[Ed. 12/2002 -This is an extremely strange report: Chocolate has anti-oxidants also as probably most plant material could have. Chocolate might be an even better and cleaner heating fuel, but do sane people want to use it? This report focuses on anti-oxidants but seem not to take into account the deadly fine particulate and gases that are emitted from all wood burning. Ms Kjallstrand seems in favor of wood as a cooking fuel and heating fuel. We presume Ms. Kjallstrand has measured this new technology in the field? She has extracted her magic protective bullets with syringes, they are not human lungs subject to the scaring and severe inflammation that wood smoke does elicit. How much benzene or dioxin is a 'safe' amount. Excuse me, we could have to have the body do the math. Poison + poison + carcinogens + fine particulate + current age + current health - all those antioxidants! Voila - wood smoke is wonderful again. This paper has been seized upon by even government scientists who love wood smoke.]
1: Sci Total Environ 2001 Sep 28;277(1-3):69-75
Phenolic antioxidants in wood smoke.
Kjallstrand J, Petersson G.
Department of Chemical Environmental Science, Chalmers University
of Technology,
Goteborg, Sweden.
Ten prominent dimethoxyphenols were determined in birchwood smoke from choked and open laboratory burning and in chimney smoke from a tiled stove. The structures of the methoxyphenols are similar to those of the well-known tocopherol and ubiquinol antioxidants. The 2,6-dimethoxyphenols characterizing hardwood smoke are stronger antioxidants than the corresponding 2-methoxyphenols present mainly in softwood smoke. The antioxidant activity is highest for the 2,6-dimethoxyphenols with 4-alkenyl and 4-alkyl groups, which constitute 60-70% of the total amount of dimethoxyphenols. Phenolic antioxidants are scavengers of oxygen radicals and should be considered when health hazards of small-scale incomplete biomass burning are estimated.
PMID: 11589408 [PubMed - indexed for MEDLINE]
Subject: Phenolic Antioxidants in Wood Smoke (http://www2.lib.chalmers.se/cth/diss/doc/0
Date: Mon, 2 Dec 2002 1
Phenolic Antioxidants in Wood Smoke : Chalmers dissertations
Jennica Kjällstrand
School of Chemical and Biological Engineering, Department of Chemical
Environmental Science Postgraduate Programme in Bioscience, 2002
Smoke from residential wood burning constitutes a complex mixture
of organic compounds with varying environmental and health effects.
This thesis focuses on antioxidants and aromatic hydrocarbons
emitted from small-scale burning. Smoke samples were collected
from laboratory experiments and in chimney outlets from stoves,
using gas-tight syringes or adsorbent cartridges. Specific components
were assessed by gas chromatography and mass spectrometry.
Primary thermal decomposition products from cellulose and lignin
constituted a large part of the organic fraction from incomplete
combustion of wood. The lignin-related methoxyphenols are, due
to their varying chemical structures, more or less effective antioxidants.
Smoke from hardwood burning contained the more efficient 2,6-dimethoxyphenols,
whereas softwood smoke almost only contained 2-methoxyphenols.
An alkenyl or alkyl side-chain renders the antioxidant stronger,
while a carbonyl group reduces the effect. The presence of phenolic
antioxidants should be considered when the health hazards of wood
smoke are estimated. Antioxidative 2,6-dimethoxyphenols were the
predominant aromatic compounds in smoke from birchwood burning
as well as from low-temperature pyrolysis of alder chips, used
for meat curing. They improve both the taste and the quality of
the foods. [ ?Ed. I have lost my 'taste' for smoked foods I feel
like I am becoming smoked meat myself]. Incomplete combustion
of newsprint released coniferyl alcohol as the major methoxyphenol.
Newsprint is often used to set wood on fire.
Methoxyphenols as well as 1,6-anhydroglucose from cellulose were
released at inefficient burning. These compounds appear mainly
condensed on particles at ambient temperatures. On more efficient
burning, the total amount of organic compounds decreased in the
smoke. However, the proportion of the hazardous polycyclic aromatic
compounds increased. The carcinogenic benzene was assessed
as a prominent aromatic compound in smoke from all studied types
of biomass burning, although the ratio to other organic compounds
increased with the combustion temperature.
A comparison was made between smoke from a tiled stove and a conventional
wood boiler. Stove burning released methoxyphenols and 1,6-anhydroglucose,
while the boiler emitted large proportions of benzene and polycyclic
aromatic compounds. Oxidative pyrolysis of wood pellets released
methoxyphenol antioxidants from the flaming combustion phase.
Benzene was the predominant aromatic compound from glowing
pellets. New available technology for residential wood burning,
including wood pellets and eco-labelled boilers, drastically decreases
the emissions of antioxidants as well as hazardous aromatic hydrocarbons
through highly efficient combustion.
Keywords: methoxyphenols, biomass, wood, lignin, smoke, combustion,
antioxidants, benzene
( jennica kjallstrand )