摘要：Tomatoes are very popular fruit rich in vital vitamins and minerals, but highly perishable once harvested. Sun drying is one of the most common methods of tomato preservation in Nigeria resulting in an unattractive dried tomato chips. The objective of this work is to evaluate the effect of sun and oven drying methods and pretreatment on some vitamins content of tomato powder. With the initial ascorbic acid, thiamin, riboflavin, niacin and β.Carotene contents of freshly harvested tomatoes determined, twenty kilograms of tomatoes were washed, sorted and divided into four equal portions of 5kg each. The first and second portions were sun and oven dried respectively; while the third and fourth were dipped in 1% metasulphite for 5 minutes. The third and fourth portions were then sun dried and oven dried. Vitamin contents of samples were determined using standard methods. Results showed that drying generally increases the ascorbic acid, thiamin, niacin and β.Carotene content of tomato powder significantly (p<0.05) compared to the fresh ones. Drying and pretreatment has no significant effects (p<0.05) on the riboflavin content of tomatoes. The use of metasulphite as pretreatment resulted in a lower increase in the vitamin content as compared to the untreated samples. Sun dried samples had higher vitamin content than the oven dried samples. It can be concluded that drying and pretreatment does not have significant effect on the riboflavin content of tomato. Sun drying method is the most suitable for tomato drying the terms of increased vitamin content compared to oven drying method
关键词：Oven drying; Pretreatment; Sun drying; Tomato; Vitamins
