Is Black Garlic Extract Safe?

Black garlic is a new type of healthy food ingredient produced using fresh raw garlic as the raw material, without any added ingredients, and through a special high-temperature, high-humidity biological fermentation process. Black garlic was first produced in Aomori Prefecture, Japan, at the beginning of the 21st century. After nearly 10 years of unremitting efforts by scholars and entrepreneurs at home and abroad, black garlic has become a new type of food with a variety of health benefits that has taken the world by storm. Compared with raw garlic, black garlic has the following main characteristics: (1) Changes in texture: Fermented black garlic has undergone a dramatic change in texture, from being raw and crispy with a pungent taste to being sweet and soft, and the unpleasant smell and pungency have been removed. (2) Changes in nutrition: Experiments have shown that fermented black garlic has lower moisture content, 7 to 10 times higher polyphenols, and significantly higher protein and free amino acids. It is 1.5 times higher than garlic, 60 times higher in soluble fructose, and the main functional component of garlic, allicin, remains basically unchanged. 5 times that of garlic, 60 times that of soluble fructose, and the main functional component of garlic, allicin, remains basically unchanged. (3) Functional changes: Experiments have shown that fermented black garlic has strong antioxidant properties, delays aging, prevents cancer, has strong antibacterial properties, lowers blood sugar, lowers blood lipids, protects the liver, and prevents heart and brain diseases [1].

In the past two years, Shandong, the source of garlic in China, and Heilongjiang, the main region for the production of green food, have become important areas for the research, development and production of black garlic. Currently, there are more than 13 companies in China involved in the production and sales of black garlic products domestically and internationally. This shows the vitality and market recognition of black garlic, a new type of processed garlic product that has only been around for less than ten years. It also raises the bar for the scientific community in terms of systematic research into the various health benefits and mechanisms of action of black garlic, creating a broader platform and more opportunities for the development of a wide range of high-tech, high value-added deep-processed black garlic products.

According to statistics from professional companies, the current production capacity of black garlic enterprises in the country can reach more than 46,500 tons per year. It is estimated that the global demand for black garlic in 2015 will exceed 55,000 tons (equivalent to 800 million heads), forming an emerging market with a production value of more than 50 billion yuan. Market demand is 50,000 tons (about 800 million heads), forming an emerging market with a value of over 50 billion yuan. Market demand is steadily rising, and the momentum is high. Therefore, as an emerging multi-functional health food, black garlic has huge market potential in China[2].

1  Domestic and international research progress on the nutritional, health-preserving and medicinal functions of black garlic

Domestic and international scholars have been researching black garlic for nearly ten years. In 2010, the Daqing Branch of the Heilongjiang Academy of Sciences invested a total of 3.2 million yuan in research funding conducted a large number of systematic experimental studies and data analysis on various nutrients, functional substances, enzymes and microorganisms in the production process, as well as the conversion mechanism and change law of biological factors, key factors and control points of the production process, toxicity, blood glucose regulation and health care functions, and domestically produced production equipment[3]. A new and uniquely innovative black garlic production process has been developed, which significantly reduces production costs and opens up an important technological gap for black garlic to enter the domestic sales market. Two invention patents have been obtained. It has reached the international leading level in terms of research on the medicinal and nutritional functions of black garlic, production technology, process design, research on the deep processing technology of black garlic and equipment processing.

1.1 The strong antioxidant and anti-aging function of black garlic

The first scholar to conduct research on the nutritional and health benefits of black garlic was the famous Japanese molecular and cell biology expert, Professor Hiroshi Taguchi of Mie University. He found that black garlic has the highest antioxidant capacity when compared to more than 300 types of food with antioxidant properties. Research conducted by the Heilongjiang Academy of Sciences showed that the antioxidant polyphenols (plant pigments produced by photosynthesis) in black garlic are 7.41 times higher than those in raw garlic. 41 times that of raw garlic. It also contains antioxidant substances such as melanoidin that are not found in raw garlic.

