS 5e)

Author Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 27 (2012): PA2207, doi:10.1029/2011PA002244.At the peak of the previous interglacial period, North Atlantic and subpolar climate shared many features in common with projections of our future climate, including warmer-than-present conditions and a diminished Greenland Ice Sheet (GIS). Here we portray changes in North Atlantic hydrography linked with Greenland climate during Marine Isotope Stage (MIS) 5e using (sub)centennially sampled records of planktonic foraminiferal isotopes and assemblage counts and ice-rafted debris counts, as well as modern analog technique and Mg/Ca-based paleothermometry. We use the core MD03-2664 recovered from a high accumulation rate site (∼34 cm/kyr) on the Eirik sediment drift (57°26.34′N, 48°36.35′W). The results indicate that surface waters off southern Greenland were ∼3–5°C warmer than today during early MIS 5e. These anomalously warm sea surface temperatures (SSTs) prevailed until the isotopic peak of MIS 5e when they were interrupted by a cooling event beginning at ∼126 kyr BP. This interglacial cooling event is followed by a gradual warming with SSTs subsequently plateauing just below early MIS 5e values. A planktonic δ18O minimum during the cooling event indicates that marked freshening of the surface waters accompanied the cooling. We suggest that switches in the subpolar gyre hydrography occurred during a warmer climate, involving regional changes in freshwater fluxes/balance and East Greenland Current influence in the study area. The nature of these hydrographic transitions suggests that they are most likely related to large-scale circulation dynamics, potentially amplified by GIS meltwater influences.This work is a contribution of the European Science Foundation EuroMARC program, through the AMOCINT project, funded through grants from the Research Council of Norway (RCN) and contributes to EU-FP7 IP Past4Future. N. Irvalı was additionally funded by an ESF EUROCORES Short-term Visit grant and a RCN Leiv Eiriksson mobility grant to support research stays at the University of Edinburgh, UK, and Woods Hole Oceanographic Institution, USA, respectively, during which parts of the data for this paper were acquired. U. Ninnemann was funded by a University of Bergen Meltzer research grant.2012-11-1