BIOCHEMICAL CHARACTERIZATION OF FLOUR FROM SEEDS OF CAMELINA SATIVA L. (CRANTZ) AFTER CHEMICAL EXTRACTION OF OIL

Camelina sativa (CS) is an oilseed crop of the Brassica family that has gained increasing popularity as a biofuel source. The use of non-food plants as feedstock for biodiesel production is successful if the by-products, remaining after chemical extraction of oil, are valorized and utilized. The study reported in this thesis was performed in order to characterize CS biodiesel by-product. Some CS varieties different by origin were cultivated in two experimental fields: one set up in Casazza (BG) -Italy- in two years of cultivation and two growing seasons and the other in Firenze-Italy-. At the end of growing season, seeds were collected, dried, defatted and the flours used for biochemical analyses. Meal protein content of nine genotypes from experimental field set up in Casazza (BG) was investigated to identify the genotype with highest protein content. The mean of meal protein content in two years of cultivation was 32.1% in defatted flour (d.f.) in autumn sowing and 36% d.f in spring sowing. ANOVA analysis showed that CS meal protein content was significantly different both for sowing season and year of cultivation. In spring sowing, seeds presented higher protein content respect to autumn sowing due to better nitrogen absorption in the warming season. Ligena was the genotype with highest protein content. SDS-PAGE of meal protein extract revealed the presence of two major bands: 27 and 15 kDa, likely belonging to cruciferin and napin fractions respectively. Meal protein extract was subjected to acid hydrolysis in order to determine amino-acid composition of CS protein by HPLC (high performance liquid chromatography). The study of amino acids (AA) profile of CS protein revealed the presence of all AA, including the ten essentials. Among the essential AA, leucine and valine were predominant while lysine was the limiting determining the biological value of CS meal. In order to evaluate the use of CS meal in animal feed diets, it was estimated the predictive digestibility of CS meal protein, in ruminants, by studies “in vitro” of ruminal protein degradation rates and RUP (ruminal undegraded protein) analysis. The digestibility of protein meal is strictly influenced by fibre content in seed coat in particular to the NDF (neutral detergent fibre, part of cell wall soluble in solutions at pH=7). For this, analyses of the fibre components of cell wall were performed. The significant differences of theoretical digestibility of protein among the CS genotypes, can be explained by fibre and NDIFP (protein bound to neutral detergent fibre fraction) content. A limitation in the use of CS by-products in animal feed is the presence of anti-nutritive compounds (glucosinolates, sinapine, phytic acid and condensed tannins). From the analyses of twelve genotypes of CS from experimental field set up in Firenze, it resulted that sinapine, phytic acid and condensed tannins can be considered low in comparison with other members of Brassicaceae and not toxic for animal. Glucosinolates (GSLs) represent the main anti-nutritive compounds in CS. Three main GSLs were indentified named GSL1 (9-methyl-sulfinyl-nonyl-GLS) glucoarabin, GSL2 (10-methyl-sulfinyl-decyl-GSL) glucocamelinin, and GSL3 (11-methyl-sulfinyl-undecyl-GSL) gluconesiliapanuculatin. GSL2 represented the most abundant GSL being between 50-60%. GSL content in CS ranged from 15.2 to 24.6 mmol/Kg (DM), with most genotypes with less than 20 mmol/Kg DM. These values are higher respect those considered safe for animal. For this, it was necessary to develop a fast and reliable method to evaluate genotypic variation in GSL content to breed CS plants low in GSLs. A new HPTLC (high performance thin layer chromatography) procedure for screening CS genotypes allowed us to save time and solvent with respect to conventional HPLC procedure and thus represents a fast and economic alternative to HPLC for the determination of CS GSLs. Therefore, CS meal presented high protein content, in particular during warming season, a balanced AA profile and a quite good ruminal digestibility of protein similar to rapeseed or soybean meal generally used in animal feed. Low-input new by-product biodiesel, CS, could strongly substitute high-input by-product biodiesel rapeseed or soybean as ingredient in animal feed formulations, as it occurred in U.S., where the introduction of CS meal in animal feed formulations was successful. The characterization of CS meal described in this thesis suggests that an experimentation on the use of CS by-product in animal feed in Europe could be now undertake.