Abstract:
Smoking is one of the oldest techniques of fish preservation and at present smoked fish has higher
consumer demand due to their specific taste and aroma which is generated using partial combustion
of woods. But, accumulation of carcinogenic Polycyclic Aromatic Hydrocarbons (PAHs) through the
wood smoke is a major problem associated with smoked fish. Hence, the present study was carried
out to evaluate the carcinogenic PAHs levels and their penetration with the storage time in smoked
Catla (Catla catla). Freshly harvested Catla fishes (2.5 – 9.7 kg) were (n=3) brought from
Handapanagala reservoir, Monaragala and equal size (6 × 5 × 2.5 cm3) fish cubes were smoked in
electrical smoker (180 ºF for 1.5 hrs.) using Cinnamon (Cinnamomum verum) and Mahogany
(Swietenia macrophylla) wood smoke separately and stored at -20 ºC. Acetonitrile extract of smoked
and raw fish samples were treated with a mixture of anhydrous MgSO4: NaCl followed by a mixture
of MgSO4: silica propylsulfonic acid cation exchanger to extract and purify PAHs at predetermined
time intervals as day 1 and day 7(QuEChERS). Outer layer and center part of the smoked fish were
analyzed for sixteen PAHs by Dionex Ultimate 3000 UHPLC system equipped with Hypersil Green
PAH column (250 mm x 4.6 mm x 5 μm) and Diode Array detector (254 nm, 1 ml/min, Acetonitrile:
water gradient elution) separately and compared with standards. Moisture content and crude fat
content of raw fish samples were also analyzed. Indeno[1,2,3-cd]pyrene was detected in one of the
raw fish sample, while Benzo[a]pyrene, Benzo[ghi]perylene, Indeno[1,2,3-cd]pyrene were detected
in fish samples smoked with Cinnamon wood. Indeno[1,2,3-cd] pyrene was found to be the most
abundant PAH and it varies between 198 – 212 μg kg-1. No pattern of penetration of PAHs to center
was observed. Detectable amounts of PAHs were not found in any of the samples smoked with
Mahogany wood. Therefore, it can be concluded that modern smokers under controlled conditions
produce lower levels of PAHs and Mahogany wood could be a suitable wood type to smoke Catla
catla.
Keywords: Polycyclic aromatic hydrocarbons; Catla; QuEChERS method; Cinnamon; Mahogany
