Effect of Initial Headspace O2 Level on the Growth and Volatile Metabolite Production of Leuconostoc Mesenteriodes and the Microbial and Sensorial Quality of Modified Atmosphere Packaged Par-Fried French Fries.

This study evaluated the effect of residual O2 level (0% to 5%) on microbial growth and volatile metabolite production on par-fried French fries packaged in a modified atmosphere with 60% CO2 (rest N2 ) at 4 °C. The results obtained showed that the initial headspace (IH) O2 level had an effect on growth of Leuconostoc mesenteroides on French fry simulation agar, whereby growth was slightly faster under 5% O2 . In terms of quantity, ethanol, 2-methyl-1-propanol, and dimethyl disulphide were the most significant volatile metabolites produced by L. mesenteroides. The production of ethanol by L. mesenteroides was highest on simulation agar packaged under low IH O2 levels (0% to 1%), indicating that the fermentative metabolism was induced under these conditions. In agreement with the results observed on the simulation medium, growth of native lactic acid bacteria was faster under an IH O2 level of 5%. In addition, ethanol, 2-methyl-1-propanol, and dimethyl disulphide were also quantitatively the most important volatile metabolites. However, in contrast, greater quantities of ethanol and dimethyl disulphide were produced on par-fried French fries packaged under 5% O2 . This was attributed to the limited growth of the native flora on the par-fried French fries under residual O2 levels of 0% and 1%. Although some significant differences (P < 0.05) occurred between the French fries packaged in 0%, 1%, and 5 % residual O2 during storage, all products were considered to be acceptable for consumption. The results of this study can be used to optimize the shelf-life of packaged chill stored potato products.

Implementation of acrylamide mitigation strategies on industrial production of French fries: challenges and pitfalls.

This study evaluated various additives or process aids on the industrial production of French fries, based on their acrylamide mitigation potential and other quality parameters. The application of acetic and citric acid, calcium lactate and asparaginase was investigated on the production of frozen par-fried French fries at the beginning and end of the 2008 and 2009 potato storage season. Despite the fact that some of these treatments significantly reduced acrylamide content of the final product in preliminary laboratory experiments, their application on the industrial production of French fries did not result in additional acrylamide reductions compared to the standard product. Asparaginase was additionally tested in a production line of chilled French fries (not par-fried). Since for this product a longer enzyme-substrate contact time is allowed, a total asparagine depletion was observed for the enzyme treated fries after four days of cold storage. French fries upon final frying presented acrylamide contents below the limit of detection (12.5 µg kg⁻¹) with no effects on the sensorial properties of the final product.