How can frozen tuna be thawed to still taste good?

In order to maintain the quality of tuna, when it is caught in the sea, the ikejime technique is used first, then rapid freezing is used as a matter of course. This means that the quality of the thawing technique is also important. Poor thawing conditions means that the drip outflow volume will be too high, shrinking the meat and worsening the texture. Here I will explain a thawing method that doesn’t cause drip, uneven thawing, or loss of color.

What exactly is drip anyway?

I’m sure you’ve seen it before in any type of thawing frozen meat, but there is a red liquid that comes out of the tuna when thawing. This is called ‘drip’. This liquid includes the tuna’s umami, and when the fish loses a lot, it naturally detracts from the flavor.

First of all, we will explain the worst thawing methods. Never thaw naturally at room temperature or in the microwave. These are common methods at home, but they are out of the question.

Next we will explain the general method of thawing.

  1. Mix 30 g of salt with 1000 cc of warm water at 40℃ to create a saltwater mixture.
  2. Place the frozen block of tuna in this 40℃ saltwater, submerge for one to two minutes and then drain the water.
  3. Wash any remaining salt off the surface of the block of fish with freshwater and remove moisture from the surface with paper towels.
  4. Wrap the fish in clean paper towels, wrap with plastic over that and leave it in the refrigerator for about a day to thaw naturally.
  5. Cut from the block directly before consuming.

Now for the thawing method used by professionals, such as sushi chefs.

The first three steps are the same as the general thawing method above.

  1. Place block in an air-tight plastic bag. Push out as much air as possible before sealing the bag.
  2. Prepare ice water in a bowl or container and submerge the plastic bag in the water for one hour. Normally the bag will float, so it must be weighed down with something.
  3. Remove the thawed tuna from the plastic bag and remove moisture with paper towels.
  4. Wrap the fish in clean paper towels, wrap with plastic over that and leave it in the refrigerator for about a day to mature.

After thawing, the meat of the tuna may have shrunk. This is called ‘chijire’. The reason for this is, after the tuna is caught, it is frozen before rigor mortis begins, so the rigor mortis process starts once the fish is thawed. Therefore, this is proof of freshness. The meat of tuna for which ‘chijire’ has begun is tough and isn’t yet matured. However, amateurs can’t tell if ‘chijire’ is happening or not. That’s why it’s better to let the fish mature in the refrigerator for half a day to one day. Please use these explanations for your own reference.


We hope this information will be helpful.

Revision date: October 2, 2020

What’s the trick to distinguishing which conveyor belt sushi restaurants are better?!

There is only one trick to distinguishing between conveyor belt sushi restaurants (kaiten-zushi), and that is to try eating the tuna as your first dish.

Why is that, you ask?

The most commonly used ingredient at kaiten-zushi is tuna. At kaiten-zushi, the tuna is imported and frozen nearly 100% of the time. The most famous is the Southern blue-fin tun, but you’ll also find Boston bluefin tuna, Canadian tuna farmed in fish preserves, inland sea tuna from Turkey and Spain, New Zealand offshore tuna, Atlantic tuna, etc. Also, the season of each type of tuna and the timing of high-volume catch differ, which makes the prices fluctuate greatly.

Therefore, the biggest task of a kaiten-zushi chain buyer is to decide where to import tuna from. Looking for high cost-performance, they watch fluctuations in the market every single day without fail, check the flavor in detail and constantly change the locality.

In other words, the chain restaurant purchaser’s efforts are concentrated on tuna. Restaurants that serve tuna that has lost its fat, is watery or rubbery, clearly either have a purchaser with a poor eye, or poor thawing skills. Therefore, if you are disappointed with that first tuna plate, then reign in your expectations for other toppings. On the other hand, if you enjoy the tuna then you’ll have a lot of other toppings to look forward to.


We hope this information will be helpful.

Revision date: August 17, 2020

What is imitation crab?

