Tuna Steaks Research Articles

Real-time monitoring of 2,5-dimethylpyrazine in solid, liquid, and gas phases during processing of fried skipjack tuna steaks using intestinal villus-like Ag nanoparticles@Au nanowires surface-enhanced Raman substrate chips

The production and distribution of 2,5-dimethylpyrazine (2,5-DMP), a key volatile flavor compound, are associated with the frying of skipjack tuna steaks. In this study, an intestinal villus-like chip was fabricated to quantitatively detect 2,5-DMP in multiphase systems based on surface-enhanced Raman spectroscopy (SERS). The chip exhibited excellent SERS performance with an enhancement factor of 1.16 × 108, excellent uniformity and reproducibility, and low detection limits of 6.49 pg/mL, 0.182, and 0.920 ng/mL for 2,5-DMP solid, liquid, and gas models, respectively. The results indicated the 2,5-DMP content with growth rates in the order of frying steam > frying steaks > frying oil, and the 2,5-DMP content in frying steam was linearly correlated (R2 = 0.992) with the trend of the acid value and total polar compounds in frying oil. Therefore, this strategy for achieving the reliable detection of 2,5-DMP can assist in monitoring the frying process and food safety.

Essential oil vapour inclusion in protective atmosphere packaging for shelf‐life management of fisheries

SummaryFish is well known for its perishable nature. Essential oils in food packaging seem to be safe and reliable both in terms of safety for the consumer and in terms of improving the shelf life of the product. This study aimed to evaluate the effects of two different essential oil vapours (one with rosemary and the other one with lemon extract) on three different types of fishery products (swordfish steaks, bluefin tuna steaks and Argentinian prawns) stored in a protective atmosphere packaging, monitoring the shelf life up to 8 days through microbiological, chemical and sensorial analyses. The results showed that the products preserved with the inclusion of essential oils have reached the end of the shelf‐life period respecting the process hygiene and food safety criteria, receiving a greater appreciation rating from the consumer panel at the end of shelf life for the prawns and swordfish samples with the addition of rosemary essential oils vapours, which instead highlighted the worst result at the end of shelf life for tuna.

Quality Characteristics, Cold Chain System, Yield and Productivity of Frozen Tuna (Thunnus albacares) Steak Processing

One of the prospective products that can be developed from tuna is frozen tuna. One processing technique to preserve tuna fish is generally through freezing. F frozen tuna steak is one of the many processed tuna products produced through freezing. The aim of the research is to analyze quality characteristics, application of the cold chain system, calculation of yield and productivity in the processing of frozen tuna steaks at PT. Wahyu Pradana Binamulia. The research method uses a qualitative descriptive method with research stages including process flow observation, organoleptic quality measurements, microbiology (ALT, E. coli, Salmonella), chemistry (histamine), yield calculations, productivity calculations. The data collection method was by directly following processing activities and interviews for the frozen tuna steak processing process, while other data was carried out by testing. The results of the research obtained the processing flow of frozen tuna steak at PT. Wahyu Pradana Binamulia has 23 stages. The organoleptic test results for raw materials have a value of 8 and the final product has a value of 9. The raw material test results for ALT are 6.2 x 103 col/g, Coliform <3 MPN/g, E. coli <3 MPN/g and Salmonella with negative results. The final product test results were ALT 5.5 x 103 col/g, Coliform <3 MPN/g, E. coli <3 MPN/g, and Salmonella with negative results. The histamine test results obtained were 6.9 ppm in the raw material and 7.4 ppm in the final product. Observation results of raw material and product temperatures ≤4.4°C, room temperature ≤20°C and air temperature ≤4.4°C. The yield at the weeding stage was 78.37%, loin formation was 69.40%, dark meat separation and skin removal was 60.77%, trimming was 45.11%, steak formation was 40.48%, retauching was 39. 02%. Employee productivity results at the weeding stage had an average value of 1,214.23 kg/hour/org, for the trimming stage 530.12 kg/hour/org, for the steak formation stage 599.66 kg/hour/org. It can be concluded. The research conclusions show that the quality of raw materials and frozen tuna steak products has met the established SNI standards.

