Effect of previous gutting on rancidity development in horse mackerel (Trachurus trachurus) during frozen storage at −20 °C

Gutting was applied to fresh horse mackerel (Trachurus trachurus) to study its effect on rancidity development during a prolonged frozen storage (up to 12 months at −20°C). To do so, chemical (free fatty acids, FFA; peroxide value, PV; thiobarbituric acid index, TBA-i; fluorescence ratio, FR) and sensory (odour and taste) analyses were carried out. The results showed that the gutting of horse mackerel led to a higher degree of oxidation in the frozen product, according to the chemical (PV, TBA-i and FR) and sensory (odour and taste) analyses. However, a lower extent of lipid hydrolysis (FFA formation) was detected at the end of the storage (twelfth month) as a result of gutting. It is concluded that the gutting of a medium-fat fish species such as horse mackerel is not recommended as previous treatment to frozen storage.     

Influence of storage time and temperature on lipid deterioration during cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) frozen storage

Lean fish deterioration during frozen storage (−30 and −10 °C) for up to 1 year was studied by the assessment of lipid changes. Comparison between a formaldehyde (FA)-forming species (cod) and a non-FA-forming one (haddock) was carried out. Lipid damages were measured on the basis of free fatty acids (FFA), peroxide value (PV), thiobarbituric acid index (TBA-i) and fluorescent compounds. In both species at −30 °C, most lipid damage indices showed significant correlations with the storage time. However, at −10 °C, only the FFA and fluorescence detections provided significant correlations with the storage time. Comparison between the fish species showed higher lipid oxidation (PV and TBA-i) and hydrolysis (FFA content) in haddock than in cod at −10 °C; however, a higher fluorescence development was observed in cod at the same temperature. At −30 °C, little differences in lipid damage indices were detected between the two species. © 1999 Society of Chemical Industry     

Effect of previous chilled storage on rancidity development in frozen horse mackerel (Trachurus trachurus)

Rancidity development during frozen storage (?20 °C) of an underutilised medium‐fat‐content fish species, horse mackerel (Trachurus trachurus), was studied. Special attention was given to the effect of previous chilled storage (0, 1, 3 and 5 days) on the quality of the frozen fish. For this, chemical (free fatty acid and conjugated diene contents; peroxide value, PV; thiobarbituric acid index, TBA‐i; fluorescent compound formation) and sensory (rancid odour and taste) analyses were carried out. Hydrolytic rancidity showed an increase with frozen storage time; however, no effect of previous chilling time was observed on the frozen product. Oxidative rancidity measured by chemical (PV, TBA‐i and fluorescence) and sensory (odour and taste) indices increased with frozen storage time and also with previous chilling time. Satisfactory quality was maintained up to 7 months of frozen storage of horse mackerel provided that a short chilling time (not longer than 3 days) was employed. © 2002 Society of Chemical Industry     

Effects of brine concentration on shelf-life of hot-smoked tilapia (Oreochromis niloticus) stored at 4 °C

This work evaluated the effect of brine concentration on the shelf-life of hot-smoked tilapia (Oreochromis niloticus) stored at 4 °C. The fish were brined in solutions of 5%, 10%, and 15% NaCl and unsalted fish were used as controls. The fish were then smoked, cooled and stored at 4 °C. Oxidative rancidity measured by the peroxide value (PV), and thiobarbituric acid number (TBA) showed increases with the storage time and also as a result of the increasing salt content in fish muscle. Hot smoked tilapia can be stored safely under refrigerated conditions for over 35 days, and 5% brine was found to be optimal for storage.     

