Combined Effect of Ozonized Water Pretreatment and Ozonized Flake Ice on Maintaining Quality of Japanese Sea Bass (Lateolabrax japonicus)

The effect of the combined application of ozonized water pretreatment and ozonized flake ice (O+OIce) as compared with traditional flake ice (CK), ozonized flake ice (OIce), and ozonized water pretreatment and traditional flake ice (O) was investigated for the storage of Japanese sea bass. Microbiological, chemical, and sensory analysis and moisture content were carried out throughout a storage period of 18 days. A slower increase of total viable mesophilic count (TVC), total volatile base nitrogen (TVB-N), and thiobarbituric acid reactive substances (TBARS) was observed for O+OIce as compared with OIce, O, and CK. Treatment of O+OIce also allowed a better control of pH as compared with OIce, O, and CK. None of the treatments resulted in a significant difference in myofibrillar protein extractability and moisture content. The shelf life of Japanese sea bass treated with CK, OIce, O, and O+OIce, determined by sensory evaluation, was 9, 15, 12, and more than 18 days, respectively. Principal component analysis results showed that the treatments significantly affected the fish quality during storage, and the sensory attributes had a significant correlation with TVB-N, TVC, and TBARS. In conclusion, the combined application of ozonized water and ozonized flake ice had the best effect on fish quality maintenance.     

Physicochemical and Gel Properties of Myofibrillar Protein from Sin Croaker (Johnius dussumieri) Fish During Ice Storage

The physicochemical and gel properties of myofibrillar protein (MFP) from sin croaker fish were studied during ice storage for 18 days. Significant changes in the trends of solubility, Ca²⁺ ATPase enzyme activity, surface hydrophobicity, and water holding capacity of extracted MFP were observed by the 6th day of storage. The Ca²⁺ ATPase enzyme activity reduced significantly (p < 0.05) by the 6th day of storage. However, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) did not show a remarkable change in the concentration of myosin heavy chain. Surface hydrophobicity increased almost four times from its original value of 18.98 µg; whereas, water holding capacity showed a fluctuating trend during storage. The emulsion capacity of the MFP was in the range of 0.89- to 1.92-mL oil/mg protein during storage. The gel strength value (313.45 g.cm) of heat-induced gel prepared from fresh minced meat decreased significantly (p < 0.05) by the 6th day of ice storage. Texture profile analysis revealed that changes in hardness and gumminess were concurrent to steeply reducing breaking force up to the 6th day. The histological observation showed gradually increasing gaps between muscle fibers. The histological observations and physicochemical quality indicated that the sin croaker fish can be used for producing good quality surimi when stored for up to 6 days in ice.     

Development of Quality Index Method Scheme for Common Carp (Cyprinus carpio) Stored in Ice: Shelf-Life Assessment by Physicochemical,Microbiological, and Sensory Quality Indices

ABSTRACT

Sensory methods are the most interesting methods to estimate fish quality. Among these, the recently developed quality index method (QIM) has gained popularity, as shown by the multiple publications of QIM schemes in the last years. The objective of this study was to create a new QIM scheme (QIM sensory table and corresponding point system) for the common carp (Cyprinus carpio), basing the definition of the rejection point on sensory, physicochemical (thiobarbituric acid reactive substances, total volatile basic nitrogen, pH, and color measurements), and microbiological criteria (counts of mesophiles, psychrotrophs, and Pseudomonas spp.). A new QIM scheme was developed and is proposed for use in the future; it will be useful for practical evaluations of carp freshness in all steps of the production chain, and it will contribute to a more effective use of the species as an alternative for human food supply.     

