Optimizing The Conditions And Processes For The Production Of Protein Nutrient From Parkia Biglobosa Seeds

ABSTRACT

African Locust Bean (Parkia biglobosa) seeds known as ‘Iyere’ in Yoruba language were fermented aerobically and anaerobically at 40, 50, 60 and 70 °С for five days (120 hours) with the aid of two starter cultures - Bacillus Subtilis and Saccharomyces Cerevisiae to a vegetable protein based food condiment known as ‘Iru’. The Fermenter was fabricated with galvanized iron, thus getting rid of the unhygienic methods of producing it locally. Samples were taken every day (24 hours) and stored in the deep freezer for further analysis. Fermentation increased the percent protein content from 32 to 40 % and to 52 % for anaerobic and aerobic fermentation processes respectively after 3 days (72 hours). Other parameters like % crude fibre, % ash content and % carbohydrate in both aerobic and anaerobic fermentation processes decreased with number of fermentation days from 9.58 to 5.29, 4.05 to 3.30, 36 to 23 and 9.58 to 3.824, 4.05 to 0.832, 36 to 19.89 respectively. The biological changes such as physiological (odour, colour and appearance) and sensory (taste and texture) were studied. From experimental data generated by the design of experiment (DOE), using MINITAB 17 software, optimum conditions were obtained at 40 ⁰C with inoculum (Bacillus subtilis) concentration of 0.005 (g broth/g seed) at fermentation duration of 3.25 days. The product of the fermentation process ‘Iru’ was analyzed physiologically and organoleptically. The products of anaerobic fermentation were not acceptable organoleptically due to their repulsive odour, although was mild at lower temperature. The organoleptic test showed that the sample fermented with Bacillus subtilis was generally acceptable for all parameters tested. The mineral compositions of the fermentation product at different temperatures were analyzed and Magnesium, Phosphorus, Potassium, Sodium, Manganese, Iron, Copper and Zinc were detected. The Scanning Electron Microscope (SEM) was used to study the effect of fermentation and temperature on the morphological structures of both fermented and unfermented samples. The deterioration rate of the fermented samples were studied to estimate the shelf life of the condiment with no additives. Dried condiment was stored for 6 weeks. The stored sample lasted for about 10 months.