Retardation of haemoglobin-mediated lipid oxidation of Asian sea bass muscle by tannic acid during iced storage

Lipid oxidation mediated by haemoglobin from tilapia was monitored in washed Asian sea bass mince with and without added tannic acid (200 and 400 ppm) during 10 days of iced storage. Control samples (without tannic acid) had the highest peroxide value (PV) within the first 2 days and possessed the greater amount of thiobarbituric acid-reactive substances (TBARS) throughout the storage of 10 days (p < 0.05). With addition of tannic acid, the lipid oxidation of washed Asian sea bass mince was retarded, especially when the higher level (400 ppm) was used, as evidenced by lowered PV and TBARS. The retarded formation of volatile lipid oxidation products in the samples with added 400 ppm tannic acid was found. Sensory analysis revealed that samples with added 400 ppm tannic acid possessed lower fishy odour score, compared with the control sample and that with added 200 ppm tannic acid (p < 0.05).     

Changes in heme proteins and lipids associated with off-odour of seabass (Lates calcarifer) and red tilapia (Oreochromis mossambicus × O. niloticus) during iced storage

Changes in heme proteins and lipids associated with off-odour development in seabass (Lates calcarifer) and red tilapia (Oreochromis mossambicus × O. niloticus) muscles during 15 days of iced storage were studied. Fresh seabass contained the higher contents of myoglobin and heme iron, compared with red tilapia (P < 0.05). An increase in metmyoglobin proportion was observed during storage. After 3 days of storage, a decreased heme iron content and a concomitant increase in non-heme iron content were noticeable in both fish (p < 0.05). Oxidation of myoglobin and released non-heme iron were associated with lipid oxidation. The increases in oxidation products and free fatty acids were observed as the storage time progressed. Fishy and rancid odours were detected at day 6 of storage for both fish and a higher intensity was found in seabass muscle. Thus, the off-odour in fish muscle was mostly governed by lipid oxidation and species specific.     

Changes of lipids in sardine (Sardinella gibbosa) muscle during iced storage

Changes in lipids of sardine (Sardinella gibbosa) muscle during 15 days of iced storage were investigated. Lipid deterioration, lipolysis and lipid oxidation, occurred throughout the storage. The progressive peroxide formation was monitored by the increase in the absorbance band at 3600–3200 cm⁻¹ in Fourier transform infrared (FTIR) spectra and increased peroxide values were observed in sardine muscle up to 6 days of iced storage, followed by a continuous decrease from then for 9 days (P < 0.05). The increase in thiobarbituric acid reactive substances (TBARS) was noticeable throughout the iced storage (P < 0.05). However, no difference in conjugated diene (CD) of sardine muscle was found within the first 12 days of iced storage (P > 0.05). Marked decreases in unsaturated fatty acids, especially eicosapentaenoic acid (EPA; C20:5(n − 3)) and docosahexaenoic acid (DHA; C22:6(n − 3)) were observed as the storage time increased. Those changes indicated that lipid oxidation occurred in sardine muscle. A gradual increase in free fatty acid formation, with decreases in triglyceride and phospholipid contents, was found during iced storage (P < 0.05), suggesting hydrolysis induced by lipases and phospholipases.     

Structural changes in sardine (Sardina pilchardus) muscle during iced storage: Investigation by DRIFT spectroscopy

Diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy has been used for the first time to evaluate the postmortem changes in structure of components from sardine muscle in relation to quality loss. Sardines (Sardina pilchardus) were stored in ice for up to thirteen days. The spectroscopic study was focussed on the structural changes produced on the lipids and proteins.     

The effect of antioxidants on the quality changes of cuttlefish (Sepia pharaonis) muscle during frozen storage

