Single-flowered vetch (Vicia articulata Hornem.): A relic crop in Italy

Single-flowered vetch (Vicia articulata Hornem.), a crop native of the Mediterranean area, is widespread mainly in south Europe, in west Asia and Australia for forage, green manure and human food. In Italy this crop was still cultivated in the 1950s but, later, no records concerning its cultivation were available. This strongly suggested to place V. articulata among the Italian crop species that disappeared in the 20th century. In the course of a collecting expedition in Sardinia, a relic population, mistaken for lentil, was found. This population has been characterised from a botanical, nutritional and cytological point of view. V. articulata appears to be lower in nutritional quality than lentil. However, within the framework of a sustainable agriculture, V. articulata could find interesting opportunities. In fact, its role in soil conservation and rescue of marginal areas could be interesting, as well as its potentialities as a source of useful genes in breeding programmes.     

Contribution of proanthocyanidins to the peroxy radical scavenging capacity of some Italian red wines

Highly reactive radicals, ROO(*), were generated from 2, 2'-azobis[2-(2-imidazolin-2-yl)propane] and linoleic acid. The ROO(*) scavenging capacity of some Italian red wines was evaluated following the changes in oxygen consumption. Under the experimental conditions the time course of oxygen consumption shows two typical behaviors: trolox-like (class I) and gallic acid-like (class II). Usually the time course of wine was similar to that of gallic acid. The rate of oxygen consumption was found to decrease exponentially with the amount of wine or gallic acid added to the test solution. On this basis the capacity of red wines to scavenge peroxy radicals was expressed as content of gallic acid (S(GA)). The S(GA) values were found to be correlated to the amount of total proanthocyanidins and total polyphenols of some Italian red wines (p < 0.01). The proanthocyanidins extracted from seeds were shown to make a major contribution to the peroxy radical scavenging capacity of red wines, whereas, interestingly, the chemical class of the low molecular weight tannins reactive to vanillin did not correlate with the S(GA) values.     

Threshold-based structure-activity relationships of pyrazines with bell-pepper flavor

Quantitative structure activity relationships (QSAR) and comparative molecular field analysis (CoMFA) are applied in order to explain the aroma of 46 bell-pepper aroma compounds. Biological activities log(1/c) values are used, where c stands for the detection threshold value of the aroma compound in water. Results of conventional QSAR and CoMFA are both satisfactory in statistical significance and predictive ability. We construct a qualitative model using the graphic features of CoMFA together with the results of "classical" QSAR analysis, which is performed by multiple linear regression. Finally, the human olfactory detection threshold values of excluded pyrazines are successfully predicted. This makes CoMFA and QSAR two important tools for designing new aroma compounds and in elucidating the mechanism of odor-receptor interaction.     

Development of biodegradable films from whey proteins by cross-linking and entrapment in cellulose

When cross-linked by heating or by gamma-irradiation and entrapped in cellulose, whey proteins can generate insoluble biofilms with good mechanical properties and high resistance to attack by proteolytic enzymes. Interchain cross-linking of proteins generated an increase in the puncture strength, and a decrease in water vapor permeability. Gelatin was added in film formulation as a stabilizer to improve the puncture strength and film appearance. The structure of the biofilms was also analyzed. SDS-PAGE revealed that heating and gamma-irradiation produce an increase of the molecular weight of the cross-linked protein. Size exclusion chromatography showed a molecular mass of 40 kDa for un-cross-linked whey proteins, whereas for the soluble fractions of the cross-linked proteins, molecular distributions were between 600 and 3800 kDa for the heated proteins and between 1000 and 2000 kDa for gamma-irradiated proteins. No major alteration of the structural conformation of the proteins was observed by FTIR for biofilms obtained after heat treatment, whereas gamma-irradiation induced some modifications in the protein structure. X-ray diffraction analysis suggests that cross-linking by gamma-irradiation seems to modify the conformation of proteins, which became more ordered and more stable.     

