The consumption of alcoholic beverages has been classified as carcinogenic to humans by the International Agency for Research on Cancer (IARC) since 1988. More recently, in 2010, ethanol as the major constituent of alcoholic beverages and its metabolite acetaldehyde were also classified as carcinogenic to humans. Alcoholic beverages as multi-component mixtures may additionally contain further known or suspected human carcinogens as constituent or contaminant. This review will discuss the occurrence and toxicology of eighteen carcinogenic compounds (acetaldehyde, acrylamide, aflatoxins, arsenic, benzene, cadmium, ethanol, ethyl carbamate, formaldehyde, furan, glyphosate, lead, 3-MCPD, 4-methylimidazole, N-nitrosodimethylamine, pulegone, ochratoxin A, safrole) occurring in alcoholic beverages as identified based on monograph reviews by the IARC. For most of the compounds of alcoholic beverages, quantitative risk assessment provided evidence for only a very low risk (such as margins of exposure above 10,000). The highest risk was found for ethanol, which may reach exposures in ranges known to increase the cancer risk even at moderate drinking (margin of exposure around 1). Other constituents that could pose a risk to the drinker were inorganic lead, arsenic, acetaldehyde, cadmium and ethyl carbamate, for most of which mitigation by good manufacturing practices is possible. Nevertheless, due to the major effect of ethanol, the cancer burden due to alcohol consumption can only be reduced by reducing alcohol consumption in general or by lowering the alcoholic strength of beverages.

As a basis for sodium reduction, interactions between sodium and wheat bread ingredients and their impact on salt perception in bread crumb were examined. The theoretical sodium binding capacities of wheat proteins revealed that a maximum amount of 0.24% NaCl (based on flour) could be bound in bread crumb by ionic interactions between sodium ions and acidic amino acid side chains. However, the sodium binding capacities of wheat proteins, determined by a magnetic beads assay and a sodium-selective electrode, were only about 0.002% NaCl. They were negligible concerning the sensory perception of saltiness, as 0.075 and 0.3% NaCl were the lowest noticeable differences using bread containing 0 and 1% NaCl as a reference, respectively. Extracting bread crumb in a mastication simulator with ultrapure water, buffer solutions, and artificial and human saliva revealed that interactions between sodium and wheat bread ingredients were sufficiently weak to enable complete sodium extraction during simulated mastication.

As a basis for sodium reduction in bread, the kinetics of sodium release from wheat bread crumb during chewing was investigated by three independent methods using two in-mouth techniques and a model mastication simulator, respectively. Complete sodium extraction in-mouth was achieved after 30 s. Using coarse-grained NaCl in breadmaking significantly accelerated sodium release and led to enhanced salt taste, allowing a sodium reduction in bread by 25% while maintaining taste quality. This salt taste enhancement by accelerated sodium delivery can be explained by the increasing contrast in sodium concentration, which is known to determine salt taste perception. For the first time, the resulting inhomogeneous salt distribution in bread prepared by using coarse-grained NaCl was visualized by means of confocal laser scanning microscopy using a sodium-selective, fluorescent dye.

As a basis for sodium reduction in bread, the influence of crumb texture on the intensity of saltiness and the release of sodium ions during chewing was investigated. A coarse-pored bread crumb was created by extending the proofing time (90/120 min vs 20/40 min as control), whereas the omission of proofing resulted in a fine-pored crumb (0/0 min). A significantly faster sodium release from the coarse-pored bread compared to the fine-pored bread (constant sample weight) was measured in-mouth and in a mastication simulator. This explained the significantly enhanced salty taste of the 90/120 min bread. Corresponding experiments with constant sample volumes revealed a significantly enhanced saltiness despite similar amounts of extracted sodium during the first seconds of chewing. Therefore, saltiness was influenced both by the velocity of sodium release and by crumb texture. Appropriate modification of crumb texture thus leads to enhanced saltiness, suggesting a new strategy for salt reduction in bread.

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