The changes in quality of cuttlefish (Sepia pharaonis) treated with 5% NaCl and 0.3% H₂O₂ and soaked with and without different antioxidants during frozen storage at -18 °C for 16 weeks were investigated. Thiobarbituric acid reactive substances (TBARS) in all cuttlefish samples increased when the storage time increased (P<0.05). Ascorbate (ASC) and erythorbate (ERT) showed a prooxidative effect while EDTA and tripolyphosphate (TPP) had no antioxidative effect in frozen cuttlefish. Soaking the cuttlefish in 5% NaCl and 0.3% H₂O₂ for 15 min could improve the color of cuttlefish by increasing the L^*-value and decreasing the a^*-value. ASC, ERT, EDTA and TPP solutions had no impact on the a^*-value and L^*-value of cuttlefish during frozen storage. However, the treated samples, which were soaked in ASC and ERT solutions had an increased b^*-value during frozen storage. Surface hydrophobicity (S₀ANS) of cuttlefish natural actomyosin increased when the frozen storage period increased up to 12 weeks. The increase in disulfide bond content was generally coincidental with the decrease in sulfhydryl content. ASC, ERT, EDTA and TPP had no significant effect on those changes. Protein solubility decreased slightly during prolonged storage. Soaking cuttlefish with 5% NaCl and 0.3% H₂O₂ together with 0.5% TPP could retard the decreases in solubility and increase in thaw drip of frozen cuttlefish. However, ASC, ERT and EDTA showed no impact on the solubility and thaw drip of frozen cuttlefish.     

Evolution of volatile odorous compounds during the storage of European seabass (Dicentrarchus labrax)

The aim of this work was to reliably identify odorous compounds of European seabass (Dicentrarchus labrax) after 1, 4 and 15 days of storage in order to find markers of freshness or spoilage. For this purpose, a dynamic headspace gas chromatography olfactometry device (DH-GC-MS/8O) was used with a panel of eight sniffers for comprehensive detection of odorants. One- and two-dimensional gas chromatography (GC-GC-MS/O) coupled with olfactometry and mass spectrometry gave reliable identification. More than 144 volatile compounds were detected in seabass flesh, of which only 13 proved to be odorant (their biochemical origins are discussed): methane-thiobis, thiophene, toluene + butanoic acid ethyl ester, hexanal, 1-hexanol, 1-octen-3-one, 1-octen-3-ol, dimethyl-trisulfide, octanal, 1-nonen-3-ol, (E)-2-nonenal and 2 unknown compounds. Amongst these compounds, only thiophene, hexanal, 1-octen-3-one, dimethyl-trisulfide, and 1-nonen-3-ol are proposed as markers of seabass quality.     

Effect of bleeding treatment and perfusion of yellowtail on lipid oxidation in post-mortem muscle

The present study investigated the effects of bleeding treatment and perfusion of antioxidant compounds on lipid oxidation in ordinary and dark muscles of yellowtail in the early stage of ice storage. The lipid hydroperoxide contents of dark muscles obtained from yellowtails with and without bleeding treatment were higher and increased more rapidly than those of ordinary muscles. There were no significant differences in the rates of change of the lipid hydroperoxide content (up to 48 h), fatty acid composition and metmyoglobin formation between dark muscles with and without bleeding treatment. Physiological saline containing ascorbic acid or 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox^®) was perfused into live yellowtail or added to minced dark muscle. Trolox^® significantly (P < 0.01) delayed the accumulation of lipid hydroperoxide in dark muscle compared to ascorbic acid in perfusion experiment. These results indicate that simply removing a portion of the blood from live yellowtail by bleeding is not sufficient to prevent lipid oxidation in the early stage of ice storage. Contrary to this, addition of antioxidants into fish flesh is effective to delay lipid oxidation in post-mortem muscle.     

Roles of lipid oxidation and pH on properties and yellow discolouration during storage of film from red tilapia (Oreochromis niloticus) muscle protein

Protein-based films prepared from red tilapia (Oreochromis niloticus) washed and unwashed mince solubilised at pH 3 and 11 were prepared and characterised. Tensile strength (TS) of films from washed mince was greater than that of films prepared from unwashed mince for both pH used (P < 0.05). TS of films prepared at pH 3 was higher than that of films prepared at pH 11 for both of washed and unwashed mince (P < 0.05). Film from washed mince with pH 3 showed the highest TS, while that from unwashed mince with pH 11 had the lowest TS with the highest elongation at break (EAB) (P < 0.05). Films from washed mince had the lower value of thiobarbituric acid reactive substances (TBARS) than did those from unwashed counterpart, regardless of pH used. Nevertheless, TBARS was much higher in films prepared at acidic pH, compared with those prepared at alkaline pH. During storage of 20 days at room temperature, films became yellowish as evidenced by the increases in b^∗ and ΔE^∗-values. Films prepared at pH 11 showed the higher b^∗ and ΔE^∗-values than did those prepared at pH 3, especially for those from unwashed mince. However, films prepared from washed mince at pH 3 showed higher b^∗ and ΔE^∗-values than did those prepared at pH 11 (P < 0.05). Films generally had the increase in TS but the decreases in water vapour permeability (WVP), film solubility and protein solubility after 20 days of storage (P < 0.05). Therefore, lipid oxidation more likely played a role in yellow discolouration of fish muscle protein film, mainly by providing the carbonyl groups involved in Maillard reaction, while pH regulated the rate of reaction.     

