Effect of Blanching and Drying Temperatures on the Nutritional Quality of Dried Leafy Vegetables in Niger State

Drying is one of the most accessible preservation methods for leafy vegetables in rural communities across North Central Nigeria. However, inappropriate processing conditions often result in significant nutrient losses that undermine dietary quality. This study evaluated the effect of blanching pretreatment and three drying temperatures (50, 60, and 70 degrees Celsius) on the nutritional quality of three commonly consumed leafy vegetables in Niger State: Amaranthus cruentus, Corchorus olitorius, and Celosia argentea. Fresh samples were sourced from Minna Main Market and processed using a cabinet dryer. Nutritional parameters assessed included vitamin C, beta-carotene, total phenolics, iron, calcium, and crude fibre. A two-factor factorial experimental design was employed and data were subjected to analysis of variance. Results showed that blanching prior to drying at 50 degrees Celsius preserved the highest levels of vitamin C and beta-carotene across all three vegetable types. Drying at 70 degrees Celsius without blanching caused the greatest nutrient degradation, with vitamin C losses exceeding 70 percent. Iron and calcium content were relatively stable across treatments. Celosia argentea retained the highest phenolic content after processing. The study recommends blanching followed by low-temperature drying as the preferred method for nutrient retention in rural vegetable preservation in Niger State. Keywords: blanching, drying temperature, leafy vegetables, nutrient retention, Niger State.