One of the common ingredients of sushi rolls is imitation crab. In Japan this is called kanikama, in Europe it’s called surimi and in the US it’s also called fake crab.

I’m sure everyone reading this has tried it before, but what is imitation crab made of?

It seems kanikama was invented in Japan. In the early 1970s, Sugiyo, a fish paste manufacturer, in a failed attempt to developed artificial jellyfish, ended up with a product that had a texture exactly like crab and shifted development to that instead.

The “kani” of “kanikama” means “crab”. “Kama” is an abbreviation of kamaboko, which is boiled fish paste, fish sausage or fish cake. It’s official name is “crab-like kamaboko”. The main ingredient is minced fish meat mashed into paste. One of the white fish used is Alaska pollack. But it contains no crab. Incidentally, there is actual crab in the kanikama sold in the US and Europe.

It has now become a staple not only in sushi rolls, but also in sandwiches or on baguettes and even on takeout salads. It’s become even more popular than it is within Japan.

Related contents

http://www.viciunaigroup.eu/en

https://www.sugiyo.co.jp/


We hope this information will be helpful.

Revision date: June 22, 2020

 

What’s the difference between Tobiko and Masago?

The tiny red balls around the outside of the rice on California rolls are tobiko (飛び子). Specifically, they are salted roe of flying fish and are known for the plump, crunchy texture. In fact, it is a registered trademark of a seafood processing company called Kanetoku, located in Hyogo prefecture, Japan. It isn’t hard to see that it’s an abbreviated version of the Japanese “Tobiuo no ko”.

Tobiko is rich in nutrients such as the minerals and vitamins potassium, phosphorus, vitamin E, vitamin C and niacin. Also, since it has a natural pigment composition called astaxanthin, which gives tobiko its bright color, it has antioxidative effects and is effective in strengthening the immune system.

What is flying fish?

Flying fish are found in the subtropical to temperate waters of the Pacific Ocean, Indian Ocean, and Atlantic Ocean. They travel along the surface of the sea and eat zooplankton. Over 50 types of flying fish have been identified around the world. More than 30 of these have been identified in Japan, of which 4 types are used as food. Since the meat is white, low in fat, and has little odor, it is prepared in various ways such as sashimi, minced, grilled with salt, and fried. In Kyushu, flying fish is called “ago,” and it is dehydrated to be used as soup stock, called “dashi” in Japanese. Ago dashi has a refined and refreshing sweetness and a deep flavor, and it is considered to be on the higher-end of dashi stock.

The dorsal side of the flying fish is a vibrant dark blue, and the ventral side is silver The pectoral fin is considerably long at about 30-40 cm long. It uses it pectoral fins to fly over the water’s surface to escape from its natural enemies, such as tuna Depending on the breed, it can fly an average of 200 m in one go. The larger the species, the longer distance it can fly and the longest can be up to even 600 m. Furthermore, the flying fish has no stomach and its other digestive organs are short and straight, which makes its body lighter and ideal for extended flight.

Flying fish contains a lot of a nutrient called Niacin which can help prevent hangovers. Additionally, it is rich in vitamin E, which works to prevent the oxidation of unsaturated fatty acids in the body, and as such is a good fish for preventing lifestyle-related diseases such as arteriosclerosis and myocardial infarction.

On the other hand, an orange-colored tobiko is often seen at conveyor belt sushi restaurants, etc., but this is the roe of a fish called capelin (カペリン), which is similar to shishamo smelt. A salted version of this is used for sushi rolls in the US and other places, where it is called masago. Compared to tobiko, the grains are smaller and the texture is a bit chewier. It is mainly rich in EPA (Omega-3 fatty acids) and collagen.

Masago (真砂子)” actually means “fine sand” and therefore is used for foods that depict that image. In other words, it refers to broken up fish roe and doesn’t indicate a specific type of fish. Dishes made using capelin roe can be called masago, but please keep in mind that dishes with broken up tarako or kazunoko are also called masago.

