Want to eat nutritious and healthy food? You need to pay more attention to phytochemicals

Phytochemicals are chemical substances produced by plants through primary or secondary metabolism. They are originally produced by plants to protect themselves from "foreign enemies" such as ultraviolet rays, pests, pathogens, etc. Their composition is relatively complex. For example, the natural aroma of plants and the foam generated after blanching plants are mostly derived from polyphenols, carotenoids contained in the pigments of yellow, orange and dark green fruits and vegetables, and organic sulfur compounds contained in the spicy ingredients of vegetables such as onions, garlic and radishes, etc., are all typical representatives of phytochemicals.

Phytochemicals can be broadly divided into polyphenols, carotenoids and organosulfur compounds. Polyphenols include phenolic acids and flavonoids, and carotenoids include carotenoids and luteins.

Flavonoids are plant pigments and bitter ingredients produced by photosynthesis. They are synthesized by plants to protect themselves from ultraviolet rays. They include flavonols such as anthocyanins, isoflavones, catechins, quercetin and kaempferol, as well as natural ingredients such as flavanones. These flavonoids have powerful antioxidant and anti-free radical effects.

Anthocyanins are the color masters of the plant kingdom and are sensitive to temperature changes and pH.

The most prestigious isoflavone is soy isoflavone, which is considered to be a phytoestrogen that can significantly improve hot flashes in menopausal women and prevent osteoporosis.

Catechins are the most important type of tea polyphenols and one of the sources of the bitter taste of tea. They are the contributors to the health benefits of tea.

Onions, kale, lettuce, tomatoes, grapes, other berries, as well as tea and wine are rich sources of flavonols, the same flavanones that give citrus peels their bitter taste.

These substances can play a great role in promoting health and preventing diseases with their powerful antioxidant function.

Phenolic acids are non-pigment components of polyphenolic phytochemicals, which generally have antioxidant and anti-fatigue effects, including ellagic acid, curcumin, chlorogenic acid, sesame, tannic acid, etc.

Ellagic acid is the star whitening ingredient in pomegranates and various berries such as strawberries, blackberries, cranberries, etc. Curcumin is the main health-promoting ingredient in turmeric and is known as herbal aspirin.

Chlorogenic acid is recognized as "plant gold" and is believed to have antioxidant, anti-aging, weight loss, blood sugar regulation and other functions. It is the source of the bitter taste of coffee and is also considered to be a powerful weapon for coffee to fight pests, so the harsh living environment may affect the flavor of coffee; however, the roasting process will destroy chlorogenic acid, so green coffee beans are used to extract chlorogenic acid, and more localized sources of chlorogenic acid include honeysuckle and eucommia leaves.

Tannic acid is the source of the astringency of wine, and the tannic acid in wine mainly comes from the grape skin, seeds, stems and container oak barrels, so red wine generally tastes more astringent than white wine. Tannic acid can cause protein denaturation due to its astringent properties, so it has certain antibacterial, antiviral and nutrient absorption promoting effects.

Carotenoid phytochemicals include carotenoids and xanthophylls. Carotenoids include α-carotene, β-carotene, γ-carotene and lycopene, while xanthophylls include astaxanthin, β-cryptoxanthin, capsaicin, fucoxanthin, zeaxanthin, lutein, etc. These are members of the " color palette " that give plants and seaweed their rich colors.

Organic sulfur compounds include alliin, allicin, isothiocyanate, diallyl disulfide, thiosulfite, sulforaphane, etc. These substances are the unique odor and spicy ingredients in garlic and onion in the Liliaceae family, cabbage and white radish in the cruciferous family. They have powerful antioxidant, antibacterial/bactericidal and cancer prevention effects.

In 1990, the National Cancer Institute of the United States published an anti-cancer dietary pyramid, and garlic and cabbage were at the top of the pyramid. Take garlic as an example. In nature, alliin only exists in garlic, and it is the most abundant amino acid, accounting for 0.6%-2% of the dry weight of garlic; alliin is almost tasteless. In intact garlic, alliin and alliinase exist independently and stably in the vacuole and cytoplasm of the cell, so there is no irritating "garlic smell" at this time, but when the cell is destroyed, alliin is converted into allicin by alliinase, and the taste comes out at this time; high temperature will make the enzyme inactive, so high-temperature cooking of intact garlic will not produce allicin; and allicin is the "big hero" of garlic's antibacterial and bactericidal effects, so if you want to better utilize the health function of garlic, it is better to eat it raw than cooked, and mashing it is more effective than chopping it. It is also because of the presence of organic sulfur compounds that bad breath is easy to occur after eating foods such as onions and garlic. At this time, brushing your teeth, rinsing your mouth, and chewing foods containing phenols such as apples, lettuce, and mint can effectively deodorize.

Phytochemicals are absent in most people's understanding of food and nutrition, but full and effective use of phytochemicals can indeed add icing on the cake to our health and beauty.