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Title of Thesis

Production and Characterization of Xylanase for Utilization in Baking Industry

Author(s)

Zulfiqar Ahmad

Institute/University/Department Details

Institute of Food Science and Technology / University of Agriculture Faisalabad

Session
2009

Subject

Food Technology

Number of Pages
207
Keywords (Extracted from title, table of contents and abstract of thesis)
Production, Characterization, Xylanase, Utilization, Baking, Industry

Abstract

Present research was conducted to synthesize xylanase enzyme by Aspergillus niger using local agricultural wastes/by products for its utilization in baking industry. Wheat bran, corn cobs and sugar cane bagasse were used as carbon source at different concentrations i.e. 2.5, 3.0 and 3.5% employing submerged fermentation. The factors like temperature, pH and incubation time affected the xylanase synthesis significantly at various levels of substrates. The outcomes of the fermentation process showed that culture conditions i.e. 30C, pH 5.5, 72 hrs & 3% substrates concentration were optimum for xylanase production. Wheat bran showed maximum xylanase activity 78.032.73 IU/mL followed by corn cob, 60.031.83 IU/mL and sugar cane bagasse 44.031.98 IU/mL. Large scale production of xylanase was carried out using wheat bran as carbon source at pre-optimized conditions. Purified enzyme showed the specific activity of 613.13 IU/mg protein as compared to crude enzyme 41.85 IU/mg protein. Characterization of xylanase indicated that pH 7.5 and 55C were optimum for maximum activity. As the ultimate goal was to apply xylanase in food products i.e. bread, so it was subjected to efficacy studies using experimental poultry birds. It is deduced that values for body growth performance, serological and hematological parameters were within normal ranges showing the safety of enzyme. In order to assess the potential of xylanase in bread making; a comparative study was conducted in which enzyme was applied in various doses at two different stages i.e. tempering of wheat kernels before milling and mixing of dough. Xylanase addition modified the rheological attributes of dough, especially farinographic, mixographic and amylographic characteristics. Furthermore, xylanase decreased dryness and stiffness of the dough whereas, resulted in increased elasticity, extensibility and coherency. It is concluded from the rheological and allied characteristics that enzyme addition improved the dough handling properties. Bread volume was increased in response to xylanase addition during tempering up to 600 IU/kg and during mixing stage up to 800 IU/kg. Additionally, specific and relative volume increased whereas, density decreased in response to xylanase application. Moisture retention capacity of bread samples also improved as a result of enzyme treatments. Lastly, sensory evaluation was conducted to study the effect of xylanase treatments on the external and internal characteristics of the bread. Enzyme treatments resulted in marked improvement in these traits, though in most of the cases, T3 (600 IU/1kg) showed better performance. The statistical results indicated that addition of xylanase during tempering is more beneficial and cost effective in enhancing the hedonic response as compared to mixing. In the nutshell, wheat bran at 3% concentration can be used as a potential carbon source for the production of xylanase enzyme under pre-optimized conditions. Overall, improvement in dough handling characteristics and bread quality traits indicates that xylanase has potential to be used in the baking industry.

Download Full Thesis
645 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 CONTENTS 10
82 KB
2 1 INTRODUCTION 5
104 KB
3 2

REVIEW OF LITERATURE

2.1 Xylans: an overview

2.2 Xylanases

2.3 Xylanase production

2.4 Purification and characterization                                                 

2.5 Xylanase: safety concerns                                                              

2.6 Food application: baking industry                                              

2.7 Xylanase in bread making

21
156 KB
4 3

MATERIALS AND METHODS

3.1 Substrates                                                                                              

3.2 Fermentative organism                                                                       

3.3 Growth on PDA for sporulation                                                        

3.4 Preparation of inoculum                                                                    

3.5 Enzyme production                                                                            

3.6 Optimization

3.7 Sample harvesting

3.8 Enzyme activity

3.9 Large scale xylanase production

3.10 Purification

3.11 Characterization

3.12 Efficacy study

3.13 Application of xylanase in baking

3.14 Rheological studies

3.15 Dough characteristics                                                                        

3.16 Bread production                                                                              

3.17 Moisture retention                                                                             

3.18 Determination of volume

3.19 Sensory evaluation                                                                            

3.20 Statistical analysis

14
156 KB
5 4

RESULTS AND DISCUSSION

4.1 production of xylanase

4.2 purification and characterization

4.3 efficacy studies

4.4 application of xylanase in bread making

140
460 KB
6 5 SUMMARY 5
  5.1 LITERATURE CITED 20
197 KB