Handling tuna steak with co-gas and liquid smoke production waste gas

In this study, liquid smoke production waste gas (LSPW) was used as a substitute for carbon monoxide (CO) and filter smoke in handling frozen tuna steaks. Tuna steaks were packed in plastic bags, then inside the bag, tuna steak were sprayed with CO and LSPW, and stored at 4°C for two days. After that, each package was vacuumed and stored at -25°C for four weeks. Observation of quality deterioration of tuna steak started from the beginning of storage until the fourth week. The results showed a significant difference in the average TPC value of tuna steak sprayed with CO and LSPW during frozen storage. While the values of pH, TVB, myoglobin, and color were not significantly different. Until the end of the observation, the quality of tuna steak was still relatively good with myoglobin content values of CO and LSPW treatments, respectively: 36.65±4.78 and 42.04±4.47 mg%, color 34.67±9.07 and 35.67±8.50 °Hue, pH 6.47±0.15 and 6.60±0.10, TVB-N 18.04±0.93 and 17.86±0.98 mg N/100g, histamine 1.92±0.05 and 1.85±0.13 ppm, and TPC 7.41x102 and 8.70x102cfu/g.

Scombroid poisoning: a traveller's tale

A 23-year-old previously well Australian woman with no known allergies developed an erythematous, non-pruritic and non-tender rash while in Bali. The rash appeared on the face and ears ten minutes after ingesting a tuna steak, spreading to the neck, chest, back and upper limbs within 20 minutes (Figure, A and B). This was associated with conjunctival injection, headache, tachycardia and light-headedness. The patient's mother, a general practitioner, made a clinical diagnosis of scombroid poisoning1, 2 and immediately administered an oral antihistamine. The rash and symptoms resolved after four hours, and the restaurant was notified. Scombroid poisoning may occur after the consumption of fish, such as tuna, salmon, mackerel, sardines and anchovies, that have been improperly refrigerated. Patients should be advised to avoid ingesting fish, particularly species with dark flesh, that have not been adequately stored. Open access publishing facilitated by University of New South Wales, as part of the Wiley - University of New South Wales agreement via the Council of Australian University Librarians. No relevant disclosures.

Development of Histamine in Fresh and Canned Tuna Steaks Stored under Different Experimental Temperature Conditions.

Among biogenic amines, histamine is most frequently involved in foodborne intoxication. To evaluate histamine formation in tuna, several storage conditions were reproduced. An LC-MS/MS method was used for analytical determinations. Fresh tuna samples (not contaminated and grafted with tuna muscle naturally incurred with histamine at 6000 mg/kg) were stored at 4, 12, and 20 °C, and daily samples were collected for 6 days. The development of histamine was observed only in grafted tuna samples. At 4 °C, histamine formation progressed from 12.8 mg/kg (day 1) up to 68.2 mg/kg (day 6). At 12 °C, higher concentrations developed (23.9 mg/kg on day 1 up to 2721.3 mg/kg on day 6) relative to 20 °C (from 12.0 to 1681.0 mg/kg). It was found that at 4 °C, if grafted tuna was submerged in oil, histamine formation progressed more slowly. In a naturally contaminated sample, it was observed that the histamine distribution was uniform, while the normal cooking process did not affect the histamine level. Furthermore, it was found that the use of histamine-contaminated equipment for food handling may result in histamine formation in food. These results confirm the importance of implementing good hygiene practices and respecting the cold chain.