What is capelin?

The shape of capelin is very similar to shishamo smelt, but the scales are very fine, barely visible to the eye. The body is a bluish silver color with an average length of 12-16 cm, but can grow up to 20 cm.

It is found in a wide area from the Arctic Ocean to the frigid sea regions and also migrates to the Sea of Okhotsk on the coast of Hokkaido. The time they spawn depends on the region. The season for Canadian capelin is June to mid-July, and the season for Icelandic and Norwegian capelin is mid-February to mid-March.

They are also known as Komochi Shishamo (Shishamo with child) and are known to have a wonderful balance of fat and roe. Compared to shishamo smelt, they are leaner and have a lighter texture. Shishamo smelt is not caught in great numbers, so capelin started to be imported as a substitute for it for Japanese homes and izakaya (Japanese bar/restaurants).

Capelin rush to the coastal area in large groups to lays eggs on the sandy bottom of the beach during spawning season. The amount of eggs it lays at one time is about 5,000 to 6,000. It has spherical, adhesive demersal eggs with a diameter of around 1 mm. The eggs hatch around spring tide about 2 weeks after spawning The total length of larvae immediately after hatching is 4-5 mm, and it is thought that they leave the coastal area by utilizing waves at high tide and reach a total length of around 10 cm in the first year of life.

Capelin is a healthy fish that can be eaten in its entirety, and boasts 7 nutrients (DHA, EPA, calcium, zinc, potassium, vitamin B2, collagen). Moreover, since the sugar content is only 0.5 g per fish, about 1/3 of the amount normally contained in fish, it is perfect for those who are dieting.

Tobiko and masago in Japan have probably been purchased at the Toyosu Market. They are not commonly found at normal grocery stores. This is because there are very few sushi restaurants that serve sushi rolls and they aren’t even made in homes often. Tobiko and masago are toppings available wholesale and used by places like conveyor belt sushi restaurants. Roe used for this is imported from Taiwan or Peru.

Finally, we’ll let you in on a not-so-pleasant secret. Flying fish and capelin roe are actually a light yellow or beige color. However, you’ll find it in bright red, orange, yellow and lately even green or black. Of course, these are colored by either natural pigments or synthetic coloring. Furthermore, tobiko is sometimes mixed with the cheaper capelin or herring roe. Unfortunately, food fraud is common in seafood products that are consumed in high quantities.


We hope this information will be helpful.

Revision date: August 3, 2020

What makes a “good” sushi restaurant?

It is probably cutting fish just before serving. For a big size fish, keep its skin on the meat during the process of preparing and cutting into half, and at every serving use sogigiri* as much as customers eat. Protected by the skin, the fish flesh will expose to air for the first time as it is cut. The skin blocks the oxidation process significantly because the fat in fish centers right  under the skin in general. Needless to say, even with any amazing fish, it loses flavor if the fat gets oxidized.

*Sogigiri-A method of cutting which makes a slice thinner with a greater surface, by holding the knife diagonally and cutting in line with the cutting board. Usually used for white fish with firm flesh because it is easier to be eaten when served thin.

Hirazukuri-A method of cutting which gives thickness to each slice so that the texture of sashimi can be enjoyable. This is used for akami like tuna.


We hope this information will be helpful.

Revision date: April 1, 2020

Why do they say that the quality and price of tuna is determined by the processing after the fish is caught?

Why is only tuna brought into certain ports high-priced, even though all of the tuna is caught in the seas near Japan? This is because the level of stress caused to the fish when it is caught has a huge impact on the quality, including taste, color and texture. In other words, the same fish may be delicious or taste unpleasant depending on how the fisher handles the fish directly after catching it. Naturally, everyone ends up wanting the fish from the ports with fisherman who are skilled in this practice*. Furthermore, it is individuals who process the fish. The quality changes drastically depending on who caught it.

