Several ring tests have been organized by the International Organisation for Standardization (ISO) and the Measurement and Testing Programme (BCR) for improving glucosinolate methods. Finally, HPLC of desulphoglucosinolates is recommended by ISO, the European Committee for Standardization (CEN), and the European Commission (EC) as the official method. X-ray fluorescence has also become particularly common for fast analysis. After checking stability of intact glucosinolates in whole rapeseeds, the BCR has three reference materials (CRM 366, CRM 190, CRM 367) available, certified for their total glucosinolate and sulphur contents. Currently, the Measurement and Testing Programme is supporting a research project concerning the stability of desulphoglucosinolates and intact glucosinolates extracts. At the present time, best results are observed with lyophilized extracts sealed in brown glass ampoules and stored at -18 degrees C.

Lipoxygenase activity in 35 seed extracts was determined on the basis of hydroperoxide synthesis using linoleic acid as substrate. The results referring to the extracted protein content show that several species of Vigna (V. unguiculata, V. radiata and V. mungo) and one of Trifolium exhibit stronger lipoxygenase activity than soybean enzyme extracts. The pH activity relationship was also established for 4 very active samples. GC-MS analysis revealed equal amounts of 9- and 13- hydroperoxides of linoleic acid in these seed extracts, indicating no enzyme positional specificity.

Tylosema fassoglensis seeds contain high levels of lipids (240-300 g kg(-1)) and proteins (446 g kg(-1) dry weight). Major fatty acids contained in the oil are linoleic (36-42% of the total fatty acids) oleic (32-35%) and palmitic (11.5-15.7%) acids. The proteins are characteristic with their high levels of lysine, proline and tyrosine. Due to their very low content, both methionine and cystine appear to be the limiting amino acids. Tylosema fassoglensis defatted meal contains substantial amounts of trypsin inhibitors and phytates 295 TUI mg(-1) and 35 g kg(-1) dry weight, respectively.

The current work is focused on the interfacial behavior of monolayers of two different forms of lipase from Mucor miehei. The adsorption kinetics and surface pressure/area (ΠA) isotherms at the air-water interface are discussed, taking into account the saline concentration and the pH of the subphase. Lipase A adsorbs rapidly at the interface whereas a phase of latency precedes the lowering of surface tension on the adsorption kinetics of lipase B. The configuration of these proteins facing the bulk solution seems different. In addition, ΠA diagrams suggest that the two enzymes adopt a different conformation at the interface. Lipase A is partly unfolded and its degree of unfolding is pH dependent, while lipase B keeps a compact globular conformation that is not altered by a pH modification. The presence of salt in the subphase increases the speed of migration for both forms by a phenomenon of “salting-out.” A mixture of lipase A and lipase B (50:50) shows an intermediate behavior. The adsorption kinetics is in its first part influenced by lipase B and in its second part by lipase A. The ΠA isotherms for this mixture deviate from the theoretical curve calculated as a mean area at the same pressure on the lipase A and lipase B diagrams. The two enzymes form a mixed miscible film in which the rigidity of the lipase B molecules reduces the tendency of the lipase A molecules to expand and compress.

