Food Biochemistry and Food Processing

18 Proteomics in Fish Processing 415

in the market value of different fish species and the
increased prevalence of processed product on the
market, it is perhaps not surprising that species
authentication is fast becoming an issue of supreme
commercial importance. Along with other molecular
techniques, such as DNA-based species identifica-
tion (Mackie et al. 1999, Martinez et al. 2001b,
Sotelo et al. 1993) and isotope distribution tech-
niques for determining geographical origin (Cam-
pana and Thorrold 2001), proteomics are proving to
be a powerful tool in this area, particularly for
addressing questions on the health status of the
organism, stresses or contamination levels at the
place of breeding, and postmortem treatment (Mar-
tinez and Jakobsen Friis 2004). Martinez et al.

(2003) recently reviewed proteomic and other meth-

ods for species authentication in foodstuffs. Since,

unlike the genome, the proteome is not a static enti-

ty, but changes between tissues and with environ-

mental conditions, proteomics can potentially yield

more information than genomic methods, possibly

indicating freshness and tissue information in addi-

tion to species. Therefore, although it is likely that

DNA-based methods will remain the methods of

choice for species authentication in the near term,

proteomic methods are likely to develop rapidly and

find commercial uses within this field. In many cases,

the proteomes of even closely related fish species

can be easily distinguishable by eye from one anoth-

er on 2D gels (Fig. 18.6), indicating that diagnostic

Figure 18.6.2DE liver proteome maps of four salmonid fish (S. Martin and O. Vilhelmsson, unpublished). Running

conditions are as in Figure 18.2. A. Brown trout (Salmo trutta),B. Arctic charr (Salvelinus alpinus),C. rainbow trout

(Oncorhynchus mykiss),D. Atlantic salmon (Salmo salar).

A

B

C D