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The effect of permitted antioxidants, including α-tocopherol, β-carotene, ascorbyl palmitate, ascorbic acid, citric acid, and their combinations, on the lipid oxidation of structured lipid (SL)-based infant formula (IF) was evaluated. The 3.5% oil-in-water IF emulsion was formulated with a human milk fat analogue enriched with docosahexaenoic acid and stearidonic acid, and the antioxidants were added at 0.005% and 0.02% of the oil. The peroxide value, anisidine value, and hexanal concentration of emulsion samples were measured over a 28-day period. The results showed that whether a compound exhibited antioxidant behavior depended on its mechanism of action, polarity, concentration, and environmental conditions. The most effective antioxidant was ascorbyl palmitate at 0.005%, and a synergistic antioxidant effect was found between α-tocopherol and β-carotene. A high correlation was observed between anisidine value and hexanal content. Our findings have important implications for the successful incorporation of SL into IF products for infant nutrition and health. [ABSTRACT FROM AUTHOR]

Highlights: [•] Lipid oxidation can be a problem during fish protein hydrolysis. [•] There was a profound contradiction between cell and chemical antioxidant assays. [•] Oxidation products can have a detrimental effect on antioxidant properties of FPH. [•] Oxidation products arised during hydrolysis may affect anti-inflammatory activity in the body. [ABSTRACT FROM AUTHOR]

Highlights: [•] Influence of authentic human gastric juice on oxidation of marine lipids is evaluated. [•] Marine lipids in emulsion and liposomes oxidised during a modelled digestion period. [•] No difference was found between oxidation in an authentic gastric juice and a hydrochloric acid solution. [•] Gastric juice inhibited pro-oxidative activity of dietary iron ions, but not met-hemoglobin. [•] Beverages may both positively and negatively affect post-prandial oxidation of marine lipids. [Copyright &y& Elsevier]

Abstract: An antioxidant composite film was developed from defatted mustard meal (DMM) without incorporating external antioxidants and its applicability as a coating to smoked salmon has been investigated. Film-forming variables included the concentration of xanthan, heat treatment, and high pressure homogenisation. Tensile strength, elongation, water vapour permeability, and water solubility of composite films of DMM and xanthan were 5.1–8.8MPa, 2.9–5.0%, 1.5–2.4gmm/kPa/h/m2, and 1.1–1.6%, respectively. The composite film with xanthan at 5% (w/w) demonstrated antioxidant properties and the coating with the solution forming the composite film (5% xanthan) retarded lipid oxidation and significantly reduced volatile changes in smoked salmon during storage at 4, 10, and 20°C for 21days. Coated salmon was preferred to uncoated salmon in glossiness and fish smell. The composite coating improved the stability of smoked salmon against lipid oxidation without imparting a negative sensory quality to the salmon. [Copyright &y& Elsevier]

Abstract: Lipid oxidation and fishy odour development in protein hydrolysate from fresh and ice-stored Nile tilapia (Oreochromis niloticus) were investigated. During iced storage of 18days, heme iron content decreased with a concomitant increase in non-heme iron content (P <0.05). Peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) values increased. Phospholipid content decreased with a corresponding increase in free fatty acid content. The results suggested that lipid hydrolysis and oxidation took place during storage. When protein hydrolysates were produced from fresh and 18days ice-stored Nile tilapia muscle, higher lipid oxidation and fishy odour/flavour along with higher amount volatile compounds were obtained in hydrolysate for unfresh sample (P <0.05). However, the addition of mixed antioxidants during hydrolysis process markedly lowered lipid oxidation, b ∗, ΔC ∗, ΔE ∗ values, fishy odour/flavour as well as the formation of volatile compounds in the resulting hydrolysates prepared from both fresh and unfresh samples. Therefore, hydrolysate from Nile tilapia muscle with reduced fishy odour and lighter colour could be prepared by using fresh fish and incorporation of mixed antioxidants during hydrolysis. [Copyright &y& Elsevier]

