Debunking the “fruit enzyme” myth

Persimmon Recently, a "fruit enzyme" trend has swept across my country. The efficacy and methods of "fruit enzymes" have become a hot topic on various online platforms. Typing the words "fruit enzyme" on the Internet will instantly return more than 8 million search results, which means it is very popular. The various benefits of "fruit enzyme" such as "weight loss", "beauty care" and "detoxification" promoted by "fruit enzyme" have made it the object of competition among beauty lovers. Coupled with the "natural" and "homemade" production methods, it seems that you will be out of date if you don't make a few bottles and jars at home to produce "fruit enzyme".

So, what exactly are “fruit enzymes” and what are their magical effects?

◆It sounds high-end, but it’s actually tacky

Although there are a lot of search results for "fruit enzyme", a closer look will reveal that most of these messages are repeated descriptions of the effects and production methods, but there is no clear definition of what "fruit enzyme" is. In order to understand what "fruit enzyme" is, let's take a look at how to make "fruit enzyme". The more common way is to wash the fruit, cut it into pieces, mix a certain proportion of sugar and water, put it into a clean container, seal it, and place it in a cool place for a week or two. The resulting liquid is the "fruit enzyme."

However, those of you who have cooked, especially those from Sichuan, do you feel that this process is familiar? If you replace fruits with vegetables and add some extra salt and chili, isn’t this a typical Sichuan pickle? The "fruit enzyme" you drink is actually equivalent to "kimchi juice" with more sugar but no salt or pepper.

For those who have studied biology, when they see the word "enzyme", they may not think that "fruit enzyme" is so high-sounding. The word "enzyme" originated in Japan, and in mainland my country, the word "enzyme" has a more well-known name: "enzyme". Just like calling strawberries "strawberries" immediately makes them look high-end, the "enzyme" imported through Hong Kong and Taiwan has surpassed the "local names" in mainland China and become an Internet celebrity.

So, what ingredients are contained in this "fruit enzyme" made in a similar way to pickling?

◆What does “fruit enzyme” contain?

It can be seen that this production method of "adding sugar to raw materials and sealed storage" is essentially a natural fermentation. The so-called natural fermentation is a fermentation process in which no bacteria are artificially added, but only relies on the microorganisms carried on the surface of the raw materials to multiply and form a certain colony structure during the production process. The fermentation process is a complex microbial physiological and metabolic process, and the types of substances produced are also quite diverse.

According to the production method on the Internet, the "fruit enzyme" obtained should taste "sweet and sour". The source of sweetness is easy to understand: it is the sugar added in advance and the sugar released by the fruit itself. The sour taste comes from the activity of lactic acid bacteria. In fact, the sour taste in kimchi and pickled vegetables is also thanks to lactic acid bacteria. Lactic acid bacteria are a type of sugar-loving bacteria. The sugar in fruits and added sugars provide them with a comfortable living environment, allowing them to multiply in large numbers and continuously convert sugar into lactic acid.

However, many people have also reported that the "fruit enzyme" they made has a taste of alcohol. This is the result of the activity of another microorganism - yeast. Yeast also has a special liking for sugar and grows rapidly in a fermentation environment. Some people say that bubbles are produced when making "fruit enzymes", which are the carbon dioxide produced by yeast. However, when the oxygen in the container is depleted, the yeast begins to produce alcohol, and the wine taste is created.

It can be seen that a bottle of "fruit enzyme" is essentially a mixture of sugars released and added by fruits, lactic acid produced by lactic acid bacteria or alcohol, amino acids, vitamins and other metabolites produced by yeast, plus a large amount of lactic acid bacteria or yeast cells. Its composition is not essentially different from sauerkraut juice or fermented glutinous rice.

Wait, something seems to be missing: where is the “enzyme” in “fruit enzyme”? In fact, enzymes, as one form of protein, are quickly decomposed and absorbed by microorganisms after being released from plant cells. After all, in the eyes of microorganisms, the enzymes in these fruits, like other proteins, can be used as nutrients. Therefore, the enzyme content from fruit in "fruit enzyme" is extremely low. And more of them are enzymes secreted by microbial activities or released after the death and decomposition of microorganisms. Perhaps it would be more appropriate to change the name of "fruit enzyme" to "bacterial enzyme" or "bacterial enzyme". Even so, the proportion of total protein in the entire fermentation broth is only about 0.02%, and the amount of active enzymes is even less.

◆Does “fruit enzyme” have those magical effects?

The biggest selling point of “fruit enzyme” is that it claims that “enzyme” can have effects such as “weight loss”, “beauty care” and “detoxification”. But the fact is, relying on "enzymes" or enzymes to achieve these effects is just a beautiful imagination. From the previous analysis, it has been concluded that the amount of protein in the entire fermentation broth is very low. Not to mention the rumor of "drinking 100 ml a day", even if you drink one kilogram of "fruit enzyme", the total protein you get is only 0.2g - not as good as eating a medium-sized apple. Moreover, even if the pitiful amount of enzymes is ingested, they cannot play their role - because they lack protection, the proteases in the gastric and intestinal juices will chop them into small pieces when passing through the digestive tract, and turn them into oligopeptides and amino acids and be absorbed.

