In addition to physical processes, some chemical substances are also used to protect food from oxidation caused by oxygen, temperature, light or microorganisms. To delay food spoilage, substances are used to stop bacterial growth and multiplication. Such substances are, for example, fruit treatment agents that protect citrus fruits from rotting and fungal attack. However, larger amounts cause adverse health effects in humans, such as growth disorders and reduced fertility.
In addition to the antibacterial effect, sulfur dioxide and sulfites also exhibit antioxidant, enzyme-inhibiting, and color-preserving effects, as well as protection against fat spoilage. Increased intake can cause headaches, diarrhea and allergic reactions. Furthermore, folic acid and vitamin B1 may be destroyed. As water-soluble vitamins, they do not tolerate alkaline compounds (alkalis) and are already destroyed in neutral to slightly alkaline environments. They are also highly sensitive to copper. Vitamin B1 is an important component of the enzyme carboxylase and plays an essential role in carbohydrate metabolism. A deficiency of this vitamin in the body causes disturbances in vital metabolic processes, because the “pyruvic acid” produced by carbohydrate breakdown cannot be broken down further due to the absence of vitamin B1. This metabolic intermediate accumulates in the blood and begins to burden the body like an effective poison. As a result, the central nervous system (CNS), the gastrointestinal tract and the heart muscle are particularly affected.
In the case of canned fish, the high temperatures, the long heating time and the high addition of water result in significant losses of nutrients and vital substances (macro- and micronutrients), which can be as high as 87%. Canned fish loses 70% of its B vitamins and vegetables 20-30% of vitamin A. In addition, large amounts of salt and sugar are added to approximate the flavor of the food and to preserve or extend shelf life.