Differential lipid damage in various muscle zones of frozen hake (Merluccius merluccius)

 A comparison of the lipid damage produced in different hake zones was carried out during frozen storage at –11 and –18  °C. Three light muscle zones and the dark muscle were considered. Lipid oxidation [conjugated dienes; thiobarbituric acid index (TBA-i); fluorescence formation] and hydrolysis (free fatty acids, FFA) were determined. The most predominant lipid damage in all zones was hydrolysis, at the end of storage reaching values of about 40% (for the light muscle zones) and 12% (for the dark muscle) of the total lipids at –11  °C. Significant (P<0.05) correlation value (r=0.67–0.85) relationships between the frozen storage time and the FFA content were obtained for the four muscle zones at both temperatures. A comparison of the regression lines slopes in the different zones showed that a lower (P<0.05) lipolitic activity was produced in the dark muscle compared to the three light zones at both temperatures. A low lipid oxidation development was produced in the three light muscle parts, so that no significant differences between them could be assessed. However, the dark muscle showed a higher oxidation development (TBA-i and fluorescence formation) as a result of a higher lipid content and the presence of prooxidant constituents. Received: 16 June 1998     

Differential lipid damage in various muscle zones of frozen hake (Merluccius merluccius)

 A comparison of the lipid damage produced in different hake zones was carried out during frozen storage at –11 and –18  °C. Three light muscle zones and the dark muscle were considered. Lipid oxidation [conjugated dienes; thiobarbituric acid index (TBA-i); fluorescence formation] and hydrolysis (free fatty acids, FFA) were determined. The most predominant lipid damage in all zones was hydrolysis, at the end of storage reaching values of about 40% (for the light muscle zones) and 12% (for the dark muscle) of the total lipids at –11  °C. Significant (P<0.05) correlation value (r=0.67–0.85) relationships between the frozen storage time and the FFA content were obtained for the four muscle zones at both temperatures. A comparison of the regression lines slopes in the different zones showed that a lower (P<0.05) lipolitic activity was produced in the dark muscle compared to the three light zones at both temperatures. A low lipid oxidation development was produced in the three light muscle parts, so that no significant differences between them could be assessed. However, the dark muscle showed a higher oxidation development (TBA-i and fluorescence formation) as a result of a higher lipid content and the presence of prooxidant constituents.     

Influence of feeding state and frozen storage temperature on the lipid stability of Atlantic mackerel (Scomber scombrus)

Lipid deterioration of mackerel caught in Icelandic waters was studied, as affected by different frozen storage temperatures (?18 °C vs. ?25 °C) and seasonal variation (August vs. September). The lipid stability was investigated by analyses of hydroperoxide value (PV), thiobarbituric acid reactive substances (TBARS), free fatty acids, as well as changes in fatty acid composition. Results showed significant lipid deterioration with extended storage time, where the lower storage temperature showed significantly more protective effects. Furthermore, a higher lipid oxidation level was recorded for fish caught in September than in August, although lipid hydrolysis occurred to be greater for fish in August than in September. Moreover, results indicated a rather stable level of omega‐3 fatty acid during the whole frozen storage period. The analysis indicated that both lipid oxidation and hydrolysis were affected by the frozen storage temperature and the stability differed with regard to season of catch.     

The effect of salt concentration on rancidity in Gaziantep cheese

Gaziantep cheese is a non‐fermented and enzyme clotted type cheese. The changes in oxidative and hydrolytic rancidity in the cheese were analysed during its storage. Storage conditions were selected as 4, 10 and 20°C and 90, 170, 200 and 230 g kg⁻¹ salt solutions by considering the traditional storage conditions. Oxidative rancidity increased with increasing temperature and NaCl concentration in the brine. Hydrolytic rancidity increased with increasing temperature and decreasing salt content of the cheese. The extent of oxidative rancidity was found to be higher than hydrolytic rancidity. The results of this study showed that the storage temperature should not be higher than 10°C and brine concentration must be higher than 90 g kg⁻¹ and lower than 230 g kg⁻¹ to minimize lipid oxidation. Gaziantep cheese was organoleptically examined after 2 months of storage at 20°C and in 90, 170 and 230 g kg⁻¹ salt solutions, and it was found that even at a peroxide value around 1 meq kg⁻¹, acceptable levels of changes in flavour were observed. Sensory analysis results showed that textural properties of Gaziantep cheese changed with salt concentration of the brine. © 1999 Society of Chemical Industry     

Factors Affecting Properties of Precooked-Frozen Pork Sausage Patties Made with Various NaCl/Phosphate Combinations

