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Title of Thesis
Characterization of Maize Germ from Various Hybrids and Use of Its Components for Value Added Baked Products

Author(s)
Muhammad Nasir
Institute/University/Department Details
National Institute of Food Science and Technology / University of Agriculture Faisalabad
Session
2009
Subject
Food Technology
Number of Pages
235
Keywords (Extracted from title, table of contents and abstract of thesis)
Characterization, Maize germ, various hybrids, components, value added, baked products

Abstract
Maize germs from six promising locally grown hybrids, namely Poineer-32-F-10 (P-1), Poineer-32-B-33 (P-2), Monsanto-6142 (M-1), Monsanto-6525 (M-2), Rafhan-2331 (R-1) and commercial were characterized for proximate composition, selected minerals, amino acid & fatty acid profiles and tocopherols. Based on the germ recovery and compositional analysis, one best hybrid germ, Pioneer 32-F-10 (P-1), was selected for further analysis and product development. Refined maize germ oil (MGO) from selected hybrid, was analyzed for various physical and chemical characteristics. The MGO was evaluated for cake preparation through blending with normal shortening at different levels. Moreover, defatted maize germ (DMG) meal was subjected to biological and safety evaluation using Sprague Dawley rats. Later, DMG flour was blended with wheat flour in different combinations; evaluated for functional properties, textural analysis (SMS Texture Analyzer) and Farinographic behavior. Flour blends were further used to develop value-added products like bread and cookies. Germ recovery from the experimental hybrids ranged from 6.31-7.68%, while the highest germ yield was observed in P-1 hybrid. Germ samples were found to be nutrient dense; crude protein 16.34-20.96%, crude fat 32.10-38.80%, crude fiber 2.63-4.79%, ash 3.08-4.94%, α-tocopherol 4.63-9.68 mg/100g and γ-tocopherol 29.52-35.51 mg/100g. The germ samples were rich in polyunsaturated fatty acids (46.74-58.00 g/100g) and essential amino acids (33.30-39.04 g/100g). Additionally, in germ samples, minerals like P (1.06-1.79 g/100g), K (1.19-1.64 g/100g), Mg (0.43-0.78 g/100g) and Fe (9.08-14.46 mg/100g) were in substantial amount. MGO from selected germ (P-1) was successfully incorporated in cake recipe with high sensory quality. Defatted maize germ (DMG) meal was found to be considerable source of protein (32.1%), dietary fiber (31.87%) and allied minerals. In the experimental rats, in-vivo protein quality of DMG flour was: 87.100.78% true digestibility, 76.701.25% net protein utilization, 88.06o.67% biological value, 5.120.21 net protein ratio and 2.150.03 protein efficiency ratio were significantly higher than that of wheat-based diet and comparable with casein. Favorable impact of DMG flour on serum biochemical profile was observed; cholesterol, triglyceride, LDL and glucose levels decreased up to 6.80, 12.45, 16.19 and 6.50 %, respectively. DMG flour resulted in improvement of functional properties of DMG flour-wheat flour blends with special reference to improved water & oil absorption capacity, gelling and emulsion properties; revealed its worth in food preparations. Protein and fiber enriched cookies and breads were prepared up to 15% wheat flour substitution with DMG flour. Consumer response to purchase defatted maize germ flour fortified cookies was very positive e.g. 64% of the respondents said that they would prefer to purchase cookies containing DMG flour if available in market. It is concluded from the present exploration, that maize germ components especially oil and defatted meal can successfully be used for value-addition of baked products. Moreover, DMG flour bears a potential to cope with protein deficiency in the vulnerable segment of population

Download Full Thesis
823 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 Contents 11
81 KB
2 1 Introduction 5
92 KB
3 2 Review of Literature

2.1. Food Security and Un-Conventional Foods

2.2. Maize Germ Characterization

2.3. Protein Quality

2.4. Efficacy and Safety Evaluation

2.5. Composite Flour

2.6. Functional and Rheological Properties

2.7. Product Development

27
162 KB
4 3 Materials and Methods

3.1. Procurement of Raw Material

3.2. Maize Germ Separation

3.3. Analysis of Germ

3.4. Maize Germ Selection

3.5. Oil Extraction 

3.6. Refining

3.7. Analysis of Refined Maize Germ Oil (MGO)

3.8. Product Development

3.9. Preparation of Defatted Maize Germ(DMG) Flour

3.10. Chemical Analysis

3.11. Biological Evaluation

3.12. Safety Evaluation

3.13. Preparation of DMG-Wheat Flour Blends

3.14. Analyses of Flour Blends

3.15. DMGF-Wheat Flour Blends for Product Development

3.16. Statistical Analysis

19
194 KB
5 4 Results and Discussion

4.1. Maize Germ Recovery

4.2. Analysis of Germ

4.3. Characteristics of Maize Germ Oil (MGO)

4.4. Maize germ oil (MGO) for Cake Development

4.5. Chemical Composition of DMG Flour

4.6. Efficacy Studies

4.7. Defatted Maize Germ-Wheat Flour Blends

4.8. DMGF-Wheat Flour Blends for Product Development

123
483 KB
7 6 Summary 7
  6.1 References 23
272 KB
  6.2 Appendices 14