*This is a method of cutting off the medulla oblongata and aorta of a fish, essentially keeping the body alive while killing the fish. There is also a method of inserting a thin wire, like a piano wire, into the backbone. This technique paralyzes the nerves while at the same time suppressing the putrefied substance that comes from the spinal cord. Using the ikejime method extends the time until rigor mortis starts, and makes it easier to maintain freshness, while at the same time preventing raw fish odor and damage to the body by inserting a butcher knife into the base of the tail to drain the blood and keep oxidized blood from running throughout the body.


We hope this information will be helpful.

Revision date: December 17, 2019

What is the ideal temperature for sushi toppings?

Tokyo Health Centers stipulate that refrigerated cases where sushi toppings are stored should be kept at 5℃ or lower. This is to maintain the temperature of the toppings at below 10°C at which point bacterial growth is slowed.

However, sushi chefs will remove the topping from the refrigerator and leave it standing out for a while (in the case of tuna, the fat will melt at around 23℃). They do this because if the topping is cold, it becomes difficult to taste the essential nature of the fish. The temperature of the shari is best at human skin temperature (around 36℃) to maximize the taste and sweetness of the rice. However, the ideal temperature differs very slightly depending on the topping.

For example, conger eel which is often lightly grilled or prepared in another, similar way, should have a slightly higher temperature (around 42℃) than the shari, and kuruma prawn, which are boiled, should be the same temperature as the shari.

Overseas, there are laws that state that sushi must be served at 10℃ or lower. This ignores that sushi is best enjoyed at skin temperature. Serving it straight out of the refrigerator makes it no better than purchasing takeout sushi from the supermarket.


We hope this information will be helpful.

Revision date: November 18, 2019

When does Kinmedai taste the best?

No one is more sensitive to the changing of the seasons than sushi lovers. This must be because the taste of sushi toppings is directly tied to the seasons. There are terms to describe this such as Hashiri (early season), Peak (in-season) and Holdover, and using these words to understand what state the sushi topping is in allows you grasp and enjoy the various different flavors. There is nothing that says a sushi topping is less delicious because it has a lower fat content.

For example, everyone wants to get in there and be the first eat early season toppings. It’s obvious that these would all be toppings with low fat content. But early-season toppings have a liveliness that you can’t find in other foods, and some believe that eating these types of food will give you new vitality.

Once a fish is in peak-season, we eat it as sushi. This is because the fish has grown as it approaches breeding season, gradually gaining more fat, and at this stage in its development it has a richer flavor.

And the ‘holdover’ perhaps means that since the season is about to end, we need to get our fill now. While we may feel a bit sad that the season is ending, we can look forward to it coming around again the next year.

On the other hand, there are sushi toppings that don’t seem to fit into the seasons, although the seasonal dishes are one of the important reasons that Japanese food was registered under UNESCO World Heritage.

Those are deep sea fish such as Largehead hairtail, Japanese bluefish, Pollack and Splendid alfonsino.

Deep sea fish live at least 200 m below the surface of the ocean. For example, Splendid alfonsino lives at a depth of between 100 to 800 m deep, so it would generally be thought of as in-season in the winter when it has the highest fat content. However, except just before and after spawning season, the flavor of the Splendid alfonsino doesn’t change much throughout the year. Therefore, even high-end sushi restaurants always keep it in the topping case and it’s a popular choice.

Therefore, Splendid alfonsino is never actually “in-season”.

Since very little light reaches the deep sea, the water temperature remains more or less constant. In other words, there aren’t really seasonal (temperature) changes. The concept of season may not exist there.

Even so, you can think of it as especially delicious in the winter between December and February, when it has a higher fat content. Otherwise you might start to think of it as a fish that is “in-season” all year round, like salmon, and that just doesn’t feel quite as splendid.


We hope this information will be helpful.

Revision date: October 28, 2019

What is the real reason for the emphasis on freshness in seafood?

