A.-M. Sjöberg

Quality characteristics of edible linseed oil

In this review the quality properties of linseed oil for food uses are discussed as well as factors affecting this quality. Linseed oil has a favourable fatty acid composition with a high linolenic acid content. Linseed oil contains nearly 60% α-linolenic acid, compared with 25% for plant oils generally. The content of linolenic acid and omega-3 fatty acids is reported to be high in linseed grown in northern latitudes. The composition of fatty acids, especially unsaturated fatty acids, reported in different studies varies considerably for linseed oil. This variation depends mainly on differences in the examined varieties and industrial processing treatments. The fatty acid composition leads also to some problems, rancidity probably being the most challenging. Some information has been published concerning oxidation and taste, whereas only a few studies have focused on colour or microbiological quality. Rancidity negatively affects the taste and odour of the oil. There are available a few studies on effects of storage on composition of linseed oil. In general, storage and heat promote auto-oxidation of fats, as well as decrease the amounts of tocopherols and vitamin E in linseed oil. Several methods are available to promote the quality of the oil, including agronomic methods and methods of breeding as well as chemical, biotechnological and microbiological methods. Time of harvesting and weather conditions affect the quality and yield of the oil.

Soiling Tendency of Worn, Plastic Flooring Materials Related to their Surface Topography

Abstract The soiling and cleanability of eleven worn commercial plastic floor coverings were examined. The new and worn floor coverings appeared very similar in both visual and stereo microscopic inspection. However, wear had caused changes to both topography and cleanability parameters. Profilometer measurements provided information on the topography of new and worn floor coverings. According to the results new surfaces did not always clean better or become soiled more easily than worn coverings. Therefore, we cannot derive a general rule of relationship between wear, soiling and cleanability. The general premise that a rough surface will yield poor cleanability was not confirmed here for all materials.

Cleanability of Plastic Flooring Materials Related to their Surface Properties

Abstract The purpose of this study was to test the feasibility of contact angle measurement in evaluating soilability and cleanability of 11 different surfaces of flooring materials. The surface properties were examined using an expanding contact angle technique and the cleanability was evaluated colorimetrically. The values of advancing contact angles θA were related to the soil residues on particle-soiled surfaces and oil-soiled surfaces. The results indicate the potential of contact angle measurements to evaluate cleanability of flooring materials.

Evaluation of on‐farm biological treatment processes for wastewaters from vegetable peeling

This study highlights the need for the development of simple, efficient, and cost‐effective farm‐scale applications to treat wastewater arising from vegetable‐peeling operations. The aim was to evaluate two full‐scale biological wastewater treatment systems, a sequencing batch reactor (SBR) and a biofilter, and a chemical wastewater treatment system on farms carrying out peeling of vegetables. The types, design criteria and parameters of the processes, as well as properties of the untreated and treated wastewaters were presented and evaluated. Seven‐day biochemical oxygen demand (BOD7) entering the SBR was 3100 ± 529 mg l−1 (mean ± standard deviation). The results showed that the SBR was very stable and effective in the treatment of carrot‐processing wastewaters, the BOD7 for effluent being about 10 mg l−1. The biofilter examined did not operate well because the pH too low: the reduction for BOD7 was 63% and, for COD, 58%. When wastewater from potato processing was treated with aluminium sulphate and conveyed to an artificial pond, removal of BOD7 was 67% and that of COD 69%. This method is only suitable for pre‐ or post‐treatment of these wastewaters. Control of the treatment processes appeared to be essential for their proper functioning.

Cadmium content of Finnish linseed and estimated consumer intake

�-1 ). The Cd contents of the crush samples were between 0.47 and 1.5 mg kg -1 (mean 0.85 mg kg -1 ). There were differences between the Cd contents of the three examined varieties and years at the experimental farm. Increase in nitrogen fertilization somewhat increased the Cd uptake of linseed. The permitted intake of linseed depends on body weight and on the Cd content of the product and is in most cases higher than the dietary recommendation (24–30 g daily dose of linseed).

Application of radiochemical determination methods in cleanability research of building materials

During recent years increasing effort has been made to modify surface properties with easy-to-clean or self-cleaning characteristics, and concomitantly there is a need to be able to quantify cleanability. Methodology is a complex issue, including aspects of selection and characterization of the surface materials, the soiling materials (contaminants), soiling and cleaning methods, and the detection methods. Different biological, chemical, physical and visual methods have been included in studies of surface cleanability. One challenge has been to obtain quantitative information about soiling. The radiochemical methods, gamma spectrometry (NaI(Tl)-crystal) and liquid scintillation counting, have been shown to be suitable for evaluating cleanability of different surface materials and different soiling material types, providing quantitative information about the amount of soiling material both on and beneath the surface. Due to the different labelled soiling components, the interaction of the surface with different soiling material types can be evaluated. Radiochemical methods have unique benefits particularly for examining porous materials and surfaces. However, they are suitable only for highly controlled studies because of the hazards. Different features and details of radiochemical methods are discussed with the view to aid planning of future cleanability studies.

Evaluation of different floor materials in cattle barns.

Floor surfaces in livestock barns are of special interest, since they should withstand strong mechanical and chemical stress and they should also be as comfortable as possible to stand and lie on. Furthermore, the floors should be easy to clean. The aim of this project was to develop well-functioning floor surface materials for use in animal houses. Both laboratory and field tests were performed. Changes in repellence and surface properties, cleanability, colour and gloss of materials were measured. Materials for the field test were chosen according to the results of laboratory studies with the exception of silane-impregnated concrete. The other materials selected were epoxy-, polyurethane- and acrylic coatings for floorings and feeding tables, and polyester coating for feeding tables. Two materials not tested in the laboratory were also included in the field tests. Traditional concrete was used as reference. The surface materials had more effect on changes in cleanability and repellence of tested materials than the chemical stresses introduced. SEM pictures showed that during wear the surfaces became rougher or scratches appeared on them. According to profilometer measurements no significant differences between the changes in the surface roughness of test materials were observed. The results of colour and gloss measurements varied considerably, but in general, coating decreased the changes of colour and gloss of the surface materials. The field study provides practical information about the behaviour of the surface materials examined.