Differences In Oxidative Stability Research Articles

Metabolomic profile of muscles from tilapia cultured in recirculating aquaculture systems and traditional aquaculture in ponds and protein stability during freeze-thaw cycles

Muscle protein stability during freeze-thaw (F-T) cycles was investigated with tilapia cultured in recirculating aquaculture systems (RAS) and traditional aquaculture in ponds (TAP). This study found that fatty acids (eg., palmitic acid) were enriched in TAP, while antioxidants (eg., glutathione) were enriched in RAS. Generally, proteins in the RAS group exhibited greater stability against denaturation during the F-T cycle, suggested by a less decrease in haem protein content (77% in RAS and 86% in TAP) and a less increase in surface hydrophobicity of sarcoplasmic protein (63% in RAS and 101% in TAP). There was no significant difference in oxidative stability of myofibrillar protein between the two groups. This study provides a theoretical guide for the quality control of tilapia cultured in RAS during frozen storage.

Oxidative stability differences of aqueous model systems of photoautotrophic n–3 LC–PUFA rich microalgae: The antioxidative role of endogenous carotenoids

Microalgae rich in omega-3 long-chain polyunsaturated fatty acids (n–3LC–PUFA) have already shown their potential for developing functional food rich in these healthy fatty acids. Not only could they offer a more sustainable alternative for the fish stock that is currently relied upon but is unable to keep up with the demand, enrichment with certain microalgae also leads to oxidatively stable products. Although the reason for this stability has been attributed to the presence of endogenous carotenoids, further insight into their antioxidative role is missing and would be clarifying for selecting the proper microalgae for food enrichment. In trying to further accomplish this, a storage experiment (4 weeks, 37 °C) was set up with the parallel analysis of both oxidation products (primary and secondary) and carotenoids of two aqueous model systems of different (promising) microalgae (Nannochloropsis and Phaeodactylum). The results showed a clear difference in oxidative stability despite both microalgae containing endogenous carotenoids: Nannochloropsis led to oxidatively unstable and Phaeodactylum to oxidatively stable products. This was clearly confirmed by the analysis of n–3LC–PUFA throughout storage which showed a breakdown of half of the n–3LC–PUFA for Nannochloropsis. All carotenoids (violaxanthin, zeaxanthin and β-carotene for Nannochloropsis, and fucoxanthin and β-carotene for Phaeodactylum) acted as an antioxidant as shown by their degradation throughout storage, but the difference in oxidative stability pointed out an impact of carotenoid content and (possibly) type. The presence of a sufficient amount of carotenoids seems to be an important factor for perceiving oxidative stability. Phaeodactylum has shown to be more potent for food enrichment.

Differences in Oxidative Stability, Sensory Properties, and Volatile Compounds of Pepper Aromatized Sunflower Oils Prepared by Different Methods during Accelerated Storage

AbstractThe study aims to compare the differences in the oxidative stability, sensory properties, and volatile compounds during accelerated storage of pepper aromatized sunflower oil (PASO) samples prepared by maceration method (PASO‐M), co‐pressing method (PASO‐C), and direct addition method (PASO‐A), respectively. The results exhibit that their oxidative stability is in the relative order: PASO‐A > PASO‐C > PASO‐M. Meanwhile, the PASO‐A sample is the most preferable aromatized sunflower oil by consumers according to sensory analysis. In addition, a total of 83 volatile compounds are identified in the three PASO samples during the storage, and the principal component analysis (PCA) shows that their volatile compounds are quite different at the initial stage of the storage. Still, they are similar among each other from the middle of storage period. As consequence, the aromatized sunflower oil sample prepared by the direct‐addition method during the storage possesses better oxidative stability and sensory attributes, and there is not much difference among their volatile compounds, indicating that the aromatized sunflower oil prepared by direct‐addition method can be developed as promising aromatized sunflower oil.Practical applications: This study shows that aromatization increases oxidative stability and sensory properties of sunflower oil. By this way some sunflower oils with special sensory properties are obtained: special smell and taste, special color, etc. These peppers aromatized sunflower oils can be used to increase taste and smell in some dishes. For example, they can be used in some salads and some roast meats to give more taste and color.

