Effect of Frozen Storage Temperature on Quality-Related Changes in Rainbow Trout (Oncorhynchus mykiss)

The effect of frozen storage temperature on quality-related parameters of rainbow trout (Oncorhynchus mykiss) muscle was studied in the interval from ?10 to ?80°C on samples stored for 1 to 18 months. The following quantities were measured: drip loss, water holding capacity and water distribution, color, lipid oxidation (thiobarbituric acid-reactive substances, TBARS), and membrane stability (enzyme activity). No effect of temperature on drip loss, water holding capacity, water distribution, or membrane stability was observed for samples stored below ?20°C, whereas storage at ?40°C or lower compared to ?30°C or higher resulted in a reduced level of secondary lipid oxidation (TBARS). No advantage was gained by using temperatures below ?40°C for frozen storage of trout regarding any of the properties investigated.     

Effects of Freezing and Frozen Storage on Protein Functionality and Texture of Some Cephalopod Muscles

The aim of this study was to investigate the effects of freezing and frozen storage on protein functionality and texture of squid (Loligo vulgaris), octopus (Octopus vulgaris), and cuttlefish (Sepia officinalis) muscles. Squid, octopus, and cuttlefish samples were cut into pieces of 4 × 4 cm. These pieces were packed in polyethylene bags. The bags were frozen in a blast freezer at ?45°C until the thermal center reached ?18°C. Frozen samples were stored in a deep freezer at ?18°C for 30 days. After freezing and during frozen storage, total soluble protein and water holding capacity decreased and total free amino acid and cooking loss increased in all cephalopod muscles. According to instrumental texture analysis results, freezing and frozen storage affected textural characteristics of squid and cuttlefish but not of octopus. Sensory hardness and chewiness values of all cephalopods increased after freezing, but elasticity values did not change. There were no significant differences between storage days in hardness values of squid and octopus. However, significant differences in hardness values of cuttlefish were observed between the 1st day of storage and the last day.     

The Effects of On-Board Handling and Frozen Storage on Gaping in Hoki (Macruronus novaezelandiae)

Abstract

Hoki were trawl-caughl under commercial conditions and subjected to one of five treatments before heading and gutting and freezing to ?35°C. Fish were either processed within 1 hour of capture, held at ambient temperatures or in ice until rigor was established or held at ambient temperatures or in ice until rigor was resolved. Fish from each treatment were then stored at ?20°C for periods of up to 56 weeks and tested for gaping, pH and other related physical and sensory properties. Fish frozen post-rigor showed the most gaping and fish frozen pre-rigor had less than those frozen in rigor. The temperature of storage before freezing had little effect on gaping other than extending the time taken to proceed through rigor. Extended time in frozen storage resulted in decreased water-holding capacity but had little effect on gaping. Gaping was not related to pH levels and did not affect the texfural properties of the cooked fish.     

Prevention of thaw-rigor during frozen storage of bigeye tuna Thunnus obesus and meat quality evaluation

Thaw-rigor is often found in frozen meat of bigeye tuna Thunnus obesus. Excessive amounts of drip loss and stiffness greatly lower the commercial value of tuna meat. In order to prevent thaw-rigor in meat stored at −60°C post-capture, we adapted a temperature shift technique that stores the meat at −7°C for 1 day or −10°C for 7 days before thawing. Biochemical changes in muscle of bigeye tuna before and after the temperature shift to −7 or −10°C were characterized. Contents of ATP, NAD⁺, glycogen, and creatine phosphate decreased after the temperature shift. NAD⁺ levels decreased faster than ATP levels and were highly correlated with the rigor index. Thaw-rigor occurred in muscle containing NAD⁺ at 1 μmol/g and ATP at 7 μmol/g. On the other hand, the meat color of tuna during frozen storage changed to brown depending on the storage temperature and reflected the rate of metmyoglobin (met-Mb) formation. Met-Mb formation increase was dependent on the decrease in NADH levels during the frozen storage. A temperature shift technique with storage at −7°C for 1 day or −10°C for 7 days before thawing prevented thaw-rigor and met-Mb formation.     

