Biochemical and trace elements composition of faba bean ( Vicia faba L . ) cultivated in Panjgur and Kech districts of Balochistan

Legumes have a very important place in human food. Historically they have been grown since antiquity. Due to high nutritive value they are recommended in daily intake diet. The present study was conducted to determine the biochemical profile and assessment of trace elements in faba beans (Vicia faba L.) from two districts of Balochistan. Biochemical studies indicated that they have different moisture content (7.5 % and 9.5 %), ash content (3.7 % and 3.8 %), fat content (2.07 % and 1.73 %) and protein content (21.62 % and 22.44 %) for samples collected from both locations Panjgur and Kech districts. Trace elements analysis showed the concentration of manganese (Mn) 0.127 and 0.129 μg/g, zinc (Zn) 1.132 and 0.951 μg/g, copper (Cu) 0.57 and 0.60 μg/g, Iron (Fe) 0.07 and 0.09 μg/g respectively, in samples from both districts. The concentration of chromium (Cr) and Nickel (Ni) were not detected in samples from Panjgur district, whereas, their concentrations in samples from Kech district were found 0.01 μg/g. The study concludes that the faba beans grown in Balochistan have high nutritive value and low trace metallic content profile which makes it fit for food and feed. Moreover, a significant correlation was found by comparing obtained profiles of faba beans from both districts. The study suggests that faba beans genotypic evaluation and soil analysis is required for better crop production.


Introduction
Legumes are very important for human consumption due to its high protein content [1].Legumes, generally described by their unusual podded fruit [2].Globally, 800 million people are malnourished [3].
Unfortunately, advances in legume crop in term of yields have not kept back pace as compare to cereals [2].In local market various wild species are available.The scientific data available is very limited on potential plants [4].Origin of faba beans is reported from North Africa and West Asia [5].These legume seed beans are grown globally on 2.5 million ha of land, with 36% in Central and East Asia and about 21% in Sub-Saharan Africa under its cultivation [5].Faba bean is considered one among the best crop has grain legume with over 7.0 grain yield potential with an advantages of addition of atmospheric nitrogen to the soil.Faba bean is very important cash and food crop.It is high in protein (23-26%) and composes plentiful of health-benefiting antioxidants [6].Being so important crop, there is a need to enhance faba bean cultivation [7].Pakistan has an agro-based economy, a producer of diverse kinds of legumes like lentil, chickpea, broad and kidney beans etc. Consumption of legumes in food as a source of protein is increasing with the passage of time [8].Therefore, pulses are considered as the most significant source of vegetable protein in Pakistan and are cultivated on 5% of the total cropped area [9].The local people living in both districts have wealthy culture which as a treasure for the ethnographers and botanist, plant has significant place in their culture [10].District Kech (Turbat district) is in the south west of Balochistan [10].It produces many vegetative products suitable in the warm climate.The climate in this area is so warm that the temperature sometime increased up to 50⁰C, the climate and environment are the most influence factors in the agricultural growth of an area [10].Panjgur has a warm climate in the summer and cold weather in winter.In winter, season faba beans sown normally and eaten as a delicious food [10,11].Faba beans locally known as "Bakalink" and are one of the major grown vegetable.People in this area use it as a food throughout the year.It is cooked and served in the restaurant as a good source of nutrition.Most of the people living in Panjgur, Kech and nearing districts eat "Bakalink" as delicious food during its winter season in green formation and rest of the year as dry legume [11].There is no data available regarding biochemical value of faba beans as a cultivated crop in Balochistan.Moreover, lack of knowledge among local people regarding its nutritive value [10] strongly pushes the work towards assimilation and assessment of biochemical value of faba beans.Keeping in view of the nutritive importance of the legume, this study was conducted to explore the biochemical composition and trace elements content of faba beans (Vicia faba L.) from Panjgur and Kech districts of Balochistan, Pakistan.

