Stability of Vitamin A in Nigerian Wheat Flour

Abstract

Objectives: Flour has been fortified in Nigeria but vitamin A is unstable.  Study aimed at determining vitamin A stability in flour at point of consumption. Methods: Seventeen commercial wheat flour samples were randomly collected from 15 bread bakeries in five Local Government Areas (LGAs) (Agege, Oshodi/Isolo, Mushin, Lagos Island and Ikorodu) in Lagos, Nigeria. Initial vitamin A (retinol) content of samples was analyzed using High Performance Liquid Chromatography.  All samples were stored for 30 days in airtight plastic containers. Final vitamin A content was determined at end of storage. Samples were then grouped according to post-production dates 1, 2 and 3 months. Stability was calculated as percentage of recommended value (30IU/g).Data were analyzed using descriptive, T-test, and ANOVA statistics at p<0.05 significant level. Results: Vitamin A concentration in flour was 19-83% below recommended value in 88% (15/17) of samples tested and exceeded recommended value in 12% (2/17) with overages of 5.56-48.58%. Mean vitamin A content of flour samples was 18,221.26IU/kg±10.7 (1 month); 9,181.90IU/kg±7,441.50 (2 months) and 6,432.70IU/kg±5,193.62 (3 months). Vitamin A stability in flour at 1 month, 2 months and 3 months were 60.7%, 30.6%, and 21.4%. Statistically significant difference existed between vitamin A content of samples and recommended value (30IU/g). Time had a statistically significant effect on stability of vitamin A samples in various flour brands at 1 month, 2 months and 3 months. Conclusions: Vitamin A stability was good at 1 month storage.  Stability in samples will be improved with high quality premix.