Whole hog sausage patties made with (1) no phosphate, (2) 0.375% sodium tripolyphosphate (STP) and (3) 0.441% Lem-0-Fos® in combination with salt levels of 1.5, 1.0, 0.5 and 0.0% NaCl were precooked, frozen and packaged. Use of phosphates increased pH values, cooking yield, saltiness and juiciness scores and decreased the formation of off-flavor and rancidity. Higher NaCl levels increased saltiness scores and maintained juiciness scores and reheating yields over extended periods of frozen storage. Sodium chloride alone increased TBA values but did not affect (P > 0.05) off-flavor scores. The use of phosphates or vacuum packaging reduced the development of off-flavor and rancidity during extended periods of frozen storage.     

Changes in lipids and proteins of marine catfish (Tachysurus dussumieri) during frozen storage

Changes in lipids and protein of marine catfish ( Tachysurus dussumieri ) were followed over a period of 300 days storage at –20°C. Phospholipids decreased and free fatty acids (FFA) and peroxide value (PV) increased. A linear relationship between the decrease in phospholipid and increase in FFA was observed, suggesting that FFA were formed by hydrolysis of phospholipid. Fatty acid analysis showed that polyunsaturated fatty acids (PUFA) increased in the neutral lipid fraction and decreased in the phospholipid fractions; this also suggests hydrolysis of the latter and release of free PUFA into the neutral fraction.
A decrease in water soluble protein (WSP) and salt soluble protein (SSP) indicated denaturation of proteins on prolonged frozen storage; both changes were strongly associated with the changes in peroxide value and free fatty acids.     

Stabilization of Lipids in Minced Fish by Freeze Texturization

Minced meats of Baltic cod (Gadus morhua) with added krill (Euphausia superba D.), krill precipitate, or bream (Abramis brama) were freeze-textured or frozen conventionally. Lipid composition and oxidation were analyzed after 6–8 mo storage at –20°C. Analyses included peroxide value, fluorescence, lipid classes (thin-layer chromatography), and fatty acid composition (gas chromatography). Peroxide value was 4–9 times lower in freeze-textured meat minces than in conventionally frozen samples. Docosahexaenoic acid (DHA) was higher, by 22% in bream minces to 80% in cod minces without additives, in all freeze-textured minces than in conventionally frozen samples. Texturization could reduce lipid oxidation in minced fish during frozen storage.     

Effects of Mechanically Separated Beef with Various Chloride Salts in Restructured Beef Steaks

The effects of various chloride salts (NaCl, MgCl₂, KCl or 65% NaCl + 35% KCl) in combination with mechanically separated beef (MSB at 0, 10 or 20%) on the quality of restructured steaks formulated from bullock chucks were determined. As level of MSB increased, objectionable connective tissue, flavor desirability and overall palatability decreased and off-flavors increased. The development of oxidative rancidity during frozen storage was not affected by MSB level and MSB had little effect on textural traits. NaCl and NaCl + KCl treated steaks received superior flavor and overall palatability ratings over steaks containing MgCl₂ or KCl. Oxidative rancidity developed faster in steaks containing NaCl than the other salt types. Partial replacement (35%) of NaCl with KCl resulted in restructured steaks with sensory properties equal to and storage life superior to steaks with NaCl alone.     

Effect of lipid oxidation and frozen storage on muscle proteins of Atlantic mackerel (Scomber scombrus)

The effect of storage on the lipids and proteins in Atlantic mackerel stored for up to 24 months at ?20 and ?30 °C was studied. Traditional methods including the peroxide value, thiobarbituric acid‐reactive substances (TBARS) and a reverse phase HPLC method were used to determine the primary and secondary lipid oxidation products. All tests showed an increase in lipid oxidation products with storage time and at a higher storage temperature of ?20 °C compared with samples stored at ?30 °C. Antioxidants had a significant effect (P < 0.01) on the inhibition of lipid oxidation, as shown by the reduction in peroxide value and hydroxides, and malondialdehyde formation. Similarly, deterioration of protein structure and functionality in mackerel stored for 3, 6, 12 and 24 months was greater at ?20 than ?30 °C. ATPase activity in the myosin extract of Atlantic mackerel showed a significant decrease (P < 0.01) with progressive frozen storage. Protein solubility in high salt concentration (0.6 M NaCl) decreased (P < 0.01) during storage at both ?20 and ?30 °C but was greater at ?20 °C. Interestingly, antioxidants BHT, vitamin C and vitamin E protected the proteins against complete loss of ATPase activity and protein solubility to a significant level (P < 0.01) for up to 1 year at ?20 °C compared with samples stored without antioxidants. This study confirms the deleterious effect of lipid oxidation products on protein structure and function in frozen fatty fish. © 2002 Society of Chemical Industry     

