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  • Author: Fahriha Nur-A Kabir x
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Abstract

The research was concerned with the enzymatic hydrolysis followed by alcoholic fermentation of corn flour. Commercial corn flour purchased from local market contained starch of 87.25%, moisture 11.86% and ash 0.70%. The kinetics of corn flour hydrolysis was performed at 50°C, 65°C and 80°C using commercial thermos table-∞-amylase and ∞-amyloglucosidase. During hydrolysis the residual starch content was decreased with increasing hydrolysis time. The line weaver- Burk plot for enzyme hydrolysis of corn starch for 2.5%, 5% and 10% flour solution showed a Km value of 2.46, 2.27 and 1.73 mg/ml and Vmax values 1.23, 1.21 and 0.96 U/ml for 50°C, 65°C and 80°C respectively. Thin layer chromatography (TLC) was used to detect the presence of dextrose in the hydrolyzates. The Rf (Retention factors) values showed that the starch was mainly composed of dextrose and depended on carrier solvent use for dextrose assessment. When 100% ethyl alcohol used as carrier solvent the Rf value was 0.72 and ethyl alcohol: ethyl acetate= 1:1 the Rf value was 0.65. Both corn flour solution and its enzymatic hydrolysates were fermented with commercial baker’s yeast. Both the cases starch content was decreased and alcohol content was increased during hydrolysis and alcohol production was 3 times more from hydrolysates. The results obtained here will be useful for further research in the production of other value added products like white vinegar from the produced alcohol from con flour.

Abstract

This research conducted with the fully fresh, ripe and sound tomato (Lycopersicon esculentum Mill.) was collected then washed, peeled, seeds removed and transferred to the juice extractor. Sugar, preservatives were added to the extracted filtrated juice. Then the juice was heated, cooled and bottled for preservation. Tomato juice was prepared with three different treatments. Among the three treatments T1, T2 and T3 sample were prepared with no preservative, Na-benzoate preservative and potassium meta-bisulphite (KMS) preservative respectively. The organoleptic observation of this tomato juice was studied for 60 days storage period. Chemical analysis and sensory tests were carried out during the 30 days at an interval of 15 days to assess the effect of chemical additives on the shelf life of tomato juice. Negligible Change in chemical constituents except vitamin C was observed in the prepared juice throughout the 30 days storage period. Color was gradually faded and slightly off flavor develops at the end of the storage periods. The treatment T2 secured highest score for color, flavor, taste and overall acceptability and ranked as “Like very much” by a taste testing panel. Tomato juice prepared with no preservative (T1) spoiled after 45 days storage and juice prepared with KMS preservative (T3) spoiled after 60 days storage. Total number of viable bacteria was highest in tomato juice treated with no preservative (T1) and KMS preservative (T3). Tomato juice with Na-benzoate preservative (T2) contained least viable bacteria which was better than T1 and T3 sample. Considering all the parameters, Na-benzoate tends to be better additives than potassium meta-bisulphite (KMS) for preservation of tomato juice.