Toward a valence × arousal circumplex-inspired emotion questionnaire (CEQ) based on emoji and comparison with the word-pair variant

Product-focused emotion research continues to be in ascendency. Corresponding method development is ongoing, and is the focus of the present research which takes a first step towards developing and testing an emoji variant of the valence × arousal circumplex-inspired emotion questionnaire (CEQ). In Study 1, through a consumer-driven approach to identifying the meaning of candidate emoji, an emoji CEQ variant was developed using emoji with meanings similar to those of the 12 word-pairs. Study 2 then compared the emoji CEQ with the word-based variant in a study with 15 written food stimuli. This was done in an online survey with UK adults using a between-subjects design where participants completed one of the two CEQ variants. The emotion profiles for individual foods elicited by the emoji CEQ fitted expectations and were largely similar to those from the word-based variant. However, for some food names the emotion profiles were less rather than more similar, and these differences were attributed to incomplete alignment between the emoji and emotion word-pairs at specific CEQ positions. Examples of least concordance were “apple”: Active/Alert (19%) vs. warning (▪) (0%), “tuna steak”: Jittery/Nervous (4%) vs. confounded face (▪) (11%), and “blue-vein cheese”: Jittery/Nervous (8%) vs. confounded face (▪) (18%). The presented emoji CEQ is suitable for application although users should be aware of differences relative to the word-based variant. To minimise these, further improvement of the emoji CEQ is suggested, as is applications with other (tasted) stimuli to validate appropriateness of the emoji CEQ in product-focused emotion research.

Persistent and toxic chemical pollutants in fish consumed by Asians in Chicago, United States

Consumption of seafood brings health benefits but may increase the ingestion of contaminants. Compared with other ethnic groups in the U.S., Asians consume seafood more frequently. However, there is little information about how culturally specific fish consumption contributes to exposure to toxicants. In this work, we surveyed fish consumption among Chinese, Korean and Vietnamese communities and purchased 103 seafood samples from local markets in Chicago. Each sample was analyzed for mercury (Hg) and 92 organic chemicals including polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), and Dechlorane Plus and related compounds (DPs). The rank order of pollutant concentration in all samples was Hg ≫ Σ66PCBs > Σ17OCPs > Σ8PBDEs > Σ8DPs. Positive correlations were noted among most contaminant groups. Bluefish, pike and tuna steak had the highest mean Hg (>1 mg/kg). The mean Σ66PCBs was highest in pike and bluefish (>100 ng/g) followed by pollock and mackerel (>40 ng/g). Overall, octopus, shrimp and tilapia were the least contaminated; while pike, bluefish, and pollock were the most contaminated. Omega-3 fatty acids were more strongly affiliated with the organic contaminants than mercury. A risk assessment identified seven types of fish that should have consumption limitations and six that should not be consumed. For these seafoods, consumption advice based on Hg levels would adequately protect health. In the survey participants, 17% of seafood mass consumed is from types of fish that should be limited to 1 or 2 meals/week, while 7% of the seafood mass consumed comes from types that should not be consumed at all. This work adds additional contaminants to the profile of health risks resulting from fish consumption among Asian Americans, which can be used in interventions aimed at conserving consumption of healthy fish while avoiding contaminants.

Hazard Analysis and Critical Control Points in Handling Frozen Tuna Steak (Case Study at PT. Awindo International, Jakarta, Indonesia)

This research aims to analyze the hazard and determine critical control points in the process of handling frozen tuna steak at PT. Awindo International located in Muara Baru, North Jakarta. The research was conducted at PT. Awindo International from March to April 2021. The research was conducted using the case study method. The research procedure includes observation of the handling process flow, analysis of potential hazards, identification of critical control points, organoleptic, microbiological and chemical testing. The data obtained from the study were analyzed descriptively. Hazards that have the potential to occur in the process of handling frozen tuna steak are biological, physical and chemical hazards. The results of the hazard analysis obtained critical control points at the stage of receiving raw materials and metal inspection. The results of the organoleptic test of raw materials as a whole have a good value and are in accordance with company standards and Indonesian national standards (SNI), so that they can proceed to the production stage. The results of the microbiological test showed that complied with the standards, namely Salmonella sp. negative, Vibrio cholerae negative, Escherichia coli <1.8 MPN/g, Coliform <1.8 MPN/g, ALT 12 x 103 colonies/g. The results of the chemical test showed good results with the value of the chemical content that complied with the standards, namely histamine 2.92 mg/kg, mercury 0.05 mg/kg, negative lead, and cadmium 0.019 mg/kg.