Factors Affecting Properties of Raw-Frozen Pork Sausage Patties Made with Various NaCl/Phosphate Combinations

Whole hog sausage patties made with (1) no phosphate, (2) 0.375% sodium tripolyphosphate (STP) and (3) 0.441% Lem-O-Fos® in combination with salt levels of 1.5, 1.0, 0.5, and 0.0% NaCl were frozen and packaged. Use of phosphates decreased off-flavor and rancidity development, improved binding, and increased pH values, cooking yields and scores for saltiness and juiciness. The prooxidant effect of NaCl was masked by the antioxidant properties of STP and Lem-O-Fos®. Extended periods of frozen storage reduced cooking yields, juiciness and texture scores and enhanced development of off-flavor and rancidity. However, use of phosphates or vacuum packaging exhibited an antioxidant effect during extended periods of frozen storage.     

Effect of brine freezing on the rancidity development during the frozen storage of small pelagic fish species

Brine freezing was applied to two small pelagic underutilised fish species (mackerel, Scomber scombrus; horse mackerel Trachurus trachurus). Rancidity development was studied during their frozen (–18 °C) storage up to 9 months, and quality change results were compared to common freezing conditions (control treatment). Fish samples treated under brine freezing conditions showed a higher lipid oxidation development (peroxide value and thiobarbituric acid index) and worse marks on some sensory attributes (general aspect, odour and colour) than control fish. However, samples treated under brine freezing conditions provided a lower lipid hydrolysis development (free fatty acid formation) and better scores for consistency. Comparison between both fish species led to a higher secondary lipid oxidation formation (thiobarbituric acid index) for mackerel, while horse mackerel showed to be more prone to interaction compound formation (fluorescence detection); however, both fish species showed the same shelf-life times (3 and 5 months for brine and control freezing conditions, respectively). As a result of the brine freezing conditions, an increase in NaCl content in white muscle of both species was observed. According to the results obtained in the present work, the brine freezing treatment is not recommended for these two small pelagic fish species.     

Rancidity development in frozen pelagic fish: Influence of slurry ice as preliminary chilling treatment

The slurry ice technology has shown profitable advantages when employed instead of traditional flake ice for the manufacture of chilled aquatic species. The present work is aimed at evaluating the effect of slurry ice as a preliminary treatment prior to frozen storage. For it, specimens of a small pelagic fatty fish species (sardine; Sardina pilchardus) were stored in slurry ice for 2, 5 and 9 days, then subjected to freezing (-80 °C; 24 h) and finally kept frozen (−20 °C) during 1, 2 and 4 months. At such times, rancidity development in frozen sardine was measured by sensory (odour, skin, colour and flesh appearance) and biochemical (lipid hydrolysis and oxidation) analyses and compared to a control batch previously chilled in flake ice. Sensory analysis indicated an extended shelf-life time for frozen sardine that was preliminary stored under slurry ice for 2, 5 or 9 days, as compared to their counterparts subjected to flake icing. Sensory results were corroborated (P<0.05) by biochemical lipid oxidation indices (thiobarbituric acid reactive substances and the fluorescence formation). The present work opens the way to the use of slurry ice instead of flake ice as preliminary treatment of fish material prior to the frozen storage.     

