Providing a protein-enriched menu in conjunction with individualized dietary counseling significantly increased protein and energy intake in hospitalized patients at nutrition risk.

Several physical and chemical properties of waste fish oils (FOs) and used cooking oils (UCOs) were of acceptable levels for utilization as renewable fuels in marine engines. However, the relatively high acid number of FOs and its increase with ageing might lead to increased risk of corrosion. The physical properties density, dynamic viscosity and kinematic viscosity, as well as water content were measured using different standard methods. Similarly, the acid number, the content of unsaturated fatty acids and the ash content were measured with standard methods. The chemical composition of fatty acids and monoglycerideswere measured with gas chromatography-flame ionization detector and Fouriertransform infrared spectroscopy. The sulphur and phosphorus content were measured using inductively coupled plasma-optical emission spectroscopy.Finally, the thermal properties were measured with thermogravimetric analysis while the heat content was measured with an adiabatic oxygen-bomb calorimeter.The results suggested that these locally produced waste stream-based bio-oils have potential as carbon dioxide neutral fuels. Several properties could be correlated with the fatty acid content of the oils. The results suggested that for waste derived bio-oils the earlier history (storage, thermal treatments before waste classification, ageing), all affect their suitability as fuels in marine engines.

The corrosion behavior of three used cooking oils and one non-edible fish oil was experimentally investigated by the immersion test of iron rods at room temperature. The corrosivity of the tested oils was indirectly determined from the amount of the dissolved iron in the tested oils after the immersion test. Different factors that affect the corrosive behavior of the tested oils were assessed. Among the tested oils, the fish oil showed the highest amount of dissolved iron owing to its chemical properties such as high water content and acid number. In general, water content and acid number have direct effects on the amount of dissolved iron. The addition of oleic acid to the used cooking oil resulted in a 60% less amount of dissolved iron. It was suggested that the addition of oleic acid prompted the formation of a monolayer, which inhibited the permeation of oxygen and water to the surface of the iron rod. Moreover, the addition of glycerol gave the lowest amount of dissolved iron in the oil sample owing to its ability to bind water molecules and form microemulsions in the presence of a surfactant (for example, oleic acid).

Waste fish oils (FOs) and used cooking vegetable oils (UCOs) are increasingly becoming alternative renewable fuels. However, different physicochemical aspects of these renewable fuels, including the effect of storage, are not well-known. In this work, the effect of the storage period on physicochemical properties of selected samples of FOs and UCOs was investigated. The bio-oils were stored at 4 °C for up to five years before each experimentation. The chemical properties were characterized using capillary gas chromatography with flame ionization detection (GC-FID) and high-performance size exclusion chromatography including an evaporative light scattering detector (HPSEC-ELSD). Water contents and acid numbers of the bio-oils were determined using the Karl Fischer (KF) titration and the ASTM D 664 methods. Furthermore, the average heating values and surface tension of the bio-oils were determined. According to the results obtained, for all bio-oil types, the concentrations of polymerized triglycerides, diglycerides, and fatty acids and monoglycerides had increased during the storage periods. The physical properties of the bio-oils also showed a small variation as a function of the storage period. The overall results observed indicate that the deterioration of the physicochemical properties of bio-oils can be controlled through storage in dark, dry, and cold conditions.

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