Lipid oxidation and fishy odour development in protein hydrolysate from Nile tilapia (Oreochromis niloticus) muscle as affected by freshness and antioxidants

Lipid oxidation and fishy odour development in protein hydrolysate from fresh and ice-stored Nile tilapia (Oreochromis niloticus) were investigated. During iced storage of 18 days, 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 18 days 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.     

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).     

Effect of bleeding on lipid oxidation and quality changes of Asian seabass (Lates calcarifer) muscle during iced storage

Lipid oxidation, microbial load and fishy odour development in the slices of bled and un-bled Asian seabass during 15 days of iced storage were comparatively investigated. Bled samples showed the lower peroxide value (PV) and thiobarbituric acid-reactive substances (TBARS) throughout the storage period (P < 0.05). Bleeding effectively lowered the total haem and non-haem iron contents in Asian seabass slices. The release of non-haem iron was pronounced in the un-bled samples during the storage. Solid phase micro-extraction coupled with gas chromatography and mass spectrometric (SPME-GCMS) analysis revealed that the bled samples stored in ice for 15 days contained the lower amount of volatile compounds. Heptanal, the major volatile compound detected in the un-bled samples, was four-fold higher than that of bled counterparts. The contents of aldehydic compounds, including hexanal, octanal, nonanal and nonenal were also higher in the former. Bled samples had the lower fishy odour, compared with the un-bled counterparts during storage (P < 0.05). The lower total viable counts (TVC) and psychrophilic bacterial counts (PBC) were observed in the bled samples, in comparison with the un-bled ones (P < 0.05). Thus, bleeding was a potential means in retarding lipid oxidation, fishy odour development, and microbial growth of Asian seabass slices during storage in ice.     

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.     

Effects of binary organic solvents and heating on lipid removal and the reduction of beany odour in Bambara groundnut (Vigna subterranean) flour

Effects of various binary organic solvents at different temperatures on the removal of lipids and beany or grassy odour of Bambara groundnut flour were studied. The highest lipid removal was achieved at 60 °C (P < 0.05), regardless of binary organic solvents used. Under the optimal temperature, chloroform/methanol showed the highest lipid removal (87%), followed by hexane/isopropanol (78%). All binary solvents containing methanol had higher efficiency in removal of phospholipids, and inactivation of lipoxygenase and trypsin inhibitors, as compared to isopropanol containing solvents (P < 0.05). Based on FTIR spectra, lipids removed by methanol containing solvents had high content of phospholipids. The flours defatted by methanol containing solvents exhibited the lowest peroxide value, thiobarbituric acid-reactive substances and beany odour intensity than the non-defatted flour and those defatted by isopropanol containing solvents throughout the storage (P < 0.05) of 30 days at refrigerated and room temperatures. In general, chloroform/methanol was the most effective in inactivating lipoxygenase and trypsin inhibitors, retarding lipid oxidation as well as beany odour development in flour. Therefore, chloroform/methanol could be used to lower beany or grassy odour in Bambara groundnut flour.     

Comparative studies on molecular changes and pro-oxidative activity of haemoglobin from different fish species as influenced by pH

Oxygenation, autoxidation as well as pro-oxidative activity of haemoglobins from tropical fish (Asian seabass, tilapia and grouper) as influenced by different pH (6, 6.5 and 7) were comparatively studied. Relative oxygenation of all haemoglobins decreased in the acidic conditions. Haemoglobin from Asian seabass was more oxygenated and stable against autoxidation at both pH 6 and 7, compared to those from tilapia and grouper. Haemoglobin from tilapia and grouper was fully oxidised at pH 6 after 120 h. Lipid oxidation of washed Asian seabass mince added with haemoglobin from various fish at different pH (6, 6.5 and 7) was monitored during 10 days of iced storage. Haemoglobins accelerated lipid oxidation more effectively at pH 6, compared with pH 6.5 and 7 as indicated by the higher peroxide value (PV) and thiobarbituric acid-reactive substances (TBARS). At the same pH values, haemoglobins from tilapia and grouper were more pro-oxidative than that from Asian seabass as evidenced by the higher PV and TBARS (P < 0.05). Volatile lipid oxidation compounds detected by gas chromatography–mass spectrometry (GC–MS) were also formed at higher rate in the washed mince added with haemoglobin from tilapia or grouper with coincidental stronger fishy odour development, compared to the control and that added with haemoglobin from Asian seabass. Thus, lipid oxidation in fish muscle was more likely governed by haemoglobin, whose pro-oxidative activity varied depending upon the pH as well as molecular properties of haemoglobin.     