Sunflower Oil Flavored by Spearmint through Conventional and Ultrasound-Assisted Maceration: Differences in Oxidative Stability, Microbial Contamination and Sensory Properties

The preparation of flavored vegetable oils using spice and herb plants is considered to be an indispensable opportunity for the application of these plants. In the present exploration, sunflower oil (SFO) samples flavored by Mentha spicata L. (spearmint) were prepared using the maceration method (MM) and ultrasound-assisted maceration (UM). The antioxidant effects, sensory evaluation and the oxidative stability during accelerated storage; the physicochemical properties including the levels for acid value (AV), peroxide value (PV) and p-anisidine value (AnV); and the specific extinction values at 232 nm (K232) and 268 nm (K268) of the SFO samples were measured. The contents of beneficial ingredients including chlorophylls, carotenoids, polyphenols and tocopherols, and the micro-organism colonies for yeasts, molds, Listeria monocytogenes and Enterobacteriaceae bacteria were determined. The results show that the physicochemical properties, beneficial ingredients, antioxidant effects, sensory attributes and the oxidative stability in accelerated storage were greater in the flavored SFO sample than the control. Therefore, the SFO flavored by spearmint can be developed as flavored vegetable oils, and the ultrasound-assisted maceration can be widely employed in the preparation of flavored vegetable oils in the future.

Effects of interface generation, droplet size and antioxidant partitioning on the oxidation rate and oxidative stability of water–in–oil emulsions: A comparison of coarse emulsions and nanoemulsions

In order to gain an in–depth understanding of the factors affecting the oxidation of water–in–oil (W/O) emulsions, both initial oxidation rate and long–term oxidative stability were applied to assess the degree of oxidation of W/O emulsions. The results showed that the generation of the oil–water interface exacerbated lipid oxidation in W/O emulsions and the oxidation rate was independent of the initial droplet size (8 days). The difference in oxidative stability between coarse and nanoemulsions depended on the change in droplet size during storage and the formation of reverse micelles by the excess polyglycerol polyricinoleate (PGPR). The antioxidant (AO) esters with different alkyl chain lengths were added to the W/O emulsions to assess the effects of AO partitioning on lipid oxidation. The lipid oxidation results confirmed the applicability of the non–linear hypothesis in W/O emulsions. There was a critical chain length (CCL, octyl gallate, C8). Below or above CCL, the efficiency of the AOs decreased. C8 showed a ‘dual effect’, acting at both the oil–water and oil–air interface (interfacial tensions reduced by 0.36 and 4.66 mN/m, respectively). Future research should focus on means of effectively migrating AOs from the two phases to the oil–water interface to delay lipid oxidation.

Late-dropping macadamia nuts have reduced shelf life

The quality of tree nuts can be influenced by their harvest time, cultivar and seasonal growing conditions. Some macadamia cultivars retain mature nuts in the tree for several months before fruit abscission and this can result in variations in harvest time. It is not known how the variations in harvest time affect the quality and shelf life of macadamia cultivars. We investigated how harvest time and cultivar influence the quality and shelf life of macadamia kernels. We tested the shelf life of kernels using two techniques: (1) a long-term shelf-life method; and (2) a short-term accelerated-aging method that assessed oxidative stability based on hexanal concentrations. Cultivars HAES 344 (344) and Hidden Valley A16 (A16) were harvested in May and late-abscising nuts of cultivar A16 were also harvested in September. Peroxide values, free fatty acid levels and fatty acid composition of kernels in the long-term experiment were measured after 0, 6, 12, 15 and 18 months of storage at 25 °C. Kernels in the short-term accelerated aging experiment were incubated at 45 °C, and hexanal concentrations were measured before incubation and after 6, 12 and 18 days. Kernels from late-abscising nuts (September) had much higher free fatty acid levels after 18 months of storage than kernels from early-harvested nuts (May). Cultivar A16 (September) kernels had significantly higher hexanal concentrations than cultivar 344 (May) and A16 (September) kernels at 12 and 18 days of incubation. The accelerated aging technique could detect differences in oxidative stability between different batches. Nuts harvested in September had shorter shelf life by about 3–6 months than those harvested in May, based on both predicted shelf life and actual time taken to reach acceptable-quality limits. Therefore, we recommend harvesting macadamia nuts as soon as possible after maturity to minimise quality losses.