Effect of Temperature on Quality-Related Changes in Cod (Gadus morhua) During Short- and Long-Term Frozen Storage

Cod (Gadus morhua) was stored at eight temperatures (?10 to ?80°C) for 1 to 18 months, after which quality indicators were measured—including drip loss, water holding capacity, low field NMR spin-spin relaxation, color, amount of thiobarbituric acid reactive substances, and sarcoplasmic reticulum Ca2+-ATPase and lysosomal Cathepsin D activities. Results from samples stored up to 12 months showed no significant differences between ?30°C and lower temperatures. The NMR measurements, however, indicated some changes in the water distribution of samples stored at ?30°C for 12 or more months compared to storage at ?40°C or lower.     

Suppressive effect of ATP on autoxidation of tuna oxymyoglobin to metmyoglobin

The discoloration of tuna meat proceeds during frozen storage at around ?20 °C. On the other hand, the discoloration of highly fresh tuna meat could effectively be suppressed even if stored at ?20 °C. However, the suppressive mechanism of the discoloration is not well understood. Here the effects of ATP on the autoxidation rate and molecular structure of tuna myoglobin are reported. The autoxidation rate of southern bluefin tuna Thunnus maccoyii myoglobin at 25 °C was suppressed in the presence of ATP especially in acidic pH range. Mixing ATP with myoglobin induced a spectral perturbation in the soret region of myoglobin. This spectral perturbation was observed as a function of the ATP concentration. Quenching of myoglobin fluorescence was also caused by ATP, saturating at around 0.5 mM ATP. According to dynamic light-scattering measurements, the molecular weights of tuna Mb changed from 15.5 to 11.3 kDa with ATP and zeta-potential measurements gave also a negative surface charge without ATP and a positive one with ATP, respectively. The above results indicate that ATP-induces changes in the conformational structure of myoglobin. The effects of ATP on myoglobin could thus provide a possible mechanism to regulate the autoxidation of myoglobin.     

Effect of a Previous Washing Step with Tannic Acid on the Quality of Minced Horse Mackerel (Trachurus trachurus) During Frozen Storage

Fatty fish have been recognized as potential raw material for production of minced meat; however, they are prone to oxidation and further deterioration. In the present study, the effect of washing and antioxidant (tannic acid) treatment on the quality of minced meat of Trachurus trachurus (horse mackerel) during frozen storage was observed. Minced meat of Trachurus trachurus was divided into three lots (T0, T1, and T2). T1 was washed with cold water, T2 with cold water containing tannic acid (100 mg/kg), and T0 was not washed. All the lots were frozen at ?40°C and stored at ?20 ± 2°C for 125 days and were subjected to biochemical, microbiological, and sensory evaluation at regular intervals of 25 days. The antioxidant treatment with tannic acid at the dosage used was found effective in minimizing the rancidity problems of minced meat (T2), compared to T0 and T1. During the whole period of storage, samples from T2 showed good quality in terms of microbiological, biochemical, and sensory analysis compared to T1 and T0.     

Effects of Conservation Method and Time on Fatty Acid Composition,Taste, and Microstructure of Southern King Crab (Lithodes santolla Molina, 1782) Meat

This study reports the changes in fatty acids, taste, and microstructure of cooked southern king crab meat (Lithodes santolla) during storage at 0°C for 10 days and at ?20°C for 90 days. At the end of both storage times, the iodine value decreased by 16.5%, while 83.5% of the initial fatty acid quality remained unchanged. The polyene ratio decreased by 32% at 0°C and 35.9% at ?20°C, whereas the atherogenic and thrombotic indices remained at values that do not represent any risk to human health. Free amino acids that contribute to taste (taste activity value, TAV > 1) were: glycine and alanine (sweetness), arginine (bittersweetness), and histidine (bitterness). The bittersweet taste imparted by arginine (initial TAV = 16.4) was prevalent even at the end of frozen storage (TAV = 7.9). The umami taste was elicited by disodium 5′-adenosine monophosphate (AMP) nucleotide. The equivalent umami concentration in g MSG/100 g meat changed from 0.031 to 0.045 in refrigerated samples and to 1.6 in frozen samples. A loss of the original fibrous structure of the meat was evidenced during both treatments. Refrigerated samples presented a disintegrated and homogeneous texture at 10 days, while freezing formed a spongy tissue at 90 days.     

