Marin did not believe in evil, and put other cabbage leaves with different drying degrees on the kang into the water. But after a while, the leaves are as full as ever.

"Is this just a dehydrated vegetable? No, I remember that dehydrated vegetables have a ...... of cryogenic freezing" Marin was a little puzzled.

But Marin didn't know that there were actually two major factions of dehydrated vegetables: hot air drying and freeze vacuum drying. And what he remembered happened to be the freeze-vacuum drying method. In later generations, most of the frozen areas in supermarkets were sold like this. This is because dehydrated vegetables that have been freeze-dried vacuum-dried have very low nutrient loss. After soaking in water, the original nutrients, including vitamins, can be fully restored.

However, freeze-vacuum drying technology only appeared in the 20th century. At that time, there was a well-established freezing technology. Marin remembers that when dehydrated vegetables were processed, they needed to be as low as -30 degrees Celsius.

However, before the advent of freeze vacuum drying technology, there was actually a dehydrated vegetable technology - hot air drying technology!

This technology appeared very early, and there were rudiments in ancient times. In modern times, it has become more mature. For example, during the American Civil War, the army was supplied with dehydrated vegetables in large quantities.

However, the dehydrated vegetables produced by this thermal drying technology have a lot of nutritional loss, especially vitamin loss. Therefore, the later generations were gradually eliminated. After all, the freezing technology of later generations has been very developed, and there is no need for such outdated gadgets. There are various refrigerated transport trucks on the road, and there are also refrigerated container ships on the sea.

Marlin had not been exposed to early dehydrated vegetables, so naturally he did not know about dehydrated vegetables with thermal drying technology. After all, he began to remember, and it was already the 90s. At that time, the transportation industry was developed, and there were greenhouse vegetables everywhere. If you want to buy vegetables, you can go directly to the vegetable market to buy fresh vegetables, and you don't have to think about what dehydrated vegetables you have.

Therefore, he doesn't know much about vegetables. Later, after working and becoming independent, I was exposed to some freeze-dried dehydrated vegetables in the supermarket. Because, there is a refrigerator in his residence. And frozen dehydrated vegetables can be stored for several months, which is most suitable for otaku like him. Moreover, he usually doesn't have time to go to the vegetable market to buy vegetables when he goes to work, and the vegetable market is closed after work. Therefore, it is very convenient to buy this frozen and dehydrated vegetable that can be stored for several months.

But in ancient times, there must have been no refrigerators. Therefore, dehydrated vegetables with thermal drying technology are king.

However, Marlin remembers that vitamin C is very delicate. It is afraid of sunlight, heat (it starts to transform when it exceeds 80 degrees), oxidation, and salt (pickles do not have vitamin C). Therefore, Marlin had never thought of using hot air drying technology to produce dehydrated vegetables. Mainly, in his cognition, dryness is exposure to the sun. And the vitamin C in vegetables will be lost when exposed to the sun, so it is meaningless. After all, dehydrated vegetables are the most suitable for great voyages, and they are also suitable for marching and fighting. But if there is no vitamin C, vegetables are of little significance, similar to pickles.

However, today's mischievous little Ma Yun's troublemaking made Marin suddenly realize that there is really a dehydration processing method that does not destroy vitamin C as much as possible......

……

Vitamin C afraid of high temperatures? That's not a problem. Isn't it just 80 degrees? The temperature of the kang is not high. Even if you don't have a quilt, the surface of the bare ondol is only forty or fifty degrees Celsius, which is about the same as the warm water in the bathhouse. As long as the temperature does not exceed 80 degrees, it can avoid destroying the vitamin C in vegetables as much as possible.

Moreover, if the kang is heated, it can avoid exposing vegetables to the sun and will not be converted into vitamin C by sunlight. As for oxygen or something, heating the stove indoors will definitely consume a lot of oxygen to avoid the oxidation of vitamins in vegetables. Of course, when people take processed vegetables, it is best to open the doors and windows to avoid suffocation due to lack of oxygen......

Although he had never been exposed to dehydrated vegetables made by this thermal drying technique, Marin was vaguely aware of another "lower-level" dehydrated vegetable, which was said to have a large nutrient loss.

But for Marlin, nutrient loss or anything is not a problem, the most important thing is to have!

Just like the backward poor countries of later generations, the first thing it pursues should not be high-tech, but the question of whether it has or does not have. Isn't it nonsense that you don't have any low-level stuff to practice, so you just pursue top-level high-tech?

Why can Huaxia develop? In addition to China's abundant coal resources, it itself has a complete but backward industrial system. Then, to upgrade on this backward but complete industrial system, naturally, there is no problem.

