Investigation of liquid smoke's composition from peach tree wood using GC-mass and its microbial and physiochemical properties on hotdogs

Abstract

Fumigation is one of the oldest methods of meat preservation, and it has been used to improve sensory properties of fish and other meat products for over 30 years. Liquid smoke has antimicrobial and antioxidant activities, in addition to its sensory properties. In this research, the effects of liquid smoke made from peach tree wood were evaluated. In the first step, the compound composition of liquid smoke was evaluated by a GC-mass system. The primary components of this essential oil consisted of phenolic and acidic compounds. In addition, the ascorbic acid was removed from the hotdog formulation, and the amount of applied nitrite and nitrate were reduced to one half (60 ppm). In the second phase of the research, hotdog samples containing 0.4% and 0.6% liquid smoke were evaluated for antimicrobial ability, antioxidant capability, sensory properties, moisture reduction, and pH over a period of 14 d. The results of this research showed that liquid smoke, in a concentration of 0.6%, has a significant effect in the reduction of the microbial load (total count of Clostridium perfringens) in hotdog samples over 14 d (p < 0.0001), and it is effective in oxidation reduction by d 7 (p = 0.0051), and 14 (p = 0.0001), while also significantly reducing the product's moisture on d 1 (p = 0.0269) through d 14 (p = 0.05). In colorimetric tests, liquid smoke did not have any significant effect on the b∗ factor, but concentrations of 0.4% liquid smoke on d 14 (p = 0.0313) and 0.6% liquid smoke on d 1 (p = 0.0355), d 7, and d 14 (p = 0.0003) affected the a∗ factor, and the concentration of 0.6% affected the L∗ factor, in comparison with the control sample on d 1, d 7 (p = 0.0451), and d 14 (p = 0.027). In pH tests, both concentrations of 0.4% liquid smoke on d 1 (p = 0.0133), d 7 (p = 0.0422), and d 14 (p = 0.005), and 0.6% liquid smoke (p < 0.0001) significantly reduced the pH in comparison to the control samples. The statistical results from the sensory evaluation test showed that between all applied concentrations (0.01%, 0.02%, 0.04% and 0.06%) of liquid smoke, the two concentrations of 0.06% and 0.4% had the best scores among the panelists and qualified for the next phase of the research. General results of this study showed that in addition to sensory properties' improvement, liquid smoke has antimicrobial and antioxidant activity, and the ability to reduce pH, due to the presence of phenolic and acidic compounds, and this ability increases with greater concentrations of the liquid smoke.