Lipids from cephalothorax and hepatopancreas of Pacific white shrimp (Litopenaeus vannamei): Compositions and deterioration as affected by iced storage

Lipids from cephalothorax and hepatopancreas of Pacific white shrimp (Litopenaeus vannamei) stored in ice for up to 6 days were extracted and characterised. The extraction yields of lipids from hepatopancreas (10.65–12.64%) were higher than those from cephalothorax (2.59–2.88%). However, no changes in the extraction yield were observed during the storage (p > 0.05). The carotenoid contents of lipids from cephalothorax and hepatopancreas slightly increased within the first 2 and 4 days of iced storage (p < 0.05), respectively, but decreased thereafter (p < 0.05). With increasing storage time, a progressive formation of hydroperoxide was found as evidenced by the increase in the absorbance band at 3600–3200 cm⁻¹ in Fourier transform infrared (FTIR) spectra, and increased peroxide values (PVs) (p < 0.05). The increases in thiobarbituric acid reactive substances (TBARS), p-anisidine value (AnV) and free fatty acid (FFA) content of lipids were noticeable when iced storage time increased (p < 0.05). Those changes indicated that lipid oxidation and hydrolysis occurred in both samples. Phospholipids (PL) were the major components in lipids from cephalothorax (82.51% of total lipids). Nevertheless, lipids from hepatopancreas contained triglyceride (TG) and PL as the dominant components (45.35% and 38.03% of total lipids, respectively). A decrease in the TG content with a concomitant increase in free fatty acid was observed at the end of storage (day 6) (p < 0.05). Decreases in unsaturated fatty acids, especially eicosapentaenoic acid (EPA; C20:5(n-3)) and docosahexaenoic acid (DHA; C22:6(n-3)) were noticeable at day 6 of storage (p < 0.05). Thus, the extended storage time resulted in the enhanced deterioration of extracted lipids.     

Physicochemical changes of tilapia (Oreochromis niloticus) muscle during salting

The effect of wet and dry saltings on the physicochemical changes of tilapia (Oreochromis niloticus) muscle was investigated. Dry salting resulted in the higher rate of salt uptake into tilapia muscle facilitating the faster decrease in A_w (p < 0.05). The pH of both dry and wet salted fish muscles tended to decrease throughout the salting time and the lower pH was found in dry salted fish (p < 0.05). The increase in the protein content in the salting medium was found during wet salted tilapia production (p < 0.05). The TCA-soluble peptide content tended to decrease with increasing the salting time in both salting methods (p < 0.05), suggesting a leaching effect of the salting medium or the exudative loss occurred in salted tilapia. Wet salting caused the greater formation of metmyoglobin in tilapia muscle when compared to dry salting at all time points (p < 0.05) and the content of metmyoglobin increased as salting time increased in both salting methods (p < 0.05). A lowered metmyoglobin with a lowered redness index of dry salted tilapia muscle was found, indicating the continuous oxidation of metmyoglobin to other hypervalent derivatives and hence the discolouration of salted tilapia. Lipid hydrolysis and oxidation of tilapia meat occurred with varying degrees in both salting methods and these changes depended on salting time. Dry salting resulted in a higher oxidation of tilapia muscle lipid as indicated by the higher PV and TBARS throughout the salting period when compared with that of wet salting (p < 0.05). In conclusion, the physicochemical changes of tilapia muscle during salting are governed by the salting method and the salting time applied.     

Effect of tannic acid and kiam wood extract on lipid oxidation and textural properties of fish emulsion sausages during refrigerated storage

Effect of tannic acid (0.02% and 0.04%) and ethanolic kiam wood extract (EKWE) (0.04% and 0.08%) on lipid oxidation and textural properties of fish emulsion sausages during 20 days of refrigerated storage was investigated. Control samples (C) had the highest peroxide value (PV) and thiobarbituric acid-reactive substances (TBARS) value up to day 16 and 8 of storage, respectively. With the addition of tannic acid and EKWE, PV and TBARS values in the sausages were retarded effectively, compared to the control (P < 0.05), especially when the tannic acid and EKWE at higher level were used. At the same level, EKWE showed the lower ability in retarding the lipid oxidation, in comparison with tannic acid. Tannic acid at both levels (0.02% and 0.04%) was also effective in retarding the formation of fishy odour in the samples throughout the storage, compared to the control and EKWE treated samples (P < 0.05). Both tannic acid and EKWE had no detrimental effect on the sensory attributes of sausages. However, EKWE treated sample had lower L^∗ and higher a^∗ and ΔE^∗ values, compared to the control samples (P < 0.05). After 20 days of storage, the sample added with 0.04% tannic acid had higher hardness, gumminess and chewiness, compared with others (P < 0.05). Samples added with 0.04% tannic acid also displayed more compact structure with no visible voids. Furthermore, oil droplets with smaller size were dispersed more uniformly, compared to others. Thus, tannic acid (0.02% and 0.04%) and EKWE (0.08%) were effective in retarding lipid oxidation and fishy odour development as well as could maintain the textural properties of fish emulsion sausages during the refrigerated storage of 20 days.     

