What? Cockroaches can also make oil? Cooking oil!

What? Cockroaches can also make oil? Cooking oil?!

You read that right. Just like the cooking oils in our kitchen - peanut oil extracted from peanuts and rapeseed oil extracted from rapeseed, this new type of cooking oil is extracted from cockroaches .

Don't rush to vomit your dinner. They are still in the experimental stage ; and the cockroaches used here are not the American cockroaches or German cockroaches that appear in the corners and trash cans of your home, but another insect belonging to the order Blattia, called Dubia cockroach (Blaptica dubia).

——It doesn’t seem so disgusting anymore? Then let’s see how it is done.

Protein shortages in the future?

Insects added!

Of course, this is a serious experiment, not just for curiosity.

In fact, for the possible food crisis in the future, especially the problem of protein shortage, eating insects has always been regarded as one of the solutions . After all, the insect class is the most prosperous animal in the world, with the largest number of species in the entire animal kingdom, rich in diversity, and huge potential for breeding. Previous studies have also found that if we eat less meat and eat insects instead, we can effectively reduce the use of arable land and greenhouse gas emissions.

Moreover, people in many regions have the custom of eating insects, such as Yunnan in China. Today, the modern insect-eating industry has also emerged . There are more than 300 insect companies in Europe alone, and insect products are also rich and diverse, including whole insects and derivatives, such as mealworm pate, black fungus insect pie, cricket powder potato chips, etc.

Some kind of potato chips with cricket powder | Six Food

But one thing we can eat is food, but if we want to use insects to make oil, do they contain enough oil ?

In fact, the oil content of different insects varies greatly , ranging from less than 10% to as high as 50%. This is not much worse than the 55-60% body fat rate of fat-producing pigs. Insects also have a wide variety of oil types , including saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids. Linolenic acid and linoleic acid, which must be obtained through food, are also found in many insects.

So this time, the researchers chose four common edible insects and tried to bring them into the kitchen in the form of cooking oil . In addition to the Dubia cockroach mentioned above, there are also house crickets (Acheta domesticus), mealworms (Tenebrio molitor) and black fungus worms (Alphitobius diaperinus).

Swipe left to see four insects

The latter two may sound a bit unfamiliar. In fact, the larvae of yellow mealworms are the famous mealworms, which are commonly used feed for spiders, lizards, fish and birds; black fungus worms are a kind of grain storage pests that like to eat grains and are serious hazards to grain depots, rice processing plants, and flour processing plants.

The researchers soaked four types of frozen insects in water, vibrated them with sound waves, crushed them, mixed them, and separated them into layers through two rounds of centrifugation. Finally, they obtained oils from the four types of insects . According to the researchers, this method of water extraction is more environmentally friendly and produces better oils than traditional organic solvent extraction.

E is the extracted oil | References

What is the most important thing about food?

Color, aroma and taste!

It is not enough to just refine the oil. What is more important is whether it is suitable for the table . The researchers conducted a detailed and rigorous evaluation of the four new edible oils in terms of color, smell, melting point and other aspects.

>> Color

The following picture shows the four insect oils they obtained - at room temperature, they are all obvious yellow liquids . The researchers did not just rely on the naked eye to judge, they also used a spectrophotometric method to quantify the color professionally and systematically. From the data, the cockroach oil of contestant No. 4 has the darkest yellow, and the mealworm oil of No. 1 has the lightest yellow; at the same time, all four liquids have a faint red color, especially the house cricket oil.

Yellow with red | References

Researchers speculate that this yellow-red color may be related to carotenoids , a natural pigment found in the outer shells of insects and the blood-like fluid flowing in their bodies. If this speculation can be confirmed, insect oil will also become a food source of carotenoids, similar to the effect of eating broccoli and carrots. In addition, this color is very similar to the peanut oil and rapeseed oil we are used to. In the view of the researchers, these characteristics can make consumers more accepting of this novel edible oil .

>> Incense

To evaluate the smell, the researchers analyzed the aromatic compounds contained in each oil, each of which has its own corresponding odor characteristics . In terms of quantity, the aromatic substances in these oils are relatively rich. House cricket oil ranks first with 20 aromatic compounds, followed by Dubia cockroach oil with 19, while mealworm oil and black fungus worm oil are relatively few, with 10 and 11 respectively.

In terms of smell type, house cricket oil is also far ahead. You can smell the sweetness of cheese and butter, mixed with the fruity aroma of banana, coconut and citrus lemon, as well as some plant smells like mint, grass, pine and cypress; but it is not entirely so fresh and sweet, it also has a wine smell like whiskey and a sour smell like vinegar - these mixed together should be a very high-level and layered smell . The only drawback is that house cricket oil also contains a terpene substance that smells like vomit and rancid butter.

The smells of mealworm oil and black fungus oil are relatively simple . The former is mainly sweet, with some plant aromas like camphor and herbs, as well as acetic acid and fish. The latter is also mostly sweet, grassy and fruity, with a little sour and rancid taste.

Many of the aromatic compounds contained in these three insect oils are present in our existing edible oils - so it seems that they have a good chance of passing the smell test and becoming a new type of edible oil.

In comparison, Dubia cockroach oil is disappointing. Although it also has aromas such as almond, grass, sweet and fruity, it has 7 aromatic compounds that are not so pleasant to smell , either rancid or pungent. The researchers also complained in the paper that they smelled some bad smells during the process of refining cockroach oil.

The smell of these oils may be affected by the extraction method . There was another previous study that believed that insect oils were odorless; the researchers explained that the previous study had an evaporation step, and at a certain temperature, it may be possible to evaporate certain aromatic compounds from the oil. So, when the extraction method is improved, we may still be able to enjoy Dubia cockroach oil!

>>Flavor

Unfortunately, the study did not use the insect oils to prepare a few dishes to further evaluate the taste.

Fried house crickets | Wikimedia Commons

In addition, the researchers also measured the crystallization point and melting point of the four insect oils and calculated their extraction efficiency. They believe that the oil refining methods of the four insects need to be optimized, and we can get more oil from the insect bodies; at the same time, the oil that has been refined can also be further extracted and separated to obtain higher quality edible oil .

Maybe in the future, we won’t eat fried chicken or pork chops anymore. Instead, the table will have fried house crickets and mealworms, or fried cockroaches with black fungus and insect oil… Imagine, wouldn’t it be nice to have something crunchy and crispy?

References

DA Tzompa-Sosa, L Yi, HJF van Valenberg and CMM Lakemond. Four insect oils as food ingredient: physical and chemical characterization of insect oils obtained by an aqueous oil extraction. Journal of Insects as Food and Feed. 2019.

DOI 10.3920/JIFF2018.0020

Author: Mai Mai

Editor: Li Zi Li Zi SMS

Title image source: Gintama