The Effect of Processing on Some Nutritional Indices of Purple Onion, (Allium cepa Linn), Bulb

Onion (Allium cepa L.), also referred to as “Queen of the kitchen†, is a common vegetable that is widely consumed all over the world. It is has peculiar taste, unique flavor, highly valued aroma, and various health benefits. This all important condiment however, has a short shelf life which is a major cause of postharvest losses during the peak of harvesting season. Scarcity resulting from the losses has led to a thought of its processing with the aim of retaining its medicinal and nutritional properties. The present study was therefore, aimed at evaluating the effect of processing on the Vitamins and Minerals composition of purple onion using two processing methods (sun drying (SD) and oven drying (OD) at 70oC), compared to fresh samples. These Parameters were evaluated using standard Biochemical methods. The results obtained showed that all the parameters tested were affected significantly (P˂0.05) by oven drying process when compared to the fresh sample. The Vitamins (A, B1, B2, B3, B6, B9, C, and E,) composition showed an increasing composition of the parameters in the order of Fresh ˂ SD ˂ OD. From the foregoing, it can be suggested that oven drying (70oC) is an efficient method of processing and preservation of purple onion. The results from the study could be a direction towards the promotion of preservation of purple onions and an encouragement of the industrialization of the process of producing onion powders, which is readily available in all seasons and meet consumer requirements.