Increased Value Added of Tuna Flakes (By-Product) from Steak Processing Through Development of Halal Commercial Food Products (Tuna Topping Spaghetti)

Yellowfin tuna is one of Indonesia's main export commodities, its meat contains high protein and can be processed into a variety of commercial food products. In the processing of loin, fillet and tuna steak, ± 10% of flaked meat is produced which can be used for processing commercial products. Spaghetti is one of the commercial products that is easily processed with raw materials and additives that are cheap and easy to obtain as well as halal and thoyib. The raw materials used are tuna flakes, spaghetti noodles and seasonings. The research objective was to analyze the chemical composition of tuna flakes and tuna topping spaghetti as well as the added value and level of consumer preference. This research uses laboratory methods, the percentage of additional selling value and consumer preferences. Proximate chemical composition of tuna flakes, namely: water content (74.80 - 75.25%); protein (16.35 - 17.00%); fat (1.43 - 1.50%); minerals (5.38 - 5.45%); carbohydrates (0.65 - 0.80%). Chemical composition of tuna topping spaghetti, namely: water content (62.73 - 69.13%); protein (7.08 - 8.34%); fat (0.42 - 0.76%); minerals/ash (0.93 - 1.16%) and carbohydrates (24.41 - 25.54%). The added value of tuna flakes in the processing of tuna topping spaghetti for two packages of spaghetti noodles (18 portions) is Rp. 147,355 (80.79%). The level of consumer preference (25 panelists) towards the visual value of tuna topping spaghetti is “very like” (76.0%) and “like” (24%); smell values, namely "really like" (72.0%) and "like" (28%); the value of taste, namely "really like" (80.0%) and "like" (20%); Texture values are “really like” (80.0%) and “like” (20%) and taste values are “really like” (76.0%) and “like” (24%).

Content of toxic metals and As in marine and freshwater fish species available for sale in EU supermarkets and health risk associated with its consumption.

The present study investigated Pb, Cd and As concentrations in canned tuna, tuna steak, rainbow trout, smoked mackerel, and Baltic and Atlantic cod, as well as Atlantic salmon. The aim was to spot check the quality of the most commonly purchased types of fish that are available for sale in most common supermarket chains throughout the Poland, as well as to determine potentially less contaminated sources of fish available for retail. A dry ashing digestion protocol followed by inductively coupled plasma mass spectrometry analysis was employed to achieve a better recover of heavy metals and As from fish muscle tissues. The cumulative concentration of metals and As in fish muscle tissue decreases in order: farmed Atlantic salmon > mackerel > Baltic cod > rainbow trout > canned tuna fish > Atlantic cod > yellowfin tuna steak. It was found that canned tuna from Central and Eastern Pacific Ocean were more contaminated than tuna from East and West Indian Ocean, Baltic cod was significantly more contaminated than cod from North-East Atlantic. Smoked mackerel from North-East Pacific Ocean is three times more contaminated than mackerel from Northern North Sea. All fish, except for yellowfin tuna steak, should not be intended for retail because they exceed maximum levels for Cd and Pb. Consuming only one serving (140 g) of Baltic cod exposes one to 51% of the daily acceptable Cd intake, while the same portion of canned tuna and smoked mackerel from the Pacific Ocean deliver 69% and 72% of this element respectively. The most cadmium is consumed with smoked mackerel from the North Sea, comprising as much as 162% of the daily acceptable dosage . © 2020 Society of Chemical Industry.