Influences of potassium ferrocyanide on lipid oxidation of salted cod (Gadus morhua) during processing, storage and rehydration

The effects of added potassium ferrocyanide (CN) in different concentrations (2.5 ppm, 7.5 ppm and 100 ppm), in salt, on lipid oxidation in cod during salting, storage and rehydration were examined in this study. An increase in CN concentration accelerated lipid oxidation of the salted cod, as observed by increases in lipid hydroperoxides (PV) and thiobarbituric acid-reactive substances (TBARS), as well as in the development of fluorescence compounds (δF_or and δF_aq). A yellow discolouration (higher b^∗ value) of salted cod was associated with higher levels of oxidation derivatives. High correlation between PV, TBARS and free fatty acid (FFA), as well as between FFA and δF_or, was found. The results of principal component analysis showed that TBARS, b^∗ value and δF_or were the strongest indicators of lipid oxidation during salting and storage.     

Effect of high-pressure treatment on lipid oxidation in turkey thigh muscle during chill storage

 Formation of secondary lipid oxidation products during chill storage of vacuum-packed (99% vacuum), pressure-treated turkey thigh muscle was found to depend on working pressure (pressure range up to 500 MPa at 10°C) and to a lesser degree on pressurization time (10 and 30 min). Pressure treatment at 400 MPa and lower pressures for 30 min (and for 10 min) resulted in less formation of thiobarbituric-acid-reactive substances (TBARS) during 6 days of storage at 5°C compared to heat treatment at 100°C for 10 min, while pressure treatment at 500 MPa for 30 min gave similar development of TBARS as did the heat treatment. The formation of TBARS during storage at 5°C was found to depend exponentially on the pressure used for treatment at both 10 min and 30 min, and apparent volumes of activation are proposed as a parameter for quantification of the effects of pressure on lipid oxidation in meat during subsequent storage. Received: 18 November 1996     

Pink discoloration and quality changes of squid (Loligo formosana) during iced storage

Pink discoloration and quality changes of squid (6-10 squids/kg) with and without deskinning during iced storage at different squid/ice ratios (1:1 and 1:2, w/w) for 16 days were investigated. The increases in a* and b*-values of squid mantle were observed with increasing storage time (p < 0.05), indicating the formation of pink color on the mantle. The increase was more pronounced in squid without deskinning with a squid/ice ratio of 1:1 (p < 0.05). No changes in a*-value were observed in deskinned squid throughout the storage, regardless of squid/ice ratio (p > 0.05). However, the slight increase in b*-value was found in the squid with deskinning during the storage. Psychrophilic bacteria counts of squid increased continuously as the storage time increased. Coincidental increases in total volatile base (TVB), trimethylamine (TMA) and ammonia contents were observed during the storage. The rates of increase were greater in the samples with a squid/ice ratio of 1:1 than those found in the samples kept in ice with a squid/ice ratio of 1:2. Pink discoloration, psychrophilic bacteria count, TVB and TMA contents were much lowered when the squid without deskinning was treated with 0.1 g/100 mL sodium azide (NaN₃) prior to storage, suggesting that microbial growth was associated with those changes. Therefore, deskinning together with icing using a sufficient amount of ice as well as the use of safe antimicrobial agent could be a means to lower the pink discoloration and retard the losses in quality of squid stored in ice.     

Effect of different cooking methods on lipid oxidation and formation of volatile compounds in foal meat

The influence of four different cooking methods (roasting, grilling, microwaving and frying) on cooking loss, lipid oxidation and volatile profile of foal meat was studied. Cooking loss were significantly (P < 0.001) affected by thermal treatment, being higher (32.5%) after microwaving and lower after grilling (22.5%) and frying (23.8%). As expected, all the cooking methods increased TBARs content, since high temperature during cooking causes increased oxidation in foal steaks, this increase was significantly (P < 0.001) higher when foal steaks were microwaved or roasted.     

