APPLICATION OF MORINGA OLEIFERA OIL AS SPROUTING SUPPRESSANTS FOR IRISH POTATOES STORAGE

Abstract

This study examined the “storage of Irish potatoes using Moringa oleifera oil as sprouting suppressantâ€. Oil was extracted from moringa seeds using cold press extraction method. The percentage yield and physico-chemical properties of moringa oils were carried out. Characterization of the oil was done using GC-MS. Five tubers of potatoes were put into khaki bags to prevent the oils from venting out. Oil was applied using spraying method with hand sprayer, by spraying on the potatoes in the bag. The oil treated potatoes were aired and allowed to coat, transferred to storage crates, to allow further coating. This was in single, double, triple and quadruple doses (after 72 hours) to allow them coat in layers, giving it thicker coats. The treated samples were stored for 10 weeks, and the sprout length, sprouting percentage, weight loss, number of sprout per tuber were determined. Oil had creamy yellow coloured, pleasant odour and pleasing taste. The Moringa oleifera oil had high percentage yield of 12.7%, refractive index of 1.4606, specific gravity of 0.9022 MgKOH, viscosity (mpa/s) of 76.50. A low moisture content of 6.21%, high acid value of 6.42 mgKOHg. The oil had low peroxide value (meg O2/kg oil) of 4.42, low iodine value (g/100g) of 66.8, high saponification value (mg KOH g) of 192.82, free fatty acid (mg KOH g) value of 3.24 and a PH value of 4.58. Nine compounds were detected in the oil. There was no significant difference (p>0.05) in the number of sprouts for week 1-5 but from week 6-10 was significantly different (p<0.05), the other samples showed no significant difference (p>0.05) throughout the storage period. The control sample showed no significant difference (p>0.5) for the first three (3) weeks but there was significant difference (p<0.05) for the remaining 7 weeks, with week 10 having the longest length of sprout (4.77 mm) and the rest samples showing no significant difference (p.0.005) in the length of sprout. The control sample had the highest weight scores at week 1 (179.6 g) with the control and the single coated Irish potatoes had significant differences (p<0.05) in the values for the different weeks of storage. The double, triple and quadruple coated samples had no significant difference with the double coated having the highest weight of 196 g for week 1 after storage. This study reveals the potentials of moringa oleifera oil to inhibit sprouting of Irish potatoes and thus, prevent postharvest loss of the crop.