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

Muhammad, Nasir (2009) Characterization of Maize Germ from Various Hybrids and Use of Its Components for Value Added Baked Products. PhD thesis, University of Agriculture, Faisalabad .

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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: 87.10�0.78% true digestibility, 76.70�1.25% net protein utilization, 88.06�o.67% biological value, 5.12�0.21 net protein ratio and 2.15�0.03 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

Item Type:Thesis (PhD)
Uncontrolled Keywords:Characterization, Maize germ, various hybrids, components, value added, baked products
Subjects:Engineering & Technology (e) > Technology (e2) > Food Technology(e2.2)
ID Code:2821
Deposited By:Mr. Javed Memon
Deposited On:10 Feb 2010 12:08
Last Modified:10 Feb 2010 12:08

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