Quality and Shelf Life Assessment of Puffer Fish (Lagocephalus guentheri) Fillets during Chilled Storage

The aim of the study was to quantify the shelf life and quality characteristics of puffer fish, Lagocephalus guentheri, fillets on chilled storage at 2 ± 1°C. The puffer fish muscle contains 16.14% protein, 80.76% moisture, 0.99% ash, and 0.17% fat. The mouse bioassay proved the absence of tetradotoxin in muscle, liver, skin, and gonads of the fish. The polyunsaturated fatty acid to saturated fatty acid (P/S) ratio of puffer fish was found to be 1.3, with n-3 to n-6 ratio of 3.27. The puffer fish had hypocholesterolemic/hypercholesterolemic ratio (H/H) value of 2.68, artherogenicity index of 0.43, and thrombogenicity index of 0.29. Beheaded and deskinned fishes were filleted and were studied for 10 days of chilled storage. The physical, chemical, sensory, and microbiological parameters showed significant (p < 0.05) changes during the entire storage period. While the hydrolytic rancidity was significantly correlated to springiness, gumminess, and chewiness of fillets, the peroxide value (PV) correlated with the color attributes and pH. The hardness of the samples decreased significantly and was evident in both sensory and instrumental analysis. With storage time, the yellowness of the fillets increased steadily. The results of this study can help in improving processing, preservation, and marketing aspects and enhance the utility of puffer fish.     

Changes in Biogenic Amines and Bacteria of Tiger-Toothed Croaker (Otolithes ruber) during Ice Storage

Changes in the content of biogenic amines (BA; e.g., putrescine, tyramine, and histamine) and the mesophilic and psychrotrophic bacterial counts of tiger-tooth croaker (Otolithes ruber) were monitored during ice storage for 18 days. BA and bacterial loads gradually increased (p < 0.05) with storage time. On the first day of storage, no amines were detected, and no histamine was detected up to 6 days. The best linear regressions between BA and bacterial counts were found between putrescine and psychrotrophic bacteria. Furthermore, it was found that psychrotrophs were the dominant microorganisms during storage and showed significant (p < 0.05) differences with storage time. The initial concentration of putrescine was 1.27 μg g^?1 and reached 18.8 μg g^?1 when the psychrotrophic bacterial load was over 10⁸ CFU g^?1. The results suggest that the level of putrescine is a suitable indicator of freshness for O. ruber, and the shelf life of O. ruber stored in ice as determined by BA content and microbiological data was 10 days.     

Effect of Storage Conditions on Total Volatile Base Nitrogen Determinations in Fish Muscle Extracts

Total volatile base nitrogen (TVBN) is a widely used fish spoilage indicator. Because TVBN is typically measured from muscle extracts, analytical laboratories would benefit from understanding how different conditions for storing extracts affect TVBN results. To examine this question, extracts from the muscle of gilthead sea bream (Sparus aurata) were prepared and stored. Different storage temperatures (4,??20, and??80°C) and storage periods (7 days to 2 months) were tested. To compare how well the different storage conditions worked for different TVBN levels, the study took advantage of the fact that TVBN values change depending on how long the gilthead sea bream is stored before extracts are prepared. Extracts were prepared from fish maintained in ice for 0, 4, and 10 days postmortem. Comparing the storage conditions tested, all offered statistically identical results independent of the storage period and temperature. Nevertheless, only the extract maintained at 4°C for 7 days achieved statistically equal values to not stored extracts.     

Quality Index Method (QIM) Scheme Developed for Whole Nile Tilapias (Oreochromis niloticus) Ice Stored under Refrigeration and Correlation with Physicochemical and Microbiological Quality Parameters

ABSTRACT

A quality index method (QIM) scheme was optimized to evaluate the freshness of whole tilapias (Oreochromis niloticus) ice stored under refrigerated conditions, which is the most common format of commercialization between primary producers and retailers. QI showed a high prediction accuracy, estimating a rejection point of 10.8 days. Principal component analysis showed the influence of the storage time on sensory, physicochemical (instrumental color and texture profile, total volatile base nitrogen, thiobarbituric acid-reactive substances, pH), and microbiological (total aerobic mesophilic count and total aerobic psychrotrophic count) quality parameters and the correlations between them. The suitability of the QIM scheme for assessing the freshness of whole tilapia was demonstrated to be a fast and accurate tool to maintain proper quality control along the production chain.     

