Vitamin C belongs to a group of exogenous nutritional components that must be supplied in the daily diet. It is a compound showing multidirectional actions. Vitamin C is an unstable compound owing to its high chemical activity. It degrades rapidly in plant tissues owing to the impact of external stress factors, including, among inter alia, culinary treatments. On the other hand, its slow decomposition is a natural process that occurs during storage of fruits and vegetables. Sweet and spicy peppers are vegetables rich in vitamin C. Storing fruits after harvest and the method of preserving them prior to a long-term storage affect changes in the concentration of that ingredient.
In the research study, there were determined the content and the durability of vitamin C (sum of L-ascorbic acid and dehydroscorbic acid) in the fruits of four varieties of red pepper. Two sweet (‚Aifos’, ‚Barbórka’) and two spicy (‚Cyklon’, ‚Cayenne’) varieties were analysed. The fruits were stored as fresh fruit under the refrigeration conditions for two weeks and also in the long term as frozen and lyophilized fruit. The content of vitamin C was determined by an aspectro-fluorimetric method in a reaction with o-phenylenediamine (OPDA). The highest losses of the compound analysed were recorded in the fruit of peppers stored under the refrigeration conditions in the first week of its storage. Of the four varieties studied, in the ‚Cayenne’ hot variety was recorded the highest  concentration of vitamin C (470.9 mg/100 g f.m.). Based on the results obtained it was found that in the pepper  varieties analysed the stability of vitamin C varied during storage and processing of pepper fruits. Freezing was the  most beneficial method to preserve peppers both in quality and economic terms.