Growth-promoters are banned by the European Community, but different hormonal cocktails are still illegally used. This experiment was therefore conducted to evaluate the effects of one of the most currently used cocktails on some hormonal parameters and spermatogenesis in finishing bulls in an attempt to provide a suitable screening technique for their illegal use. Sixteen double-muscled Belgain White Blue finishing bulls (mean weight: 535 (s.d. 37) kg) were blocked into control (C; no. = 7) and treated (Dex; no. = 9) groups. Animals were treated i.m. with the hormonal preparation (dexamethasone isonicotinate and phosphate, chlormadinone acetate and ethinyl oestradiol) on day 0, day 15 and day 30. Animals were slaughtered on day 45. Three h before each treatment and just prior to slaughter, jugular blood samples were collected to monitor the testosterone (T) response to an i.v. injection of gonadotropin releasing hormone (GnRH) (0.5 mug GnRH per kg body weight). Testicular tissue was also collected at slaughter. Plasma T and insulin-like growth factor-1 (IGF-1) concentrations were measured by radioimmunoassay. IGF-binding proteins (IGFBPs) were evaluated using Western ligand blotting. Daily weight gains were lower in the control group (1.29 (s.d. 0.13) kg for C v. 1.60 (s.d. 0.39) kg for Dex) but the difference was not significant. After treatment, spermatogonia, spermatocytes, spermatids and spermatozoa disappeared from the testis and seminiferous tubules consisted only of Sertoli cells; these observations suggest that treated animals were sterile. Moreover, plasma T concentrations in response to GnRH stimulation were suppressed (P < 0.001) in the Dex group between day 15 and day 45 (mean maximal responses: 5.4 to 7.9 mug/l in C group v. < 0.2 mug/l in Dex group at day 15, 30 and 45). Treatment did not show any prominent effect on plasma IGF-1 levels but increased IGFBP-3 band intensity. In conclusion, treatment with a cocktail containing dexamethasone esters, chlormadinone acetate and ethinyl oestradiol for a short period induced a number of changes in finishing bulls which might be possible to develop as a screening method for the identification of illegally treated animals.

Citronellol esterification catalyzed byCandida antarctica lipase is performed with high yields (74%) in a solvent-free medium. The use of dessicants gives a 10% yield enhancement and substrate excess consumption by adding calculated amounts of acetic acid lead to a 80% pure citronellyl acetate. Quantities up to 100 ml are treated with success.

Seasonal variations of mycorrhizal colonisation of European beech, Fagus sylvatica L. and Norway spruce, Picea abies Karst., rootlets in two stands, were investigated by comparing ergosterol content and very-fine root tip counts for a 3 yr period. Significant correlations and interactions between three environmental factors, ‘year’, ‘season’ and ‘horizon’ and the measured data, were interpreted. It was shown that root tip counting together with ergosterol analysis of rootlets enables us to follow changes induced by the environment on a long-term basis.

The sterols of three Reference Materials: a vegetable oil (RM162: a mixture of Soya oil and Maize oil) and two animal fats (RM163: a blend of Pig and Beef fats and RM164: Milkfat) were identified by GC-MS in two experienced laboratories. The techniques used were practically the same nevertheless, Lab. 1 and 2 used respectively an HPLC and a classical TLC method to isolate the sterols from the unsaponifiable matter. Many minor components were detectable when the high efficient HPLC fractionation technique was used but the only molecules similarly identified by the two Labs were considered for the certification of sterol identities. In this article, we present the results of the certification study together with the interpretation of mass spectra.

The preparation of certified rapeseed reference materials and the steps taken to establish the certified values for total glucosinolate contents are described. Details are given of the studies to demonstrate the homogeneity and stability of the material. The results of the certification exercise for total glucosinolate content, which involved European laboratories who applied a variety of methods (high-pressure liquid chromatography, gas liquid chromatography, determination of enzymatically released glucose and sulphate), are presented and discussed. The certified values for the glucosinolate content (μmol/g of non-defatted whole seeds) and the 95% confidence level are the following: CRM 366 (12.1±0.8 μmol/g), CRM 190 (25.5±0.9 μmol/g) and CRM 367 (102.4±3 μmol/g) (CRM = certified reference material). Indicative values (not certified) for individual glucosinolates are also given. Certified sulphur values (mg/g of non defatted whole seeds) have been determined by other laboratories: CRM 366 (3.41±0.12 mg/g), CRM 190 (4.93±0.15 mg/g) and CRM 367 (10.5±0.40 mg/g).

The production of essential oil by tissue cultures of Anthemis nobilis L. including cell suspension, shoot and crown-gall cultures is reported. The biosynthetic capability of these different cultures was compared with that of plants grown in a field.The addition of crude polysaccharide fraction prepared from yeast extract and from the plant itself to shoot cultures affected the composition and total essential content (from 0.08% to 0.30% dry weight). The essential oil content of the crown-gall tissue of A. nobilis was 0.25% of the dry weight and the composition of the essential oil was comparable to that of the flowers.

