Dynamic models for the production of glucose syrups from cassava starch

Modeling Based Identifiability and Parametric Estimation of an Enzymatic Hydrolysis Process of Amylaceous Materials

This work presents the modeling of an enzymatic hydrolysis process of amylaceous materials considering the parameter identification problem as a basis for the construction of the model. For this, a modeling methodology is modified in order to apply the identifiability property and improve the proposed model structure. A brief theoretical explanation of the identifiability is described. This concept is based on the observability property of a nonlinear dynamic system. The used methodology is based on the phenomenological based semiphysical model (PBSM). This methodology visualizes that the structure of a dynamic model can only improve with new mass or energy balances suggested by model suppositions. Additionally, a computer algorithm is included in the methodology to validate if the model is structurally locally identifiable or know if the parameters are unidentifiable. Also, an optimization algorithm is used to obtain the numeric values of the identifiable parameters and, hence, guarantee the validity of the result. The methodology focuses on the liquefaction and saccharification stages of an enzymatic hydrolysis process. The results of the model are compared with experimental data. The comparison shows low errors of 7.96% for liquefaction and 7.35% for saccharification. These errors show a significant improvement in comparison with previous models and validate the proposed modeling methodology.

Hydrolysis of cassava starch by co-immobilized multi-microorganisms of Loog-Pang (Thai rice cake starter) for ethanol fermentation

Loog-Pang (Thai rice cake starter) is an effective and inexpensive microbial source for the hydrolysis of cassava starch to glucose. A process for hydrolysis of cassava starch to glucose by Loog- Pang was improved by co-immobilized multi-microorganisms (IC) using thin shell silk cocoon (TSC). After incubation at 35°C for 120 h, the IC-TSC system converted 20% w/v cassava starch slurry into clear glucose syrup containing a glucose concentration of 145.5 g/L (composed of 98.8% glucose and 1.2% oligosaccharides), with little or no contamination by microorganisms. The glucose concentration from the starch hydrolysis process using the IC-TSC system was approximately 1.3 times more than that of suspended cultures (SC). The starch hydrolysate could be used as the carbon source for ethanol fermentation without sterilization. A concentration of ethanol of 71.2 g/L (9.1%, v/v) was obtained at 36 h fermentation of the starch hydrolysate by Saccharomyces cerevisiae M30.

Production of high fructose syrup from cassava and sweet potato flours and their blends with cereal flours

Despite being a rich source of starch, root crops such as cassava and sweet potato have not been widely exploited for the production of high fructose syrup (HFS), which is a highly valued sweetener for the food and beverage industries. The major factors contributing to the cost of production of HFS are the cost and labor-intensive steps in the production of starch, different processing temperatures and pH for the enzyme reactions, poor extractability of starch, etc. With the objective of overcoming the cost associated with the preparation of starch, the feasibility of using native cassava/sweet potato flours and their blends with rice flour and wheat flour, as the raw material for HFS production was investigated. The saccharified slurry from cassava--rice flour blends contained 70-72 g reducing sugars/100 g, which was higher than that released from native cassava flour (~69%). Blends of sweet potato with rice or wheat yielded saccharified mash with lower content of reducing sugars (60-66%). Although the percentage conversion to fructose after isomerization was similar for cassava/sweet potato or their blends with cereal flours (42-43%), fructose yield was higher in native cassava flour and cassava-rice blends (28-29 g/100 g) than the other flour blends.