Lipolysis and lipid oxidation in bacon during curing and drying–ripening

Dry-cured bacons were processed using pig bacon belly as material by dry-salting and drying–ripening. Lipolysis and lipid oxidation in intramuscular lipids were studied by evaluating the changes in lipid composition, lipolytic enzymes and lipoxygenase (LOX) activities, peroxide value (POV) and TBARS during processing. Lipid composition showed a significant decrease (p < 0.05) in phospholipids and an increase (p < 0.05) in free fatty acids (r = −0.85, p = 0.0004). All lipolytic activities decreased (p < 0.05) with increasing process time. Acid lipase showed higher activity than did neutral lipase (p < 0.05) throughout the processing. LOX activity increased significantly during salting (p < 0.01) and thereafter decreased. High salt content inhibited acid lipase and phospholipase activities but promoted LOX activity. Both POV and TBARS decreased (p < 0.05) with temperature rising during the last ripening period, suggesting that rising temperature in this period could lower oxidation indices in products. LOX was closely correlated with TBARS (r = 0.94) but not with POV (r = 0.36), indicating that LOX could facilitate lipid secondary oxidation.     

Effect of iced storage of bigeye snapper (Priacanthus tayenus) on the chemical composition,properties and acceptability of Som-fug,a fermented Thai fish mince

The effect of iced storage of bigeye snapper (Priacanthus tayenus) on the chemical composition, properties and acceptability of Som-fug was investigated. During 15 days of iced storage, total volatile base (TVB), trimethylamine (TMA) and TCA-soluble peptide contents as well as thiobarbituric reactive substances (TBARS) of fish muscle increased continuously after 3 days of storage (p < 0.05). It was suggested that deterioration, protein degradation and lipid oxidation proceeded with increasing storage time. Som-fug prepared from surimi of bigeye snapper stored in ice for different times had similar pH, acidity and lactic acid bacteria count at the end of the fermentation (30 °C, 48 h). Generally, higher content of TCA-soluble peptides and higher TBARS were found in fermented Som-fug produced from bigeye snapper stored in ice for a longer time (p < 0.05). Hardness, adhesiveness, springiness, cohesiveness, and resilience of fermented Som-fug decreased with a concomitant increase in weight loss, released water and expressible water contents when fish kept for a longer time were used (p < 0.05). L^∗, a^∗, b^∗, whiteness and the likeness for appearance, colour, texture and flavour of Som-fug decreased when fish kept in ice for an extended time were used (p < 0.05). However, the taste likeness was not affected by iced storage time (p > 0.05). No differences in overall liking were noticeable when fish kept in ice for up to 12 days were used for Som-fug production (p > 0.05). Therefore, the quality of fish used as raw material should be an important factor in determining the characteristics of Som-fug.     

Post-mortem changes of muscle from fresh water prawn (Macrobrachium rosenbergii) as influenced by spawning stages

Post-mortem changes of the muscle from pre- and post-spawned fresh water prawn (Macrobrachium rosenbergii) were comparatively monitored during 7 days of iced storage. During the storage, the muscle of pre-spawned prawn had a greater value of trichloroacetic acid (TCA) soluble peptide, heat soluble collagen and pepsin-soluble collagen (PSC) contents than did post-spawned counterpart. Those components in the muscle of both prawns increased markedly after 3 days of storage (p < 0.05). Conversely, insoluble collagen (ISC) content, shear force value and texture liking of both prawns decreased (p < 0.05), indicating the softening of muscle. No changes in protein patterns were observed, except the decreased band intensity of 66 kDa protein in water soluble fraction of both prawns was found after 3 days of storage. T_max and enthalpy of PSC from both prawns decreased during the first 4 days of storage (p < 0.05), suggesting the degradation or denaturation of collagen in the muscle. Light microscopic study showed the lowering of intercellular connection of raw meat and higher gaping in cooked meat when the samples were stored for a longer time. Therefore, post-mortem characteristics of prawn muscle was affected by storage time and spawning stages.     