去除内脏对冰藏鲤感官、化学和微生物变化的影响

以感官、TVBN、菌落总数、假单胞菌为指标,探讨去除内脏对冰藏鲤(Cyprinus carpio)品质变化及货架期的影响。结果表明,去除内脏和未去除内脏冰藏鲤的高品质期分别为333h和330h,货架期分别为575h和654h;去除内脏鲤冰藏的货架期略短,但无显著性差异(P0.05)。在冰藏过程中二者假单胞菌数量占优势,高品质期终点,去除内脏和未去除内脏鲤的菌落总数(CFU/g)的对数值分别为6.33±0.02和6.07±0.03;假单胞菌数(CFU/g)的对数值分别为6.15±0.19和6.04±0.01;挥发性盐基氮值分别为(10.86±0.50)mg/(100g)和(10.15±0.01)mg/(100g)。货架期终点,二者细菌总数(CFU/g)的对数值分别为7.06±0.18和6.90±0.14;假单胞菌数(CFU/g)分别为6.89±0.13和6.31±0.05;挥发性盐基氮值分别为(19.03±0.90)mg/(100g)、(21.15±0.80)mg/(100g)。二者在高品质期终点和货架期终点的各指标均无显著性差异(P0.05)。与未去除内脏鲤相比,冰藏初期去除内脏鲤的挥发性盐基氮值略低,而其细菌增殖较快且直接进入对数增长期,这可能是由于去除内脏过程对鱼体造成破坏所致,而过了高品质期后,无论是挥发性盐基氮值还是感官评分都比未去除内脏的高,因此去除内脏鲤的货架期略短。     

Dietary Spirulina (Arthrospira platensis,Gomont, 1892) improved the flesh quality and shelf life of rainbow trout (Oncorhynchus mykiss,Walbaum, 1792) fed fish meal or plant‐based diet

This study was carried out to determine the effects of fish meal or plant‐based diets with supplementation of dietary Spirulina (4%) on shelf life of rainbow trout, Oncorhynchus mykiss. Rainbow trout (initial weight: ~135 g) were fed four experimental diets (fish meal‐based FM, plant meal‐based‐PM, Spirulina included at 4% of fish meal‐based‐FM/S or plant meal‐based PM/S) for 12 weeks. After the feeding trial, trout were stored on ice at 4°C for 0, 5, 10, 15 and 20 days. The chemical, microbiological and sensory analyses of fish were subjected to each sampling days for flesh quality evaluation. TBA of supplemented dietary Spirulina was lower than that non‐supplemented dietary Spirulina. pH values of all groups decreased significantly between days 0 and 20 during the storage period (p < 0.05). Luminosity (L*) value of all groups increased with time in storage period. Fish fed Spirulina supplemented diets showed an increased red/green tonality (a*) (p < 0.05) compared with fish fed non‐Spirulina supplemented diets. In the end of the storage period, the total coliforms values of fish fed with PM/S diet lower than that of other all diets. In conclusion, dietary Spirulina could be allowed the shelf life of the rainbow trout to be extended.     

软颗粒饲料与鲜杂鱼糜对大黄鱼养殖水质的影响

在水温18．0～21．0℃、盐度21．0～25．8下,给平均体质量为280．0 g／尾的大黄鱼投喂软颗粒饲料（试验组）和鲜杂鱼糜（对照组）,评价两种饲料对环境影响,其中试验组、对照组各设3个平行,空白组（不放鱼也不投料,仅有砂滤海水）不设平行。试验结果表明,试验组和对照组养殖水中总氮、总磷和化学需氧量含量均与空白组差异显著（P＜0．05）,对照组最高,空白组最低;试验组与对照组水中总磷差异不显著（P＞0．05）,而总氮和化学需氧量含量均差异显著（P＜0．05）;试验组水中沉积物总量显著少于对照组（P＜0．05）;试验组水中沉积物中总氮、总磷总量均显著少于对照组（P＜0．05）。软颗粒饲料对养殖环境的影响显著小于鲜杂鱼糜,可在海水鱼类网箱养殖中应用推广。     

Sensory Quality and Shelf Life of MAP Redfish (Sebastes marinus) Fillets as Affected by Previous MA Bulk Storage of Whole Fish

