Pigment Reduction in Corn Gluten Meal and Its Effects on Muscle ...

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corn gluten meal exceed<strong>in</strong>g 12% reduced astaxanth<strong>in</strong> muscle concentration as well as importantcolour attributes <strong>in</strong> the flesh.Low concentrations of all-trans lute<strong>in</strong> <strong>and</strong> all-trans zeaxanth<strong>in</strong> were determ<strong>in</strong>ed <strong>in</strong> musclefrom ra<strong>in</strong>bow trout fed all diets used <strong>in</strong> this trial. This result is <strong>in</strong> accordance with previousstudies report<strong>in</strong>g deposition of yellow xanthophylls <strong>in</strong> muscle from salmonid fish (Bowen et al.2002; Kitahara, 1983; Welker et al. 2001).Consider<strong>in</strong>g the significant reduction of carotenoids from corn gluten meal obta<strong>in</strong>ed <strong>in</strong>Chapter 3, but aim<strong>in</strong>g to develop a more practical process<strong>in</strong>g methodology from a commercialpo<strong>in</strong>t of view, the bleach<strong>in</strong>g of carotenoid pigments from corn gluten meal dur<strong>in</strong>g steep<strong>in</strong>g(dur<strong>in</strong>g conventional corn wet mill<strong>in</strong>g process) was addressed <strong>in</strong> Chapter 5.Two varieties of corn kernels, with high carotenoid content <strong>and</strong> different pigment profile,were utilized <strong>in</strong> order to simulate variation <strong>in</strong> pigment content of different batches of cornkernels used <strong>in</strong> commercial production. Hydrogen peroxide, an antioxidant widely utilized forcolour reduction of cellulosic <strong>and</strong> dairy products, was added <strong>in</strong>to steepwater as a bleach<strong>in</strong>gagent. Based on the effective reduction <strong>in</strong> colour of wheat stillage us<strong>in</strong>g alkal<strong>in</strong>e hydrogenperoxide (Abdel-Aal et al., 1996), pH of steepwater was modified <strong>in</strong> order to assess thebleach<strong>in</strong>g of carotenoids under acidic <strong>and</strong> alkal<strong>in</strong>e conditions.High gluten yields but low starch yields were obta<strong>in</strong>ed <strong>and</strong> attributed to the <strong>in</strong>completeseparation of these two fractions due to limitation related to gr<strong>in</strong>d<strong>in</strong>g equipment utilized <strong>in</strong> thistrial thus not affect<strong>in</strong>g bleach<strong>in</strong>g of pigments. About 50% of the <strong>in</strong>itial carotenoid content wasbleached us<strong>in</strong>g this methodology. <strong>Corn</strong> variety, hydrogen peroxide <strong>and</strong> steepwater pH had asignificant effect on carotenoid bleach<strong>in</strong>g.135
<strong>Reduction</strong> of pigments from corn gluten meal dur<strong>in</strong>g steep<strong>in</strong>g of corn kernels dur<strong>in</strong>g cornwet mill<strong>in</strong>g represent a straight forward, cost-effective approach that might f<strong>in</strong>d a wide use <strong>in</strong>commercial production of low carotenoid corn gluten meal for specific applications such asaquaculture feed manufactur<strong>in</strong>g.6.1 Metabolism of carotenoids <strong>in</strong> fishMetabolism of carotenoid pigments <strong>in</strong> fish is assumed to be similar to that of dietary fat <strong>in</strong>mammals (Olsen <strong>and</strong> Baker, 2006).After <strong>in</strong>gestion carotenoids are emulsified <strong>in</strong>to lipidemulsions. Polar xanthophylls distribute with<strong>in</strong> the emulsions’ surface from where they arespontaneously transferred <strong>in</strong>to bile salt micelles before be<strong>in</strong>g absorbed through the <strong>in</strong>test<strong>in</strong>alepithelial cells (Borel et al., 1996). Whether occurrence of different types of xanthophylls with<strong>in</strong>lipid emulsions affects astaxanth<strong>in</strong> transfer <strong>and</strong>/or allocation <strong>in</strong>to mixed micelles rema<strong>in</strong>s to beclarified.Mixed lipid micelles reach the <strong>in</strong>test<strong>in</strong>al bush border membrane where carotenoids areabsorbed through passive diffusion. <strong>Pigment</strong>s can compete for absorption or facilitate theabsorption of another (Ishida <strong>and</strong> Bartley, 2005). Whether the presence of a mixture of polarxanthophyll with<strong>in</strong> the surface of mixed micelles can reduce astaxanth<strong>in</strong> absorption <strong>in</strong> ra<strong>in</strong>bowtrout needs to be addresses.The mechanisms govern<strong>in</strong>g carotenoids translocation <strong>and</strong> <strong>in</strong>corporation <strong>in</strong>to lipoprote<strong>in</strong>swith<strong>in</strong> the enterocyte are unknown. As no specific <strong>in</strong>tracellular transport for carotenoids has beendescribed, a non-discrim<strong>in</strong>atory transport has been proposed (Parker, 1996; Dem<strong>in</strong>g <strong>and</strong> Erdman,1999), this suggests that when mixtures of different xanthophylls are absorbed, comb<strong>in</strong>ations of136
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Pigment Re
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ingredients. Furth
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Thanks to all my colleagues, friend
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2.10.1 Enzymatic treatments .......
