Mora L.,University of Milan |
Limbo S.,University of Milan |
Maiocchi P.,Velp Scientifica Srl
Italian Journal of Food Science | Year: 2011
Lipid oxidation is one of the most serious problems occurring during storage of fatty foods, causing a shortage of their shelf-life. In order to predict the shelf life, food industry is very interested in easy, quick and reliable solutions able to estimate the oxygen sensitivity of a product. The degree of lipid oxidation can be measured by physical or chemical methods (i.e. peroxide value -PV) as well as stability tests, which measure the stability of a fatty food under conditions that attempt to accelerate the normal oxidation process. In the field of accelerated shelf-life testing, Oxitest permits food stability to be investigated: it is based on the absolute pressure change in a closed and thermostatted chamber, assumed as the oxygen uptake by reactive substances. The aim of the present study was firstly the assessment of the Oxitest ability to discriminate the growing oxidation degree of soybean oil at different temperatures and secondly to verify the existence of correlation between a common method such as PV and a more innovative accelerated technique like Oxitest. Soybean oil samples were stored at growing temperatures: the evolution of the oxidation was monitored during time by analyzing the samples by both Oxitest and PV. The increase of PV and decrease of the Induction Period (IP) values followed a zero order kinetic at all the different temperatures tested. On consequence the reaction rate constant (k) for each temperature, the Arrhenius parameters and the Q10 index were estimated. The degree of correlation between the two techniques was also evaluated pointing to the Oxitest method as a reliable alternative to classic methods.
Cavazza A.,University of Parma |
Corti S.,Velp Scientifica Srl |
Mancinelli C.,Velp Scientifica Srl |
Bignardi C.,University of Parma |
Corradini C.,University of Parma
JAOCS, Journal of the American Oil Chemists' Society | Year: 2015
Red chili pepper represents an excellent source of functional bioactive compounds, and its use as food additive could be useful for protecting other products from spoilage. Olive oils show a limited shelf-life due to a progressive quality deterioration linked mostly to oxidation reactions providing a loss of quality in terms of organoleptic and healthy properties. In this work, the addition of red chili pepper powder to virgin, extra-virgin olive and sunflower oils was proved to be effective in improving their stability during 12 months of shelf-life. Oil stability was monitored by employing the Oxitest system, based on accelerating the oxidation process. Three pepper powders of different pungency were added to the virgin olive oil samples with the aim of investigating whether capsaicinoids could be responsible for the observed effects. The strongest effect was recorded when employing the less pungent pepper showing that the protective effect could not be attributed to the capsaicinoids content. Besides, a screening on different oils demonstrated that the less stable samples received a stronger protective effect. The evaluation of a possible dose-effect relation was also carried out pointing out that a threshold dose of about 1 % was required to record an effect. The results suggest potential perspectives in the field of food technology, as addition of a small amount of sweet pepper could be proposed to prolong food shelf-life. © 2015 AOCS.
Verardo V.,University of Bologna |
Riciputi Y.,University of Bologna |
Sorrenti G.,University of Bologna |
Ornaghi P.,VELP Scientifica srl |
And 2 more authors.
LWT - Food Science and Technology | Year: 2013
The influence of nitrogen (N) fertilisation on the content of lipids and phenolic compounds in walnut kernels (cv. Chandler) has studied for three consecutive growing years. Moreover, a new technique (OXITEST) was set up to analyse the oxidative stability of the kernel directly from the whole sample. Significant differences in the fatty acid composition were observed, and linoleic acid was the main fatty acid present. N fertilisation reduced the oleic acid content relative to the control. High amounts of N increased the linoleic acid content and reduced the linolenic acid content. On the other hand, the control and the lower N fertilised samples had the highest levels of n-3 fatty acids. Comparing control and fertilised samples, there were no statistical differences in the sterol and tocopherol compositions (with the exception of α-tocopherol). With regard to phenolic content, N fertilisation had a significant negative effect on the phenolic compounds in walnut kernel samples. The OXITEST technique confirmed that the oxidative stability of kernels was related to the fatty acid composition and the PUFA (polyunsaturated fatty acid) content. © 2012 Elsevier Ltd.