In later generations, many African countries did not understand this and blindly pursued the high. To learn technology, you must go to virtue. As a result, even if you learn it, you can't learn it, and it's meaningless. However, Huaxia has slowly improved from the original foundation, and even introduced a large number of foreign obsolete production lines at the beginning. Although it may seem ridiculous, those outdated production techniques are more suitable for the needs of Huaxia learning and improving. Then, a few decades later, Huaxia, which had absorbed enough of all kinds of technologies, began to explode technologically......

Marin suddenly felt that although there may be a lot of loss of vitamin C in the dehydrated vegetables made by this hot drying technology, there must be a lot of leftovers. As long as you eat more of this dehydrated vegetable, the crew will definitely stay away from scurvy.

……

What the? You say it's good to eat canned food? Please, the canned food of Marlin's age uses high-temperature cooking technology, and the vitamin C is very destructive. Even if it is canned fruit, it is estimated that only a small part of vitamin C is left. So, it's better to dehydrate vegetables.

Moreover, dehydrated vegetables can be bagged. Unlike canned fruits and vegetables, which need to be bottled. In these days, there were no plastic bottles and aluminum cans, and only glass bottles could be used for cans. Glass bottles are fragile and need to be fixed with wooden boxes, which is very troublesome, costly, and takes up space.

However, if you use bagged vegetable leaves, you can pack dehydrated vegetables in oil-paper bags, which is very convenient for transportation. Because, vegetable leaves packaged in oily paper bags can be piled up casually. Unlike glass bottles, the wooden box needs to be fixed before it can be stacked. Not to mention the waste of space, a large number of wooden boxes are also required. If you use oil paper bags, with the current papermaking technology in Beihai, the cost is much lower than that of wooden boxes and glass bottles.

……

In addition, the processing of dehydrated vegetables can also have technical barriers. At least, other countries don't know that dehydrated vegetables must be protected from light, and that the temperature must be below 80 degrees Celsius when dehydrated. If it is above 80 degrees, vitamin C is destroyed.

In this way, even if other countries imitate the North Sea Kingdom, as long as they don't know the main point. Rashly use sun-dried leaves as dehydrated vegetables, or dry vegetables at a high temperature of more than 80 degrees. The dehydrated vegetables that come out of this way are actually worthless. Because, vitamin C is all destroyed......

……

With the idea in mind, Marin built a dehydrated vegetable processing base on a secret estate outside the city.

The base adopts the method of ondol heating and indoor stove to raise the indoor temperature to about 70 degrees (there is a mercury thermometer to monitor the temperature). Then, place the vegetables on the kang and turn them over regularly. Medium-high heat drying is carried out, and the drying time. After several days of trying, it was finally set at more than 10 hours.

After the vegetables are dried, they will be packed into oiled paper bags, heated at medium and high temperatures on another kang for sterilization, and then sealed with glue to isolate the air.

In this way, a bag of dehydrated vegetables is processed. Then, it could be supplied in large quantities to the crews of the Great Voyages, and to the army in times of war.

When eating, you only need to tear open the packaging of the oiled paper bag, soak it in water for a while, and then you can eat it raw......

……

What the? You say you want to stir fry? Sorry, after stir-frying, the loss of vitamin C is too great. If you want to get vitamin C, it's best to eat it raw.

Moreover, in Europe in this era, Europeans were also accustomed to eating raw vegetables. But the fruit, in turn, is boiled in water......

So, don't worry if the crew is not used to lettuce, people go from snacks to big ones like this!

The dehydrated vegetables processed by thermal drying technology can be stored for more than a year as long as they are stored properly after being sealed and packaged. In this way, enough for the crew of the great voyage to eat vegetables halfway.

As for the processing cost of dehydrated vegetables? The cost of oil paper bags is not expensive at the Cape Breton Island paper mill in Canada, and there is no shortage of coal for heating the ondol. Compared to the great voyage, this consumption is nothing......

Even if the dehydrated vegetables with thermal drying technology lose a lot of vitamin C, there is no problem if you eat too much. After all, vegetable leaves packaged in oily paper bags can be piled up without worrying about broken glass bottles or something.

At this point, the future ocean-going ships of the North Sea Kingdom were full of oil-paper bags filled with dehydrated vegetables. During the voyage, the crew nibbled on bread and ate dehydrated vegetables soaked in water, which was much more convenient than carrying canned food.

As for the raw materials for making dehydrated vegetables, Marin tentatively uses Chinese cabbage, cabbage and lettuce. Especially Chinese cabbage, the yield per mu is high and the cost is low. In this way, the dehydrated Chinese cabbage produced is not costly even if it is openly supplied to the crew. It's even cheaper than soaking lemon leaves in water......

Marin will then set up dehydrated vegetable processing centers in Cuba, Panama and Keelung, where the nautical relay stations are located. Boats passing by, ready to replenish dehydrated cabbage. In this way, the crew does not have to worry about the lack of vitamins......

Later, there was a popular saying in the navigation circle of Beihai - a cabbage every day to stay away from scurvy......