Sweet Potato_Anthocyanins
Function of Anthocyanins
Anthocyanin pigments are widely present in the tissues of plants such as sweet potatoes, grapes, blood oranges, red cabbage, blueberries, eggplant skins, cherries, red oranges, raspberries, strawberries, mulberries, hawthorn skins, perilla leaves, black (red) rice, morning glory flowers, etc.
Research and Application of Anthocyanins
Modern people have found that despite the in-depth research on antibiotics and vitamins, they cannot solve modern diseases such as cardiovascular disease, diabetes, cancer, and sub-health conditions. They also cannot address issues of longevity and anti-aging in humans. Scientific research shows: if the problem of free radical damage is resolved, human cells can truly grow freely, and the average human lifespan will certainly reach 125 years. Therefore, the length of a person's life directly depends on their ability to resist oxidation and free radicals, and the discovery of anthocyanins has provided the simplest and most effective method for global antioxidation and anti-aging.
The discovery and application of anthocyanins have led humanity from the antibiotic and vitamin era of the 20th century into the anthocyanin era of the 21st century!
With the development of science and technology, people are increasingly concerned about the safety of food additives, and the types and quantities of synthetic colorants used have significantly decreased. Thus, the development and application of natural colorants have become the general trend in the global edible colorant industry.
Anthocyanins are water-soluble pigments widely found in plants, belonging to the flavonoid compounds. There are six common types in plants: pelargonidin (Pg), cyanidin (Cy), delphinidin (Dp), peonidin (Pn), petunidin (Pt), and malvidin (Mv). Free anthocyanins are rarely seen under natural conditions; they usually form anthocyanidins by bonding with glucose, rhamnose, galactose, xylose, arabinose, etc., through glycosidic bonds. The glycosides and hydroxyl groups in anthocyanidins can bond with one or several molecules of coumaric acid, ferulic acid, caffeic acid, p-hydroxybenzoic acid, etc., via ester bonds, forming acylated anthocyanidins. It is known that there are over 250 naturally occurring anthocyanidins found in plants across 27 families and 73 genera. Anthocyanins bring various benefits to the human body. Fundamentally, anthocyanins are powerful antioxidants that protect the body from damage caused by harmful substances called free radicals. Anthocyanins can also enhance vascular elasticity, improve circulation, and attract animals for pollination and seed dispersal. They are commonly found in the tissues of flowers and fruits, as well as in the epidermal cells and lower epidermis layers of stems and leaves. In some fruits, the market price is determined by the depth of color. Anthocyanins belong to the flavonoid class of phenolic compounds. Their basic structure includes two benzene rings connected by a three-carbon unit. Anthocyanins are produced through the phenylpropanoid pathway and flavonoid biosynthesis pathway, regulated and catalyzed by many enzymes. The six main non-glycosylated forms include pelargonidin, cyanidin, delphinidin, peonidin, petunidin, and malvidin. The colors vary depending on the number of hydroxyl groups, methylation, glycosylation, sugar types, and connection positions. The color expression changes according to biochemical environmental conditions, such as anthocyanin concentration, copigmentation, and pH levels in vacuoles.
Orange and yellow colors are due to carotenoids. β-carotene was discovered in carrots in 1910, and subsequently, two other carotenoid isomers were found: α, β, and γ isomers. β-carotene was patented in 1958 and is currently mainly extracted from the ocean but can also be synthetically produced.
There are over 300 different anthocyanins in nature. They come from various fruits and vegetables like sweet potatoes, bilberries, cranberries, blueberries, grapes, elderberries, blackcurrants, purple carrots, and red cabbages, with colors ranging from red to blue. These anthocyanins mainly include delphinidin, cyanidin, petunidin, and pelargonidin.
The color of anthocyanins changes with pH values, from raspberry red at pH 3 to deep blueberry red at pH 5. In most applications, these pigments exhibit good light, heat, and pH stability and can withstand pasteurization and UHT heat treatments. Anthocyanins are widely used in beverages, candies, jellies, and jams. The color change of sweet potato anthocyanins at different pH values is shown in the figure below: Color change of sweet potato anthocyanins at different pH values.
In recent years, attention has increasingly focused on the potential health benefits of anthocyanins as polyphenols. In the future, this characteristic of anthocyanins could see increasing application in functional foods and health supplements. They smooth the skin, inhibit inflammation and allergies, and improve joint flexibility. Below are some of the effects of anthocyanins:
1. Helps prevent various diseases associated with free radicals, including cancer, heart disease, premature aging, and arthritis;
2. Reduces the occurrence of heart disease and strokes by preventing stress reactions and platelet aggregation caused by smoking;
3. Enhances the immune system's ability to resist carcinogens;
4. Reduces the frequency of colds and shortens their duration;
5. Has antimutagenic functions to reduce the formation of carcinogens;
6. Has anti-inflammatory properties, thus preventing inflammation, including arthritis and swelling;
7. Alleviates pollen allergy and other allergic conditions;
8. Enhances the elasticity of arteries, veins, and capillaries;
9. Protects the inner walls of arterial vessels;
10. Maintains normal flexibility of blood cells, helping red blood cells pass through small capillaries, thereby enhancing overall blood circulation, bringing direct benefits to organs and systems throughout the body, and enhancing cell vitality;
11. Relaxes blood vessels to promote blood flow and prevent hypertension (blood pressure lowering effect);
13. Prevents the increase in blood pressure caused by angiotensin-converting enzyme released by the kidneys (another blood pressure lowering effect);
14. Acts as a barrier to protect brain cells, preventing the formation of amyloid β-protein, glutamate toxicity, and free radical attacks, thus preventing Alzheimer's disease;
15. Through the inhibition of elastase and collagenase, it makes the skin smooth and elastic, preventing skin damage caused by excessive sun exposure both internally and externally.
Potential anthocyanin pigments in the future are widely present in grapes, blood oranges, red cabbage, blueberries, eggplant skins, cherries, red oranges, raspberries, strawberries, mulberries, hawthorn skins, perilla leaves, sweet potatoes, black (red) rice, morning glory flowers, etc. In the 1980s, Japan extracted and separated four types of anthocyanins from red cabbage leaves and used them as food coloring agents (red to reddish-purple), widely applied in the production of candies, juices, sodas, ice cream, and preserved plums. The main components of perilla pigment are perilla pigment and perilla red, which are natural red pigments found in varieties of the perilla family with purple leaves. Japan designated it as a food additive in 1993 and used it in chewing gum, fruit drinks, etc., considering its ability to prevent allergies, cavities, and inflammation. Perilla is a traditional Chinese medicinal plant and one of the 33 varieties announced in Document No. 57 of 1987 by the Ministry of Health of China that can be used both as food and medicine. In recent years, extracting anthocyanins from sweet potatoes has become an international hot research topic because sweet potatoes have high yields, are easy to cultivate, and are an ideal way to economically obtain anthocyanins. Especially the breeding of high-anthocyanin sweet potato varieties provides high-quality raw materials for large-scale anthocyanin production!
Sweet potatoes With continuous research, significant progress has been made in improving the stability of anthocyanins through artificial acylation. Additionally, plant tissue culture technology can also be used for the production of other anthocyanin pigments. Due to their bright colors, antioxidant properties, and other health benefits, anthocyanins will undoubtedly be put into industrial production to enrich people's work and lives.