In developing countries, traditional control methods are commonly used against stored-product insects and mites. In Senegal, the leaves of Cassia occidentalis L. (Caesalpiniaceae) are used to protect cowpea seeds (Vigna unguiculata L. (Walpers)) against Callosobruchus maculatus (Coleoptera: Bruchidae). The biological activity of the leaves, the seeds and oil of C. occidentalis was evaluated in controlled conditions (28 ± 2°C, 45 ± 5% r.h.) against C. maculatus. At the rate of 10% (w/w), both fresh and dry leaves as well as whole and ground seeds had no contact toxicity on the cowpea beetle. In contrast, seed oil induced an increase in mortality of C. maculatus eggs and first larval instar at the concentration of 10 ml/kg cowpea. The basis of the ovicidal and larvicidal activities are discussed in this paper. Several trials using pure compounds have highlighted that several fatty acids (linoleic, oleic and stearic) are responsible for C. occidentalis toxicity. C. occidentalis seed oil did not reduce the oviposition of C. maculatus at 10 ml/kg seed.

Two labdane diterpenes were isolated from the seeds and the rhizomes of AFRAMOMUM ALBOVIOLACEUM (Ridley) K. Schum (Zingiberaceae) and identified by GC-MS, (1)H-, and (13)C-NMR as ( E)-labda-8(17),12-diene-15,16-dial ( 1) and ( E)beta,17-epoxy-labd-12-ene-15,16-dial ( 2). A third minor compound could be the methyl ( E)-14xi,15-epoxylabd-8(17),12-dien-16-oate. The simultaneous occurrence of these three molecules has been mentioned only in one other species of the same genus, AFRAMOMUM DANIELLII (1).

Biological activity of leaves, fruits and extract of the African shrubBoscia senegalensis (PERS.) LAM. ex Poir. was evaluated against five stored-grain insects. When added to cowpeas at 2–4% (w/w), fresh ground fruits and leaves caused 80–100% mortality inCallosobruchus maculants (F.) adults and significantly reduced both emergence and damage of the F1 progeny. Acetone fruit extract exhibited a potent fumigant effect onProstephanus truncatusHorn, C.maculatus, andSitotroga cerealella OLIV.; with LT50 values of 3.8, 2.3, and below 1.5 hr, respectively. LC50 determination forB. senegalensis fruits and leaves as well as pure methylisothiocyanate (MITC) onTribolium castaneum HERBST,Sitophilus zeamais MOTSCH. andC. maculatus showed a differential response of the insects to plant parts or MITC. Quantitative dosage ofBoscia active components and LC50 values obtained for the plant tissues, compared to those of pure molecules, indicate that the biological activity ofB. senegalensis is due to the liberation of MITC from a glucosinolate precursor glucocapparin contained inBoscia fruits and leaves.

The work reported here is integrated into a programme organized by the Community Bureau of Reference with the aim of developing edible oil reference materials (RMs) certified for cholesterol content. One vegetable oil (RM 162, a blend of soya and maize oils) and two animal fats (RM 163, a blend of pig and beef fats, and RM 164, an anhydrous milk fat) possessing, respectively, low, medium and high cholesterol contents were chosen for this purpose. The present paper summarizes the analytical conclusions resulting from three interlaboratory trials carried out to identify and correct for the major sources of random and systematic errors linked to the protocol and to the gas-liquid chromatographic analysis. Several improvements to the methodology, and recommendations, have been proposed for the determination of individual sterols within the certification exercise. The latter will be reported elsewhere.

AbstractRenealmia alpinia Rott. (Maas) (Zingiberaceae) seeds contain 14% of a dark brown oleoresin which was investigated by a combination of chromatographic and spectrometric techniques. The volatiles (4.4% of the oleoresin) extracted from the oil by hydro‐distillation were mainly monoterpene hydrocarbons (β‐pinene 22.3%, limonene 18.4% and β‐phellandrene 38.0%). The oleoresin was further fractionated by column chromatography. β‐Carotene, nerolidol and manool were detected. The main constituent (45%) was unambiguously identified as 8(17),12 (E)‐labdadien‐15,16‐dial and details of its structure were provided by NMR spectroscopy. Three other unidentified labdane diterpenes were also found in low amounts.