Materials and methods
Faba beans locally known as Bakalink were purchased from Panjgur and Kech district headquarters at the time of a market day when farmers and consumers come from different parts of the district for trade.During the purchase, information regarding the origin was recorded.Cleaned Faba bean seeds were sun dried, and stored in airtight polythene bags until required for analysis.It was difficult to removed seed skin on dry seeds, for this purpose the seeds were soaked in distilled water until the skin burst and was removed manually.After peeling the seeds were dried in an oven at 70 0 C to remove moisture.Then the seeds were crushed and screened with sieve mesh 60.The crushed material was stored in desiccators for analysis of biochemical profile.The samples were divided into two broad categories i.e. from Panjgur and Kech.

Proximate analysis
Faba beans collected from both locations were subjected to analyses in triplicate.Moisture, ash, fat and crude fiber contents were determined by using methods described in [12].The percentage of nitrogen was measured by Kjeltech system and conversion factor 6.25 was employed for calculation of crude protein.

Trace elements determination
The samples were wet digested for elemental analysis which involve the chemically degradation of sample matrices in solution, generally with a mixture of acids in order to enhance solubility.Each sample was digested in triplicate and three repeated measurements were performed on each sample by atomic absorption spectrophotometer (AAS) equipped with an air-acetylene burner.Trace elements Mn, Zn, Cu, Fe, Cr and Ni were determined by using a hollow cathode lamp at the recommended conditions and currents.

Statistical analysis
The values of biochemical as well as trace element content of seed samples collected from both areas Panjgur and Kech were analysed.Finally, the results obtained were analyzed by using specific version of SPSS v 22 and statistical assessments.The values of biochemical markers i.e. moisture content, ash content, fat content and total nitrogen were presented in their percent per 100 grams of the seed.After determination of trace element, contents are presented in microgram per gram (μg/g).

Results and discussion
The present study was conducted to determine the biochemical and mineral traces profile of faba beans grown in districts Panjgur and Kech of division Makran, Balochistan.The statistical test was applied to complete data comparisons between the samples from both sites.The data obtained regarding biochemical profile are given in Table 1. Figure 1 show the chemical compositions of faba beans samples investigated.The results showed that the collected samples contain abundantly water and Protein.The moisture contents of samples were 7.5% and 9.5% while protein contents of samples were 21.62% and 22.44%.The result also showed that the analyzed samples were low in ash and fat content.The ash contents of samples were 3.7% and 3.8% whilst fat contents of samples were 2.07% and 1.73%.Significant difference was observed in moisture content, which was also reported by Gasim et

Conclusion
There is no standard reference material to compare analytical data with reference material in order to validate the obtained results.By comparing the results of the present study with the investigations made in other countries by other researchers, the present study indicated that the faba beans grown in both districts of Balochistan province of Pakistan have rich nutritive value.Due to high protein content it can be replaced with a low protein diet and can also be helpful in overcoming nutritive deficiencies of the area.As far as to author's knowledge, no investigation is yet made on the assessment of major nutrients and trace elements in faba beans grown in Balochistan.Lower in fat contents and trace elements makes it a non-toxic safe food and feed for the local people as well as a source of revenue for the national and international market.

Figure 2 .
Figure 2. Concentration of Mn, Zn, Cu, Fe, Cr and Ni (μg/g) of trace elements in faba bean

Table 1 . Biochemical composition of faba bean on dry basis
[16], 2.49% by Costa et al.[22]and 1.5 to 2.12% by Alghamdi[16].The obtained results were lower than those reported byHossain and Mortuza [17]who obtained a value of 3.12 to 3.29%.The protein content of faba bean was 21.62 % for samples collected from Panjgur district and 22.44% for samples collected from Kech district.Significant difference was also observed in protein content of both cities samples and this was also observed byGasim etal.[13].The results are in agreement with those values obtained by Welsch and Griffths [24] who reported 21.9 to 29.1%, by Osorio-Dıaz et al. [19] who reported 19.9%, and also in agreement with a value 20.9% reported by Costa et al. [22].It is also evident in another studies that protein content was very high in almost all faba bean germplasms which ranges from 19.5 to 33.3 % on dry matter basis [25].The results disagree and were lower than those found by Elsayed [18] who reported 28.0 to 37.8%, Elsheikh et al. [20] found 31.8%,

Figure 1. Average moisture, Ash, Fat and protein content presented in faba beanTable 2 . Trace elements concentrations in faba bean Element Content a , μg/g Measured b
a Dry weight, b Mean ± SD, ND not detected