Abstract: Marama bean (Tylosema esculentum) is an underutilised legume indigenous to the Kalahari Desert region of southern Africa. The bean has high lipid content and hence is a potential source for production of edible oil. The headspace volatile composition of freshly pressed marama bean oil was explored and the oil was further studied during 7months of storage under different light and temperature conditions. The oxidative stability of the oil was examined by measuring peroxide value, vitamin E content and FT-IR spectra. Additionally, the headspace volatile composition of the oil was investigated during storage by use of dynamic headspace GC–MS. The results showed that marama oil is highly stable and has good natural antioxidant properties; enzymatic lipid oxidation does not take place in marama oil. Light has a greater effect on the lipid oxidation than has temperature, and hence marama oil should preferably be stored in darkness and rather at 25°C than 35°C. Under these conditions, the marama oil has a shelf life of at least 7months. [Copyright &y& Elsevier]

Abstract: 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. [Copyright &y& Elsevier]

Abstract: Numerous protocols and modifications of the thiobarbituric acid (TBA) test are available in the literature. The present paper compares the effectiveness of different TBA tests in minimizing the interferences caused by the addition of phenolic-rich materials (wild fruits) as antioxidants in cooked burger patties. The aqueous acid extraction procedure (EM) and a modified distilation TBA method (DM) were tested with different conditions of incubation – boiling (B) vs. room temperature (RT) – for monitoring lipid oxidation in cooked burger patties during refrigerated storage. DM-B and DM-RT were more suitable than EM procedures for assessing TBA-reactive substances (TBA-RS) in meat samples containing compounds such as anthocyanins, with similar spectral properties than that of the TBA–malondialdehyde (MDA) adduct. Additionally, interferences caused by browning development during incubation were avoided by DM procedures or by performing RT incubations. Correlations between TBA-RS numbers and hexanal contents in cooked pork burger patties were calculated in order to corroborate the suitability of the tested TBA procedures. The DM-RT procedure showed the highest correlation with hexanal content (R 2 =0.90; p <0.001). [Copyright &y& Elsevier]

Abstract: The use of peroxide value (PV), free fatty acids (FFA), thiobarbituric acid reactive substances (TBARS) and p-anisidine value (PA) proved suitable for studying lipid hydrolysis and primary and secondary lipid oxidation in samples of Atlantic halibut throughout frozen storage. After twelve months, the FFA values in the samples packaged with the film containing natural antioxidants (extracted from barley husks) were similar to the FFA value in the control sample after 9 months. Maximum peroxide value in the samples packaged with the antioxidant-containing film was found one month after the maximum value observed in the control sample. After six months, the concentration of malondialdehyde in the control sample was approximately 30–50% higher than in samples packaged in film containing antioxidants. The results confirm the efficacy of natural antioxidants derived from barley husks and antioxidant active packaging film in slowing down lipid hydrolysis and increasing the oxidative stability of Atlantic halibut flesh. [ABSTRACT FROM AUTHOR]

Abstract: Bulk oils and oil-in-water emulsions were subjected to high hydrostatic pressure (HHP) (200, 650MPa) treatment so as to estimate the effect of applied pressures on lipid oxidation. HHP-treated and non-treated samples were left to autoxidise under accelerated conditions (2weeks, 70°C) and their oxidative status was periodically estimated by measurement of conjugated dienes and peroxide value. Total changes of thiobarbituric acid-reactive substances were recorded as additional oxidative markers for emulsions. Results showed an increase in oxidation as pressure was increased especially at 650MPa. Lipid oxidation rates that were more pronounced for HHP-treated samples can be correlated to measured dissolved oxygen that was also higher. HHP did not seem to have an effect on emulsion droplet size. The addition of Majorana syriaca (200ppm) ethyl acetate extract led to protection against lipid oxidation under HHP and atmospheric conditions, 20.9–38.7% and 28.9–43.2%, respectively. It was observed that the antioxidant effect of M. syriaca extract under HHP was weaker. [ABSTRACT FROM AUTHOR]

