Filled hydrogel particles as a delivery system for n-3 long chain PUFA in low-fat frankfurters: Consequences for product characteristics with special reference to lipid oxidation.

This article examines the suitability of filled hydrogel particles for use as a delivery system for n-3 long chain PUFAs in low-fat frankfurters. Their effects on product characteristics over chilled storage were compared with those of frankfurters containing all-pork fat (control) or a comparable amount of fish oil (n-3 LCPUFA) incorporated in liquid form or in an oil-in-water emulsion. In modified samples n-3 fatty acids ranged between 801.34 to 996.37 mg/100g as opposed to 66 mg/100g in all-pork fat product. As compared with the control, hardness and chewiness values were similar (P>0.05) in filled hydrogel frankfurter. The presence of fish oil favoured lipid oxidation to varying degrees depending on delivery system, in descending order: direct oil addition>oil-in-water emulsion>hydrogels. Sensory evaluation demonstrated the advantages, from a sensory point of view, of hydrogel filled particles as n-3 delivery systems in frankfurters.

Oxidative stability of n-3 fatty acids encapsulated in filled hydrogel particles and of pork meat systems containing them.

The effect of storage time (2°C, 19 days) and heating (70°C, 30 min) on physical characteristics and oxidative stability of fish oil encapsulated in filled hydrogel particles was determined and compared with a conventional oil-in-water (O/W) emulsion with the same oil content (8.5%). Subsequently they were used to enrich meat systems with n-3 LCPUFAs, and their lipid oxidation was evaluated and compared with two other meat systems: one containing all animal fat and another with fish oil added directly. Filled hydrogel particles were more effective in lowering the oxidation rate than O/W emulsion, even when thermal treatment was applied. Oxidative stability over the storage time was best in the n-3 LCPUFA-enriched meat system containing filled hydrogel particles, in which TBARS levels were up to 62% lower than other systems containing fish oil. Hydrogel particles offer a promising means of controlling lipid oxidation in n-3 LCPUFA-enriched meat products.

Konjac-based oil bulking system for development of improved-lipid pork patties: technological, microbiological and sensory assessment.

Improved-lipid pork patties were manufactured following two different reformulation strategies: fat reduction by replacement of pork backfat with konjac gel (KG), and fat reduction/lipid improvement by replacement of pork backfat with an improved oil combination (olive, linseed and fish oils) bulking system based on konjac gel (O-KG). Technological, microbiological and sensory properties were analyzed as affected by the type of formulation and by chilled storage (9days, 2°C). Fat was reduced by between 30 and 86%. In the cases where O-KG was incorporated, 12 and 41% of total fat in patties came from the oil combination. There was no observable effect on color parameters in samples with O-K. Higher KG levels produced harder cooked patties. Animal fat replacement in patties promoted an increase in lipid oxidation, which was more pronounced in samples with an oil combination. In general, during chilled storage no major changes were observed in the studied properties as a result of the different treatments.

Effect of cooking method on the fatty acid content of reduced-fat and PUFA-enriched pork patties formulated with a konjac-based oil bulking system.

The effect of cooking methods (electric grilling and pan-frying in olive oil) on the composition of reduced-fat and reduced-fat/PUFA enriched pork patties was studied. Fat reduction was performed by replacing pork backfat (38% and 100%) with konjac gel and PUFA-enrichment by replacing pork backfat (49%) with a konjac-based oil bulking system stabilizing a healthier oil combination (olive, linseed and fish oils). Cooking losses (13%-27%) were affected (p<0.05) by formulation and cooking procedure. Compared with raw products, cooked samples had higher (p<0.05) concentrations of MUFAs and PUFAs (both n-3 and n-6); the difference was greater (p<0.05) in the pan-fried patties. Fatty acid retention was generally better in pan-fried than in grilled samples. When cooked, the PUFA levels in the medium-fat/improved sample containing the oil bulking system ranged between 1.4 and 1.6g/100g (0.47-0.51 from n-3 PUFAs), with EPA+DHA concentrations of around 75mg/100g. Konjac materials were successfully used to produce pork patties with a better lipid composition.

Antioxidant activity of hydroxytyrosol in frankfurters enriched with n-3 polyunsaturated fatty acids.

The capacity of hydroxytyrosol (HXT) to inhibit lipid oxidation in cooked pork meat batter, oil-in-water emulsions and potential functional frankfurters formulated with a healthier oil combination (as animal fat replacer) was studied during chilling storage, and its effect compared with those produced by synthetic antioxidants (BHA/BHT). Although efficiency varied, HXT was an effective antioxidant during chilling storage in the three food matrices studied. In general the order of inhibition capacity of HXT against lipid oxidation (thiobarbituric acid-reactive substances-TBARS) was cooked meat batter>oil-in-water emulsion>frankfurters, whereas in the case of BHA/BHT (with lower inhibitory activity than HXT) it was cooked meat batter>oil-in-water emulsion, and there was no antioxidative effect in frankfurters. Whereas significant correlations were established between lipid oxidation (TBARS) and antioxidative capacity measured by photochemiluminescence (PCL) in frankfurters supplemented with HXT and BHA/BHT, no significant correlations were found between ferric reducing/antioxidant power assay (FRAP) and TBARS and PCL.