Effect of Kiam (Cotylelobium lanceolatum Craib) Wood Extract on the Haemoglobin-Mediated Lipid Oxidation of Washed Asian Sea Bass Mince

Introduction

Effect of ethanolic kiam wood extract (EKWE; 12 0.05% and 0.1%, w/w) on the retardation of haemoglobin-mediated lipid oxidation of washed Asian sea bass mince added without and with menhaden oil stored in ice up to 10 days was investigated.

Results and discussion

Samples containing haemoglobin had the highest peroxide value (PV) within the first 8 days and possessed the greater amount of thiobarbituric acid-reactive substances (TBARS), compared to those added with no haemoglobin (P?<?0.05), regardless of 5% menhaden oil addition. Incorporation of 5% (v/w) menhaden oil to the washed mince had no impact on the formation of PV and TBARS, compared with oil-free samples during the storage (P?>?0.05). With addition of EKWE, lipid oxidation in washed mince added with haemoglobin and menhaden oil was retarded, especially when the higher level (0.1%; w/w) was used, as evidenced by lowered PV and TBARS. Formation of volatile lipid oxidation compounds was retarded in the sample containing oil and haemoglobin and treated with 0.1% EKWE, compared with that without the addition of EKWE after 10 days of storage in ice (P?<?0.05).

Conclusion

Sensory analysis revealed that samples containing haemoglobin without and with oil added had the highest intensity of fishy odour, compared to those treated with EKWE (0.05% and 0.1%) and the control sample (washed mince; P?<?0.05). Thus, EKWE, especially at a level of 0.1%, could serve as a potential natural antioxidant in prevention of lipid oxidation and retardation of development of fishy odour and volatile lipid oxidation compounds in washed mince during iced storage.     

Fatty acid composition of three freshwater fishes under different storage and cooking processes

Fatty acid composition of common carp (Cyprinus carpio), Nile tilapia (Oreochromis niloticus) and tambacu, a hybrid of tambaqui (Colossoma macropomum) and pacu (Piaractus mesopotamicus), was evaluated by gas chromatography. Raw, roasted and steamed fishes with and without skin were analyzed fresh and after 15, 30 and 45 storage days at −20 °C. Total lipid content was 9.3 g/100 g in carp, 0.79 g/100 g in tilapia and 1.3 g/100 g in tambacu with skin, with reductions of about 63%, 39% and 71% in the fishes without skin, respectively. The carp showed a high content of monounsaturated fatty acids (about 50%). In tilapia, palmitic and oleic acids were present in larger proportion, 26.55% and 23.86%, respectively. In tambacu, the fatty acid profile was 37% saturated, 34% monounsaturated and 21% polyunsaturated. Fatty acid composition did not present wide variations due to storage time and preparation, indicating that the storage and cooking methods used did not interfere in fatty acid composition.     

Storage stability of liver oil from two ray (Rhinoptera bonasus and Aetobatus narinari) species from the Gulf of Mexico

The effect of storage time on the quality of liver oil from two commercial rajiform species (Rhinoptera bonasus and Aetobatus narinari) captured in the Gulf of Mexico (State of Campeche coast line) was evaluated. Oil characterisation was conducted by physical (specific gravity, saponification index and water content) and chemical analyses (fatty acid content, carotenes and tocopherols) whilst storage stability (peroxide value, free fatty acids, conjugated dienes, anisidine value and changes in docosahexaenoic acid, DHA and content) was studied for 87 days at 25 °C. Increases (p < 0.05) in free fatty acids, conjugated dienes, peroxide value and anisidine value, and a decrease (p < 0.05) in DHA were observed during the storage time for both oil species as oxidation proceeded. It was concluded that R. bonasus and A. narinari oils lasted for 52 and 66 days under these storage conditions, respectively.     

Retardation of myoglobin and haemoglobin-mediated lipid oxidation in washed bighead carp by phenolic compounds

Antioxidative activities of phenolic compounds (caffeic acid, gallic acid and tannic acid; 200 ppm) in washed mince (pH 6), with added myoglobin (Mb) and haemoglobin (Hb), from bighead carp (Hypophthalmichthys nobilis), during 9 days of iced storage, were studied. Tannic acid exhibited the preventive effect on discolouration of washed mince containing Mb or Hb during storage (P < 0.05). High peroxide value (PV) was found and large amount of, thiobarbituric acid-reactive substances (TBARS) and hexanal were formed in washed mince containing haem proteins, especially Hb. As determined by apo Streptococcal haem-associated protein, Hb had the lower haem affinity than Mb. Phenolic compounds, especially caffeic acid and gallic acid, could lower lipid oxidation induced by Mb or Hb throughout storage (P < 0.05). Prevention of haem release, as well as inhibition of lipid oxidation induced by haem proteins with selected phenolic compounds, should be an alternative means in lowering discolouration and lipid oxidation in fish muscle.     