The enzymes in “fruit enzymes” can no longer be relied upon, so can other ingredients achieve the effects mentioned above? The situation is not optimistic. Lactic acid and alcohol are the main fermentation products, and they do not have the effects advertised as "fruit enzymes". As for substances such as vitamins, they are also decomposed and destroyed due to the activity and utilization of microorganisms. For example, after one week of fermentation, the content of vitamin C can drop to 1/10 of the initial value. However, since yeast and lactic acid bacteria have limited ability to decompose cellulose-based plant tissues, if you only rely on drinking "fruit enzymes", the cellulose substances that can indeed have certain health benefits will not be able to be absorbed by the human body.

So, can the yeast and lactic acid bacteria contained in "fruit enzymes" have health benefits? Although research on intestinal flora has become increasingly in-depth in recent years, at present, the effect of improving intestinal flora through flora obtained through daily diet is still far from ideal. The reason is that, first of all, the microorganisms ingested in the diet are not protected by auxiliary materials like intestinal bacteria agents, but have to face the harsh gastric and intestinal fluid environment directly. Whether they can enter the intestines smoothly is a big problem. Secondly, even if they can enter the intestines, facing the huge intestinal flora of up to 1014, the microorganisms ingested through diet are really "a strong dragon cannot defeat a local snake", and it is difficult for them to colonize and play the corresponding role.

In summary, the possibility of relying on drinking "fruit enzymes" to achieve health care purposes is very small. Even larger amounts of nutrients are sealed inside plant cells that have not yet been completely destroyed. However, if you need to eat the solid matter in the "fruit enzyme", why not eat the fruit directly?

◆Making your own enzymes poses great health risks

Well, since those beautiful wishes cannot be fulfilled, it's okay to just do it for fun and enjoy the sour and sweet taste, right? Although this is a personal hobby, the risks involved are still worth considering.

First of all, a large amount of sugar needs to be added when making "fruit enzyme". According to online information, the ratio of sugar, fruit and water ranges from 1:3:10 to 1:1:5. In other words, the sugar content of "fruit enzyme" is above 10%. While so much sugar makes the taste "delicious", it also invisibly increases the sugar intake.

If excessive sugar intake can be solved by exercise, the next problem is worth paying attention to. Since "fruit enzyme" uses natural fermentation, the composition of the colony during the fermentation process is greatly affected by the initial conditions. In nature, the microbial composition on the surface of fruits is very complex. In addition to the yeast or lactic acid bacteria needed for fermentation, there are other microorganisms including pathogenic bacteria. If there is a slight mistake in the production process, and miscellaneous bacteria are allowed to take over the fermentation process, then the "fruit enzyme" produced in this way will not only fail to play a health-care role, but will also pose a threat to health.

Among the various types of bacterial contamination, mold contamination is the most important. Some molds, including various species of Penicillium and Aspergillus, can produce a substance called patulin (also known as patulin). Patulin has shown neurotoxicity, embryotoxicity and certain carcinogenicity in animal experiments, and has an inhibitory effect on the animal immune system. Although there is no clear conclusion on the harm to the human body, the provisional maximum daily intake is 0.4 micrograms per kilogram of body weight. In other words, a 70-kilogram adult should not consume more than 28 micrograms of patulin per day. However, for fruit products contaminated by mold (especially apples), the patulin content can reach 1 microgram/gram. According to the 3:10 ratio of fruit to water in "fruit enzymes", drinking 100 ml a day is close to or even exceeds the provisional maximum daily intake. Therefore, if you see that the "fruit enzyme" you made has grown hair, it is better to throw it away quickly!

In addition, even "fruit enzymes" that are not moldy contain substances that are not beneficial or even harmful to human health. Nitrite is a harmful substance produced during the fermentation process of "fruit enzyme" that cannot be underestimated. Since natural fermentation is used, the bacteria strain is difficult to control, so more nitrite will be produced compared to inoculation fermentation. During the lactic acid bacteria fermentation process, nitrite showed a trend of first increasing and then decreasing, with the peak concentration reaching its peak in about 1 week and then decreasing. About a week is the recommended drinking time for some "fruit enzymes" on the Internet. Although the nitrite content will decrease with the extension of storage time, the increased fermentation time will increase the production of other substances. Fruits contain a lot of pectin, and one of the major products of pectin after microbial fermentation is methanol. During the yeast fermentation process, the methanol content can reach nearly 20 mg/ml. In "fruit enzymes" that do not have such a strong alcohol taste, the methanol content can also reach several milligrams per milliliter. Butyric acid is also produced during the lactic acid fermentation process. The special fishy smell in kimchi and "fruit enzyme" comes from the butyric acid produced.

In the industrial production of kimchi and pickled vegetables, the production of these substances that are useless or even harmful to the human body can be reduced as much as possible through the selection of bacterial strains and the control of production conditions. However, for homemade "fruit enzymes" and kimchi and pickled vegetables, since it is impossible to control the bacterial strains and production conditions, these unwelcome substances are inevitably produced. Although the content of these substances is not enough to make people sick in one meal (except for bacterial contamination), drinking "fruit enzymes" in pursuit of unreliable "health" effects and thus increasing real health risks is not worth the cost. It is undoubtedly ironic that today, when people are encouraged to eat less kimchi and pickled vegetables, people are instead chasing after "fruit enzymes" which are nothing but a new name.

in conclusion

"Fruit enzyme" is essentially a kind of natural fermentation product. No matter in terms of principle or actual ingredients, it cannot achieve the various magical effects claimed by "fruit enzyme". At the same time, since natural fermentation is difficult to control, it is easy to cause contamination by bacteria, produce toxins, and generate other harmful substances. Drinking such "fruit enzymes" will actually increase health risks. If you really want to get the beneficial ingredients from fruit, eating it directly is the most direct and effective way.