Comparison of Postmortem Changes in Blunt-Snout Bream (Megalobrama amblycephala) During Short-Term Storage at Chilled and Partial Freezing Temperatures

In order to obtain more information about the consumption and process of blunt-snout bream, this study investigated postmortem changes of pH, cooking loss, texture properties (hardness, cohesiveness, springiness, and gumminess), and adenosine triphosphate (ATP)-related compounds in blunt-snout bream during short-term storage at 4 and ?3°C. The pH value declined quickly within 12 h postmortem, and those samples stored at ?3°C were lower than 4°C. High values of cooking loss occurred within 2–4 h postmortem, with maximum values of 20.94% (4°C) and 27.64% (?3°C), respectively. The cooking loss rapidly decreased to 13.59% (4°C) and 17.62% (?3°C) at 8 h postmortem, respectively. Texture properties (hardness, cohesiveness, springiness, and gumminess) decreased with storage time at both temperatures. Fish stored at ?3°C had a higher level of inosine monophosphate (IMP) compared with 4°C and was more than 15 μmol g^?1 during 8–24 h postmortem. The overall results indicated that it is better to preserve blunt-snout bream at ?3°C for short-term storage and utilize the fish within 8–24 h postmortem.     

Quality of Filleted Atlantic Mackerel (Scomber Scombrus) During Chilled and Frozen Storage: Changes in Lipids,Vitamin D,Proteins, and Small Metabolites,including Biogenic Amines

Quality changes of vacuum-packed Atlantic mackerel (Scomber scombrus) fillets during 12 months’ frozen storage at ?27°C and 9 days’ chilled storage at +4°C were evaluated. Freezing at ?27°C preserved the long chain n-3 polyunsaturated fatty acids (LC n-3 PUFAs), both in light and dark muscle, vitamin D, and the low molecular weight metabolites (LMW) (studied by high resolution nuclear magnetic resonance spectroscopy, HR NMR). Protein oxidation took place, especially between 1 and 7 months, decreasing water holding capacity and protein extractability. During chilled storage, no lipid or protein oxidation was observed, but lipolysis increased, and several LMW metabolites relevant for sensory and nutritional quality degraded into non-favorable compounds. The content of biogenic amines was high at day 9 (e.g., 18 mg histamine/100 g), jeopardizing safety. Preservation of mackerel fillets by freezing at ?27°C is thus a better option compared to prolonged chilled storage at +4°C; the quality was well preserved for 12 months’ frozen storage.     

Lipid Degradation of Cod Liver During Frozen Storage as Influenced by Temperature,Packaging Method,and Seasonal Variation

ABSTRACT

Lipid degradation of cod liver during frozen storage was studied, where the effects of storage temperatures (?18/?24°C), packaging methods (vacuum packing/regular plastic bag and waxed cardboard box), and seasonal variations (March/June/September) were evaluated. For this, the formations of free fatty acids (FFA) and peroxide value (PV) were analyzed. Lipid degradation within different parts of the liver (middle/surface) was also investigated. Increase in FFA and PV was observed for most of the samples throughout the frozen storage period. Vacuum packaging and lower storage temperature had a significantly stronger preservative effect on lipid degradation in all seasons. Higher FFA content was observed in cod liver captured in June than in its counterparts from September and March. More intense increase in PV was observed for liver collected in June compared to September. Furthermore, significant difference in PV was observed in different layers of the liver while FFA showed minimum variation between the surface and the middle part of the cod liver. Based on the present results, packaging method and storage temperature have a significant effect on lipid hydrolysis and oxidation in frozen cod liver.     

