Dose response to soluble fiber in barley in lowering blood lipids in hamster

Diets containing 0, 25, 50, or 75% finely ground barley (high in soluble fiber and soluble -glucans) were fed to groups of hamsters. After four weeks, serum total cholesterol (CH) levels in these animals were most elevated in the group fed the barley-free (0% barley) diet. Compared to animals eating this diet, the 25% barley diet lowered CH by 16.4%. However, the 50% barley diet lowered CH further by only 4.1% while the 75% barley diet caused virtually no further lowering of CH. Thus, the CH-lowering response to barley cannot be viewed as a dose dependent response. The lowering pattern for serum triglycerides, however, suggested a dose dependent response. Serum total-CH: high-density-lipoprotein (HDL)-CH or low-density-lipoprotein (LDL)-CH:HDL-CH ratios were not significantly affected by barley level in the diets.     

The application of chemical mutagenesis and biotechnology to the modification of linseed (Linum usitatissimum L.)

Summary In the early 1980s the phenomenon of somaclonal variation induced by cell culture was exploited to produce genetic variation in linseed. The linseed variety Andro, derived from the widely grown Canadian variety McGregor, was selected in saline culture and was released for production in Canada. Andro possesses traits very different from its parent, such as increased seedling vigour and tolerance to heat stress. Additional stable somaclonal variation in characters such as yield, days to maturity, seed weight and oil content were subsequently induced in McGregor. However, despite extensive screening of the somaclonal variants, no significant variation in the fatty acid profile was found.Chemical mutagenesis using ethyl methanesulphonate was, however, succesful in modifying the fatty acid profile of McGregor. Initial screening of M₂ seed by the thiobarbituric acid colourimetric procedure was followed by gas chromatography to select half-seeds with atypical fatty acid profiles. Two independent, partially dominant genes were identified that were responsible for reducing the linolenic acid (18 : 3) from 50% to 2% while increasing linoleic acid (18 : 2) to 70%. A single, partially dominant gene, inherited independently of the linolenic acid genes, increased palmitic acid (16 : 0) from 7% to 30% and palmitoleic acid (16 : 1) from trace amounts to 4%. Agrobacterium-mediated transformation of linseed has also been successful. Herbicide tolerance genes for glyphosate, sulfonylurea and phosphinothricin have been incorporated into Canadian varieties. Commercially useful levels of tolerance to sulfonylurea herbicides have been achieved with no adverse agronomic affect. It is expected that a transgenic variety containing this resistance will be registered for commercial production in Canada in 1994.Standard breeding techniques, the application of antisense technology and the overexpression of fatty acid synthesis genes are being used to further modify the fatty acid profile of linseed, as well as for the transfer of abiotic stress-related genes identified in bromegrass.     

Composition and nutritional quality of pea (Pisum sativum L.), faba bean (Vicia faba L. spp. minor) and lentil (Lens culinaris Medik.) meals,protein concentrates and isolates

Pea (Pisum sativum L.), faba bean (Vicia faba L. spp. minor), and lentil (Lens culinaris Medik.) meals, protein concentrates and isolates were analyzed for proximate composition, oligosaccharides, and amino acid composition. Protein quality was evaluated using a mouse bio-assay. The concentrates contained 59.2 to 70.6% and the isolates 86.7 to 90.8% protein (N × 6.25) on moisture-free basis. Glucose, sucrose, raffinose, stachyose and verbascose were present in the highest concentrations in the protein concentrates (7.1 to 11.1%), the pea protein concentrate contained 8.7% sugars and faba bean and lentil protein concentrates 7.1% and 6.6% respectively. The protein isolates were almost free (containing less than 0.79%) of the sugars. Amino acid composition of the meals, concentrates and isolates showed, as expected, sulfur-amino acid deficiency (about two thirds of the rat requirement), which was probably largely responsible for the low protein efficiency ratios (0.75 to 1.18), and net protein ratios (0.25 to 0.73) of the three products, compared to values of 2.56 and 2.18 respectively obtained for casein. The protein digestibilities of the meals, concentrates and isolates (81 to 90%) were similar to that of casein (87%). The poor growth-promoting abilities of the meals, concentrates and isolates were possibly also due to growth-depressing factors such as tannins, trypsin inhibitors and hemagglutinins present, particularly in faba bean and lentil.