Oxidative stability of vegetable purees enriched with n‐3‐LC‐PUFA microalgal biomass: impact of type of vegetable

SummaryVegetable purees can be interesting food products to enrich with omega‐3 long‐chain polyunsaturated fatty acids (n‐3‐LC‐PUFA), since they are important carriers of nutrients and fibres and essential in a healthy diet. Due to their large number of double bounds, n‐3‐LC‐PUFA are highly susceptible to lipid oxidation. Different vegetable purees, containing different types and amounts of endogenous antioxidants, may possibly show differences in oxidative stability. This study contributes to obtain more insight into the impact of the type of vegetable (broccoli, carrot or tomato) on the oxidative stability of purees enriched with heterotrophic (Schizochytrium) n‐3‐LC‐PUFA‐rich microalgal biomass. Therefore, different vegetable purees enriched with microalgae were compared with each other and analysed for their amount lipid oxidation products and antioxidants. Broccoli and tomato puree enriched with Schizochytrium showed a higher oxidative stability compared to enriched carrot puree. However, all of these Schizochytrium‐enriched purees were prone to oxidation.

Exploring the Acid Gas Sorption Properties of Oxidatively Degraded Supported Amine Sorbents

Amine-supported mesoporous oxide materials have proven to be effective acid gas sorbents. While the primary application of these supported amine species has been CO2 capture, they have also shown to be proficient at adsorbing other damaging flue gas impurities such as SOx and NOx. The precise nature of the amine (primary, secondary, or tertiary) is known to dictate the gas–amine interactions, with tertiary amines of particular interest due to their inability to adsorb dry CO2, favoring SOx and NOx species. The different amine sites also provoke differences in oxidative stability, when exposed to temperatures similar to those used for thermal desorption procedures. Herein we focus on the structural and chemical changes that occur in a range of class 1 (amine-impregnated) and class 2 (amine-grafted) sorbents upon oxidation and correlate these with their variation in acid gas (CO2, NO2, and SO2) uptakes, as a function of the oxidation temperature. These studies suggest that oxidatively degraded or “spent” su...

Unsaturated fat fraction from lard increases the oxidative stability of minced pork

Lard from pork back fat was dry fractionated based on crystallization temperature, resulting in fractions with a ratio of saturated to unsaturated fatty acids of 1.10 and 0.61. Lean minced pork was mixed with the saturated and unsaturated fat fraction and stored in modified atmosphere (80% O2 and 20% CO2) at 5 °C for 2, 5, 7, 9, and 12 days under light to investigate the effect on oxidative stability of lipids and proteins. The saturated fat group developed higher TBARS values and lower levels of free thiol groups during storage, indicating that the unsaturated fat fraction in minced pork promoted increased oxidative stability of both lipids and proteins. A higher content of α-tocopherol in the unsaturated fat fraction suggests that the differences in oxidative stability is causatively linked to the balance between the fatty acid composition and content of antioxidants. The TBARS values and free thiol content were negatively correlated, suggesting a relationship between lipid and protein oxidation.

Survival, oxidative stability, and surface characteristics of spray dried co-microcapsules containing omega-3 fatty acids and probiotic bacteria

