Biochemical evaluation of some faba bean cultivars under rainfed conditions at El-Sheikh Zuwayid

Two field experiments were carried out during 2009/2010 and 2010/2011 seasons at Agricultural Experimental Station of Desert Research Center (DRC) located in El-Sheikh Zuwayid region (North Sinai), Egypt, to study the biochemical evaluation of some faba bean cultivars (Giza 843, Giza 3, Sakha 4, Nubaria 1, Missr1, Sakha 2, and Sakha 3) under rainfed conditions at El-Sheikh Zuwayid. The main results could be summarized as follows:
• Sakha 3 and Sakha 4 exceeded the other cultivars in plant height, fresh weight, seed yield/plant, 100-seed weight, seed yield, protein yield, and total vicine yield. On the other hand, the lowest values of such parameters were achieved by Giza 843 except protein yield under the same conditions. These results associated with increase in photosynthetic pigments under rainfed conditions at El-Sheikh Zuwayid, which related to the counteraction of faba bean cultivars to stress conditions. Concerning the yield of antinutritional factors, Sakha 4 recorded the highest value of vicine yield followed by Nubaria 1 and Sakha 3 in a descending order.
• Total vicine was found in high amount in seeds of Nubaraia 1. Also, the greatest protein content was produced from Sakha 3 followed by Sakha 2, Sakha 4, and Missr1 as compared with the other cultivars. Potassium and calcium contents were found in high amounts in seeds of Sakha 4, Sakha 3, and Sakha 2. On the other hand, the lowest value of sodium content was produced from Sakha 3. In addition, Sakha 3 surpassed other faba bean cultivars in K/Na ratio and Ca/Na ratio.
• Faba bean cultivars greatly varied in total vicine. The hulled seeds of all faba bean contain higher values of total vicine more than the whole seeds without any treatments (control). Approximately all treatments (processing conditions) significantly decreased total vicine in whole and milled seeds for all faba bean cultivars as compared with the control (whole seeds without any treatments). In this respect, the minimum values of such content were produced from milled seeds of all cultivars after treatment (soaking) with water, citric acid, sodium bicarbonate, and acetic acid as compared with the control.
• Amino acids composition indicated the presence of 16 amino acid including essential and non-essential amino acids. In this regard, the predominant essential amino acid is arginine followed by leucine. Sakha 3 followed by Missr 1 and Sakha 2 exceeded the other cultivars in arginine content. In addition, methionine is present in low quantities comparing with other amino acids for all faba bean cultivars. In this respect, glutamic acid is the most abundant amino acid followed by aspartic and proline. Comparison between faba bean cultivars, Sakha 2 followed by Sakha 4 and Giza 3 had higher concentration of glutamic acid than other cultivars. Data also showed that non-essential amino acids are more than essential amino acids in seeds of all faba bean cultivars under investigation.
• Analysis of gel (SDS–PAGE) revealed that Sakha2 and Sakha3 were resolved into 30 bands, while Giza 843, Giza 3, Nubaria 1, and Missr 1 were resolved into 31 bands. Also, Sakha 4 was resolved into 32 bands. The molecular weight of protein sub units ranged between 14 and 95 kDa. The more intensive bands are presented at molecular mass 20, 41, and 43 kDa. The increase in band intensities in addition to the other obtained results may be a part of response these cultivars to rainfed conditions at El-Sheikh Zuwayid.
• According to the previous observed data, it could be recommended that the use of tolerance cultivars such as Sakha3 and Sakha4, which are associated with yield and biochemical constituents under rainfed conditions at El-Sheikh Zuwayid. Also, to reduce total vicine (antinutritional factors) in seeds, the study recommended soaking seeds of faba bean before human consumption in some safe chemicals such as citric acid, sodium bicarbonate, and acetic acid.