In a preliminary experiment, 74 faba bean genotypes including winter genotypes (autumn-sown) and spring genotypes (spring-sown) and isogenic population pairs (tannin-containing ν. tannin-free and vicine/convicine-high ν. vicine/convicine-low), were analysed for the chemical composition of their seeds. A large variability was found for the main constituents (starch, protein and fibre). Autumn-sown genotypes contained 2.3 % less proteins but 2.5 % more starch in the seed dry matter (DM) than spring-sown genotypes. The vc - gene, which lowers the vicine and convicine contents, did not significantly modify the main seed components in the isogenic comparisons. The zt1 and zt2 genes, which eliminate condensed tannins in the seed coats, lowered by 2.1% the proportion of the seed coat in the DM. In the isogenic comparisons, the zt2 gene had a stronger effect than zt1 in reducing the total seed fibre and increasing the protein content. In a second experiment, from the original 74 genotypes. 12 contrasted genotypes were selected and multiplied for animal nutrition trials. Their chemical analysis confirmed the variability between the faba bean categories observed in Expt 1, but detailed chemical analyses illustrated the variability in amino acid, fatty acid, amylose and oligosaccharide composition, trypsin inhibitory activity, condensed tannins, lectins and phytic phosphorus contents.

Genetic variability for feeding value of faba bean seeds ( Vicia faba ): Comparative chemical composition of isogenics involving zero-tannin and zero-vicine genes

Protease inhibitor activity was determined for a wide range of differing field bean (Vicia faba) varieties and genotypes. Although a two-fold variation was observed under the assay conditions used, the highest values were approximately five times less active in inhibiting trypsin than either soya or navy beans. No correlation was found between protein content and protease inhibitor activity. Water extracts from the testa from coloured-flower varieties inhibited the activity of α-amylase, lipase and trypsin. The addition of polyvinylpyrrolidone reactivated these enzymes to varying degrees. No inhibitory activity was found in similar extracts from white-flowered varieties. It was concluded that the enzyme inhibition exhibited by extracts of the seed coat of coloured varieties was due to the presence of tannins.

The inhibition of digestive enzymes by extracts of field bean (Vicia faba).

The Leguminosae family comprises almost 700 genera and 1800 species. The most widely cultivated are the oilseeds, soybeans (Glycine max), and groundnuts (Arachis hypogaea), which provide 50 and 16% of world grain legume harvests, respectively. Apart from the oilseeds, scientists have given more attention to protein nutritional quality than to useful functional properties. Traditional and modern processes of transformation and fractionation of high and low lipid legumes are reviewed and the useful biochemical and biophysical properties of various components and derivatives are discussed. Protein properties examined include water activity in relation to solubility, dispersibility, viscosity, gel, and foam stabilities. Practical systems of protein fractionation and the properties of derived fractions are described. Particular properties of legume lipids and carbohydrates are examined. Attention is given to sources and control of mycotoxins and to quality implications related to the progenies of wide transgenic crosses. Priorities for future research and opportunities for utilization are suggested.

Nature, composition, and utilization of food legumes

The growth and yield of four crops of field bean cv. Maris Bead in response to irrigation and sowing date were analysed in relation to leaf area expansion and senescence and their absorption and utilization of photosynthetically active radiation (PAR). Total dry matter (D.M.) production and seed yield were strongly correlated with total green area duration (GAD) and post-flowering GAD respectively.Total D.M. production was also strongly related to radiation absorbed by the green surfaces of the crop although autumn sowing and drought both decreased the constant of proportionality, i.e. the growth efficiency (Eg). Autumn sowings yielded more than spring sowings because they grew for longer and received 22% more radiation. Their harvest index was also about 40% higher than in spring sowings. These more than compensated for their smaller Eg. Drought decreased yield mainly by decreasing radiation received and Eg. Growth duration was shorter and harvest index was smaller.The rate of phenological development was strongly dependent upon temperature and to a lesser extent on photoperiod. The average thermal duration from emergence to flowering was 790 °Cd above a base of 0 °C. The time from sowing to the end of the pod growth was well represented by a simple multiplicative model in which development rate was a linear function of temperature above a base of 0 °C and photoperiod above a base of 6 h. The average photothermal duration required for 10 crops was 980 °Cd.An attempt was also made to determine the crop physiological and environmental factors which govern the change in size of the yield components of field bean crops caused by irrigation and sowing date. The final number of pods per plant was closely correlated with the rate of supply of assimilates during pod filling. Irrigation increased assimilate flux by increasing leaf area, growth rate and total dry matter during pod growth. Both the rate and duration of pod growth were little affected by irrigation. Autumn sowings produced heavier pods and beans due to both a faster rate and a longer duration of growth which were associated with a greater production of assimilate during the seed growth period. Seed growth depends on both the current assimilate and stored reserves, the latter especially when plants were subjected to environmental stress.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0021859600083180

The response of field beans (Vicia faba L.) to irrigation and sowing date. 2. Growth and development in relation to yield.

Considerable variation was found in the phytate and total phosphorus contents of varieties, selections and genotypes of field beans (Vicia faba L.) The phytate phosphorus content of seeds taken from single plants of the variety Dacre indicated that large variations (1.93-4.03 g kg−1), not significantly correlated with protein content, existed within an established variety. Although some variation in the ratio of phytate to total phosphorus was observed (0.40-0.60), highly significant correlation coefficients were obtained for total and phytate phosphorus contents. The significance of the results obtained is discussed in relation to the potential for improving the nutritive value of field beans by breeding for lower phytate content.

Phytate and total phosphorus content of field beans (Vicia faba L.)

Studies were made of the proximate and mineral compositions of modern strains of both spring· and winter-sown beans. The majority of the winter beans were of the Throws M.S. variety, of the spring beans Minors. On the dry-matter basis spring beans averaged 31·4% crude.protein, winter beans 26·5%—a highly significant difference. The true protein values showed a parallel trend. Winter beans averaged 9% crude fibre, spring beans 8%, again a highly significant difference. The strains confirmed the usually accepted levels of oil and of the principal mineral components, except that modern beans appear to be richer in phosphorus.

A. Eden

Papers

A survey of the analytical composition of field beans Vicia faba L.