The effect of liquid smoke obtained from fast pyrolysis of a hardwood on physical properties and shelf life of cheddar cheese

Quantification of cresols in liquid smoke samples employing liquid-liquid extraction with low-temperature purification and analysis by gas chromatography-mass spectrometry

Liquid smoke is a food additive and cresols are among its chemical constituents, potentially toxic to human health. Thus, the objective of this study was to develop a method to quantify cresols in liquid smoke. First, the liquid-liquid extraction with low temperature purification (LLE-LTP) was validated for cresols in water, as there are no cresol-free liquid smoke samples. Analyzes were performed by gas chromatography coupled to mass spectrometry in full scan mode. LLE-LTP was subsequently applied in five commercial samples of liquid smoke. Validation results showed that the proposed extraction method was selective for cresols, linear in the range of 0.5 to 35 mg L-1, limit of quantification of 0.5 mg L-1, recovery rate between 90% and 104% and relative standard deviation lower than 10%. The quantification of cresols in liquid smoke samples ranged from 3.0 to 38.3 mg L-1 and the concentration of these chemical contaminants in liquid smoke remained constant for at least 21 days at 25 °C.

Using liquid smoke to control infestations of the ham mite, Tyrophagus putrescentiae, on dry-cured hams during aging

Eight treatments of edible coatings and nets including liquid smoke (SP and 24P) and xanthan gum (XG) were used to evaluate their effectiveness at controlling mite growth on dry-cured hams. Mite growth was controlled (P < 0.05) in both coating and netting treatments of 1% SP + 1% XG. Increasing SP concentration from 1% to 2% in the SP only treatments without XG did not control mite growth (P > 0.05) in the coating but controlled mite growth (P < 0.05) when infused in the nets. Both coating and netting treatments with 2% 24P + 1% XG controlled mite growth (P < 0.05), and ham cubes with 1% and 2% 24P in infused nets had mite numbers of 4.6 and 9.4, respectively. SP did not impact the sensory attributes of the ham. Results indicate that liquid smoke can potentially be added in coatings or ham nets to control mites and used in an integrated pest management program for dry-cured hams.

The effects of ageing treatment on bioactive contents and chemical composition of liquid smoke food flavourings

Liquid smoke food flavouring is an alternative to traditional food smoking. Ageing treatment of liquid smoke can remove tar to improve a consistent sensory experience but traditionally takes months by storage. This study proposed a thermal treatment approach to accelerate the ageing process. Liquid smoke samples from kānuka and hickory woodchips were prepared by fast pyrolysis. The obtained liquid smoke samples were subjected to ageing by storing them at ambient temperature for 18 months. Accelerated ageing of liquid smoke was carried out by heat treatment at 80 °C for 24 and 48 h. Tar formed during the ageing process, with a yield ranging from 2.2 to 4.1 wt.%. Both ageing treatments resulted in decreases in bioactive content and their activities in terms of total phenolic content (TPC), total flavonoid content (TFC), ferric reducing antioxidant power assay (FRAP) and 2,2-diphenyl-1-picrylhydrazyl scavenging activity (DPPH). Chemical composition and principal component analyses indicated that liquid smoke chemical compositions were influenced by wood type and ageing conditions. It was found that thermal treatment at 80 °C for 24 h was sufficient to age liquid smoke.