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

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level, respectively) resulted <strong>in</strong> significant different values for colour attributes <strong>and</strong> texture(expressed as maximum shear strength) <strong>in</strong> fillet from ra<strong>in</strong>bow trout fed non-pigmentsupplemented experimental diets for 12 weeks (Kaushik et al., 1995). Higher hardness, lesssweetness <strong>and</strong> odour <strong>in</strong>tensity, <strong>and</strong> a trend to lower juic<strong>in</strong>ess, as well as significant differences <strong>in</strong>redness (a*) <strong>and</strong> yellowness (b*) <strong>in</strong> different sections (dorsal, ventral <strong>and</strong> caudal site) weredeterm<strong>in</strong>ed <strong>in</strong> fillets from ra<strong>in</strong>bow trout fed a diet supplemented with 70% of a plant prote<strong>in</strong>blend composed of corn gluten meal, wheat gluten meal, extruded peas <strong>and</strong> rapeseed meal (<strong>in</strong> a2:2:2:1 ratio) compared to those obta<strong>in</strong>ed from fish fed a fish meal based diet conta<strong>in</strong><strong>in</strong>g 0.01%of astaxanth<strong>in</strong> for 24 weeks (de Francesco et al., 2004).2.3 Fish muscle <strong>and</strong> quality st<strong>and</strong>ardsMuscle is the soft, contractile tissue responsible for produc<strong>in</strong>g force <strong>and</strong> caus<strong>in</strong>g motion <strong>in</strong>animals. Three different types of muscle tissue are recognized <strong>in</strong> vertebrates, skeletal or‘voluntary’ muscle controll<strong>in</strong>g locomotion, <strong>and</strong> two types of ‘<strong>in</strong>voluntary muscle, smooth found<strong>in</strong> <strong>in</strong>ternal organs (i.e. esophagus, stomach, among others) <strong>and</strong> cardiac muscle, found only <strong>in</strong> theheart.The major edible part of fish fillets is composed by ‘W’ shaped stacks of skeletal musclecalled myomeres. These muscle blocks are separated from adjacent myomeres by th<strong>in</strong> horizontal(myosepta) <strong>and</strong> vertical (myocommata) layers of connective tissue. Three different types ofskeletal muscle have been described <strong>in</strong> fish based on their metabolic <strong>and</strong> contractilecharacteristics: 1) red muscle (slow twitch or type 1 cells): composed of superficial cells with ahigh capacity for aerobic energy supply, 2) white muscle (fast twitch or type 2b cells): formed by7
deep <strong>and</strong> fast glycolytic cells, <strong>and</strong> 3) p<strong>in</strong>k muscle (located between red <strong>and</strong> white muscle),shar<strong>in</strong>g metabolic properties of red <strong>and</strong> white muscle (Fauconneau et al., 1997).Myofibers (myocytes, muscle cells or muscle fibers) are cyl<strong>in</strong>drical mult<strong>in</strong>ucleated cellsarranged with<strong>in</strong> myomeres <strong>in</strong> clusters of cells called fascicles. Myofibers are composed of longcontractile prote<strong>in</strong> bundles (conta<strong>in</strong><strong>in</strong>g act<strong>in</strong> <strong>and</strong> myos<strong>in</strong> complexes) called myofribrils. Act<strong>in</strong><strong>and</strong> myos<strong>in</strong> are organized with<strong>in</strong> myofibrils <strong>in</strong> units of repetition named sarcomeres.Flesh quality is determ<strong>in</strong>ed by a comb<strong>in</strong>ation of muscle characteristics <strong>in</strong>clud<strong>in</strong>g fleshfirmness <strong>and</strong> colour (Anderson, 2000). Flesh quality traits dramatically <strong>in</strong>fluence the price of thef<strong>in</strong>al product, thus achiev<strong>in</strong>g high st<strong>and</strong>ards <strong>in</strong> flesh quality will result <strong>in</strong> premium price. On theother h<strong>and</strong>, fillets present<strong>in</strong>g poor physical characteristic will be downgraded (i.e. reduction ofthe economic value of the product) at process<strong>in</strong>g plants (Johnston et al., 2006).2.4 Salmonid fish fillet colour <strong>and</strong> consumers’ perceptionThe conspicuous red to p<strong>in</strong>k colour <strong>in</strong> fillets from salmonid fish is an important qualityparameter. Colour has been positively related to consumer purchas<strong>in</strong>g decision at sell<strong>in</strong>g po<strong>in</strong>ts.Consumers associate colour with characteristics such as age, orig<strong>in</strong>, expected flavour/texture <strong>and</strong>freshness (Anderson, 2000).<strong>Reduction</strong> of expected colour <strong>in</strong> muscle from salmonid fish negatively affects its appeal <strong>and</strong>reduces its economic value as consumers relate this treat with a more expensive product. There isa clear preference from consumers for redder fillets compare to pale ones. Consumers’will<strong>in</strong>gness to pay (WTP) was positively correlated to fillet redness <strong>in</strong> a real choice experiment,8
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: leached when 5% of soy flour as LOX
Page 21 and 22: observed in ra<str
Page 23 and 24: Chylomicron constituents are remove
Page 25 and 26: Muscle growth in r
Page 27 and 28: 2.7.2 Corn gluten
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
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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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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
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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