Abstract: Lipid oxidation of horse mackerel (Trachurus trachurus) patties covered with fish gelatin-based films containing a borage seed extract were evaluated, including commonly used analytical indexes (peroxide value, thiobarbituric acid reactive substances, polyene ratio), as well as determination of volatile compounds, quantitation of oxidized triacylglycerols and analysis by Fourier transform infrared (FTIR) spectroscopy, during 240days of frozen storage and subsequent thawing and 4days-chilling. Vacuum packaged-patties and control uncovered patties were also tested for comparative purposes. Methods applied to evaluate lipid oxidation in extracted lipids, i.e. peroxide value, quantitation of oxidized triacylglycerols and FTIR, clearly provided a better picture of the oxidation progress and led to similar conclusions. Film had protective effects on lipid oxidation of horse mackerel patties throughout frozen storage and particularly after thawing and chilled storage. Furthermore, when compared to vacuum packaging, film was found to be similarly effective until advanced stages of oxidation were reached and exerted enhanced protection once samples were thawed and exposed to air oxygen under chilling temperature; with the additional advantage of increasing the antioxidant capacity of muscle. [ABSTRACT FROM AUTHOR]

Abstract: The efficacy of a previously developed antioxidative potato protein hydrolysate (PPH) for the stabilisation of oil droplets and inhibition of lipid oxidation in soybean oil-in-water (O/W) emulsions was investigated. Emulsions (10% lipid, pH 7.0) with PPH-coated oil droplets were less stable than those produced with Tween 20 (P <0.05). However, the presence of PPH, whether added before or after homogenisation with Tween 20, retarded emulsion oxidation, showing reduced formation of peroxides up to 53.4% and malonaldehyde-equivalent substances up to 70.8% after 7-d storage at 37°C (P <0.05), when compared with PPH-free emulsions. In the emulsions stabilised by PPH+Tween 20, 8–15% of PPH was distributed at the interface. Adjustment of the pH from 3 to 7 markedly increased ζ-potential of such emulsions (P <0.05). Inhibition of lipid oxidation by PPH in soybean O/W emulsions can be attributed to both chemical and physical (shielding) actions. [Copyright &y& Elsevier]

Abstract: The present experiments were designed to study the effects of different natural antioxidants in an experimental fish feed, made directly from marine raw materials. A rosemary extract (Herbalox®) and crystalline ascorbic acid were the most effective antioxidants in this feed and the effect of ascorbic acid was enhanced by adding a tocopherol mix. Ascorbyl palmitate, citric acid, a phosphate mix designed to enhance the effect of ascorbic acid, and spermine had minor antioxidant effects, no effect or pro-oxidant effects. It was necessary to add higher concentrations of the rosemary extract than the vitamin C/E combination to obtain an optimal antioxidant effect. A minor effect of adding ethoxyquin to a diet with tocopherol mix and ascorbic acid was detected in one of the experiments, but this effect was not reproduced in the other experiments. It is therefore concluded that the diet used in the present study can be protected against oxidation using natural antioxidants. Since antioxidants must be tested in the oxidising system in which they are going to be used, the present results have to be confirmed before applying them to commercial fish feeds and feed ingredients. [Copyright &y& Elsevier]

Abstract: Antioxidative activities of different phenolic compounds (catechin, caffeic acid, ferulic acid and tannic acid) at various levels were determined by different assays. Among all the phenolic compounds tested, tannic acid exhibited the highest 2,2-diphenyl-1-picryl hydrazyl (DPPH) and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities and ferric reducing antioxidant power (FRAP). Nevertheless, catechin showed the highest metal chelating activity (P <0.05), whereas caffeic acid had the highest lipoxygenase (LOX) inhibitory activity (P <0.05). The impact of different phenolic compounds at a level of 100mg/l on lipid oxidation of menhaden oil-in-water emulsion and mackerel mince was investigated. Tannic acid showed the highest efficacy in retardation of lipid oxidation for both model systems as evidenced by the lower peroxide value (PV), conjugated diene (CD) and thiobarbituric acid-reactive substances (TBARS) values. This was also related with the lower non-heme iron content in tannic acid treated samples. Tannic acid was therefore considered as the most potential natural antioxidant for controlling oxidation of fish oil-in-water emulsion and fish mince, whereas ferulic acid seemed to possess the lowest preventive effect on lipid oxidation. [Copyright &y& Elsevier]

