Detection Tuna and Processed Products Based Protein and DNA Barcoding

Abstract

Tuna is the second largest fishery commodity in Indonesia after the shrimp. Since the
high demand and the limited stock of tuna resulted in fraudulent chance. Authentication
is required to meassure consumers regarding the accuracy of its labeling and food
safety. In this study, the authentication was based on protein and DNA barcoding using
cytochrome-b gene (cyt-b) of the mitochondrial DNA as the target of gene. Primer of
cyt b gene was designed based on the tuna species. This study aimed to identify the
authenticity of tuna fresh and its processed products through protein using SDS-PAGE 

and DNA barcoding techniques. The phases of this research were protein electrophoresis
by SDS-PAGE, DNA extraction, PCR amplification, electrophoresis and sequencing.
Samples of fresh fish (Tu1, Tu2, Tu3, Tu4, and Tu5) and processed tuna (canned and
steak) were successfully extracted. Result showed that SDS-PAGE proved the damage of
proteins in the processed tuna, so this method was not appropriate if it is used to identify
the authenticity of tuna. PCR electrophoresis results showed that the samples of tuna,
tuna steak, sushi, meat ball, abon, and caned tuna were successfully amplified in the range
of 500-750 bp except Ka3, which was in line with the target of DNA (620 bp). Resulted
sequences of Tu2, Tu3, Tu4 and Tu5 were identified according the results of morphometric
namely T. albacares, while Tu1 was identified as T. obesus with homology level of 99%.
Processed tunas (steak and canned tuna) were identified as T. albacares, as stated on the
labels.
Keywords: Authentication, cytb, DNA barcoding, design primer, SDS-PAGE