Acrylamide in fried and roasted potato products: a review on progress in mitigation.

The workshop of the European Commission and the Confederation of the Food and Drink Industries of the European Union (CIAA) held in March 2006 in Brussels, Belgium, discussed the key knowledge and achievements in the mitigation of acrylamide. This paper presents the progress made by the potato sector and identifies areas for future research. Because of the important contribution of potato products to acrylamide intake, it is an area that has received much attention. The discovery of the method of formation and the role of reducing sugars meant that long-standing knowledge in respect of sugar and fry colour could be used to identify methods of mitigation. Improvement in parameters such as (1) potato variety, (2) potato storage temperature, (3) process control (thermal input, pre-processing), (4) final preparation, and (5) colour have all contributed to a significant overall reduction in the average acrylamide content in French fries and potato crisps (termed 'chips' in the USA). There is evidence that the limit of reduction that these measures can offer for crisps has now been approached, but clearly more can be done for French fries and roasted potato products. The use of asparaginase offers potentially significant reduction in certain prefabricated potato products. More research is required into new potato varieties and the agronomical factors that influence the levels of asparagine and sugars in potatoes.

A study of cyanide-insensitive respiration in the genus Dekkera and Brettanomyces.

Dekkera intermedia and Brettanomyces custersii were shown to have a respiratory pathway resistant to cyanide, antimycin A, and azide. This respiration remained sensitive to salicylhydroxamic acid (SHAM). The "cyanide-resistant" respiration was induced mainly at the end of the growth phase and could reach 50% of total respiratory capacity. The mitochondrial "petite colony" mutation had no effect on this oxidation pathway. The presence of this respiration pathway in these strains constitutes a compensation mechanism for the reducing activity of acetaldehyde dehydrogenase. This alternate pathway would thus be a fundamental element of the Custer effect, a characteristic feature of these strains.

Fermentation of cellodextrins by different yeast strains.

The fermentation of cellodextrins by eight yeast species capable of fermenting cellobiose was monitored. Only two of these species, Torulopsis molischiana and T. wickerhamii, were able to ferment beta-glucosides with a degree of polymerization between one and six. These two species showed exocellular beta-glucosidase activity. Four other species were able to ferment cellotriose, and the last two species only fermented cellobiose. These latter six species produced a beta-glucosidase capable of attacking cellodextrins, but this enzyme was endocellular.