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LIST OF TABLESTable 3. 1 - Factors
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LIST OF FIGURESFigure 2. 1 - Molecu
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Ingredients commonly in</st
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CHAPTER - 2 LITERATURE REVIEW2.1 In
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leached when 5% of soy flour as LOX
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deep and fast glyc
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observed in ra<str
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Chylomicron constituents are remove
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Muscle growth in r
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2.7.2 Corn gluten
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2010). However, due to its imbalanc
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No differences in
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supplemented with 42% of a vegetabl
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Soybean seeds are the richest known
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2.10.1.4 Bleaching
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2.11 ConclusionInclusion of <strong
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4.0%*68%* 5.6%* 12%* 3.5%* 6.5%*Fig
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Figure 2. 4 - Schematic representat
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3.1 IntroductionThe characteristic
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many factors such as LOX source lev
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During the 12-week
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3.2.3 Analytical methodsDry matter
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solution was generated by mix<stron
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3.2.4 Statistical analysisData from
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Factors defined as
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chromatography). Relative amounts o
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After carotenoids are absorbed thro
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and ended up <stro
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Table 3. 2 - Experimental design us
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Table 3. 4 - Analysed proximate com
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Proximate composition (Analysed; dr
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Table 3. 7 - Lipoxygenase activity
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18 1 0 -1 0 120 15 0 10 2519 -1 0 1
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Table 3. 10 - HPLC carotenoid profi
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Table 3. 12 - Retain</stron
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Table 3. 14 - Fillet carotenoid con
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Total yellow pigment(mg•kg -1 )25
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Figure 3. 4 - Growth curve of ra<st
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effects of dietary CGM and<
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soybean meal in a
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were randomly samp
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An aliquot (1 ml) of chloroform low
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Retained nitrogen
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Page 97 and 98: Values for all-trans astaxanth<stro
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Page 101 and 102: Proximate composition (analysed), d
Page 103 and 104: Table 4. 2 - Growth performance of
Page 105 and 106: Table 4. 3 - Carcass chemical proxi
Page 107 and 108: Table 4. 4 - Retain</strong
Page 109 and 110: Table 4. 5 - Pigment</stron
Page 111 and 112: Table 4. 6 - Colour attributes <str
Page 113 and 114: FiguresFigure 4. 1 - Growth curves
Page 115 and 116: Figure 4. 3 - Muscle colour attribu
Page 117 and 118: the effects of dietary reduced-caro
Page 119 and 120: astaxanthin deposi
Page 121 and 122: After steeping, ke
Page 123 and 124: 0.9994 and 0.9999,
Page 125 and 126: under acidic and a
Page 127 and 128: oxidation within t
Page 129 and 130: colour difference usin</str
Page 131 and 132: TablesTable 5. 1 - Analyzed proxima
Page 133 and 134: Effects of
Page 141 and 142: Data are mean (n=2).a Steepwater pH
Page 143 and 144: CHAPTER - 6 GENERAL DISCUSSIONCurre
Page 145: significant reduction in</s
Page 149 and 150: though wheat gluten meal conta<stro
Page 151 and 152: BibliographyAas, G.H., Storebakken,
Page 153 and 154: Bjerkeng, B., Hatlen, B., Wathne, E
Page 155 and 156: Choubert, G., Cravedi, J., Laurenti
Page 157 and 158: Fauconneau, B., Andre, S., Chmaitil
Page 159 and 160: Johnston, I., Li, X., Vieira, V., N
Page 161 and 162: Li, M.H., Oberle, D.F., Lucas, P.M.
Page 163 and 164: Peter, C.M., Han, Y., Bolin
Page 165 and 166: Skonberg, D.I., Hardy, R.W., Barrow
Page 167: Ytrestoyl, T., Struksnæs, G., Kopp
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