title: Chemical characterization of commercial liquid smoke products.
abstract: The objective of this study was to determine important chemical characteristics of a full-strength liquid smoke, Code 10-Poly, and three refined liquid smoke products (AM-3, AM-10 and 1291) commercially available (Kerry Ingredients and Flavors, Monterey, TN). The pH of the products were significantly different (P < 0.05) and ranged from 2.3 (Code 10-Poly) to 5.7 (1291). The pH was inversely correlated with titratable acidity (R (2) = 0.87), which was significantly different (P < 0.05) among products ranging from 10.3% acetic acid (Code 10-Poly) to 0.7% acetic acid (1291). Total phenol content was quantified using the Gibbs reaction; the only liquid smoke containing appreciable level of phenolic compounds was Code 10-Poly at 3.22 mg mL(-1). Gas chromatography-mass spectrometry (GC-MS) analysis of liquid smoke dichloromethane extracts revealed that carbonyl-containing compounds were major constituents of all products, in which 1-hydroxy-2-butanone, 2(5H)-furanone, propanal and cyclopentenone predominated. Organic acids were detected by GC-MS in all extracts and correlated positively (R (2) = 0.98) with titratable acidity. The GC-MS data showed that phenolic compounds constituted a major portion of Code 10-Poly, and were detected only in trace quantities in 1291. The refined liquid smokes had lighter color, lower acidity, and reduced level of carbonyl-containing compounds and organic acids. Our study revealed major differences in pH, titratable acidity, total phenol content, color and chemical make-up of the full-strength and refined liquid smokes. The three refined liquid smoke products studied have less flavor and color active compounds, when compared with the full-strength product. Furthermore, the three refined products studied have unique chemical characteristics and will impart specific sensorial properties to food systems. Understanding the chemical composition of liquid smokes, be these refined or full-strength products, is an important step to establish their functions and appropriate use in food systems.
authors.affiliation: Kodiak Seafood and Marine Science, Center School of Fisheries and Ocean Sciences, University of Alaska Fairbanks Kodiak, Alaska, 99615.
authors.forename: Naim
authors.initials: N
authors.lastname: Montazeri
authors.affiliation: Kodiak Seafood and Marine Science, Center School of Fisheries and Ocean Sciences, University of Alaska Fairbanks Kodiak, Alaska, 99615.
authors.forename: Alexandra Cm
authors.initials: AC
authors.lastname: Oliveira
authors.affiliation: Kodiak Seafood and Marine Science, Center School of Fisheries and Ocean Sciences, University of Alaska Fairbanks Kodiak, Alaska, 99615.
authors.forename: Brian H
authors.initials: BH
authors.lastname: Himelbloom
authors.affiliation: Institute of Arctic Biology, Department of Biology and Wildlife, University of Alaska, Fairbanks Fairbanks, Alaska, 99775.
authors.forename: Mary Beth
authors.initials: MB
authors.lastname: Leigh
authors.affiliation: Kodiak Seafood and Marine Science, Center School of Fisheries and Ocean Sciences, University of Alaska Fairbanks Kodiak, Alaska, 99615.
authors.forename: Charles A
authors.initials: CA
authors.lastname: Crapo
keywords: GC-MS; Gibbs reaction; liquid smoke; phenol content