Effect of Starter Culture on the Fatty Acid and Amino Acid Profile of Fermented Parkia biglobosa Seeds

Iru, a condiment used for seasoning soup is often obtained from the fermentation of Parkia biglobosa seeds. The present study therefore investigates the effect of different starter culture on the amino and fatty acid profile of Parkia biglobosa seed fermented to produce iru. Starter culture of Lactobacillus plantarum, Bacillus subtilis and Leuconostoc mesenteroides were used to ferment Parkia biglobosa seeds. The bacterial load increased from 0.00 log10cfu/g in boiled raw sample to 8.67 log10cfu/g in naturally fermented sample. Fermentation significantly (P<0.05) increased the quantity of the amino acids in fermented samples. Aspartic acid (25.85 g/100g) and linoleic acid (42.99 %) were the highest amino and fatty acids respectively in the fermented samples. The result from this study reveals that fermentation significantly increase the amino and fatty acid profile of Parkia biglobosa fermented to produce iru, a Nigerian condiment. Introduction Fermented food form an integral part of the African diet. These foods are generally fermented as a method of preservation, to increase the safety and also to produce a lot of varieties [1]. Fermentation has been reported to also increase the nutritional value of the fermented product, increase the digestibility and also degrade hazardous components in the raw materials. In the African countries, rural dwellers who cannot afford animal products such as meat or dairy, which supplies the needed protein requirement in diets rely on fermented legumes [2, 3, 4]. Legumes has been providing the needed daily requirement of protein for these rural population because of the reduced cost of production, less difficult to process and the high energy value supplied [5]. Among the leguminous plants used by African population, Parkia biglobosa seeds had gained popularity. It is a perennial tree belonging to the family Leguminoseae and sub-family Mimosadeae. The seeds of Parkia biglobosa are fermented into ‘iru’ which is an indigenous fermented food condiment among the Yoruba people of Western Nigeria in West Africa [6]. The production process is usually on a small scale house-hold basis under varying condition [7]. The production of iru involve soaking the Parkia biglobosa seeds for about 30 minutes before cooking [1]. The cooked seeds were dehalled and cotyledon washed and recook, the cotyledon were then packed in containers for fermentation to take place [1, 2, 4, 6, 7]. However, the optimum condition for the fermentation procedure has been documented to be 35 oC for 36 hours [8]. The production of ‘iru’ is left to chance inoculation. This often cause variation in the product. The presence of varying array of bacteria may also be a factor that leads to contaminating organisms producing secondary metabolites which often lead to inconsistency in the final product. Elemo et al. [9] had earlier reported that the seeds of Parkia biglobosa could be a good source of amino and fatty acids. Both fatty acids and amino acids plays multiple role in living cells. They form part of the major component of the cell. The fatty acid containing lipids form the back bone of all cell membrane. Fatty acids are important energy sources and can be stored in unlimited quality in the body [10, 11]. Therefore, to get a product that is nutritionally stable, consideration should be given to the use of starter culture where known bacteria are used to ferment the seeds. The present study was therefore Sustainable Food Production Submitted: 2020-02-20 ISSN: 2624-876X, Vol. 9, pp 15-22 Revised: 2020-06-05 doi:10.18052/www.scipress.com/SFP.9.15 Accepted: 2020-06-1