Moringa oleifera lam kernel oil refining and applications in emulsion-based food products

Food security is a complex issue to resolve, where it is important to increase food production at the same time reducing harmful effect on the environment. Moringa oleifera (MO) is potentially one of the most valuable crops in addressing food security issues. Specifically, the mature seed kernels contain Moringa oleifera kernel oil (MOKO) which is a high-oleic oil composed of 70-75% oleic acid. The oil needs to undergo refining process prior to its application in food products. Thus, this study aimed to: 1) determine the effect of individual refining stages of degumming (water- and acid-), neutralization (10 and 15) °Bé NaOH, bleaching (acid-activated bleaching earth [BE] type A and B; and a natural one), and deodorization (200, 235 and 270) ˚C on the physicochemical and oxidative properties of MOKO, 2) determine the effect of multiple refining stages on the physicochemical and oxidative properties of MOKO of different grades, and 3) determine the effect of different refined MOKO-soybean oil (SBO) blend ratios on the physicochemical properties of mayonnaises during storage. Acid degumming contributed to better oxidative properties as compared to water degumming, except for AV (p < 0.05) which were 4.233 ± 0.021 mgKOH/g and 4.158 ± 0.027 mgKOH/g, respectively. Neutralization using 15 °Bé NaOH performed better for all oxidative properties than that of 10 °Bé. Acid-activated BE type B resulted in lowest AV (3.965 ± 0.022 mgKOH/g) and MC (0.007 ± 0.001 %) as compared to other BEs. Deodorization at 270˚C resulted in lowest AV (2.439 ± 0.096 mgKOH/g) and MC (0.002 ± 0.000 %) than the use of other lower temperatures. Neutralization (15 °Bé NaOH) was better than deodorization (270˚C) in lowering the AV. Therefore, a combined series of refining stages comprising acid degumming, neutralization by using 15 °Bé NaOH, and bleaching using acid-activated BE Type B were further carried out on two crude MOKO batches (Batch Y and Z) of different grades. Significant decrease (p < 0.05) was observed in phosphorus content (98.20%; 97.18%), PV (66.67%; 50.00%), MC (85.71%; 85.71%) and AV (99.57%; 99.57%) in both refined Batch Y and Z, respectively. The IV (80.94-81.03) and FAC were unaffected except for the saturated and unsaturated fatty acids of Batch Z. The refined MOKO color was lighter based on significant changes (p < 0.05) in the L*, a*, and b* values, while the total tocopherol content significantly increased (p < 0.05) in both Batch Y (52.28 %) and Batch Z (23.25 %). Different blend ratios of refined MOKO-SBO did not significantly affect (p > 0.05) the physicochemical properties of mayonnaises except for their color and rheological properties at storage week 0 and week 6. The MOKO-SBO blend at 50:50 (w/w) ratio (i.e., MOKO 50%) exhibited desirable properties especially due to its lowest droplet size on day 0, insignificantly difference (p > 0.05) in droplet size with other MOKO-based mayonnaises after 6 weeks, and its highest crossover value. In overall, the establishment of refining processes for MOKO is advantageous for the oil to be applied in various types of food products.

Text 122553.pdf Download (1MB) Official URL or Download Paper: http://ethesis.upm.edu.my/id/eprint/18608

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