Colour,lipid and protein stability of Rhea americana meat during air- and vacuum-packaged storage: Influence of muscle on oxidative processes

Physicochemical characteristics and oxidative stability during storage were determined in Gastrocnemius pars interna (GN) and Iliofiburalis (IF) muscles of Rhea americana. Glycolytic potential (GP) and pH decline of muscles were measured within the first 24 h post mortem. Colour, lipid and protein stability were determined during storage of meat, i.e. 5 days under air-packaging at 4 °C, or 28 days under vacuum-packaging at 4 °C. In parallel, anti-oxidant status of muscles was estimated by measuring α-tocopherol content and anti-oxidant enzyme activities (superoxide dismutase and catalase), while pro-oxidant status was evaluated by determining haeminic iron and long chain fatty acids (especially polyunsaturated fatty acids). The ultimate pH was similar in both muscles, but the GP value was significantly higher in IF than in GN muscle. Haeminic iron and alpha-tocopherol content differed between muscles, with 30% more haeminic iron (p < 0.05) and 134% more alpha-tocopherol (p < 0.001) in IF than GN muscle. The IF muscle presented higher lipid content and lower PUFA/SFA ratio (polyunsaturated fatty acids/saturated fatty acids) than GN muscle. With storage under air-packaging, lipid and protein oxidation of rhea muscles increased up to 275% and 30%, respectively. This increase was more rapidly and marked in IF muscle. The IF also showed high level of metmyoglobin accumulation after 3 days of storage (47%) and was rejected by 1 consumer out of 2 in sensorial analysis. Under vacuum-packaging, both muscles showed a high stability of colour and no oxidation of lipids and proteins.     

Effect of the ripening time under vacuum and packaging film permeability on processing and quality characteristics of low-fat fermented sausages

The effect of vacuum ripening of low-fat fermented sausages packaged in films with different permeabilities on their microbiological, physicochemical and sensorial characteristics was studied. High-fat control sausages were produced with 30% initial fat and low-fat sausages with 10% initial fat. The low-fat sausages were separated into: (a) non-packaged (control) and (b) packaged under vacuum on 7th, 12th and 17th day of processing, remaining under vacuum during the ripening period for 21, 16 and 11 days, respectively, in three different oxygen (100, 38 and ? 5 cm³/m²/24 h/1 atm) and water vapour (4.5, <2.5 and 1 g/m² 24 h) permeability plastic bags. Vacuum packaging reduced (p < 0.05) the weight loss, the hardness and extent of lipid oxidation in the sausages, increased (p < 0.05) their lightness, but had no effect (p > 0.05) on the redness, compared to the control sausages. Packaging low-fat fermented sausages under vacuum for the last 11 days of ripening in packaging film with high permeability increased (p < 0.05) the lactic acid bacteria count. The same product packaged in film with medium permeability had a higher (p < 0.05) Micrococcaceae count and the same (p > 0.05) hardness and overall acceptability as the high-fat control sausages. A ripening time of 11 days and the medium packaging film permeability were the most appropriate conditions for the vacuum packaging of low-fat fermented sausages.     

Postmortem changes in cazon fish muscle stored on ice

The biochemical, chemical and physical postmortem changes and their relation to the cazon muscle eating quality were studied during an 18 day storage period at 0 °C (ice). Content of ATP and breakdown products, K value, pH, trimethylamine (TMA-N), total volatile bases (TVB-N), water-holding capacity (WHC), colour and texture changes were examined. At the beginning of the study, the cazon muscle showed a low concentration of ATP and a high value of IMP. Regarding to the signs of freshness and deterioration, K value presented a linear increase (r² = 0.97) with an initial value of 1.05% and a final value of 58.9%. The TBV-N and TMA-N significantly increased (P < 0.05). As for the physical analysis whereas the pH and the WHC changed (P < 0.05); texture was not affected (P < 0.05). The overall results of this study indicated that the edible quality of cazon fish muscle was maintained during at least 18 days of ice storage.