What is vitamin C
Vitamin C is soluble in water, slightly soluble in ethanol, and insoluble in ether, chloroform, benzene, petroleum ether, oil, and fat. Its aqueous solution exhibits an acidic reaction. When exposed to air, it undergoes rapid oxidation to form dehydroascorbic acid with a sour taste similar to citric acid. It acts as a potent reducing agent and gradually develops varying degrees of light yellow color upon prolonged storage. This compound is naturally present in various fresh vegetables and fruits. It plays a crucial role in biological redox reactions and cellular respiration while facilitating nucleic acid synthesis and promoting the production of red blood cells. Additionally, it aids in the reduction of Fe3+ to Fe2+, enhancing its absorption by the body and supporting cell proliferation.
Why should vitamin C be added to food
1. Collagen synthesis requires the participation of vitamin C. Therefore, a deficiency in vitamin C hinders normal collagen synthesis, leading to cellular connection disorders. The human body is composed of cells that rely on the intercellular matrix for cohesion, with collagen being a key component of this matrix. Collagen constitutes one-third of the body's proteins and forms connective tissues such as bones, blood vessels, and ligaments. It also determines skin elasticity, protects the brain, and aids in wound healing.
2. Scurvy occurs when there is insufficient vitamin C in the body. The strength of blood vessel walls greatly depends on vitamin C levels. Microvessels are the smallest blood vessels with walls as thin as a single cell layer; their strength and elasticity are crucial for connecting cells through collagen function. Inadequate vitamin C can cause microvessel rupture, resulting in bleeding into neighboring tissues. This manifests as bruises and purple discoloration on the skin or pain and tenderness within the body. Severe cases may involve bleeding in organs like stomach, intestines, nose, kidneys or beneath periosteum which could even lead to death. 3.Gum recession and bleeding occur due to inadequate protein intake along with calcium and vitamin C deficiencies.The healthy periodontal tissue tightly surrounds each tooth but gum recession becomes more likely when these essential nutrients are lacking.
3. Vitamin C helps prevent arteriosclerosis by promoting cholesterol excretion from arteries' inner walls while dissolving deposited atherosclerotic plaques.
4. Vitamin C acts as a water-soluble powerful antioxidant that safeguards other antioxidants like vitamins A & E along with unsaturated fatty acids against free radical damage within our bodies.
5. Treating anemia involves facilitating absorption/utilization of trivalent iron by reducing it to divalent iron while enhancing intestinal iron absorption thereby improving liver function.
6. Cancer prevention: Abundant collagen aids in inhibiting the proliferation of cancer cells; the antioxidant effect of vitamin C (VC) combats cellular damage caused by free radicals, thereby preventing cell mutation; it also hinders the formation of potent carcinogens, nitrosamines, by blocking nitrite and secondary amines. Autopsies conducted on cancer patients who succumbed to their illness have revealed an almost negligible level of VC content in their bodies.
Application of vitamin C in food
1. Fruit and vegetable preservation
After fruit picking, rapid aging and the subsequent metabolism of its pulp produce a significant amount of reactive oxygen species (ROS), which is closely associated with oxidative stress if intracellular ROS cannot be efficiently cleared by the antioxidant system in a timely manner. Vitamin C, as an essential antioxidant substance in plants, has been shown in some studies to enhance post-harvest preservation effects on fruits and vegetables when their vitamin C content is improved during the storage process.
2. Anti-browning:
The discoloration of fruits and vegetables is a common occurrence following damage during transportation, packaging, or processing. Vitamin C serves as an effective anti-browning agent by employing two distinct mechanisms to prevent browning.
3. Improvement of protein properties:
The instability of vitamin C in aqueous solution is attributed to the presence of an oxidizing-reducing ascorbic acid system. Research has demonstrated that the initial stable oxidized product of vitamin C, known as DHA, along with other further oxidized products (such as threonine and oxalic acid), possess reactive carbonyl groups capable of cross-linking with amino acid residues and augmenting protein-protein interactions.
4.Inhibition of fat oxidation:
The presence of vitamin C can effectively inhibit lipid oxidation and enhance the antioxidant properties of emulsions, thereby addressing a significant concern in fatty foods that negatively impacts their shelf life and nutritional value. This is attributed to the excellent reducing ability of vitamin C, which facilitates the removal of oxygen from food matrices and safeguards fats and oils against oxidative deterioration.
5.Reduce nitrite content:
The reaction between nitrite and amines in meat products leads to the formation of nitrosamines, which possess potential carcinogenic effects upon consumption. Vitamin C, functioning as an antioxidant, can effectively reduce nitrite to NO and consume NO2- under acidic conditions, thereby diminishing the concentration of nitrite.
6.As an SO2 supplement:
The addition of SO2 to wines serves as a protective agent, functioning both as a fungicide that effectively eliminates stray bacteria in grapes and as an antioxidant that prevents the wine from aging while preserving its natural fruit characteristics. In the context of winemaking, there are stringent regulations regarding SO2 residues, thus exploring an optimal substitute or alternative for SO2 has become a subject of research.
7. Protects the stability of tea polyphenols and improves the quality of black tea
The presence of Vitamin C promotes an increase in the levels of theaflavin and thearubigin, while simultaneously reducing polymerization reactions. The quality of black tea is directly influenced by the content of theaflavin and thearubigin, whereas polymerization products have a detrimental effect on its overall quality.
