Assessment of Ascorbic Acid Content in Fresh Fruits and Vegetables Under Different Storage Conditions in Plateau State

Ascorbic acid, commonly known as vitamin C, is a water-soluble vitamin essential for immune function and collagen synthesis, and its retention in fresh produce is highly sensitive to storage conditions including temperature, light exposure, and duration. Plateau State in North Central Nigeria has a temperate climate that supports diverse fruit and vegetable production, yet post-harvest losses and nutrient degradation under ambient market conditions are poorly quantified. This study assessed ascorbic acid content in six fruits and vegetables, namely guava, orange, tomato, green pepper, spinach, and cabbage, stored under three conditions: refrigerated at 4 degrees Celsius, ambient open-air market conditions, and covered cool storage. Sampling was carried out at days 0, 2, 4, 6, and 8 of storage. Ascorbic acid was determined by the titrimetric 2,6-dichlorophenolindophenol method. Initial ascorbic acid contents ranged from 56 mg/100g in tomato to 182 mg/100g in guava. All stored samples showed progressive ascorbic acid loss over time. Refrigerated storage retained the highest proportion of initial ascorbic acid at 72 to 88 percent of initial values after 8 days. Ambient open-air market conditions resulted in 52 to 64 percent retention. Covered cool storage was intermediate. Green pepper showed the greatest absolute losses. These results indicate that improved cold chain infrastructure and consumer education about the impact of storage on nutritional quality are priorities for reducing nutrient losses in the Plateau State fresh produce market.

Keywords: ascorbic acid, vitamin C, storage conditions, fresh produce, Plateau State