Abstract

The shelf life of iced redfish is known to be 16–19 days. This study evaluated the effects of modified atmosphere (CO₂/N₂: 60/40) in bulk storage of redfish and subsequent modified atmosphere packaging (MAP) of fillets. Fish were evaluated by sensory, microbiological and chemical methods. Modified atmosphere (MA) bulk storage of whole fish for more than 5 to 10 days did not improve their sensory quality or significantly increase shelf life. In fact, the study showed negative effects in texture and overall appearance. MAP of fillets processed from 10-day MA bulk stored fish showed a modest increase in shelf life, but negatively affected their texture. Sensory qualities, i.e., tenderness, that decreased under MA bulk storage were improved upon aerobic storage for fish stored under MA for 5 to 10 days, but not 14 days. Lower microbial levels were found in MA bulk stored fish and MAP fillets compared to traditionally iced fish, while higher TMA levels were found in MAP fillets.     

Texture and Quality Assessment of Ready-to-eat Farmed Obscure Puffer Fish (Takifugu obscurus) Fillet by Evaluating Bacterial and Myofibrillar Degradation and Biochemical Changes during Refrigerated Storage

ABSTRACT

Obscure puffer fish (Takifugu obscurus) flesh, often eaten as raw fish fillet, is susceptible to softening. To investigate the mechanisms for the softening of flesh and changes in firmness, the proliferation of total microbial flora, Enterobacteriaceae, Pseudomonas spp., and lactic acid bacteria (LAB), total volatile basic nitrogen (TVBN), trimethylamine (TMA), and pH were periodically assayed during storage at 0, 4, and 8ºC. Myofibril extraction and separation of puffer fish flesh was carried out and the length of the separated myofibrils was measured periodically using an optical microscope during the entire storage time. Transmission electron microscopy was also used to inspect the changes in myofibrillar characteristics of the fish flesh at the beginning and end of the storage period. The results indicated that lower chilled temperature can contribute to reduced proliferation of microbial flora and less variation in TVBN, TMA, and pH and further maintain the integrity of myofibrils and retain firmness of puffer fish flesh during storage.     

饲料脂质对养殖鱼类品质的影响

目前,高脂饲料在鱼类养殖中的应用已越来越广泛。然而,目前全球每年鱼油产量虽然基本恒定,但水产饲料中鱼油的需求量却在持续上升,到2010年,鱼油的使用量将超出产量的70%。鱼油的有限供给和过量消耗,以及其中可能积蓄的二噁英和多氯联苯,使鱼类养殖业迫切需要采用其他脂肪源来代替饲料中的鱼油。然而,高脂饲料或用其他脂肪源替代饲料中的鱼油不仅影响养殖鱼     

Quality Indices of Squid (Photololigo duvaucelii) and Cuttlefish (Sepia aculeata) Stored in Ice

The objective quality indices of squid (Photololigo duvaucelii) and cuttlefish (Sepia aculeata) stored in ice were compared with the subjective counterparts. Sensory (overall quality rating, quality index method [QIM], and multisample difference test), microbiological (total viable count [TVC], psychrophilic count), chemical (trichloroacetic acid-soluble peptide [TCA-soluble peptide], trimethylamine nitrogen [TMA-N], total volatile bases nitrogen [TVB-N], ammonia content, and protein pattern), and physical analyses (expressible drip, color, and texture) were determined in both species during 16 days of iced storage. As storage time increased, TCA-soluble peptide, TVB, ammonia content, and expressible drip were increased (p < 0.05). TMA content was markedly increased after 10 and 8 days of storage in squid and cuttlefish, respectively. Both TVC and psychrophilic count increased as the storage time increased (p < 0.01). Myosin heavy chain was degraded with coincidental decrease in shear force and sensory texture during storage (p < 0.05). According to the overall rating score, shelf life of both species in ice was estimated to be 6 days. The increases in ammonia content and expressible drip were highly correlated with the decrease in overall quality rating and increase in quality index score of squid and cuttlefish (p < 0.01).     

