What Is Black Garlic?
Black garlic is not a new variety of garlic but is made by aging fresh garlic. The key parameters affecting the aging process are temperature and humidity, with other minor factors including moisture content, pH, and pretreatment. Temperature significantly affects the aging process; higher temperatures can shorten the aging time, but temperatures above 90°C can produce bitterness and acidity. Conversely, temperatures below 60°C can result in uneven coloration. The optimal temperature for aging black garlic is around 70°C.
Image: Color changes of garlic during different aging periods
Temperature directly affects the moisture content of garlic. Higher temperatures reduce the moisture content, resulting in lower moisture levels in the final product, making it too hard for consumption. Controlling humidity indirectly influences enzyme and non-enzymatic reactions during the aging process. The color of black garlic is the result of the Maillard reaction, a non-enzymatic browning process that ultimately provides brown pigments and a distinct flavor[1].
During the aging process of black garlic, there is an increase in water-soluble monosaccharides and organic acids. It also enhances the overall content of antioxidant components such as polyphenols, flavonoids, and S-allyl cysteine. The increase in color is mainly attributed to the products of the Maillard reaction[2]. In addition to enhancing the nutritional components of garlic, the addition of yeast during fermentation significantly improves the final product’s nutritional value[3].
Benefits of Black Garlic
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Antioxidant Capacity
Compared to raw garlic, the aging process enhances the antioxidant activity of black garlic. Several studies have indicated that black garlic exhibits good scavenging abilities against various forms of free radicals[4][5].
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Weight Control
Feeding mice a high-fat diet with black garlic for two months resulted in reduced body weight, abdominal fat volume, and waist circumference. Black garlic extract contains two major active components, S-allyl cysteine (SAC), and melanoidins. When fed to animals with metabolic syndrome, it reduced appetite, lowered body weight, triglycerides, LDL-C, and increased HDL-C. It also reduced insulin resistance and leptin resistance. Therefore, black garlic extract can enhance basal metabolic rate, reduce appetite, and control weight through multiple mechanisms[7].
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Anti-Inflammatory
Key anti-inflammatory components in black garlic, such as 2-linoleoylglycerol, pyruvate, and 5-hydroxymethylfurfural, inhibit the activity of crucial enzymes in the inflammatory pathway. They also reduce the generation of inflammatory cytokines, resulting in decreased inflammation[8][9].
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Immune Modulation
Clinical studies have found that daily supplementation of 2.56 grams of black garlic for 45 days increases the proliferation and activity of two types of lymphocytes. It can also reduce the severity and symptoms of the common cold and flu and shorten the recovery period[10].
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Cardiovascular Protection – Blood Pressure and Lipids
Feeding animals black garlic extract increases the release of nitric oxide (NO) in blood vessels and reduces damage caused by myocardial ischemia-reperfusion. In a clinical study of 49 people, supplementation with black garlic extract for 12 weeks effectively regulated blood pressure. Daily supplementation of 2.4 grams of black garlic extract for one year in diabetes patients significantly reduced the formation of non-calcified plaques. In mild hypercholesterolemia patients, daily supplementation of 6 grams of black garlic for three months effectively reduced atherosclerosis-related apolipoprotein B and increased high-density lipoprotein HDL-C[11][12][13][14].
These findings suggest that black garlic offers several health benefits, including antioxidant capacity, weight control, anti-inflammatory properties, immune modulation, and cardiovascular protection.
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Liver Protection
Black garlic has been shown to reduce the levels of liver inflammation markers GOT and GPT in various liver injury-induced animal models, such as alcoholic, carbon tetrachloride, or high-fat diet-induced liver damage. It also enhances the overall detoxification capacity of the liver[15][16].
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Nervous System
Administering black garlic extract to animals has been found to increase the number of neurons in the hippocampal region, enhancing spatial memory capabilities[17]. Another study discovered that providing black garlic extract can increase the number of Purkinje cells in the cerebellum, significantly improving motor coordination[18].
How to Consume Black Garlic?
Black garlic is the product of high-temperature aging of garlic, making it suitable for direct consumption. It can be used in a similar way to regular garlic in cooking, such as in stir-fries or soups. There are also various black garlic-related products available in the market, including dietary supplements that concentrate the beneficial components of black garlic for consumers to choose from.
Are There Any Side Effects or Contraindications to Eating Black Garlic?
Garlic is generally recognized as safe (GRAS) by the U.S. Food and Drug Administration.
During the aging process, black garlic transforms allicin into S-allyl cysteine (SAC), which has higher and more stable antioxidant activity and reduces the irritant effects of allicin on the gastrointestinal mucosa.
Unless you have a known allergy to garlic, black garlic and related products are generally safe for most people[19].
Garlic has long been recognized for its potential health benefits, and the process of black garlic production further enhances its efficacy.
When consumed in accordance with recommended dosage guidelines from the literature, black garlic is considered safe and beneficial for human health.
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