It can prevent cell oxidation, remove free radicals in the body, rejuvenate human cells, and thus delay cell and appearance aging. Medical experiments have proven that black garlic has very significant antioxidant and anti-aging effects. Zhu Bingqiao et al. conducted a study on the antioxidant activity of black garlic [4]. 144 old mice were randomly divided into a blank group, a model group, a positive control group (Group V), a low-dose white garlic group (65 mg/kg), a medium-dose white garlic group (260 mg/kg), a high-dose white garlic group (650 mg/kg), a low-dose black garlic group (65 mg/kg), and a medium-dose black garlic group (260 mg/kg), and a high-dose black garlic group (650 mg/kg).  (260 mg/kg), black garlic high dose (650 mg/kg), etc. 9 groups. After 30 days of intervention, mice were fed brominated oil to create a model of gastrointestinal oxidative damage. The malondialdehyde (MDA1 content and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity.

The results showed that black garlic can significantly reduce the content of malondialdehyde in blood and liver tissue and increase the activity of antioxidant enzymes in the tissue. Black garlic is significantly better than garlic and the positive control group in reducing the content of malondialdehyde and increasing the activity of GSH-Px. This proves that black garlic has stronger antioxidant activity and is significantly better than raw garlic.

Zhou Guangyong et al. studied the changes in the main components and free radical scavenging capacity during the storage of black garlic [5].

1.2 Anti-cancer and improves immunity

Allicin, also known as ajoene (Spanish for garlic), is a substance unique to black garlic. It is a sulfur compound produced by heating sulfur-containing amino acids such as S-allyl cysteine in garlic at 25–100 °C [6]. It mainly acts on the “initiation stage” of tumorigenesis. It prevents cancer formation by enhancing detoxification, interfering with the activation of carcinogens, enhancing immune function, blocking lipid peroxidation and anti-mutation, and other ways to prevent the transformation of normal cells into cancer cells. Selenium, a trace element contained in black garlic, can also kill cancer cells and reduce the incidence of cancer.

In the United States, the Design Food Program's anti-cancer food research ranked garlic as the food with the greatest anti-cancer effect. However, Dr. Jinichi Sasaki, a former professor at Hirosaki University's School of Medicine, found in his experiments that black garlic has a stronger anti-cancer effect than ordinary garlic. He implanted 6 million cancer cells on the skin of 10 mice to create a cancer infection model. The 10 mice were then divided into two groups of 5 each. One group was the control group, and the other group was the experimental group. While being normally fed, they were injected with 3 mg of black garlic extract 3 times every 2 days.

After 3 weeks, the transplanted cancer cells were measured. Experimental phenomena showed that the cancer cells in the control group of mice that did not receive injections of black garlic extract had multiplied twice. In the experimental group that received injections of black garlic extract, two of the cancer cells completely disappeared, and the cancer cells in the other three were 40% smaller than when they were first implanted. In a repeat experiment, the group that added raw garlic to the test showed that 0 of the 5 mice had completely eliminated cancer cells. In order to explore the anti-cancer mechanism of black garlic, Dr. Sasaki conducted an experiment in which black garlic was directly exposed to cancer cells, and it was found that the cancer cells did not change. Therefore, it can be speculated that black garlic does not directly act on cancer cells, but rather achieves an anti-cancer effect by enhancing the body's immunity to cancer cells.

Wang Xin, Sun Dongning, Feng Yonghui, Wang Yan, Sato and many other Chinese and foreign scholars have conducted in-depth research on black garlic's preventive effect against tumors, its mechanism of action in inhibiting gastric cancer, the growth intervention of H22 transplantable solid tumors in mice liver cancer, and the influence on the cellular immune response of mice have been studied in depth from multiple directions and perspectives [7-13]. In addition, Li Yang et al. also studied the therapeutic effect of black garlic extract on mouse allergic asthma, further expanding the health and therapeutic effects of black garlic [14].

1.3 Strong antibacterial, broad-spectrum anti-inflammatory, prevention of gastrointestinal diseases and influenza

Allicin and allicin are natural broad-spectrum antibacterial agents that are found in plants. They are currently the most powerful antibacterial agents found in nature. Black garlic retains 90% of the allicin in garlic and contains about 2% (dry product). Its bactericidal power is 10% that of penicillin, and it has a significant inhibitory and killing effect on a variety of pathogenic bacteria such as Escherichia coli, Salmonella, Staphylococcus aureus, Shigella dysenteriae, typhoid bacillus, pneumococcus, streptococcus, tuberculosis bacillus and Vibrio cholerae, etc.