Solubility of a proto-imogolite sol in oxalate solutions

The amounts of aluminium liberated from a proto-imogolite (P-I) sol by 1–3 mM oxalate at pH 4·8–7·1 are found to be in excellent agreement with those calculated on the basis of the solubility product of the P-I sol, and the stability constants for aluminium oxalate complexes established earlier. Calculated solubility curves are presented for proto-imogolite sols in the presence of 10^?3, 10^?4 and 10^?5 M total oxalate over the pH range 4–8, and also for the case where oxalate concentrations are controlled by solid calcium oxalate in the presence of 0·05, 0·5 and 5 mM calcium ion. We conclude that the presence of a proto-imogolite allophane in podzol B horizons of pH 5·0 requires oxalate concentrations less than 10^?5 M. For fertile agricultural soils with typical calcium concentrations (approximately 5 mM) in the soil solution, aluminium oxalate concentrations would be limited by calcium oxalate solubility to less than 10^?6 M in the presence of proto-imogolite allophane at pH values exceeding 5·5. In leached podzolic soils calcium concentrations are generally less than 0·05 mM, and would not limit the formation of aluminium oxalate complexes.     

Comparative degradation of [14C]-2,4-dichlorophenoxyacetic acid in wheat and potato after Foliar application and in wheat, radish, lettuce, and apple after soil application

The fate of 2,4-dichlorophenoxyacetic acid (2,4-D) applied foliarly as the 2-ethylhexyl ester (EHE) to wheat and potatoes, to the soil as the dimethylamine (DMA) salt under apple tree canopies, and preplant as the free acid for wheat, lettuce, and radish was studied to evaluate metabolic pathways. Crop fractions analyzed for (14)C residues included wheat forage, straw, and grain; potato vine and tubers; and apple fruit. The primary metabolic pathway for foliar application in wheat is ester hydrolysis followed by the formation of base-labile 2,4-D conjugates. A less significant pathway for 2,4-D in wheat was ring hydroxylation to give NIH-shift products 2,5-dichloro-4-hydroxyphenoxyacetic acid (4-OH-2,5-D), 4-OH-2,3-D, and 5-OH-2,4-D both free and as acid-labile conjugates. The primary metabolic pathway in potato was again ester hydrolysis. 2,4-D acid was further transformed to 4-chlorophenoxyacetic acid and 4-OH-2,5-D. For the soil applications, (14)C residues in the crops were low, and characterization of the (14)C residues indicated association with or incorporation into the biochemical matrix of the tissue. The degradative pathways observed in wheat are similar to those characterized in other intact plant studies but differ from those in studies in wheat cell suspension culture in that no amino acid conjugates were observed.     

Chlorogenic acids as a potential criterion in coffee genotype selections

A systematic study by HPLC was conducted to determine the content of chlorogenic acids in green coffee beans of the Variedad Colombia (Coffea arabica Caturra var. x Híbrido de Timor) and in other genotypes of interest of C. arabica, Coffea canephora, Híbrido de Timor, and the F1 offspring derived from the crossing Caturra x Híbrido de Timor. Comparisons were made of the total content of these acids, their quantitative differences, and the presence or absence of some of them, using parametric statistical techniques and multivariate analysis. Total content differences were found between C. canephora accessions, between Típica and Caturra varieties of C. arabica, and between Híbrido de Timor accessions. The chromatographic profile comparisons with principal component analysis separated in the first component C. canephora accessions from the rest of the genotypes, whereas the second component separated C. canephora accessions.     

Supercritical CO(2) and subcritical propane extraction of pungent paprika and quantification of carotenoids, tocopherols, and capsaicinoids.

Ground paprika (Capsicum annuum L.) was extracted with supercritical carbon dioxide (SC-CO(2)) and subcritical propane at different conditions of pressure and temperature to estimate the yield and variation in carotenoid, tocopherol, and capsaicinoid contents and composition. The yield of paprika extract was found to be affected by the extraction conditions with SC-CO(2) but fairly constant at different conditions with subcritical propane. The maximum yields of oleoresin were 7.9 and 8.1% of ground paprika by SC-CO(2) and subcritical propane, respectively. The quantitative distribution of carotenoids, tocopherols, and capsaicinoids between paprika extract and powder was influenced by extraction conditions. SC-CO(2) was inefficient in the extraction of diesters of xanthophylls even at 400 bar and 55 degrees C, whereas tocopherols and capsaicinoids were easy to extract at these conditions. Under mild conditions subcritical propane was superior to SC-CO(2) in the extraction of carotenoids and tocopherols but less efficient in the extraction of capsaicinoids.