Freer, J. B. S., Sansome, G. (1991): The influence of plant population and nitrogen fertility on the seed yield and quality of linseed. Aspects of Applied Biology: Production and Protection of Linseed , 28 , 49
initial curing stage of epoxidized linseed oil typically follows a chemically controlled reaction mechanism. Imidazole initiates the curing reaction by opening the oxiran ring under formation of a zwitterion [ 19 ] (Scheme 1 , 1). The subsequent cross
In this paper the polymerisation of linseed oil is studied in order to prove the catalytic action of some inorganic pigments.
The results show that the calorimetric technique is able to monitor the polymerisation process in the temperature range between
130 and220C; reproducible values for isothermal analysis are obtained between 130 and 150C;finally the results are quantitative
and can be justified by kinetic equations.
Wheat flour was enhanced by linseed fibre, characterised by granulation 500–700 μm. Using seeds from 2015 flax harvest, linseed fibre was gained from two golden and one brown linseed varieties (Amon, Raciol and Recital, respectively). Additions at levels 2.5% and 5.0% affected amylases activity and protein technological quality softly, evaluated by Falling Number and Zeleny sedimentation tests, respectively. Both brown and yellow linseed fibre significantly supported extensograph elasticity of non-fermented dough. Baking potential of composites tested evaluated as extensograph energy significantly decreased about 7–18%, likely owing to dilution of dough gluten skeleton. Pasting behaviour of flour composites reflected a hydrophilic character of non-traditional material – amylograph viscosity was elevated from 590 units to ca 700 units by Amon and Recital fibre, and to ca 930 units by Raciol fibre. Pasting profiles of flour composites, recorded by using of Rapid Visco Analyser, confirmed this finding. Dough fermentation was represented by maturograph test, during which the tested samples were differentiated in part according to the dough resistance. Reflecting small modifications in dough visco-elastic properties, specific volumes of bread buns were similar trough whole sample set. A weak worsening of buns vaulting reflected a partial disruption of dough gluten skeleton. Consumer’s quality of all enhanced bread variants was evaluated in category acceptable, determined as crumb penetration (values higher than 20 mm).
Summary Cold pressed linseed oil and paints prepared using the inorganic pigments; lead white and red lead, were characterized using non-isothermal differential scanning calorimetry (DSC) in an air atmosphere to determine the effect of the pigment on the oxidative polymerisation of the drying oil medium. For each paint sample, the onset temperature for oxidation was reduced from 166°C to the range 50 to 60°C when a heating rate of 5 K min-1 was used. In order to determine the rate of drying, the non-isothermal experiments were carried out using a range of heating rates. A change in the mechanism oxidative polymerization was observed as the heating rate was increased.
Often less than optimal PUFA content of human diet have started the research aimed to increase its quantity in meats. Including linseed and sunflower oil in rabbit feed effectively improves rabbit meat lipid composition, but its altered sensitivity to oxidative reactions could result in colour change. The effect of vegetable oil content of the diet and vitamin E supplementation was studied on the colour of rabbit loin and thigh meats and dissected fat. Meat lightness, redness, yellowness, hue and chromacity were measured with Minolta chromameter on samples cooled to 5 °C for 24 h. Including sunflower (2%) and linseed (2%) oil in rabbit diet changed the colour of the dissected fat making it lighter (L* 76.96 v. 73.79), more yellowish (b* 13.34 v. 11.41) and intense (C* 14.49 v. 12.35) coloured compared to the control diet without vegetable oils. To the effect of the vitamin E supplementation of vegetable oil containing feed redness of the thigh decreased (a* 4.41 v 5.44) and hue increased (h° 58.63 v. 49.76). The source of vitamin E supplement influenced only the colour of loin: natural vitamin E increased lightness (L* 53.03 v. 49.62), yellowness (3.86 v. 3.04) and chromacity (3.96 v. 3.25) while synthetic vitamin E did not. The changes of loin, thigh and fat colour observed in this study may be utilized in making the product more desirable to the consumer.
The nutritive value, the microbiological safety of oilseed cake (OSC) obtained from naked pumpkin seed (PuC), sunflower seed (SC), yellow linseed (LC), and walnut (WnC), and their impact on wheat flour (WF) dough and bread sensory characteristics at 5% and 10% addition ratio were investigated. The OSCs had high protein (34–50%), fat (8–15%), total dietary fibre (23–36%) content and high energy value (383–444 kcal/100 g)). The OSC samples with a minimal exception fulfilled the requirements of feed legislation in force. An increased water absorption, dough development time, and reduced elasticity were observed probably due to the enhanced fiber and protein content. Dough stability increased with WnC, and decreased with PuC or SC addition. Enrichment provided the appearance of a brown bread for WnC, of a half-brown bread for LC. PuC gave an unusual look. The appearance of OSC fortified bread similar to daily bread, was an advantage resulting the 1st rank for 10% WnC bread and the 2nd one for 10% LC bread (P=0.05). The studied OSCs are suitable for food enrichment, however, in case of PuC and SC fortified flour blends, hydrocolloid application is recommended. Our data suggest that the newly developed fortified breads could be a valuable source for healthy nutrition.
We evaluated the microbiological safety, the short-term storability, and the macronutrients of oil seed cake (OSC) obtained from walnut (WnC), linseed (LC), and sunflower seed with hull (SC). The OSCs had 3.6–5.8% moisture content, 0.50–0.60 water activity (aw), 29.9–39.4% protein, 15.5–23.6% fat, and 36.6–48.0% dietary fibre content. The grinded OSCs could be stored in opaque plastic bags for 4 months at temperatures of 4 °C, 14 °C, and 25 °C. Total colony count of mesophilic microorganisms depending on oxygen demand and spore-forming ability, and faecal indicator microorganisms were determined during a 4-month storage term at 4 °C, 14 °C, and 25 °C using traditional culturing methods. The OSCs were free from sulphite-reducing Clostridia and coliforms, including Escherichia coli. Data were analyzed statistically by multifactor analysis of variance. Ascending order of the average contamination of the three products (log10 CFU g−1) was aerobic sporogenic bacteria (2.39), fungal count (2.51), total aerobic microbe count (3.00), anerobic sporogenic bacteria (3.75), and total anaerobic microbe count (4.23). As for the average microbial count, WnC was the least (2.73 log10 CFU g−1) and LC was the highest (3.53 log10 CFU g−1) contaminated material. Regarding the variation of microbial contamination during storage, temperature was indifferent (P=0.191), while storage time (P=0.0033) and the product type were influential (P=0.000).