It has a significant inhibitory and killing effect on a variety of pathogenic bacteria such as Escherichia coli, Salmonella, Staphylococcus aureus, Shigella dysenteriae, It has a significant preventive and protective effect against various diseases such as influenza, diphtheria, meningitis, pneumonia, dysentery, typhoid fever and fungal infections. Dr. Hiroshi Sasaki added black garlic extract to the highly virulent bacteria O-157, the hospital-acquired infection bacterium Pseudomonas aeruginosa, MRSA (methicillin-resistant Staphylococcus aureus) and a type of influenza Candida albicans in a culture medium. The result after incubation was that black garlic juice inhibited the growth of all bacteria, especially against Pseudomonas aeruginosa and MRSA Staphylococcus aureus. Description: Black garlic can effectively prevent seasonal colds and influenza, pneumonia, enteritis and other infectious diseases.

1.4 Lowers blood lipids and prevents cardiovascular and cerebrovascular diseases

Medical experiments have shown that the amino acid allicin in black garlic can prevent active oxygen from binding to harmful cholesterol in the blood, significantly reducing total serum cholesterol, triglycerides and low-density lipoprotein. It also strongly suppresses the development of atherosclerosis, keeping the blood flowing smoothly throughout the body. It can significantly reduce the mortality rate of cardiovascular diseases.

Yokohama Soken Junior College Professor Takako Noritaka's animal experiments have proven that S-allyl cysteine can effectively lower cholesterol. It reduces the activity of 7α-hydroxylase, which significantly reduces the amount of cholesterol in the blood serum, egg yolk and liver. It also has the mechanism of inhibiting platelet aggregation, and has the effect of preventing myocardial infarction, cerebral infarction and atherosclerosis. Black garlic is therefore a special food that can prevent cancer, purify the blood and strengthen the functions of the internal organs. It can make the blood flow smoothly, while also having the powerful ability to prevent atherosclerosis and keep blood vessels unobstructed, and can relieve fatigue, sensitivity to cold, shoulder stiffness and back pain. It is therefore most suitable for people troubled by fatigue, sensitivity to cold and hyperlipidemia.

1.5 Lowers blood sugar and prevents diabetes

In 2011, Professor Ma Ruobo from the School of Public Health of Harbin Medical University and the Daqing Branch of the Heilongjiang Academy of Sciences jointly conducted a research experiment on the “Effect of black garlic on body weight and blood glucose in rats with diabetes caused by streptozotocin” and initially explored its mechanism of action. After a successful rat model of diabetes mellitus was created using intraperitoneal injection of 50 mg/kg streptozotocin, the model rats were given black garlic by continuous gavage for 30 days, and the body weight and blood glucose levels of the rats before gavage and at the end of 30 days of gavage were measured.

1.5.1 The results of the statistical analysis showed that black garlic had no significant effect on the body weight and blood glucose levels of normal rats.

1.5.2 Results of the effect of black garlic on body weight and blood glucose in experimental diabetic rats

As can be seen from Tables 5 and 6, after 30 days of continuous gavage with black garlic, there was no significant difference in body weight and fasting blood glucose values between the high and medium dose groups and the diabetic model control group (analysis of variance, P>0.05). 05); while the low-dose group showed a decrease in body weight and a relief of hyperglycemic symptoms, as indicated by a significant increase in body weight compared to the model control group and a significant decrease in fasting blood glucose values in streptozotocin-induced diabetic rats (t-test, P<0.01).

1.5.3 Results and analysis

The research analysis shows that black garlic contains S-methylcysteine sulfoxide, S-allylcysteine sulfoxide, S-allyl disulfide and other components of the ephedra family. Ephedra is a sulfide component with the property of dissolving grease, which can convert sugar into energy, thereby effectively controlling elevated blood sugar. Therefore, it can effectively regulate blood sugar levels and control blood sugar. It can inhibit G-6-P enzyme NADPH, prevent insulin from being destroyed, affect the synthesis of glycogen in the liver, reduce blood sugar levels and increase plasma insulin levels. It has a hypoglycemic effect. The components in black garlic, such as allicin, alkaloids, and isoleucine, also have the function of enhancing islet function, promoting insulin secretion, and regulating blood sugar. More importantly, it has no effect on normal blood sugar levels. Animal experiments on rabbits have shown that after 2 hours of ingesting black garlic, blood sugar concentrations decreased by 17.9% to 26.2%. This shows that black garlic has a significant effect on blood sugar control.

