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

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food, feed <strong>and</strong> <strong>in</strong>dustrial purposes are obta<strong>in</strong>ed through these processes. Figures 2.2 <strong>and</strong> 2.3show a schematic representation of the corn wet <strong>and</strong> dry mill<strong>in</strong>g, respectively.<strong>Corn</strong> kernels are composed of three different sections: pericarp (ma<strong>in</strong>ly fibre), endosperm(starch <strong>and</strong> prote<strong>in</strong>s) <strong>and</strong> germ (prote<strong>in</strong>s <strong>and</strong> oil). Ma<strong>in</strong> prote<strong>in</strong>s found <strong>in</strong> corn kernel arealbum<strong>in</strong>s, globul<strong>in</strong>s, glutel<strong>in</strong> <strong>and</strong> ze<strong>in</strong>. Album<strong>in</strong>s <strong>and</strong> globul<strong>in</strong>s are conta<strong>in</strong>ed <strong>in</strong> the germ,glutel<strong>in</strong> is homogenously distributed between germ <strong>and</strong> endosperm, <strong>and</strong> ze<strong>in</strong> is conta<strong>in</strong>ed ma<strong>in</strong>ly<strong>in</strong> the endosperm (Shukla <strong>and</strong> Cheryan, 2001). Xanthophyll pigments <strong>in</strong> corn kernels areembedded with<strong>in</strong> prote<strong>in</strong> complexes. The total xanthophyll content <strong>in</strong> whole corn ranges from 11to 30 mg kg -1 (Moros et al., 2002).<strong>Corn</strong> gluten meal <strong>and</strong> corn gluten feed are the by-products from the wet mill<strong>in</strong>g withhigher prote<strong>in</strong> level (around 60% <strong>and</strong> 23% of prote<strong>in</strong> content on a dry matter basis, respectively).Dur<strong>in</strong>g the wet mill<strong>in</strong>g, naturally occurr<strong>in</strong>g xanthophylls rema<strong>in</strong> attached to the gluten fraction(ma<strong>in</strong>ly ze<strong>in</strong>) which is ma<strong>in</strong>ly recovered <strong>in</strong> corn gluten meal. Consequently, this commodityconta<strong>in</strong>s high levels (224 to 550 mg kg -1 on a dry matter basis) of yellow carotenoids (Park et al.,1997; Moros et al., 2002), ma<strong>in</strong>ly lute<strong>in</strong> <strong>and</strong> zeaxanth<strong>in</strong>. <strong>Corn</strong> gluten feed on the other h<strong>and</strong>,conta<strong>in</strong>s a level of yellow pigment similar to that found <strong>in</strong> corn kernels (Tucker <strong>and</strong> Hargreaves,2004).Dried distiller gra<strong>in</strong>s (DDG) <strong>and</strong> DDG plus soluble (DDGS) are the dry gra<strong>in</strong> mill<strong>in</strong>g byproductswith higher prote<strong>in</strong> content (around 23%) (Shukla <strong>and</strong> Cheryan, 2001). Xanthophyllcontent <strong>in</strong> these by-products range from 22 to 40 mg kg -1 (Li et al., 2011).15
2.7.2 <strong>Corn</strong> gluten meal production<strong>Corn</strong> gluten meal is a high prote<strong>in</strong> (~60% crude prote<strong>in</strong>, on a dry matter basis), highlydigestible, by-product of the corn wet mill<strong>in</strong>g. <strong>Corn</strong> wet mill<strong>in</strong>g is an <strong>in</strong>dustrial ref<strong>in</strong><strong>in</strong>g process<strong>in</strong> which the four major constituents of the corn kernel (i.e. starch, germ, prote<strong>in</strong> <strong>and</strong> fiber) areisolated <strong>in</strong>to relatively pure fractions <strong>and</strong> transformed <strong>in</strong>to high quality products. Use of corn bythe wet mill<strong>in</strong>g process <strong>in</strong> the U.S. has grown an average of 1.2 million bushels (unit of dryvolume, 1 bushel = 35.2 litres) per month, reach<strong>in</strong>g up to 90 - 96 million bushels from January2007 to November 2009 (O’Brien, 2009).The major by-products from the corn wet mill<strong>in</strong>g used for animal feeds are steep liquor,bran, germ <strong>and</strong> gluten meal, represent<strong>in</strong>g about 30% of the total processed corn. An averageyield from the wet mill<strong>in</strong>g process gives 56% starch, 22% corn gluten feed, 3% corn gluten meal<strong>and</strong> 2% corn oil (Davis, 2001). Figure 2.2 shows the wet mill<strong>in</strong>g process overview. Briefly, afterclean<strong>in</strong>g <strong>and</strong> removal of impurities, corn kernels are placed <strong>in</strong>to large sta<strong>in</strong>less still tanks(steep<strong>in</strong>g tanks) to be soaked <strong>in</strong> steepwater (diluted sulphur dioxide solution) for 30-50 hours at52 -54 °C. Soak<strong>in</strong>g softens the kernel <strong>and</strong> the diluted sulphurous reduces the occurrence offermentation <strong>and</strong> assists <strong>in</strong> separation of the starch <strong>and</strong> prote<strong>in</strong> bounds (Galitsky et al., 2003).Dur<strong>in</strong>g soak<strong>in</strong>g, soluble nutrients from corn are transferred <strong>in</strong>to the steep water. This water isfurther evaporated <strong>in</strong> order to concentrate those nutrients <strong>and</strong> recovered them as condensed cornfermented extractives or corn steep liquor.After steep<strong>in</strong>g is completed, kernels are coarsely ground <strong>and</strong> oil-rich germ is removed.Oil is extracted from germ <strong>and</strong> the de-oiled germ leftovers are recovered as corn germ meal.Germless corn kernels are then f<strong>in</strong>ely ground <strong>and</strong> hulls are screen removed <strong>and</strong> recovered as corngluten feed.16
Page 1 and 2: Pigment Re
Page 3 and 4: ingredients. Furth
Page 5 and 6: Thanks to all my colleagues, friend
Page 7 and 8: 2.10.1 Enzymatic treatments .......
