Vitamin C Content in Fruits of Common Raspberry (Rubus idaeus L.) Cultivar Polka Depending on Storage Methods

Abstract

Сommon raspberry (Rubus idaeus L.) are highly perishable fruits rich in bioactive compounds, including vitamin C, which is highly sensitive to post-harvest processing and storage conditions. Preservation of their nutritional quality remains an important challenge for both producers and consumers. This study investigated the effect of different processing and storage methods on the vitamin C (ascorbic acid) content in fruits of Rubus idaeus cultivar Polka collected in the Chernihiv region. The aim was to identify the most effective method for preserving the nutritional value of the fruits during post-harvest handling. Vitamin C content was determined using the Tillmans titration method. The studied preservation techniques included drying at 40 °C and 60 °C, freezing at −17 °C, boiling, and treatment with 0.4% chitosan solution. The results showed that drying at 40 °C was the most effective traditional method for vitamin C retention, followed by freezing, while boiling caused the greatest losses of ascorbic acid. Chitosan treatment demonstrated the highest efficiency in preserving vitamin C during storage and significantly reduced nutrient degradation compared to untreated fruits. Thus, chitosan coating represents a promising natural and environmentally friendly alternative to conventional preservation methods, effectively maintaining the nutritional quality of raspberry fruits by reducing vitamin C degradation and microbial spoilage, while also extending shelf life during storage.