食盐含量对猪肉肌内脂肪水解和氧化的动力学影响

为探究猪肉加工中不同食盐含量对肌内脂肪水解和脂肪氧化的影响,以猪背最长肌为原料,分别加入1％、2％、3％、4％和5％的食盐,经不同温度(15～30℃)处理后,研究肌内甘油三酯和磷脂水解的动力学规律及游离脂肪酸和脂肪氧化的动力学变化.结果表明,磷脂水解、甘油三酯水解和脂肪氧化均符合一级动力学模型,游离脂肪酸变化符合零级动...     

Deterioration of Fresh-Water Whitefish Muscle During Frozen Storage at −10°C

SUMMARY— Organoleptic and chemical deterioration of freshwater whitefish muscle frozen at −10°C for periods up to 16 weeks was assessed. As frozen storage of muscle progressed, the toughness and rancidity of baked muscle increased. The solubility of the myofibrillar protein fraction, "actomyosin," dropped from about 72 to 22% over the 16 week storage period of whitefish muscle. No change in the solubility of sarcoplasmic protein in frozen stored muscle was observed. However, with polyacrylamide disc electrophoresis, two new sarcoplasmic protein bands were detected after 16 weeks of storage. With storage of frozen muscle, water-binding capacity diminished. Although the total lipid and cholesterol contents of muscle remained constant throughout frozen storage, the phospholipid content decreased as the free fatty acid content increased. Oxidative deterioration of lipid in frozen muscle was estimated.     

Effect of caffeic acid on haemoglobin‐mediated lipid and protein oxidation in washed cod mince during ice and frozen storage

BACKGROUND: Little is known about the relation between haemoglobin (Hb)‐mediated lipid and protein oxidation in muscle foods and how these two reactions can be inhibited by naturally occurring antioxidants. This study was aimed at evaluating (1) lipid oxidation and protein oxidation induced by 20 µmol L^?1 Hb during chilled and frozen storage of washed cod mince and (2) the efficiency of 10–1000 ppm (0.063–6.3 mmol L^?1) caffeic acid in preventing these reactions. RESULTS: Addition of 20 µmol L^?1 Hb increased peroxide value (PV), rancid odour, protein carbonylation, protein insolubilisation, redness loss and α‐tocopherol loss in ice‐stored washed cod mince. Since both lipid and protein oxidation developed at the same time, it was not possible to conclude which reaction initiated the other. All studied reactions were efficiently inhibited by ≥ 50 ppm caffeic acid, which could be a result of α‐tocopherol regeneration, general radical scavenging, reduced formation of oxidised Hb forms and/or conformational changes in Hb structure. During frozen storage the only clear effect of Hb was increased PV, and here caffeic acid was less efficient as an antioxidant. CONCLUSION: Hb‐induced lipid and protein oxidation occurred quickly in ice‐stored washed cod mince, and the two reactions could not be separated in time. During frozen storage, Hb caused only limited lipid oxidation. Caffeic acid (≥50 ppm) was an efficient antioxidant during ice storage. Copyright © 2010 Society of Chemical Industry     

Effects of sea trout egg quality on stability of salted roe during cold storage

Sea trout eggs were salted in NaCl solution after 4 and 14 days of cold storage. The study indicated that the egg resistance to crushing decreased during cold storage from the initial 220 g to 180 g after 14 days. Changes in hardness of the egg membrane accelerated salt diffusion by about 30% to 80% during immersion in NaCl solution. Salting the eggs to 2.3% and 4.0% NaCl content decreased the hardness during cold storage, the decrease being larger in the roe manufactured from a lower quality raw material. In the eggs containing 5.3% and 7.0% NaCl the resistance to crushing increased during storage at 4°C to the extent similar in both egg freshness states obtained prior to salting. The salt content in sea trout eggs ranging from 23% to 7.0% only slightly activated hydrolysis and oxidation of lipid components at 4°C. Lipid oxidation was more rapid in eggs salted after 14 than in those salted after 4 days of storage in ice. Carotenoids of the salted eggs showed a decrease in undesirable cis-bonds during cold storage. Salting the sea trout eggs after 14 days of storage at 2°C shortened the storage time of the final product at 4°C by at least 1 month as compared to the salted roe kept in ice for 4 days before salting.