Changes in Protein Oxidation,Water-Holding Capacity,and Texture of Bighead Carp (Aristichthys Nobilis) Fillets Under Chilled and Partial Frozen Storage

This study aimed to evaluate the contribution of protein oxidation to the changes in the water-holding capacity (WHC) and texture of bighead carp (Aristichthys nobilis) fillets under chilled and partial frozen storage (4°C and ?3°C). The results indicated that less protein oxidation occurred to fillets at ?3°C than at 4°C, which was reflected by the higher value of salt-soluble protein contents (SSP), total sulfhydryl content (SH), Ca²⁺-ATPase activity, lower water-soluble protein contents (WSP), total disulfide content (SS), and surface hydrophobicity (So-ANS). However, the fillets had better WHC and texture at 4°C, as well as lower drip loss and higher centrifugal loss, hardness, and springiness. A significant linear relationship existed between protein oxidation parameters with WHC and texture characteristics for fillets under both types of storage, but the process of freezing and then thawing, instead of protein oxidation, was the main factor affecting the texture and WHC of fillets at ?3°C.     

Frozen Storage Studies of Formulated Skipjack Tuna Patties

Plain and flavored formulated skipjack tuna patties with textural characteristics similar to that of ground beef were developed for use in school lunch programs. Shelf life studies of these patties indicated that the nutrient composition of raw and cooked fish patties held under frozen storage for nine months essentially remained the same. In a 100 gm edible serving, raw and cooked tuna patties contained 71%-75% moisture, 18%-21% protein, 0.15%-0.22% fat, 1.8%-2.1% ash, and 3.3%-4.0% carbohydrate. Mean caloric content ranged from 88 to 91 kilocalories/patty. Furthermore, a 100 gm patty serving provided about 29% of the U.S. Recommended Dietary Allowance (RDA) for protein, 18%-20% for niacin, about 14% for phosphorous, 10%-11% for iron, 6% for magnesium, less than 5% for zinc, copper, and manganese, about 2% for thiamin, and less than 2% for vitamins A, E and calcium. Sensory testing on fish patties indicated that cooked patties could be stored up to nine months in frozen storage (minus 24°C) with only slight changes in odor, taste and texture. The storage life for frozen, raw patties appeared to be about three months. If uncooked patties were frozen, they should be cooked and eaten within a three month period. Based on the data gathered in this study it was recommended that the tuna patties be fully cooked, frozen quickly, vacuum-sealed, and stored at -24°C or below in order to maintain a frozen shelf-life of up to nine months.     

Histamine formation in flying fish contaminated with <Emphasis Type="Italic">Staphylococcus xylosus</Emphasis>

Histamine is the main causative agent of scombroid poisoning. However, unlike scombroid fish, histamine poisoning due to consumption of flying fish has never been reported. In this study, the white muscle of flying fish had high levels of free histidine at approximately 423.9 mg/100 g, and was inoculated with Staphylococcus xylosus Q2 isolated from dried flying fish at 5.0 log CFU/g and stored at ?20 to 35°C to investigate histamine-related quality. The histamine contents quickly increased to higher than 50 mg/100 g in samples stored at 25 and 35°C within 12 h as well as stored at 15°C within 48 h. However, bacterial growth and histamine formation were controlled by cold storage of the samples at 4°C or below. Once the frozen flying fish samples stored at ?20°C for 2 months were thawed and stored at 25°C after 24 h, histamine started to accumulate rapidly (>50 mg/100 g of fish). Therefore, flying fish muscle was a good substrate for histamine formation by bacterial histidine decarboxylation at elevated temperatures (>15°C) when it is contaminated with S. xylosus. In conclusion, since the improperly contaminated flying fish muscle with S. xylosus could lead to production of hazardous levels of histamine over time when stored at temperatures >15°C, the flying fish should be stored below 4 °C or below to control proliferation of S. xylosus, and TVBN and histamine production.     