ABSTRACTThe objective of the study was to determine optimum inlet and outlet air temperatures of spray process for producing co-microcapsules containing omega-3 rich tuna oil and probiotic bacteria L. casei. These co-microcapsules were produced using whey protein isolate and gum Arabic complex coacervates as shell materials. Improved bacterial viability and oxidative stability of omega-3 oil were used as two main criteria of this study. Three sets of inlet (130°C, 150°C, and 170°C) and outlet (55°C, 65°C, and 75°C) air temperatures were used in nine combinations to produce powdered co-microcapsule. The viability of L. casei, oxidative stability of omega-3 oil, surface oil, oil microencapsulation efficiency, moisture content, surface elemental composition and morphology of the powdered samples were measured. There is no statistical difference in oxidative stability at two lower inlet air temperatures (130°C and 150°C). However, there was a significant decrease in oxidative stability when higher inlet temperature (170°C) was used. The viability of L. casei decreased with the increase in the inlet and outlet air temperatures. There was no difference in the surface elemental compositions and surface morphology of powdered co-microcapsules produced under these nine inlet/outlet temperature combinations. Of the range of conditions tested the co-microcapsules produced at inlet-outlet temperature 130–65°C showed the highest bacterial viability and oxidative stability of omega-3 and having the moisture content of 4.93 ± 0.05% (w/w). This research shows that powdered co-microcapsules of probiotic bacteria and omega-3 fatty acids with high survival of the former and high stability against oxidation can be produced through spray drying.

Influence of protein type on oxidation and digestibility of fish oil-in-water emulsions: Gliadin, caseinate, and whey protein

The influence of three surface-active proteins on the oxidative stability and lipase digestibility of emulsified ω-3 oils was examined: deamidated wheat gliadin (gliadin); sodium caseinate (CN); whey protein isolate (WPI). Gliadin and WPI were more effective at inhibiting lipid oxidation (hydroperoxides and TBARS) of fish oil-in-water emulsions than CN. Protein oxidation during storage was determined by measuring the loss of tryptophan fluorescence. The CN-emulsions exhibited the highest loss of tryptophan fluorescence during aging, as well as the highest amount of lipid oxidation. Potential reasons for the differences in oxidative stability of the emulsions with different proteins include differences in interfacial film thickness, protein chelating ability, and antioxidant amino acids profiles. During in vitro digestion, gliadin-stabilized emulsions had the lowest digestion rate of the three proteins. These results have important implications for using proteins to fabricate emulsion-based delivery systems for ω-3 oils.

Characteristics of Korean value-added eggs and their differences in oxidative stability

Twenty brands of eggs including 17 value-added ones from different egg suppliers on the Korean markets were examined for their oxidative status and oxidative stability. The contents of hydroperoxides and malondialdehyde (MDA) were low over all the eggs, and were not appreciably different from supplier to supplier and between value-added eggs and ordinary control ones. When the eggs were subjected to iron-induced oxidation system to assess their oxidation stability, MDA contents of the ordinary control eggs increased rapidly with the incubation time. On the other hand, the value-added eggs showed large variations in their susceptibility to lipid oxidation from supplier to supplier. It indicates that, for the different brands of eggs that are claimed to be enriched with same functional materials, the claim of egg suppliers (feed supplementation with same functional materials) might not always guarantee the same magnitude of functionality of the eggs.

Oxidative stability of whole wheat bread during storage

The oxidative stability was examined in whole wheat bread packed in modified atmosphere (nitrogen) using vacuum grade plastic bags and stored for up to 5 weeks. Small, but significant, differences in oxidative stability developed with time for whole wheat bread crumb and crust. The samples were evaluated by direct electron spin resonance (ESR) spectroscopy for detection of free radicals, peroxide value (POV), overall antioxidative capacity using Trolox equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC) assays, and by the content of tocopherols as determined by HPLC. The overall antioxidative capacity was reduced during storage with an accumulation of lipid hydroperoxides peaking after 2–3 weeks of storage. Bread crust was generally found to be more oxidative stable when compared to crumb. Quality of bread with extended shelf life may accordingly be improved minimising oxidation.

