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Production, Purification And Characterization Of Carboxymethyl Cellulase For Food Applications

Muhammad, Tahir Nadeem (2009) Production, Purification And Characterization Of Carboxymethyl Cellulase For Food Applications. PhD thesis, University of Agriculture, Faisalabad .

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Abstract

Agricultural wastes/byproducts have great potential for the production of value added products with special reference to enzymes. Two indigenous carbon sources namely, wheat bran and sugar cane bagasse were used as substrates for carboxymethyl cellulase (CMCase) synthesis by Aaspergillu niger through submerged fermentation. The fungus produced highest CMCase activities at 3% level of wheat bran using 30�C and pH 5 over 96 hrs of incubation. The enzyme was purified for its further use in food processing. During the purification process, a 3.05 fold purification of enzyme was observed after gel filtration. Characterization of purified enzyme was carried out to find out the most suitable conditions for the CMCase performance; the best enzyme activity was observed at 50�C and pH 4.5. The enzyme was quite stable and retained 37% of its maximum activity at 90�C. The SDS-PAGE of the purified enzyme revealed its molecular weight as 47.1 kDa. For efficacy purpose, the enzyme added feeds were given to the broiler chicks in order to investigate their effects on body performance, feed efficiency and for safety concerns. The enzymatic treatment exhibited positive effects on body weight, carcass weight and chest muscle weight. Non-significant variations in the serum biochemistry and hematological parameters were observed. After safety evaluation, the enzyme was employed at various levels in bread preparation. Different treatments exhibited significant variations in rheological properties of the dough. The CMCase application in the bread making process resulted in increased volume (15.45%) up to a level of 250 IU/100g flour (T2) however, excessive dose showed a decreasing trend for this parameter. The treatment T2 produced bread with specific volume 3.99 cm3/g in contrast to that of T0 i.e. 3.37 cm3/g. The external and internal characteristics of bread were also improved by the enzyme addition. Later, the enzyme application in citrus juice extraction also showed beneficial effects. Although the enzymatic treatment had non-significant effect on TSS, density and pH of pulp and juice however, a momentous reduction in pulp viscosity i.e. 74.79% was observed in T6 (CMCase and pectinase 50 IU/100g each). Moreover, the treatment T6 gave more clarified juice with 95.70% transmittance than that of control (78.00%); also resulted in 20.00% increase in the juice yield with 90.00% juice recovery. The sensory evaluation of the enzyme treated juice reflected improved taste, flavor and sweetness however; caused slight color deterioration of the resulting juice. The purified enzyme was also employed in carotenoid extraction from citrus peel and the maximum yield (8.60�0.94 mg/100g peel) was calculated in case of T4 (250 IU of each enzyme/100g peel). The pigment showed more stability in dark as compared to light at 30�C. Furthermore, higher pigment loss was observed at 45�C than that at refrigeration temperature (4�C). It was also observed that freeze drying of the pigment enhanced its stability. It is concluded from the present investigation that wheat bran has a potential for CMCase production that can efficiently be used in bread production, juice processing and carotenoid extraction

Item Type:Thesis (PhD)
Uncontrolled Keywords:Purification, characterization, carboxymethyl, cellulose, food applications
Subjects:Engineering & Technology (e) > Technology (e2) > Food Technology(e2.2)
ID Code:2820
Deposited By:Mr. Javed Memon
Deposited On:09 Feb 2010 16:31
Last Modified:09 Feb 2010 16:31

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