Effect of Zataria multiflora Boiss (Avishan Shirazi) Essential Oil on Oxidative Progress in Frozen Cobia Fish Fillets During Storage

Antioxidants have been widely used as additives to provide protection against oxidative degradation of foods by free radicals. The effect of thyme essence (Zataria multiflora Boiss) on the rancidity development in cobia (Rachycentron canadum) fillets during frozen storage was studied. Cobia fillets were treated with thyme essence (250 and 500 ppm) and then stored at??18°C for up to 6 months. Rancidity development was measured by several biochemical indices including free fatty acids (FFA), peroxide value (PV), thiobarbituric acid (TBA), and complemented by sensory analysis (flesh odor, consistency, and appearance). Also, pH and expressible moisture were measured during 6-month storage. Proximate composition was also determined in the first day. TBA, PV, and FFA levels increased in all treatments due to lipid oxidation. Thyme essence showed an antioxidative effect in cobia fillets during frozen storage as indicated by TBA, PV, and FFA levels. Results showed that FFA, primary and secondary oxidation products, expressible moisture (EM), and pH of thyme essence treated samples were significantly lower than those of the control samples (p < 0.05). Thyme essence retarded oxidative changes in frozen cobia fillets, and the best oxidation inhibition was obtained using thyme essence at 500 ppm.     

Changes in Red Hake (Urophycis chuss) Muscle Induced by Different Freezing Strategies

The effect of single and double freezing at ?20°C on fresh and aged red hake with two different holding times of the thawed fillets between the first and second freezing treatments was determined. In addition, twice-frozen fresh red hake was treated with two antioxidation systems to assess their effectiveness in reducing lipid oxidation. Fresh, untreated red hake at 0 time was used for comparison. Significant dimethylamine (DMA) production occurred with all frozen samples, and the differences were not marked after 7-month storage. With a storage time of 3 months, however, there were differences between the treatments in both the fresh and aged samples with the once-frozen sample producing the least DMA, the twice-frozen sample with the 24-h holding time between freezings the most, and the twice-frozen sample with a 6-h holding time between freezings giving intermediate values. All samples showed a greater than 50% loss in protein solubility as determined by lithium chloride extraction after 3 months of storage, and the protein solubility declined further when samples were tested at 7 months. Samples with the best (once-frozen fresh) and worst (twice-frozen with 24-h holding time between freezings of 5-day aged muscle) treatments had the highest thiobarbituric acid-reactive substances (TBARS) values. Both antioxidant treatments were effective in reducing TBARS development.     

Histamine and Histidine in New Zealand Marine Fish and Shellfish Species,Particularly Kahawai (Arripis trutta)

Forty-seven retail samples of fish (28 species) were tested for levels of free histidine, histamine and aerobic plate counts. Five samples had elevated levels (≥ 20 mg/100 g) of histamine and all had < 100 mg/100 g. Three species had free histidine levels of more than 1000 mg/l00 g and these have been implicated in scombroid poisoning in New Zealand. One species with high histidine levels, kahawai (Arripis trutta), was chosen to determine the conditions under which potentially hazardous levels of histamine might develop. Two trials were carried out in which kahawai were stored under 17 regimes at temperatures between 0 and 35°C. For 10 of these treatments the fish were transferred from elevated storage temperatures to refrigerated storage during the trials. Levels of histidine and histamine, aerobic plate counts at 20°C and 35°C and sensory quality were monitored. The levels of free histidine in kahawai varied with season, and in Trial 2 there was a net loss of histidine + histamine during storage. Bleeding kahawai did not significantly affect the levels of histidine. Histamine levels varied greatly in fish held under identical conditions. Fish held at ambient temperatures developed the highest levels of histamine. Elevated histamine levels (> 20 mg/100 g) were first recorded in fish stored for 0.9, 0.9, 1, 2, 2.7, and 8 days at 35, 30, 25, 20, 15 and 10°C respectively. Storage at 5°C after storage at higher temperatures did not result in elevated levels. Of the 59 samples with elevated histamine levels, 9 had acceptable sensory characteristics while all had aerobic plate counts exceeding 10⁶ colony-forming units/g. Aerobic plate counts at 20°C are recommended over those at 35°C. It is concluded that fresh kahawai will only present a hazard from scombroid poisoning under conditions of extreme temperature abuse and that the presence of high numbers of bacteria is a good indicator of the hazard while sensory quality is not.     

