Food Biochemistry and Food Processing (2 edition)

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416 Part 3: Meat, Poultry and Seafoods

In beef (Bos taurus), a correlation was found between ante-

mortem and postmortem activities of some proteases, but not

others (Vaneenaeme et al. 1994). As discussed in the earlier

section, postmortem proteolysis is a matter of considerable im-

portance in the fish and seafood industry and any antemortem

effects thereupon are surely worth investigating.

In a recent study on the feasibility of substituting fish meal in

rainbow trout (O. mykiss) diets with protein from plant sources,

2DE-based proteomics were among the techniques used (Martin

et al. 2003a, b, Vilhelmsson et al. 2004). Concomitantly, various

quality characteristics of fillet and body were also measured (De

Francesco et al. 2004, Parisi et al. 2004). Among the findings

was that, according to a triangular sensory test using a trained

panel, cooked 5-day-old trout that had been fed the plant pro-

tein diet had higher hardness, lower juiciness, and lower odor

intensity than those fed the fish meal-containing diet, indicating

an effect of antemortem metabolism on product texture. The

study identified a number of metabolic pathways sensitive to

plant protein substitution in rainbow trout feed, such as path-

ways involved in cellular protein degradation, fatty acid break-

down, and NADPH (nicotinamide adenine dinucleotide phos-

phate) metabolism (Table 22.2). In the context of this chapter,

Table 22.2.Protein Spots Affected by Dietary Plant Protein Substitution in Rainbow Trout as Judged by

Two-dimensional electrophoresis and Their Identities as Determined by Trypsin Digest Mass Fingerprinting

Spot

Reference

Number pI

MW

(kDa)

Normalized

Vo l u m e

Diet FMa

Normalized

Volume Diet

PP100a

Fold

Difference P

Downregulated:

128 6.3 66 303 ± 57 60 ± 19 Vacuolar ATPaseβ-subunit 5 0.026

291 6.4 42 521 ± 37 273 ± 30 β-ureidopropionase 2 0.004

356 6.3 38 161 ± 37 44 ± 19 Transaldolase 4 0.031

747 5.6 43 101 ± 19 19 ± 11 β-actin 2 0.040

760 6.3 39 41 ± 621 ± 5 ND 2 0.040

766 4.8 27 12 ± 16 ± 1 ND 2 0.004

Upregulated:

80 4.4 82 9 ± 447 ± 8 “Unknown protein” 5 0.007

87 5.7 75 58 ± 14 262 ± 21 Transferrin 5 <0.001

138 5.5 67 99 ± 16 267 ± 39 Hemopexin-like 3 0.009

144 5.4 63 26 ± 6 265 ± 66 l-Plastin 10 0.018

190 5.9 54 6 ± 250 ± 9 Malic enzyme 9 0.018

199 5.9 53 60 ± 16 156 ± 13 Thyroid hormone receptor 3 0.020

275 6.1 45 1 ±0.6 11 ±0.6 NSH 9 <0.001

387 5.6 35 97 ± 3 251 ± 49 Electron transferring flavoprotein 3 0.035

389 5.8 35 192 ± 45 414 ± 54 Electron transferring flavoprotein 2 0.027

399 6.8 33 59 ± 12 130 ± 10 Aldolase B 2 0.028

457 4.7 29 26 ± 757 ± 5 14–3-3 B2 Protein 2 0.021

461 4.7 27 75 ± 9 190 ± 12 Proteasome alpha 2 3 0.004

517 4.4 22 15 ± 6 135 ± 29 Cytochromecoxidase 9 0.013

539 4.9 19 7 ± 318 ± 3 ND 3 0.033

551 4.1 17 40 ± 11 143 ± 28 ND 4 0.018

563 5.2 15 814 ± 198 3762 ± 984 Fatty acid-binding protein 5 0.039

639 6.4 84 10 ± 628 ± 5 NSH 3 0.047

648 6.1 55 17 ± 5 154 ± 46 Hydroxymethylglutaryl-CoA synthase 9 0.040

678 5.3 48 26 ± 769 ± 15 Proteasome 26S ATPase subunit 4 3 0.044

746 4.4 46 45 ± 13 107 ± 15 “Similar to catenin” 2 0.012

754 4.1 15 6 ± 236 ±4ND 7 <0.001

761 6.1 36 44 ± 21 204 ± 34 Transaldolase 5 0.006

764 6.2 65 0 102 ± 17 NSH > 10 NA

770 5.0 21 4 ± 118 ± 4 ND 4 0.026

aValues are mean normalized protein abundance (±SE). Data were analyzed by the Student’sttest (n=5). In the diet designated FM, protein was

provided in the form of fish meal; in diet designated PP100, protein was provided by a cocktail of plant product with an equivalent amino acid

composition to fish meal.

NSH, no significant homology detected; ND, identity not determined; NA, not available.