Different levels of animal fat replacement by a high omega-3 content carrageenan gelled emulsion in dry fermented sausages were studied in order to improve their fatty acid composition. Percentages of fat replacement were 26.3% (SUB1), 32.8% (SUB2) and 39.5% (SUB3). α-linolenic acid (ALA) content increased up to 1.81, 2.19 and 2.39g/100g (SUB1, SUB2, and SUB3 products) as compared to the Control (0.35g/100g), implying an increment in polyunsaturated fatty acids (PUFA) supply (up to 10.3%) and reductions in omega-6/ omega-3 ratio (75, 82 and 84%, respectively). Peroxides and TBARs values were not affected (P>0.05) by the fat modification and a slight low formation of volatile aldehydes derived from lipid oxidation was detected. Fat replacement did not cause relevant modifications on the instrumental color properties and no sensory differences (P>0.05) were found between Control and SUB2 products (32.8%) for taste and juiciness, pointing out the viability of this formulation for human consumption.

The effect of storage temperature (65°C, 48 hours) on the oxidative stability of a food-grade water-in-oil-in-water (W/O/W) emulsion was studied by comparison with an oil-in-water (O/W) emulsion. The emulsions were prepared with linseed oil or olive oil, and in each case, two antioxidants were evaluated, an aqueous Melissa lyophilized extract and BHA. Emulsions were characterized using brightfield light microscopy and the oxidation was monitored by measuring the lipid hydroperoxides, thiobarbituric acid reactive substances (TBARS),

1The optimization of a gelled oil-in-water emulsion was performed for use as fat replacer 2 in the formulation of -3 PUFA-enriched cooked meat products. The linseed oil 3 content, carrageenan concentration and surfactant-oil ratio were properly combined in a 4 surface response design for maximizing the hardness and minimizing the syneresis of 5 the PUFA delivery system. The optimal formulation resulted in a gelled emulsion 6 containing 40 % of oil and 1.5 % of carrageenan, keeping a surfactant-oil ratio of 0.003. 7The gel was applied as a partial fat replacer in a Bologna-type sausage and compared to 8 the use of an O/W emulsion also enriched in -3. Both experimental sausages 9 contributed with higher -3 PUFA content than the control. No sensory differences 10 were found among formulations. The selected optimized gelled oil-in-water emulsion 11 was demonstrated to be a suitable lipophilic delivery system for -3 PUFA compounds 12 and applicable in food formulations as fat replacer. 13

No abstract

The oxidative stability of seven oils with different fatty acid profiles was assessed.Oxidation at 0, 2 and 4h at 180ºC was monitored by measuring the absorbance of thiobarbituric acid reactive substances (TBARS) along the absorption spectrum (300-600 nm), the volatile aldehydes (HS-SPME-GC-MS) and the fatty acid profile (FID-GC).TBARS absorption spectrum behavior depended on the lipid composition of heated oils.Higher absorbance increments during heating were noticed at 390 nm compared to 532 nm (from 2 to 21 fold higher depending on the oil), pointing to its better sensitivity to detect oxidation. Furthermore, a close relationship between ABS 390 , the loss of

A water and an acetone extract of the Icelandic brown algae Fucus vesiculosus were evaluated as potential natural sources of antioxidant compounds in skin care emulsions. To assess their efficacy in inhibiting lipid oxidation caused by photo-or thermoxidation, they were stored in darkness and room temperature as control conditions, and compared to samples stored under accelerated conditions (light and room temperature, or darkness and 40°C). The presence of extracts in the skin care emulsions induced remarkable colour changes when the emulsions were exposed to light, and more extensively under high temperature. High temperature also caused greater increments in the droplet size of the emulsions. The analysis of the tocopherol content, peroxide value and volatile compounds during the storage revealed that, whereas both water and acetone extracts showed (at 2 mg/g of emulsion) protective effect against thermooxidation, only the water extract showed antioxidant activity against photooxidation.Practical applications: This research is the basis of developing natural antioxidants derived from seaweed to limit lipid oxidation in skin care products.

The characteristics of the lipid matrix surrounding sterols exert a great influence in their thermal oxidation process. The objective of this work was to assess the oxidation susceptibility of equal amounts of cholesterol and stigmasterol within a sunflower oil lipid matrix (ratio 1:1:200) during heating (180 ºC, 0 to 180 min). Remaining percentage of sterols was determined and seven sterol oxidation products (SOPs) were analyzed for each type of sterol along the heating treatment. Evolution of the fatty acid profile and vitamin E content of the oil was also studied. Overall oxidation status of the model system was assessed by means of Peroxide Value (PV) and TBARS. PV remained constant from 30 min onwards and TBARS continued increasing along the whole heating treatment.Degradation of both cholesterol and stigmasterol fitted a first order curve (R 2 = 0.937 and 0.883, respectively), with very similar degradation constants (0.004 min -1 and 0.005 min -1 , respectively). However, higher concentrations of oxidation products were found from cholesterol (79 µg/mg) than from stigmasterol (53 µg/mg) at the end of the heating treatment. Profile of individual oxidation products was similar for both sterols, except for the fact that no 25-hydroxystigmasterol was detected. 7α-hydroxy and 7-ketoderivatives were the most abundant SOPs at the end of the treatment. PUFA and vitamin E suffered a significant degradation along the process, which was correlated to sterols oxidation.

Gelled emulsions with carrageenan are a novel type of emulsion that could be used as a carrier of unsaturated fatty acids in functional foods formulations. Lipid degradation through volatile compounds was studied in gelled emulsions which were high in polyunsaturated oils (sunflower or algae oil) after 49 days of storage. Aqueous extract was tested as a natural antioxidant. Analysis of the complete volatile profile of the samples resulted in a total of 40 compounds, classified in alkanes, alkenes, aldehydes, ketones, acids, alcohols, furans, terpenes and aromatic hydrocarbons. During storage, the formation of the volatile compounds was mostly related to the oxidation of the main fatty acids of the sunflower oil (linolenic acid) and the algae oil (docosahexaenoic acid). Despite the antioxidant capacity shown by the extract, its influence in the oxidative stability in terms of total volatiles was only noticed in sunflower oil gels ( < 0.05), where a significant decrease in the aldehydes fraction was found.