The human tongue tends to sense food that is slightly acidic as delicious, and tends to sense it as not delicious when there is alkaline. When fish is alive, the alkaline levels are low, but after dying and beginning to stiffen, the glycogen in the muscle meat turns into lactic acid and becomes acidic. However, as more time passes, the rigor morris releases and the body softens. This is when it tastes the best. After that the proteins break down increasing the amount of alkalines such as ammonia. Also, since the proteins dissolve when they become alkaline, the body breaks down as the alkaline increases. This is the reason that fish tastes worse as it loses its freshness.


We hope this information will be helpful.

Revision date: October 1, 2019

What’s the difference between Japanese mustard and Western style mustard?

Japanese mustard refers to oriental (yellow) mustard and is a condiment with a strong spiciness. It is used for cooking Japanese and Chinese food. Western style mustard refers to white mustard, which has a more subtle flavor and fragrance and is not as spicy. It is used for sandwiches and sausages. Whole grain mustard is made by mixing white mustard with black mustard seeds and used for things like flavoring vinegar. Sushi chefs use Japanese mustard to offset the greasiness of fatty fish such as bonito and tuna.


We hope this information will be helpful.

Revision date: September 16, 2019

What are fish seasons?

Fish seasons are categorized as the ‘catch season’ and the ‘flavor season’. The ‘catch season’ is the time when lots of fish can be caught and are cheap. Take Japanese Spanish mackerel (Sawara), for example, they approach the coasts during the spring to spawn and this is the peak season. This is the catch season. Once they’re about to spawn and their bodies fatten for winter, we’ve entered the tasting season. However, these seasons differ depending on the region, and may be longer or even happen twice a year.


We hope this information will be helpful.

Revision date: September 4, 2019

What’s the difference between mariage and pairing?

In the past, the word ‘mariage’ was often used when matching sushi and sake. Of course, that word is still used, but ‘pairing’ is more common now. It doesn’t matter which you use, both have the meaning of ‘matching’ or ‘combining’. The only real difference is that pairing is closer to just matching things, while mariage has the implication of combining things to create something new.

 


We hope this information will be helpful.

Revision date: August 7, 2019

It’s not just only farmed fish which has been accumulated toxic substances.

Natural fish are part of the food chain and have concentrations of harmful substances. Since 2000 the amount of mercury found in fish has become an issue. The American Natural Resources Defense Council has said tuna is a fish that should be avoided if pregnant or planning to get pregnant. A more recent problem is the large amounts of micro plastics found in fish meat. This shocking phenomenon will likely be reported by research organizations at some point in time. If it does reach that extreme, then it will be better to avoid the danger of eating fish.


We hope this information will be helpful.

Revision date: April 22, 2019

Why does it taste a little bland when you had tuna at high-class sushi restaurant?

Tuna at top-end restaurants is light in flavor. Its Akami (red meat) has an indescribable acidity with a delicate harmony between the shari vinegar, the nikiri soy sauce, and wasabi. However, on the other side of the coin, it feels almost like a waste to eat it without a sense of luxury. Of course tuna with delicious akami, also has delicious fatty tuna (toro). And you’ll never get tired of it. It would be easy to polish off 10 pieces as a light snack. Contrary to popular belief, it’s not the high fat content that makes it so easy to eat. However, it is because of that popular belief that many people feel that the big chain store farmed fish with lots of fat is more delicious than luxury natural fish.

 


We hope this information will be helpful.

Revision date: April 16, 2019

Reevaluating the serious risk to health posed by farmed salmon!

Before continuing, please read the exclusive articles in major media and research papers.

The red tide (algal bloom) frequently occurs off the coast of Chile and it is resulting a large amount of salmon deaths. In 2015 27 million salmon died in a mass event, of which 25,000 tons were powdered and then fed to the healthy salmon (according to the UK’s Guardian reports).

