Effect of Cold Smoking on Polycyclic Aromatic Hydrocarbon Content and Sensory Properties in Selected Foods

Kaloti, Shaan
Kam, Rothman
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Master of Science (Research)
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Auckland University of Technology

Smoking is a traditional method of food preservation and has improved over time with technology. The biggest problem with smoking is that the combustion of wood results in the formation of polycyclic aromatic hydrocarbons (PAHs). These compounds are carcinogenic and can contaminate food. Thus, the European Union has imposed an upper limit (dependant of food type) of 1 to 50 μg/kg of carcinogenic PAH (sum of benzo(a)pyrene, benz(a)anthracene, benzo(b)fluoranthene and chrysene). New methods such as cold smoking, friction smoking, liquid smoking, and electrostatic precipitation have been introduced to reduce PAHs in smoked foods. Currently, PAHs are analysed in food using solid-phase extraction, followed by the “QuEChERS” method to clean the extract. PAHs are then quantified using gas chromatography mass spectrometry (GCMS). The purpose of the review section of this study is to give a comprehensive view on the process of food smoking, the benefits, the regulations and ways to quantify PAH in foods.

In this study chicken, cheese and crackers were cold smoked with Native New Zealand wood chips (Manuka, Tawa, Rewa Rewa and Pohutukawa). The QuEChERS technique was used to extract PAHs, followed by quantification using gas chromatography in tandem with mass spectroscopy (GC-MS). Cold smoking time (5 to 120 minutes) had the most influence on final PAH concentration (varied from 10.84 ± 1.70 to 112084.74 ± 8784.14 μg/kg). Chicken breast that was cold smoked for 5 minutes using Manuka wood and had the lowest PAH concentration. An untrained sensory panel (n=50) rated chicken breast that had been cold smoked with Manuka, Tawa, Rewa Rewa and Pohutukawa based on overall liking, odour, appearance, texture, smokiness, and flavour. One-way analysis of variance (ANOVA) showed that Manuka cold smoked chicken was most favoured among panellists.

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