Changes induced by storage method variability on the mineral composition and some selected phytochemicals content of red and white onion (Allium cepa). bulbs
Sanusi Shamsudeen Nassarawa, Salamatu Ahmad Sulaiman
Purpose: The influence of different storage conditions (ambient temperature, refrigeration storage and Wooden Cabinet storage) in minimising the postharvest losses of onions was investigated. The fresh onions varieties (red and white) were obtained from Modibbo Isah Farms, Bichi, Kano State, Nigeria. The experiment followed a completely randomized design in a factorial 3 x 2 x 8, with a total of 48 treatments, corresponding to three storage temperature conditions, two onion varieties and eight-week storage duration. The storage temperature conditions were ambient temperature (30±2 ºC), refrigeration storage (5-7 ºC) and hot air wooden cabinet storage (45-50 ºC) while the two onion varieties were white and red types. The prevailing relative humidity during the storage period ranged between 70 and 95 %. During the storage period of onion bulbs the red onion showed less damage when compared with white onion. The result showed that some nutritional components of the stored onions decreased with increase in the storage period including sodium content (12.13-11.77mg/kg) and ascorbic acid (9.62-3.87mg/100g. Other parameters such as potassium content (30.00-72.12mg/kg), calcium content (55-105mg/kg) and flavonoid content (1.25-2.31g/100g), increased with an increase in the storage period. . It may be concluded that the different storage conditions to which the onions were subjected led to diverse responses of onion components to such conditions while ambient storage condition may be regarded as the best of the three storage conditions investigated.