The Effects of Carbon Monoxide Treatment on the Physical and Chemical Qualities of Tuna Steak during Iced Storage

Injection or modification of the atmosphere in the meat packaging by carbon monoxide (CO) has been known to retain the color stability of red meat including those of tuna. The red color in tuna meat has been commonly used as a freshness indicator by consumers, especially those for raw consumption. However, other information on the freshness level in fish, in addition to color, is also important to assess in the food safety of marine and fisheries products. This study aims to evaluate the effects of CO on the chemical and physical properties of tuna steak during storage on ice. This study was conducted using bigeye tuna (Thunnus obesus) as the raw material. The tuna was cut into loins to form steaks and divided into two groups, one group without CO injection or control, and another group was injected with CO. Both CO-treated tuna steak and control were preserved in a cool-box filled with ice for 14 days. The observation was conducted every two days by determining color (chromameter method), sensory preference (hedonic method), and several chemical parameters, including total volatile base (TVB), K value, and histamine content that related to the spoilage process. Results showed that after 14 days of preservation in iced storage, the reddish color of CO-treated tuna steak was retained, whereas that of control turned brown. In the sensory tests, the panelists preferred the CO-treated tuna steak to control due to its reddish color. There were no significant differences between the content of TVB accumulation and the K value in CO-treated tuna steak and the control. Furthermore, the K value of CO-treated tuna steak and control reached the rejected level on day 14. The difference between CO-treated tuna steak and control was based on the content of histamine, where that of control was significantly higher than tuna steak treated with CO. Therefore, this research showed that the effects of CO treatment were only on the appearance of the steak; meanwhile, the deterioration process in fish is generally unaffected. Precautions are thus needed for consumers, since color may not be the only factor that indicates the freshness of tuna steak.

Change in color and quality of tuna during treatment with carbon monoxide gas

The yellowfin tuna steaks (ca. 8 × 5 × 2 cm) sealed in a package and treated with 99.5% carbon monoxide (CO) gas at 4°C for 5 days were compared with the control steaks without CO gas treatment stored at same condition. The surface layer (2 mm thick), middle layer (2 ∼ 4 mm from surface) and inner layer (4∼6 mm from surface) were separately cut from the fish steak. For each layer, the Hunter's color value (L, a, b), metmyoglobin formation (metMb%), volatile basic nitrogen (VBN) and CO residue were measured and compared. The results revealed that Hunter +a value of tuna steaks treated with CO gas for 4 hr increased higher than that of the control steak for all three layers. However the values of L and +b between the CO gas-treated steak and the control steak differed slightly. The metMb% in the surface layer showed no significant difference with or without the CO treatment whereas the metMb% in the middle and inner layers of CO gas-treated steak were apparently lower than that of the control steak. The VBN of the steaks remained below 20 mg/100 g during the 5-day chilling storage regardless of CO gas treatment. The amount of CO residue in the surface layer increased rapidly in 24 hr of the treatment and consequently reached the highest value at 96 hr, while those in the middle and inner layers increased quickly in 48 hr. The CO residue in the inner layer remained constant after 48 hr of treatment at a value about a half as high as that in the surface layer.

Potential of novel cadaverine biosensor technology to predict shelf life of chilled yellowfin tuna (Thunnus albacares)

A considerable amount of fresh fish is wasted, due to imprecise shelf life estimations that lead to relatively short use-by dates. This study aimed at evaluating a newly developed sensor measuring cadaverine headspace concentrations, as a rapid and precise measure to estimate within a realistic DK retail scenario freshness and shelf life of imported tuna loins.To achieve this the cadaverine concentration as measured by liquid chromatography-tandem mass spectrometry (LC- MS/MS) in tuna steaks from different biological replicas undergoing storage at 2 °C, were associated to the freshness states and shelf life as determined by the Quality Index Method (QIM) and microbial measurements. The cadaverine sensor responses of tuna stored under the same conditions were compared to the validated LC-MS/MS concentrations and benchmarked towards the QIM and microbial counts estimation of shelf life.The results indicated that the novel cadaverine biosensor allowed an estimation of freshness and transition of acceptable to unacceptable quality of the tuna steaks comparable to other methods such as LC-MS/MS determination of cadaverin, QIM and determination of microbiological counts. The composition of the microbiological flora during storage, consisted mainly of Pseudomonas fragi but also other Pseudomonas spp, Vibrio spp., Brochothrix thermosphacta, H2S producing bacteria and Enterobacteriaceae, the latter only in relatively low numbers. The novel biosensor technology appear to be a promising rapid and cost efficient method for evaluating freshness of several types of fish products in addition to fresh tuna, which will support the sustainability of the fish industry.