Comparative study on molecular characteristics of acid soluble collagens from skin and swim bladder of seabass (Lates calcarifer)

Acid soluble collagens (ASCs) from skin and swim bladder of seabass (Lates calcarifer) were isolated and comparatively characterised. Higher yield (28.5%) was obtained for ASC from swim bladder, compared with that from skin (15.8%). ASCs from both skin and swim bladder had the similar protein patterns and were identified to be type I. Both α- and β-chains constituted as major components. Fourier transform infrared (FTIR) spectra revealed that both ASCs were triple helix in structure. ASC from both sources contained glycine as the major amino acid with imino acids (proline and hydroxyproline) of 194–195 residues/1000 residues). Peptide maps of both ASCs digested by chymotrypsin and trypsin showed slight differences, suggesting some differences in their primary structure. The thermal transition temperature of swim bladder ASC (35.02 °C) was slightly higher than its skin counterpart (33.33 °C). Based on zeta potential analysis, ASCs from skin and swim bladder had a net charge of zero at pH 6.46 and 6.64, respectively. Therefore, both the skin and swim bladder of seabass could be used potentially for collagen extraction.     

Potato peel extract as a natural antioxidant in chilled storage of minced horse mackerel (Trachurus trachurus): Effect on lipid and protein oxidation

The present work was undertaken to examine the utilisation of potato peel, a waste material, as a source of natural antioxidants for retarding lipid and protein oxidation in minced mackerel. Mackerel mince with two different concentrations (2.4 or 4.8 g/kg) of water or ethanol extracts of potato peel and a control with no added extracts were prepared. The samples were stored at 5 °C for 96 h and the sampling was done at time points 0, 24, 48 and 96 h. The ethanol extracts, which contained high amounts of phenolic compounds, was found to be very effective in retarding lipid and protein oxidation as it resulted in low levels of peroxide value, volatiles, carbonyl compounds and protected against the loss of α-tocopherol and tryptophan and tyrosine residues. Water extracts was less efficient especially at higher concentrations, which might be due to lower phenolic content or due to the pro-oxidative nature of some of the phenolic acids/co-extracted compounds.     

Effect of different cooking methods on lipid oxidation and formation of free cholesterol oxidation products (COPs) in Latissimus dorsi muscle of Iberian pigs

The aim of this work was to study the influence of different cooking methods (grilled (GR), fried (FP), microwave (MW) and roasted (RO)) on lipid oxidation and formation of free cholesterol oxidation products (COPs) of meat from Iberian pigs that have been fed on an intensive system. Moisture and total lipid content, TBARs, hexanal and COPs were measured in Latissimus dorsi muscle samples. Cooking did not produce changes in total lipid content in meat but induced significantly higher lipid oxidation (TBARs and hexanal values) (p < 0.001) and cholesterol oxidation (COPs) (p < 0.01). When the different cooking methods were studied, the grilled method was the least affected by lipid oxidation (TBARs and hexanal) compared to the others. There were no significant differences among different cooking methods on COPs values. The most abundant cholesterol oxides were both 7α-hydroxycholesterol and 7β-hydroxycholesterol in all groups studied.     

Early post-mortem sarcoplasmic proteome of porcine muscle related to lipid oxidation in aged and cooked meat

In order to identify specific markers of lipid oxidation generated in meat during refrigerated storage and cooking an analysis was conducted to investigate the relationships between the early post-mortem sarcoplasmic proteome, which contains the majority of enzymes involved in the oxidative process, and the level of lipid oxidation. This study was performed in Longissimus lumborum pig muscle. Proteome was analysed by 2-D electrophoresis in combination with liquid chromatography–tandem mass spectrometry (LC–MS/MS) and lipid oxidation was estimated by the TBA reactive substances (TBA-RS) measurement. Many markers of lipid oxidation were identified, but no single marker covered the oxidative process in its entirety. The role of five protein groups (albumin, redoxins, annexins, lipid transporters and enzymes of aerobic respiration), from which a link with lipid oxidation can be established, is discussed. This study, which completes a precedent work focused on protein oxidation, clearly demonstrates that a combination of several markers is needed to assess the sensitivity of meat to oxidation during both ageing and cooking.     