Effects of Seed Roasting on Tocopherols, Carotenoids, and Oxidation in Mustard Seed Oil During Heating

AbstractSeed roasting is practiced in the mustard oil industry in some areas of the world, and can affect the physicochemical properties of the oil for further applications. This research studied the differences in oxidative stability, tocopherols, and carotenoids during heating at 160 °C between oil extracted from roasted mustard seeds and that from unroasted seeds. The content of free fatty acids, polar compounds (PC), and lutein were not significantly different between the roasted and unroasted seed oils before heating. The fatty acid compositions of both oils were also similar, with high amounts of erucic, linoleic, and oleic acids, moderate amounts of linolenic and eicosenoic acids, and low amounts of palmitic and stearic acids. However, the levels of tocopherols and conjugated dienoic acids (CDA) were higher in the roasted seed oil. Heating increased the content of CDA and PC in both oils, but decreased tocopherols and lutein. The rates of increase in CDA and PC and the degradation rates of tocopherols and lutein during heating were lower in the roasted than in the unroasted seed oil. Overall, the increased thermo‐oxidative stability of the mustard oil by roasting the seeds before oil extraction was highly correlated with improved heat stabilities for both tocopherols and lutein.

The effect of olive leaves supplementation on the feed digestibility, growth performances of pigs and quality of pork meat

The influence of olive leaves supplementation on feed digestibility, growth performance of pigs and pork meat quality was investigated. Pigs fed diets with olive leaves at 5% (OL5) and 10% (OL10) levels had lower daily weight gain (DG) and daily feed intake (DFI) than pigs fed a conventional diet (OL0) but differences were not observed between groups fed with the different quantities of leaves. Additionally, pigs fed diets with leaves had the worst feed:gain ratio and showed a decrease in overall backfat. Chops from pigs fed the leaf diets had lower peroxide (PV) and conjugated diene (CD) contents than chops from pigs fed conventional diets. Moreover, chops from pigs fed with the higher quantity of leaves also showed a lower drip loss. After a storage period of 8 days at 4 °C, meat obtained from both OL5 and OL10 animals also differed ( P < 0.05) in PV and %CD values from those fed a conventional diet. Since the fatty acid composition of the longissimus muscles was not different, differences in oxidative stability could only be explained by the significantly higher α-tocopherol concentration in intramuscular fat and backfat in pigs fed with olive leaf diets.

EFFECTS OF FAT LEVEL AND STORAGE TIME ON LIPID AND COLOR STABILITY OF NATURALLY FERMENTED TURKISH SAUSAGES (SUCUK)

ABSTRACT Lipid oxidation, lipolysis and color stability of naturally fermented Turkish sausages with different initial fat content (10, 20 and 30%) were studied during 60 days of storage of the vacuum‐packed sausages at 4 ± 2°C. During storage, thiobarbituric acid (TBA) and total free fatty acids (FFAs) were measured to determine lipid oxidation and lipolysis. Changes in color were determined by measuring Commission Internationale de l'Eclairage (CIE) L* (lightness), a* (redness) and b* (yellowness) color variables. Vacuum packing prevented any drying. Initial fat content and storage time had a significant impact on FFA and TBA values of sausages. High fat contents and prolonged storage times resulted in high lipolytic activity and lipid oxidation. CIE L*, a* and b* color variables of the sausages were affected by fat content, whereas only the a* variable was affected by storage time. Higher initial fat content in the sausages and residual oxygen in vacuum packing could be responsible for the observed differences in oxidative stability. Lipid and color stability were not maintained in vacuum‐packed sausages with a high fat content.

Effects of EDTA and a combined use of nitrite and ascorbate on lipid oxidation in cooked Japanese sardine ( Sardinops melanostictus) during refrigerated storage

To elucidate the effects of EDTA and a combined use of nitrite and ascorbate on oxidative rancidity of cooked Japanese sardine ( Sardinops melanostictus) stored at refrigeration temperature (2 °C), changes in peroxide values (PV), thiobarbituric acid (TBA) value and fatty acid composition were monitored. The PV and TBA values of the meat with and without EDTA (250 mg/100 g meat) increased gradually, while they remained unchanged when a mixture of sodium nitrite (10 mg NO 2/100 g meat) and sodium ascorbate (200 mg/100 g meat) was added. Total polyenoic acids in the nitrite and ascorbate mixture-treated meat decreased at a slower rate than in the control group. These changes in PUFA composition were due to differences in oxidative stability between the meats containing different antioxidants. In conclusion, a combined use of nitrite and ascorbate showed a greater antioxidativity in terms of the lower PV and TBA values than did EDTA and resulted in preventing the development of warmed-over flavour in cooked sardine during of 14 day refrigerated storage.