Therefore, this experimental diabetes model is based on the use of streptozotocin to cause severe damage to the rat's pancreatic β cells, reducing insulin secretion and leading to a disorder of the sugar metabolism mechanism. This can lead to a decrease in the rat's body weight, and the ingested carbohydrates cannot be used by the body's normal metabolism and are lost. During the experiment, the experimental diabetic rats became increasingly emaciated, showing typical diabetic symptoms such as increased drinking, eating, urination and hair loss, and even death.

However, after 30 days of oral administration of black garlic, it was found that the weight loss and elevated blood glucose levels of diabetic rats treated with a low dose of black garlic (2.5 g/kg·bw) were alleviated compared to the model control group, suggesting that black garlic has a certain effect on alleviating weight loss and elevated blood glucose levels in streptozotocin-induced diabetic rats at a certain dose, and thus has a certain effect on alleviating the progression of diabetes. The ability of black garlic to regulate blood sugar is not simply control, but in protecting pancreatic beta cells and actively converting sugar into energy, which can enable diabetic patients to produce sugar like ordinary people, rather than drug-induced hypoglycemic, its effect is not comparable to ordinary hypoglycemic products.

1.6 Eliminate fatigue, protect the liver and strengthen the essence, restore physical strength

Black garlic contains allicin, which has the miraculous effect of eliminating fatigue and boosting stamina. It also contains creatinine, an essential component involved in muscle activity, which has a strengthening effect on the production and quantity of semen.

2 Safety of black garlic 

In 2011, Ma Ruobo from the School of Public Health at Harbin Medical University and the Heilongjiang Academy of Sciences conducted an oral acute toxicity test on self-developed black garlic. The results showed that all 20 test mice had a total oral administration of 20 g/kg·bw and were in generally good condition during the 14-day observation period, with normal weight gain. and no symptoms of poisoning were observed. No deaths occurred. Toxicity tests such as the Ames test (detection of mutagenicity of pollutants), micronucleus test in mouse bone marrow erythrocytes, mouse sperm deformity test and 30-day feeding test in rats have proven that black garlic is safe and non-toxic. This proves that there are no toxic side effects after garlic is processed into black garlic. It can be eaten with confidence.

No other chemical ingredients are added during the fermentation and processing of black garlic. Fermentation of garlic is carried out entirely using biotechnology, a safe, natural and green process. Not only does it not produce toxic substances, it also removes the allicin and garlic odor that raw garlic originally has, which is strongly irritating to the esophagus, gastrointestinal tract, liver and eyes, and also enhances a variety of important health benefits. It has higher food safety.

3 Prospects

Black garlic is sweet and sour, has perfect functions, and is delicious and healthy. It has already become popular all over the world for its unique functions and wonderful taste. It is a natural, green, safe, biological, healthy food and ingredient with a promising future. In recent years, with the continuous clinical research on the medicinal and dietary functions of black garlic by scholars in medicine, pharmacology, food and health care at home and abroad, the various medicinal and dietary effects of black garlic have been initially verified in terms of analysis of effective components, functional evaluation of animal experiments, and toxicology. This has laid an important theoretical research foundation. Black garlic has been recognized by the scientific community and many consumers for its health and medicinal benefits, such as anti-oxidation, anti-aging, tumor inhibition, immunity enhancement, blood sugar regulation, powerful sterilization, prevention of influenza, diarrhea, and liver protection.

However, the mechanism by which black garlic produces these health benefits still requires further research. Groundbreaking research on the mechanism of black garlic in the prevention and treatment of certain major diseases and its conditioning effect on people in sub-health will greatly promote the scientific research on the extraction and extraction of effective substances in black garlic, and its innovative development and application in the development of a series of products in various fields such as food, medicine and cosmetics, which will be of great significance for maintaining people's health.

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