Production of Antioxidant Rich Glucose Syrup from Ensete Ventricosum Starch through Enzymatic Hydrolysis and Preservation using Green Tea Extract

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Addis Ababa University


Ensete ventricosum is a plant native to Ethiopia with a high content of starch. This study aimed to produce antioxidant rich glucose syrup from enset starch by using alpha amylase and glucoamylase enzymes and preservatives using green tea polyphenols. The starch was isolated from the corm and pseudostem parts of Enset plant and characterized. The main process steps for enzymatic production of glucose syrup from enset starch were: gelatinization, liquefaction, saccharification, centrifugation followed by treatment with activated charcoal and evaporation to final solids ( >70%). The preservative effect of green tea extract on the shelf life of the syrup was also examined for 30days, by studying its effect on pH, moisture content and viscosity of the glucose syrup. Samples were treated with 0, 100, 200, and 300ppm of green tea polyphenols. The study showed that the moisture content, ash content, crude fat content, protein content, and amylose content of enset starch were: 8.98%, 0.15%, 0.38%, 0.1%, and 29.01%, respectively. Response Surface Methodology Design (RSMD), particularly, Box Behnken Design (BBD) was applied to investigate the effect of temperature (50, 60 and 70℃), time (12, 24 and 36hr), and glucoamylase concentration (0.1, 0.15 and 0.2wt.%), on the process of saccharification using Design expert® 12 software, which shows the significant influence on the value of dextrose equivalent (DE). The maximum concentration of glucose (95.64%) in terms of DE was found at the parameter interaction of 0.1wt.% (glucoamylase concentration), 60℃, and 36hr. The result showed that the optimum condition for the saccharification process was 62℃, 12hr and 0.2wt.% (glucoamylase dosage) which resulted in 91.79±0.5% of DE. The moisture content, total soluble solid, ash content, density, specific gravity, viscosity and pH of the product were: 24.01%, 75.32°Brix, 0.35%, 1380.8 kg/m3, 1.3833, 940 mPa.s, and 5.5, respectively. Generally, it was observed that green tea extracts with a concentration of 100ppm of TPC was found to be suitable as preservative to keep the quality and extend the shelf-life of glucose syrup at room temperature. Hence, Enset starch is a promised raw material to develop glucose syrup enriched with extracts of green tea to elevate its shelf life.



Ensete ventricosum starch, glucoamylase concentration, glucose syrup, green tea polyphenols, saccharification temperature, time