Improving the Color Shelf Life of Farmed Southern Bluefin Tuna (Thunnus maccoyii) Flesh with Dietary Supplements of Vitamins E and C and Selenium

ABSTRACT

The use of dietary antioxidants to increase the shelf life of farmed southern bluefin tuna (SBT) flesh was examined over a 10-week period using either a standard pellet (Control) or high-vitamin pellet (HV) fortified with vitamin E, vitamin C, and selenium. Following harvest, muscle samples were taken and assessed for antioxidant content. Flesh color shelf life was assessed in muscle stored at 4°C for 8 days. Muscle vitamin levels were significantly higher in the HV group than the Control group for vitamin E (20.4 ± 1.74 vs 9.7 ± 0.89 mg/kg) and vitamin C (29.1 ± 4.36 vs 4.3 ± 0.41 mg.kg^–1), but selenium levels were not higher. Muscle samples from the HV group had a slower rate of browning than did those from the Control group, particularly over days 4 to 7 of storage. Results indicated that feeding a diet approximately 10 times higher in dietary antioxidants raised levels of vitamin E and vitamin C, but not selenium, in tuna flesh and increased the shelf life of tuna.     

The Influence of Cooking Parameters and Chilled Storage Time on Quality of Sous-Vide Atlantic Mackerel (Scomber scombrus)

The aim of the present study was to evaluate the effects of various sous-vide time–temperature regimes and their interactions on quality parameters of Atlantic mackerel (Scomber scombrus) during chilled storage. The mackerel ?llets were exposed to sous-vide treatment at 60, 75, and 90°C for 10, 15, and 20 min and further stored for 1, 3, and 7 days at 4 ± 1°C before analysis. Changes in pH, water content and cook loss, amount of water- and salt-soluble proteins, texture, and color parameters, as well as accumulation of lipid oxidation products in sous-vide-cooked mackerel were assessed. Sous-vide cooking time and temperature had the lowest contribution to the formation of primary and secondary products of lipid oxidation, as well as increase in yellowness of the fish flesh due to their accumulation; whereas duration of chilled storage led to a significant increase in oxidation and yellowness (p < 0.05). Duration of chilled storage also affected structural and textural properties of the fish muscle, leading to a decreased cook loss. At the same time, sous-vide cooking decreased the firmness of the fish muscle. Duration of chilled storage was found to have the highest significant effect (p < 0.001) on all physicochemical characteristics of sous-vide-cooked mackerel.     

Physicochemical and Microbiological Assessment of Ready-to-Eat Tuna Döner Kebab During Marination,Cooking, and Different Storage Conditions

ABSTRACT

The aim of this work was to investigate the use of bluefin tuna (Thunnus thynnus) in ready-to-eat döner kebab production and determine the effects of marination, cooking, and storage conditions (4 and ?18°C) on physicochemical and microbiological properties of döner kebab. The raw tuna meat and raw, cooked, and stored döner kebab samples were subjected to moisture, protein, fat, ash, pH, cholesterol, biogenic amines, lipid oxidation, fatty acids profile, microbiological, and sensory analysis. The major fatty acids in tuna döner kebab were palmitic, stearic, oleic, omega-3, and omega-6 fatty acids; unsaturated fatty acids were higher than saturated fatty acids (p < 0.05). Low biogenic amine and cholesterol contents were determined in döner kebab. While cooking affected the proximate composition, microbial load, and the levels of histamine and tyramine (p < 0.05), marination did not have any significant effect. The study results indicated that using tuna meat in döner kebab production could be an alternative approach to provide new seafood products without posing any acceptability problems in terms of quality factors.