Effects of Modified Atmospheric Packaging Conditions on the Quality Changes of Pasteurized Oyster (Crassostrea belcheri) Meat during Chilled Storage

ABSTRACT

The effects of different atmospheric conditions on the quality and the shelf life of pasteurized oyster meat in chilled storage were investigated. The alternatives tested for pasteurized oyster meat were normal air (Control), 75% CO₂/25% N₂ (MAP-1), 75% CO₂/25% O₂ (MAP-2), 75% CO₂/5% O₂/20% N₂ (MAP-3), and vacuum packing (VP). The various observations of microbiological (total viable count (TVC), Enterobacteriaceae, Pseudomonas spp., lactic acid bacteria (LAB), and hydrogen sulfide–producing bacteria), physical (color coordinates L*, a*, and b*, and cutting strength), chemical (moisture, pH, total volatile basic nitrogen (TVB-N), peroxide value (PV), and thiobarbituric acid reactive substances (TBARS)) and sensory properties were performed every 3 days over a total of 27 days. During storage across all the treatments, L*, a*, cutting strength, pH, moisture content, and sensory scores decreased; whereas, b*, TVB-N, PV, TBARS, and microorganisms increased. However, among the various alternatives, MAP-1 had the best retention of oyster quality during storage. Based on sensory and microbiological qualities, the shelf lives in chilled storage were 9 days for control, 15 days for VP, 21 days for MAP-2 and MAP-3, and 24 days for MAP-1-treated cases.     

Fluorescence of Extracts from Argentine Hake (Merluccius hubbsi) Muscle and Its Correlation with Quality Indices During Chilled Storage

Argentine hake (Merluccius hubbsi) was stored chilled for 8 days. The evolution of fluorescence of the aqueous and organic extracts of muscle during storage at 4°C was studied and correlated with common damage indices; pH, total volatile basic nitrogen, free fatty acids, and the fluorescence intensity of the aqueous phase showed a good correlation with storage time. The excitation-emission matrices of the aqueous extracts were also obtained. A fluorescence landscape that could be attributed to tryptophan decreased with storage time, meanwhile a peak (around 340 and 400 nm for excitation and emission wavelengths, respectively) is developed during chilled storage.     

Quality and Shelf Life of Liver of Farmed Cod (Gadus morhua)

ABSTRACT

Livers of Atlantic cod (Gadus morhua) are traditionally used in cod liver oil production or consumed cooked or canned. The farming of cod is a relatively new industry in Norway. The aim of this study was to determine quality and shelf life of fresh liver from farmed cod during chilled storage on ice by hydrolysis and oxidation state and sensory quality and the influence on canned liver. In two experiments, livers from farmed cod were stored chilled and sampled from Days 0 to 13, respectively. Quality, measured as hydrolytic and oxidation degradation, was reduced after 7 days of storage, while sensory quality was reduced after 4 days. Free fatty acids increased from Day 7 in both experiments, while peroxide value and anisidine value showed no change when the livers were single wrapped. Rancid odor was the first sign of oxidation and was registered after three to four days of storage. Canning within 2 days of storage prevented leakage of oil from the canned livers. Sensory analyses of oxidation are recommended as a sensitive and rapid method to detect oxidation of chilled cod liver.     

Quality Changes in Gamma Irradiated Marinades of Anchovy (Engraulis anchoita) During Refrigerated Storage

The effect of gamma irradiation (0, 1.8, and 3.3 kGy) on the microbiological, chemical, and color characteristics of marinated (7% acetic acid and 10% NaCl) and vacuum-packed anchovy fillets was analyzed during 20 months of refrigerated storage (4 ± 1°C). Acidity, pH, water activity (a_w), total volatile basic nitrogen (TVBN), lipid oxidation, and color parameters were determined. Mesophilic and psychrotrophic bacteria, sulphite-reducing clostridia, total and fecal coliforms, Staphylococcus spp., yeasts, and molds were investigated. Gamma irradiation reduced the initial mesophilic bacterial counts and inhibited mesophils growth during 20 months. As a result, the production of TVBN during storage was lower in irradiated samples than in control. Also, lipid oxidation was lower in irradiated samples than in nonirradiated. The color of anchovy fillets was not affected by the irradiation treatment. Even if nonirradiated anchovy fillets presented a high stability in comparison with the traditional product (in flasks with vegetable oil and spices), gamma irradiation improved the microbiological and chemical quality of anchovy fillet marinades without inducing changes on its characteristic color for 20 months.