Abstract: In oil-in-water emulsions, the physical location of antioxidants has been postulated to be one of the most important factors impacting activity. The purpose of this research was to examine how the esterification of various hydrocarbon chains (C4, C8, or C12) onto chlorogenic acid (CGA) influenced physical properties and antioxidant activity in menhaden oil-in-water emulsions. Both surface activity and partitioning of CGA and its hydrocarbon esters into the lipid phase of oil-in-water emulsions increased with increasing size of the hydrocarbon chain. When CGA and its esters were added to a menhaden oil-in-water emulsion at concentration that resulted in equal free radical scavenging activity, CGA, butyl CGA and octyl CGA had similar antioxidant activity while dodecyl CGA was ineffective. These results suggest that phenolic antioxidants conjugated with hydrocarbon chains are more highly associated with lipid emulsions droplets, but these changes in physical properties did not increase antioxidant activity. [Copyright &y& Elsevier]

Abstract: The antioxidant effectiveness of different hydroxycinnamic acids for inhibiting the formation of off-flavours associated to rancidity in minced frozen horse mackerel white muscle stored at −10 and −18°C was studied. The influence of lipid oxidation on protein aggregation, protein denaturation and water holding capacity was also determined. Caffeic acid, o-coumaric acid and ferulic acid were the antioxidants tested. The order of antioxidant effectiveness was caffeic acid>ferulic acid> o-coumaric acid accordingly with previous results obtained in chilled horse mackerel. A strong dependence of antioxidant effectiveness to the ratio lipid/antioxidant concentration was observed. There was no evidence to suggest that antioxidants reduce protein aggregation or water holding capacity changes. Protein aggregation was not accompanied by gross protein denaturation, as monitored by differential scanning calorimetry. No evidence was found for a link between extent of lipid oxidation and degree of protein aggregation or water holding capacity changes. [Copyright &y& Elsevier]

Abstract: Grape phenolic compounds were obtained from grape (Vitis vinifera) pomace by pressing and posterior maceration. Phenolics resulting of the crude grape extract were fractionated by preparative chromatography. The ability of fractions, containing flavanol monomers, oligomers (procyanidins) and glycosylated flavonols, for inhibiting oxidation of fish lipids was determined. The tests were conducted in fish oils, fish oil-in-water emulsions and in fatty fish species such as mackerel during frozen storage. Partitioning coefficients of grape phenolics showed high solubility in the aqueous media and low in oily media. The results suggest that an optimal combination of procyanidin, degree of polymerization and percentage galloylation may be related to the highest antioxidant efficacy of grape polyphenols in the different systems tested. Monomers were more effective in oily systems. Flavanol oligomers were the most potent inhibitors of oxidation in emulsions and in frozen fish muscle. [Copyright &y& Elsevier]

• Only 10–18% Hb could be rinsed away from by-products with tap water or 0.9% NaCl. • Rinsing by-products without antioxidants had limited effect on lipid oxidation. • Rinsing by-products with antioxidants extended shelf life from <1 day to >12 days. • Incubating by-products with antioxidants extended shelf life from <1 day to >7 days. • The new antioxidant treatments facilitate for value adding of herring by-products. To allow value adding into foods, stabilizing strategies for fish by-products are needed based on their high susceptibility to hemoglobin (Hb)-mediated lipid oxidation. Here, three strategies for preventing lipid oxidation in herring (Clupea harengus) by-products during ice-storage were studied: (i) rinsing away Hb with water or 0.9% NaCl with/without antioxidants (Duralox-MANC, erythorbate and ethylenediamine-tetraacetic acid (EDTA)), (ii) incubation in water/0.9% NaCl with/without antioxidants, (iii) mincing with subsequent addition of the mentioned antioxidants. Only 10–18% Hb was rinsed away in (i), and the effect of this rinsing on peroxide value (PV) or TBA-reactive substances (TBARS) development was limited. Rinsing or incubating by-products in antioxidant solutions however significantly (p ≤ 0.05) increased shelf life from <1 day to >12 days; Duralox-MANC was particularly efficient. The presented strategies could hereby facilitate more diversified end-use of herring by-products from being 100% feed, to include also high-quality minces, protein isolates or oils for the food industry. [ABSTRACT FROM AUTHOR]