Effects of droplet size on the oxidative stability of oil‐in‐water emulsions

The effects of droplet size and emulsifiers on oxidative stability of polyunsaturated TAG in oil-in-water (o/w) emulsions with droplet sizes of 0.806 +/- 0.0690, 3.28 +/- 0.0660, or 10.7 +/- 0.106 microm (mean +/- SD) were investigated. Hydroperoxide contents in the emulsion with a mean droplet size of 0.831 microm were significantly lower than those in the emulsion with a mean droplet size of 12.8 microm for up to 120 h of oxidation time. Residual oxygen contents in the headspace air of the vials containing an o/w emulsion with a mean droplet size of 0.831 microm were lower compared with those of the emulsion with a mean droplet size of 12.8 microm. Hexanal developed from soybean oil TAG o/w emulsions with smaller droplet size showed significantly lower residual oxygen contents than those of the larger droplet size emulsions. Consequently, oxidative stability of TAG in o/w emulsions could be controlled by the size of oil droplet even though the origins of TAG were different. Spin-spin relaxation time of protons of acyl residues on TAG in o/w emulsions measured by H NMR suggested that motional frequency of some acyl residues was shorter in o/w emulsions with a smaller droplet size. The effect of the wedge associated with hydrophobic acyl residues of emulsifiers was proposed as a possible mechanism to explain differences in oxidative stability between o/w emulsions with different droplet sizes.

Lipid oxidation in corn oil-in-water emulsions stabilized by casein, whey protein isolate, and soy protein isolate.

Proteins can be used to produce cationic oil-in-water emulsion droplets at pH 3.0 that have high oxidative stability. This research investigated differences in the physical properties and oxidative stability of corn oil-in-water emulsions stabilized by casein, whey protein isolate (WPI), or soy protein isolate (SPI) at pH 3.0. Emulsions were prepared with 5% corn oil and 0.2-1.5% protein. Physically stable, monomodal emulsions were prepared with 1.5% casein, 1.0 or 1.5% SPI, and > or =0.5% WPI. The oxidative stability of the different protein-stabilized emulsions was in the order of casein > WPI > SPI as determined by monitoring both lipid hydroperoxide and headspace hexanal formation. The degree of positive charge on the protein-stabilized emulsion droplets was not the only factor involved in the inhibition of lipid oxidation because the charge of the emulsion droplets (WPI > casein > or = SPI) did not parallel oxidative stability. Other potential reasons for differences in oxidative stability of the protein-stabilized emulsions include differences in interfacial film thickness, protein chelating properties, and differences in free radical scavenging amino acids. This research shows that differences can be seen in the oxidative stability of protein-stabilized emulsions; however, further research is needed to determine the mechanisms for these differences.

Lipid and colour stability of Milano-type sausages: effect of packing conditions

Lipid and colour oxidative changes in Milano-type fermented sausages were studied in relation to packing conditions and extended storage under fluorescent light. Matured sausages were sliced and packed under vacuum or in protective atmosphere (100% N 2) and exposed in a display cabinet to mimic commercial conditions of light and temperature for 2 months. Lipid oxidation was measured by the determination of thiobarbituric acid reactive substances (TBARS) and cholesterol oxidation products (COP), whereas the oxidation of nitrosylmyoglobin was evaluated by a trained sensory panel. Lipid oxidation and discolouration were positively related in vacuum-packed sausages: TBARS and COP values increased significantly concurrently with increasing brown scores. Protective atmosphere came out to be more efficient than vacuum in controlling fatty acid oxidation and, to a lesser extent, cholesterol and pigment degradation: TBARS values remained constant during the whole storage period whereas cholesterol oxides and brown colour scores gradually increased but remained lower than those of vacuum-packed sausages. Higher residual oxygen in vacuum packing could be responsible for the observed differences in oxidative stability.