Laboratory scale cultivation, Nutritional Evaluation and Development of Fortified Food from Spirulina sp. (Arthrospira fusiformis) Isolated from Lake Chitu, Oromia, Ethiopia

Abstract

Microalgae offer great promise in the production of food supplements for humans. Spirulina is reach in various nutritional contents. Thus, this research aimed at evaluating Spirulina's nutritional contents and formulate food fortified with Spirulina sp. obtained from Lake Chitu. For this study, appropriate sampling stations were carefully selected in Lake Chitu and Spirulina sp. containing samples were collected from the selected sampling stations. The growth media was prepared for algal culture in the laboratory. Trichome of Spirulina was isolated from water sample using the serial dilution technique. Then, Spirulina sp. was separated and cultured using Zarrouk medium in a small flask. The pure culture was introduced into 500 ml sized Erlenmeyer flask. After enough pure culture of cell density was achieved in the Erlenmeyer flask, the inoculums were transferred to 1000 ml sized Erlenmeyer flask and then serially transferred to larger Erlenmeyer flasks and the 40-l aquarium. The trichome was observed using a light microscope for their morphological profile. The morphotypes and morphological parameters were recorded for Spirulina isolates. Growth measurement was estimated for Spirulina isolate. Nutritional profile analysis was conducted to determine the composition of protein, carbohydrates, lipids, and minerals. Food fortifications were performed using Spirulina powder. Analysis of the nutritional profile of Arthrospira fusiformis and the selected food was carried out. All data was performed via the t-test or analysis of variance (one-way ANOVA), followed by Turkey's Post Hoc test at a significance level of 95 % (p < 0.05), using the IBM SPSS (version 24).In this study, tightly coiled (H-type), spiral or loosely coiled (S-type), and intermediately coiled (C-type) morphotypes were obtained against the samples Spirulina isolates. Morphological parameters such as Trichome length (TL), Helix diameter at end (HDE), middle (HDM), Trichome diameter (TD), Hilex pitch (HP), and No of coil per trichome (NCT) were found. The highest number of morphological parameters was recorded against TL (302.88±133.81) for S-type morphotypes whereas the lowest was recorded against HDE (7.06±1.46) for the same morphotypes. The lowest (12.3±5.87) and highest (23.85±11.08) NCT were obtained from C- type and H-type, respectively. No HP was recorded for H-type morphotypes. The OD680 nm was recorded over 0.0152±0.0002 to 1.795±0.004 against 0 to 21 day of incubation period for Arthrospira fusiformis. The Spirulina powder contained higher quantities of all the studied macroelements than the microelements. Furthermore, total proteins were found in the supplemented food than in controlled food (18.2% and 7.7%, respectively). The research showed significant differences in the content of protein and essential minerals such as Na, Fe, Zn,and K between supplemented food and controlled food. Thus, the results of this study indicated that the Spirulina is a promising source of many mineral as well as serve as a rich source of protein confirming the importance and role that Spirulina can play to improve the health and nutrition particularly in malnourished populations.