Effect of myoglobin from Eastern little tuna muscle on lipid oxidation of washed Asian seabass mince at different pH conditions

The effect of pH (6.0, 6.5, and 7.0) on lipid oxidation in washed Asian seabass (Lates calcarifer) mince mediated by oxymyoglobin from the dark muscle of little Eastern tuna (Euthynnus affinis) during 8 d of refrigerated storage was studied. Metmyoglobin formation and discoloration increased with increasing storage time and the changes were more pronounced at lower pH. The highest lipid oxidation and off-odor development were observed when myoglobin was incorporated in washed mince at pH 6.0. At low pH, oxidation of myoglobin took place and lipid oxidation in washed mince was enhanced. This was concomitant with the increased fishy and rancid off odor in the sample containing myoglobin, especially at pH 6.0. Washed mince containing myoglobin at pH 6.0 had 1-octen-3-ol and hexanal as the major volatile compounds. Thus, postmortem pH and myoglobin played an essential role in lipid oxidation and off odor in fish muscle during the extended storage. PRACTICAL APPLICATION: Myoglobin plays a role in the color of fish muscle. The change of myoglobin affects not only consumer acceptability, but also lipid oxidation as well as odor. The control of pH of muscle could be a potential means to lower the lipid oxidation mediated by myoglobin. As a consequence, the prime quality of fish with a negligible fishy odor could be maintained during postharvest handling or storage.     

Oxidation of lipid and protein in horse mackerel (Trachurus trachurus) mince and washed minces during processing and storage

Protein and lipid oxidation was followed during processing and storage of mince and washed minces prepared from horse mackerel (Trachurus trachurus). Briefly horse mackerel mince (M0) was washed with three volumes of water, mimicking the surimi production and different washed products were obtained: M1, M2 and M3, with one, two and three washing steps, respectively. The different products were characterised (i.e. lipid content, protein, water, iron, fatty acid profile and tocopherol content) and analysed for protein and lipid oxidation in order to investigate the impact of the washing steps on oxidation. Subsequently the different products were stored for up to 96 h at 5 °C and samples were taken out regularly for analysis. Lipid oxidation was investigated by measuring primary oxidation products (lipid hydroperoxides) and secondary oxidation products (volatiles). Protein oxidation was followed by determination of protein solubility, protein thiol groups and protein carbonyl groups using colorimetric methods as well as western blotting for protein carbonyl groups. Lipid and protein oxidation markers indicated that both lipid and protein oxidation took place during processing and the ranking for oxidation was as follows M0 < M1 < M2 ? M3 with M0 being significantly less oxidised than M3. Results indicated that washing creates an imbalance in the initial prooxidant-antioxidant equilibrium in the muscle tissue and contributes to the observed differences in the oxidative status of the four products obtained. In contrast, during storage of different products, lipid oxidation development was faster in M0 and the ranking was as follows M0 > M1 > M2 ? M3. Lipid and protein oxidation developed simultaneously in different minces during storage, but it was not possible to determine at which level these two reactions were coupled.     

Effect of sage (Salvia officinalis) on the oxidative stability of Chinese-style sausage during refrigerated storage

The objective of this study was to assess the effect of sage, at levels of 0.05%, 0.1% and 0.15% (w/w), on the oxidative stability of Chinese-style sausage stored at 4 °C for 21 days. The results showed that inclusion of sage in sausages resulted in lower L* values (P < 0.05) and higher a* values (P < 0.05) compared to the control. During refrigerated storage, sausages containing sage showed significantly retarded increases in TBARS values, and in the formation of protein carbonyls (P < 0.05), but showed accelerated losses of thiol groups (P < 0.05). Addition of sage to the sausages at levels of 0.1% and 0.15% reduced textural deterioration during refrigerated storage (P < 0.05). Sage used in this study had no negative effects on the sensory properties of sausages.     

Effect of natural antioxidant combinations on lipid oxidation in cooked chicken meat during refrigerated storage

The effect of combinations of sage, oregano and honey on lipid oxidation in cooked chicken meat during refrigeration at 4°C for 96h was determined. Chicken samples (thigh and breast) were then separated into five groups: control; butylated hydroxytoluene; oregano+sage; oregano+sage+5%honey and oregano+sage+10%honey. Quantitative measurements of thiobarbituric acid reactive substances, conjugated dienes, hexanal, fatty acids, cholesterol and cholesterol oxides were used as indicators of lipid oxidation. Acceptability and preference were also evaluated. The effectiveness of the natural antioxidants for reducing the velocity of lipid oxidation in cooked chicken thigh and breast was demonstrated after 48 and 96h of refrigeration at 4°C. The treatments that presented the lowest hexanal values after 96h of refrigeration were oregano+sage+5%honey and oregano+sage+10%honey. Only traces of free cholesterol oxides were found (25-OH, 7-k, 7α-OH and 7β-OH). The natural antioxidants protected cooked chicken meat from oxidation processes and resulted in great acceptability.