Effect of pulsed light on shelf life of chill stored yellowfin tuna (Thunnus albacares) steaks

In this study, the effect of pulsed light (PL) treatment on the shelf life extension of yellowfin tuna (Thunnus albacares) steaks was investigated. Tuna steaks of 1 cm thickness weighing 80 g packed in 300 gauge cast polypropylene pouches were subjected to PL treatment using Xenon pulse light machine RC-847. The samples were stored at 2±1OC and analysed at specific time intervals. Shelf life studies were carried out in terms of reduction of aerobic flora as inferred from the total plate count (TPC) and the psychrophilic count. The samples were also evaluated in terms of colour (L*, a* and b*), biochemical and sensory parameters. The initial reduction as well as lower rate of increase in the microbial count on the PL treated samples clearly highlighted the efficiency of PL technology as a novel non-thermal preservation technique. Low values of chemical indicators of spoilage and better values of sensory and colour values of PL treated samples also suggested the efficacy of PL treatment in microbial inactivation. An overall extension of 13 days of shelf life was achieved for PL treated samples whereas control samples were rejected on 13th day

Restructuring steak from flakes of yellowfin tuna meat using low salt microbial transglutaminase (MTGase)

Restructuring of fish meat can be done by using fragments of by-product processing such as fillet, loin, and steak of yellowfin tuna. The binder agent that may be the most efficiently used in restructuring the product is microbial transglutaminase (MTGase). Salt is needed to optimize the binding process of the restructuring product. The objective of the study was to determine the effect of low salt MTGase concentration as a binding agent on the quality of restructured yellowfin tuna steak compared to commercial yellowfin tuna steak. Research was designed with completely randomized design using 5 treatments in the 1.5% salt concentration, namely 0%, 0.3%, 0.5%, 0.7%, and 0.9%. The analyzed parameters were proximate (water content, protein, fat, carbohydrate, and ash), texture, colour and water holding capacity. The sensory test was conducted to compare restructured products with commercial tuna steak. The results indicated that the best treatment to the addition of MTGase was 0.5% based on the physical properties of the product, the nutritional content and sensory test. In sensory, MTGase was able to maintain the colour (brightness) of the products as they were darker than the commercial tuna steak and improve the product’s texture (hardness) in the addition of 0.9% MTGase.

Effects of different freshness on the quality of cooked tuna steak

Abstract The variation in quality of yellowfin tuna (Thunnus albacares) steaks of different freshness after cooking were studied by analyzing K value, adenosine triphosphate (ATP)-related compounds content, histamine content, sensory quality, E-nose and E-tongue analysis. The results indicated that when the freshness of raw tuna steak decreased from sashimi grade to cooking grade, IMP content significantly decreased whereas HxR content significantly increased after cooking. With the decrease of freshness, K value of the 4th day sashimi-grade tuna and the 6th day cooking-grade tuna increased from 18% and 24% to 27% and 45% respectively after cooking. The higher histamine content in raw tuna steak, the more significantly increased histamine level of cooked tuna was observed. Raw tuna steaks with sashimi grade have significant variation from those with cooking grade in odor and taste by E-nose and E-tongue analysis after cooking The sensory evaluation showed that the freshness of tuna steak significantly influence the cooking quality (p Industrial relevance Tuna is well appreciated worldwide because of its high nutritional value and potential health benefits. Canned tuna is one of the most widespread and recognized fish commodities in the world. The species utilized commonly for canning are skipjack, yellowfin and albacore tuna. Cooking tuna steak is normally used as semi-manufactured products in canned tuna industry. Control of the cooking unit operation is critically important to producing cooked muscle for tuna industry. However, freshness of raw tuna steak may have close connection with the quality of cooked tuna steak. This research paper presents the effects of different freshness on the cooking quality of tuna steak. Finding in this research showed primary knowledge of mastering the freshness of raw tuna steak for ensuring the quality of cooked tuna steaks in canned tuna industry.