Page 9 and 10: LIST OF TABLESTable 3. 1 - Factors
Page 11 and 12: LIST OF FIGURESFigure 2. 1 - Molecu
Page 13 and 14: Ingredients commonly in</st
Page 15 and 16: CHAPTER - 2 LITERATURE REVIEW2.1 In
Page 17 and 18: leached when 5% of soy flour as LOX
Page 19 and 20: deep and fast glyc
Page 21 and 22: observed in ra<str
Page 23 and 24: Chylomicron constituents are remove
Page 25: Muscle growth in r
Page 29 and 30: 2010). However, due to its imbalanc
Page 31 and 32: No differences in
Page 33 and 34: supplemented with 42% of a vegetabl
Page 35 and 36: Soybean seeds are the richest known
Page 37 and 38: 2.10.1.4 Bleaching
Page 39 and 40: 2.11 ConclusionInclusion of <strong
Page 41 and 42: 4.0%*68%* 5.6%* 12%* 3.5%* 6.5%*Fig
Page 43 and 44: Figure 2. 4 - Schematic representat
Page 45 and 46: 3.1 IntroductionThe characteristic
Page 47 and 48: many factors such as LOX source lev
Page 49 and 50: During the 12-week
Page 51 and 52: 3.2.3 Analytical methodsDry matter
Page 53 and 54: solution was generated by mix<stron
Page 55 and 56: 3.2.4 Statistical analysisData from
Page 57 and 58: Factors defined as
Page 59 and 60: chromatography). Relative amounts o
Page 61 and 62: After carotenoids are absorbed thro
Page 63 and 64: and ended up <stro
Page 65 and 66: Table 3. 2 - Experimental design us
Page 67 and 68: Table 3. 4 - Analysed proximate com
Page 69 and 70: Proximate composition (Analysed; dr
Page 71 and 72: Table 3. 7 - Lipoxygenase activity
Page 73 and 74: 18 1 0 -1 0 120 15 0 10 2519 -1 0 1
Page 75 and 76: 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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significant (p
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Values for all-trans astaxanth<stro
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previous reports where colour attri
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Proximate composition (analysed), d
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Table 4. 2 - Growth performance of
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Table 4. 3 - Carcass chemical proxi
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Table 4. 4 - Retain</strong
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Table 4. 5 - Pigment</stron
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Table 4. 6 - Colour attributes <str
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FiguresFigure 4. 1 - Growth curves
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Figure 4. 3 - Muscle colour attribu
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the effects of dietary reduced-caro
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astaxanthin deposi
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After steeping, ke
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0.9994 and 0.9999,
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under acidic and a
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oxidation within t
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colour difference usin</str
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TablesTable 5. 1 - Analyzed proxima
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Effects of
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Effects of
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Effects of
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Effects of
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Data are mean (n=2).a Steepwater pH
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CHAPTER - 6 GENERAL DISCUSSIONCurre
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significant reduction in</s
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Reduction of pigme
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though wheat gluten meal conta<stro
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BibliographyAas, G.H., Storebakken,
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Bjerkeng, B., Hatlen, B., Wathne, E
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Choubert, G., Cravedi, J., Laurenti
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Fauconneau, B., Andre, S., Chmaitil
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Johnston, I., Li, X., Vieira, V., N
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Li, M.H., Oberle, D.F., Lucas, P.M.
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Peter, C.M., Han, Y., Bolin
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Skonberg, D.I., Hardy, R.W., Barrow
Page 167:
Ytrestoyl, T., Struksnæs, G., Kopp
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