Hawashi, Mohamed (2020) Optimization Of Process Conditions For Reduction Of Antinutritional Factors And Enhancement Of Nutritional Value In Cassava Leaves By Solid State Fermentation With Saccharomyces Cerevisiae. Doctoral thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
The cassava plant is grown in tropical and subtropical countries, which represents, alongside with its by-products, an important source of food and feed. Cassava leaves are a good source of protein in developing societies in African and Asian countries that do not have easy access to available protein sources. Hence, cassava has the capacity to promote the economic development of these countries and provide food security. However, their use is limited due to the presence of anti-nutrient compounds in their tissues. Thus, proper processing of cassava leaves is essential in order to reduce the anti-nutrients to a safer limit before utilization. The main objective of this study was to investigate the efficacy of solid- state fermentation using Saccharomyces cerevisiae in detoxification and protein enrichment of cassava leaves. In addition, the Box-Behnken design (BBD) of the Response Surface Methodology (RSM) was applied to optimize various process parameters, such as sucrose concentration, urea concentration, moisture content, and fermentation time for the minimum cyanide and tannin content levels in cassava leaves. The degradation of cyanide and tannin content was described by the quadratic model, which resulted in an excellent fit of the experimental data (p < 0.01). The statistical tests show that linear terms for sucrose concentration, urea concentration, moisture content and fermentation time had a significant effect on cyanide and tannin content (p < 0.01). A minimum cyanide content of 0.63 ppm was obtained at 1.33% (w/w) sucrose concentration, 0.83% (w/w) urea concentration, 66% (v/w) moisture content and with a fermentation time of 78 h. The optimal level made a significant reduction in cyanide content of 98.42%, which is lower than the toxicity level suggested by the World Health Organization of 10 ppm. While, the optimal conditions for minimizing tannin content in cassava leaves were found at 1.4% (w/w) of sucrose concentration, 0.55% (w/w) of urea concentration, 57% (v/w) moisture content, and an incubation time of 95 h. The minimum tannin content obtained under these conditions was 0.125%, which indicated a reduction of 89.31% in tannin content. Conversely, the protein content was increased with a further increase in fermentation time from 24 to 96 h (from 10.08 to 14.11 – 16.07 %). However, fermentation with S. cerevisiae did not result in any significant changes in the mineral content of the cassava leaves. 5 S. cerevisiae fermentation of the cassava leaves had a significant effect on the microbial composition, as indicated by a rapid and stable pH reduction from pH 5.9 to pH 4.1. Moreover, the enzyme activity of tannase under solid-state fermentation of cassava leaves was also evaluated. The maximum yield with an enzyme activity of 0.53 U/g was obtained after 72 h of incubation. Keywords: Cassava Leaves; Cyanide Content; Optimization; Response Surface Methodology; Solid-State Fermentation; Protein; Tannin Content; Tannase.
| Item Type: | Thesis (Doctoral) |
|---|---|
| Additional Information: | RDK 660.284 49 Haw o-1 2020 |
| Uncontrolled Keywords: | Cassava Leaves; Cyanide Content; Optimization; Response Surface Methodology; Solid-State Fermentation; Protein; Tannin Content; Tannase |
| Subjects: | Q Science T Technology > TP Chemical technology > TP156 Crystallization. Extraction (Chemistry). Fermentation. Distillation. Emulsions. |
| Divisions: | Faculty of Industrial Technology > Chemical Engineering > 24001-(S3) PhD Thesis |
| Depositing User: | Mohamed Hawashi |
| Date Deposited: | 03 Mar 2025 03:03 |
| Last Modified: | 03 Mar 2025 03:04 |
| URI: | http://repository.its.ac.id/id/eprint/75342 |
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