Chilean fish farmers are using large quantities of antibiotics to control fish diseases. They use 500-700 times more antibiotics than Norway does. 80% of antibiotics imported into Chile are intended for the fish farming industry. Faced with the risk of bacteria resistant to antibiotics emerging, as highlighted by the World Health Organization (WHO), the Chilean National Fish Service is calling for a reduction in the use of antibiotics. (Extract from Le Monde diplomatique Japanese edition)

The bright color of salmon is something that you would never see a long time ago, but is now commonplace. It is likely due to the Canthaxanthin pigment mixed into their feed. Salmon is in fact a white fish. The salmon that is caught in Japan is called “Shirozake” or white salmon and its flesh is not a pink before it goes out to sea. Once it is out at sea, it swims around consuming small plankton and crustaceans such as shrimp and krill. Its body then takes on a pink color due to the intake of natural coloring of Astaxanthin. This Astaxanthin has antioxidant effects and it is noted for playing a part in relieving fatigue and preventing aging. However, the synthetic pigmentation that creates the salmon pink does not provide the same health benefits.

The US Food and Drug Administration (FDA) gave approval for genetically modified salmon on November 19th, 2015. This genetically modified salmon is called “AquAdvantage salmon.” It grows faster than regular salmon and its body length is almost double. There are groups opposing the sale of this salmon, including US citizen group Center for Food Safety, the Japanese Seikatsu Club, and the European parliament. There are still many unknowns regarding the safety of this type of fish for human consumption, and a number of issues are still being debated. The discussion has been featured in “Nature” magazine.

Endosulfan is a type of organochlorine compound, like Dichloro Diphenyl Trichloroethane, Dicofol, Heptachlor, Chlordane, Mirex, Pentachlorophenol, and is known to be extremely toxic, but the EU approved Endosulfan for use as feed in Norway’s salmon farming industry in 2013.

Researchers analyzed the risk-benefit ratio based on levels of contaminants like dioxins, PCBs and chlorinated pesticides versus omega-3 fatty acid levels. While farmed salmon is higher in omega-3s, it is also significantly higher in these toxins (about 10 times) which can produce birth defects, lower IQ, and cause cancer. They determined the following based on origin of the salmon: “consumers should not eat farmed fish from Scotland, Norway and eastern Canada more than three times a year; farmed fish from Maine, western Canada and Washington state no more than three to six times a year; and farmed fish from Chile no more than about six times a year. Wild chum salmon can be consumed safely as often as once a week, pink salmon, Sockeye and Coho about twice a month and Chinook just under once a month.” (Extract from The Journal of Nutrition)

There is a saying, where there’s smoke, there’s fire. It is unlikely that big media outlet and research organizations would join forces to circulate incorrect information. Furthermore, this is not a problem that only affects certain countries like Chile or Norway. It should be considered as a problem for the entire farmed salmon industry.

On the other side of the debate, there are articles such as the following. Norway’s NIFES (National Institute of Nutrition and Seafood Research) sampled 13,180 farmed fish (of which 90% were salmon) and monitored them for medicines, substances that are prohibited by law, and other pollutants, publishing their report on August 17th 2015. In their latest report, it concluded that Norwegian farmed fish were safe and that illegal and undesirable substances were not observed to exceed standards. Further, it seems that they have confirmed decrease in most of the pollutants analyzed in the investigation.

But the fact is that, according to these articles, while the chemicals did not exceed standard values, they were certainly found to be present in farmed salmon. The other extreme would be to say that eating natural un-farmed salmon will not expose you to the potential risks from these types of chemicals.

However, that’s not really practical. The global production of farmed salmon is 2.5 million tons a year, approximately three times the 800,000 tons of naturally fished salmon. No matter what way you slice it, the option of farmed salmon isn’t going away anytime soon.

Related Links

UK’s Guardian reports

Reuters reports

Le Monde diplomatique reports

Nature reports

dwell


We hope this information will be helpful.

Revision date: March 1, 2019