Mercury, omega-3 fatty acids, and seafood intake are not associated with heart rate variability or QT interval

ABSTRACTMercury (Hg), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) concentrations differ across seafood types. Our aim was to investigate the association of Hg, EPA, and DHA, as well as avid consumption of diverse seafood types, with cardiovascular variables heart rate variability (HRV) and QT interval duration (QTc) in a contemporary population. We measured HRV and QTc by Holter monitor, EPA and DHA in plasma, total Hg in whole blood, and possible confounders in 94 avid seafood consumers from Long Island, NY. Participants had mean Hg of 8.4 mcg/L, mean EPA of 1.2%, and mean DHA of 3.7% of total fatty acids. Adjusted for possible confounders, EPA+DHA, Hg, and total seafood consumption were not associated with HRV or QTc. Associations with consumption of specific seafood types were suggested (eg, tuna steak with QTc and anchovies with HRV) but require verification.

Are Consumers Willing to Pay More for Sustainable Products? A Study of Eco-Labeled Tuna Steak

A high demand for seafood leads to overfishing, harms the long-term health of seafood stocks, and threatens environmental sustainability in oceans. Sustainability certification is one of the major sustainability movements and is known as eco-labeling. For instance, in the tuna industry, leading tuna brands have committed to protecting sea turtles by allowing the tracing of the source of their tuna “from catch to can.” This paper relies on an Internet survey on consumers from Kentucky conducted in July 2010. The survey investigates household-level tuna steak (sashimi grade) consumption and examines consumer preferences for eco-labeling (“Certified Turtle Safe” (CTS) in this study) while mimicking individuals’ seafood procurement processes. A random parameter logit model is utilized, and willingness-to-pay measures are calculated based on model estimation results. It was found that respondents on average preferred turtle-safe-labeled tuna steak and were likely to pay more for it; however, they were less likely to purchase wild-caught species, and insignificant results were found for pre-frozen. Moreover, significant heterogeneities were found across individuals regarding tuna steak purchases. The findings indicate evidence of public support for environmental friendliness, particularly with regard to eco-labeling.

Detection Tuna and Processed Products Based Protein and DNA Barcoding

<p>Tuna is the second largest fishery commodity in Indonesia after the shrimp. Since the<br />high demand and the limited stock of tuna resulted in fraudulent chance. Authentication<br />is required to meassure consumers regarding the accuracy of its labeling and food<br />safety. In this study, the authentication was based on protein and DNA barcoding using<br />cytochrome-b gene (cyt-b) of the mitochondrial DNA as the target of gene. Primer of<br />cyt b gene was designed based on the tuna species. This study aimed to identify the<br />authenticity of tuna fresh and its processed products through protein using SDS-PAGE </p><p>and DNA barcoding techniques. The phases of this research were protein electrophoresis<br />by SDS-PAGE, DNA extraction, PCR amplification, electrophoresis and sequencing.<br />Samples of fresh fish (Tu1, Tu2, Tu3, Tu4, and Tu5) and processed tuna (canned and<br />steak) were successfully extracted. Result showed that SDS-PAGE proved the damage of<br />proteins in the processed tuna, so this method was not appropriate if it is used to identify<br />the authenticity of tuna. PCR electrophoresis results showed that the samples of tuna,<br />tuna steak, sushi, meat ball, abon, and caned tuna were successfully amplified in the range<br />of 500-750 bp except Ka3, which was in line with the target of DNA (620 bp). Resulted<br />sequences of Tu2, Tu3, Tu4 and Tu5 were identified according the results of morphometric<br />namely T. albacares, while Tu1 was identified as T. obesus with homology level of 99%.<br />Processed tunas (steak and canned tuna) were identified as T. albacares, as stated on the<br />labels.<br />Keywords: Authentication, cytb, DNA barcoding, design primer, SDS-PAGE</p>