Prediction of critical times for water-extracted avocado oil heated at high temperatures

Vegetable oils are used in various cooking processes. However, when they are heated at high temperature and/or for a long period, chemical reactions can generate damaging substances for the health. The aim of the study was to predict the critical times at high temperatures of avocado oil. A four-level two-variable Central Composite Design was used to model the thermal oxidation of avocado oil extracted using the aqueous method. Temperature (120 – 180 °C) and time (11 – 209 min) were the independent variables. The response variable was the content in total polar compounds (TPC) with an upper limit defined at 25% (w/w). The composition and the oxidative status of fresh avocado oil were also investigated. The results obtained by a multiple regression analysis showed that data can be fitted with a second order polynomial equation (R2 = 0.98, Adj. R2 = 0.97) with all regression coefficients being significant (p < 0.05). The critical heating time ranged from 232 min to 214 min between 120 °C-140 °C and from 188 min to 4 min between 140 °C-180 °C. It was influenced by avocado oil composition. Thus, water-extracted avocado oil is not recommended for frying (140 °C – 180 °C) while it can be used for recipes involving long cooking time at moderate temperature (120 °C-140 °C)

Ginger powder protects soybean oil from oxidative degradations especially vitamin E during intermittent frying of plantain chips

This study aimed at evaluating the potential of ginger powder to improve the oxidativestability of soybean oil during intermittent frying of plantain chips. Plantain slices werefried in soybean oil with and without 15 g/l of ginger powder.The oils sampled during 5days of intermittent frying were analyzed for total polar compounds, conjugamalondialdehyde, vitamin E and fatty acid composition. The results showed that thepresence of ginger limited the oxidative deteriorations. Based on comparison of the resultsof the two types of frying, the formation of total polar compounds, conjugated dienesmalondialdehyde, were reduced respectively by 26.9%, 12.5% and 2.6%while up to 42.4%of vitamin E, and 39 % polyunsaturated fatty acids were preserved. So, the use of gingerpowder during intermittent frying of plantain chips could be an nutritional quality of soybean oils

Meat processing and colon carcinogenesis: Cooked, nitrite-treated and oxidized high-heme cured meat promotes mucin depleted foci in rats

Processed meat intake is associated with colorectal cancer risk, but no experimental study supports the epidemiologic evidence. To study the effect of meat processing on carcinogenesis promotion, we first did a 14-day study with 16 models of cured meat. Studied factors, in a 2 × 2 × 2 × 2 design, were muscle color (a proxy for heme level), processing temperature, added nitrite, and packaging. Fischer 344 rats were fed these 16 diets, and we evaluated fecal and urinary fat oxidation and cytotoxicity, three biomarkers of heme-induced carcinogenesis promotion. A principal component analysis allowed for selection of four cured meats for inclusion into a promotion study. These selected diets were given for 100 days to rats pretreated with 1,2-dimethylhydrazine. Colons were scored for preneoplastic lesions: aberrant crypt foci (ACF) and mucin-depleted foci (MDF). Cured meat diets significantly increased the number of ACF/colon compared with a no-meat control diet (P = 0.002). Only the cooked nitrite-treated and oxidized high heme meat significantly increased the fecal level of apparent total N-nitroso compounds (ATNC) and the number of MDF per colon compared with the no-meat control diet (P < 0.05). This nitrite-treated and oxidized cured meat specifically increased the MDF number compared with similar non nitrite-treated meat (P = 0.03) and with similar non oxidized meat (P = 0.004). Thus, a model cured meat, similar to ham stored aerobically, increased the number of preneoplastic lesions, which suggests colon carcinogenesis promotion. Nitrite treatment and oxidation increased this promoting effect, which was linked with increased fecal ATNC level. This study could lead to process modifications to make non promoting processed meat

Multiscale structures of lipids in foods as parameters affecting fatty acid bioavailability and lipid metabolism.

This review is respectfully dedicated to the memory of Michel Ollivon, Research Director at CNRS (Châtenay-Malabry, France), outstanding physico-chemist specialist of lipid organization, recipient of the Hilditch Memorial Lecture award, who was the initiator of the network RMT LISTRAL. We are also sadly paying tribute to Jean-Luc Vendeuvre, Food Engineer at the French Pork and Pig Institute (IFIP, Maisons-Alfort, France), outstanding expert in meat products who participated actively in RMT LISTRAL and provided unpublished data for figures in the present review, who passed away during review submission. RMT LISTRAL: Mixed Technological Network combining academic and industrial partners, devoted to the enhancement and divulgation of knowledge regarding structured dietary lipids.International audienceOn a nutritional standpoint, lipids are now being studied beyond their energy content and fatty acid (FA) profiles. Dietary FA are building blocks of a huge diversity of more complex molecules such as triacylglycerols (TAG) and phospholipids (PL), themselves organised in supramolecular structures presenting different thermal behaviours. They are generally embedded in complex food matrixes. Recent reports have revealed that molecular and supramolecular structures of lipids and their liquid or solid state at the body temperature influence both the digestibility and metabolism of dietary FA. The aim of the present review is to highlight recent knowledge on the impact on FA digestion, absorption and metabolism of: (i) the intramolecular structure of TAG; (ii) the nature of the lipid molecules carrying FA; (iii) the supramolecular organization and physical state of lipids in native and formulated food products and (iv) the food matrix. Further work should be accomplished now to obtain a more reliable body of evidence and integrate these data in future dietary recommendations. Additionally, innovative lipid formulations in which the health beneficial effects of either native or recomposed structures of lipids will be taken into account can be foreseen

Alteraciones en las carnes congeladas

International audienc

Alteraciones en las carnes congeladas

International audienc

Concept de produit et réalités concurrentielles: essai d'application au marché de l'essence à Sherbrooke

La théorie économique néoclassique date du dix-neuvième siècle, les fondements du marketing du vingtième siècle; la première semble dépassée par les phénomènes contemporains qu'elle prétend régir, la seconde apparaît trop parcellaire pour donner naissance à une authentique théorie. L'une vénère inutilement le passé, l'autre ignore délibérément ce qui l'a précédée. De cette situation découle un gaspillage auquel il semble essentiel de mettre un terme. La présente recherche tente, en traitant du concept de produit, de montrer qu'une conciliation est possible et, mieux encore, qu'elle est fondamentalement souhaitable. Un nouveau concept de produit, à quatre volets, est proposé et il est montré qu'il peut tout aussi bien être accepté par les économistes que rallier les suffrages des hommes de marketing. Ce nouveau concept, appliqué au marché de l'essence, semble à même, au vu des résultats empiriques, de rendre compte de la réalité telle qu'elle peut être observée. Ainsi, l'essence ou plutôt le produit de la pompe à essence présenterait un caractère multidimensionnel à même d'expliquer pourquoi le prix, pour important qu'il soit, est cependant insuffisant pour expliquer le volume d'essence vendu par une pompe et comment d'autres éléments ajoutés au prix permettent d'atteindre un pouvoir prédictif incomparablement supérieur. Toutefois, les résultats obtenus ici sont encore trop partiels pour se risquer à une généralisation