Effects of Use and Re-Use of Selected Vegetable Oils on the Proximate, Minerals, Mineral Ratios and Mineral Safety Index of Raw and Fried Plantain Chips: Note I

Abstract

Raw and fried plantain chips obtained from the use and re-use of olive, refined palm olein and coconut oils were investigated for the proximate, mineral compositions, computed mineral ratios and the mineral safety index using standard analytical methods. For the selected oils (both use and re-use): first and second re-use and the fresh plantain chips (unprocessed plantain chips; UPC) had the following range results: proximate composition (%) (moisture: 8.20 - 12.3, crude protein: 9.70 - 8.60, fat: 7.40 - 12.9, fibre: 3.50 - 4.90, ash: 2.80 - 3.80 and carbohydrates: 63.5 - 64.8), % energy contributions (PEC: 63.4 - 70.8, PEF: 20.2 - 28.6, PEP: 8.03 - 9.66, UEDP: 4.49 - 5.08). The mineral composition (mg/100g) of the samples had the following greater than 80.0: Ca, Mg, K and P; Fe, Cu, Mn and Zn recorded values ranging between 1.00 and 4.00; Co, Se and Ni had their concentrations between 0.00 and 0.0363 whereas Pb and Cd recorded levels lower than 0.0006. In the mineral ratios, only K/(Ca + Mg) values fell within the acceptable ideal range. No MSI aberration was observed for the minerals from all the samples obtained from the various oils. The chi-square analysis showed that on parameter wise comparisons, there were no significant differences among the levels as treated based on the various oils except gross energy, Mg, K, P, Ca/P, Fe/Pb and K/Co. Also on pairwise comparison from linear correlation and regression, all these parameters were significantly different at r = 0.01 between the unprocessed and fried plantain samples: proximate, percentage energy distribution, mineral and mineral ratios. Generally, the first (day) frying showed fairly high nutrient concentration than the first and second re-use oils products. Therefore, for optimum nutrient preservation from fried plantain chips re-use of oil for frying should be sparingly allowed. However, olive showed highest level of nutrients in terms of proximate and mineral compositions.