Oxidative properties of Moringa oleifera kernel oil from different extraction methods during storage

Abstract

BACKGROUND: Moringa oleifera (MO) kernel oil is categorized as a high-oleic oil that resembles olive oil. However, unlike olive trees, MO trees are largely present in most subtropical and tropical countries. In these countries, therefore, the benefits of oleic acid can be obtained at a cheaper price through the consumption of MO kernel oil. This study reports on the effect of different extraction methods on oxidative properties of MO kernel oil during storage for 140 days at 13, 25, and 37 ∘ C. RESULTS: All aqueous enzymatic extraction (AEE)-based methods generally resulted in oil with better oxidative properties and higher tocopherol retention than the use of solvent. Prior to AEE, boiling pre-treatment deactivated the hydrolytic enzymes and preserved the oil's quality. In contrast, high-pressure processing (HPP) pre-treatment accelerated hydrolytic reaction and resulted in an increase in free fatty acids after 140 days at all temperatures. No significant changes were detected in the oils' iodine values and fatty acid composition. The tocopherol content decreased significantly at both 13 and 25 ∘ C after 60 days in the oil from SE method, and after 120 days in oils from AEE-based methods.CONCLUSION: These findings are significant in highlighting the extraction methods resulting in crude MO kernel oil with greatest oxidative stability in the storage conditions tested. Subsequently, the suitable storage condition of the oil prior to refining can be determined. Further studies are recommended in determining the suitable refining processes and parameters for the MO kernel oil prior to application in variety food products. Aqueous enzymatic extraction with high pressure processing pre-treatment (HPP-AEE)The ground-sieved MO kernels were mixed with distilled water at a 1:1 (w/w) ratio and vacuum sealed in polyethylene bags. According to Mat Yusoff et al. (2017), 21 some preliminary tests were carried out to determine the solid-to-liquid ratio. The use of a smaller amount of water caused the formation of a very thick paste, which adhered to the polyester bag, thus wasting some of the sample. The addition of a higher water content resulted in a very dilute mixture, which thus allowed only a small amount of ground-sieved MO kernel to be processed at one time.The mixtures at 1:1 (w/w) ratio were treated with high pressure (Stansted Fluid Powder Ltd, Stansted, UK) at 50 MPa and 60 ∘ C for 35 min, followed by addition of distilled water up to 4:1 water / kernel (w/w) ratio for the subsequent AEE, as in the earlier section. The recovery of the free oil is explained in the next section.

Establishment of an Effective Refining Process for Moringa oleifera Kernel Oil

“…Table 5 also highlights oleic acid as the dominant fatty acid in batches Y and Z. However, the values obtained were higher (79.22-79.65%) as compared to those reported by Mat Yusoff et al [4] in the case of crude MO kernel oil (~75%) and by Sánchez-Machado et al [9] in the case of refined MO kernel (71-72%) produced using different refining stages of neutralization, degumming, and bleaching. Similarly, the total content of oleic, palmitic, stearic, and linolenic acids comprised approximately 98% of the total fatty acids in both Batches Y and Z, while only~87% of these fatty acids were present in refined MO kernel oil as reported by Sánchez-Machado et al [9].…”

“…This shows that the DNB refining process employed did not change the degree of unsaturation of the oil. In an earlier study conducted by Mat Yusoff et al [4], lower IVs of 54-65 g I 2 /100 g of oil were reported. These differences may be due to the different oil extraction methods employed.…”

“…These differences may be due to the different oil extraction methods employed. In this study, the oil was cold-pressed from the kernels, while Mat Yusoff et al [4] extracted the oil by using solvent and aqueous enzymatic methods. The oil oxidation rate may be affected by the solvents, enzymes, and extraction temperatures used, and this can further lead to differences in IVs [38].…”

“…Many studies have reported on the physicochemical and oxidative properties of MO kernel oil. These studies attributed its high stability to the presence of up to 75% oleic acid (i.e., comparable to olive oil), and significant amounts of tocopherol and sterol [4,5]. A diet rich in monounsaturated fat as a substitute for saturated fat is a strong and continuing trend due to its beneficial impact on coronary heart disease and overall heat [6].…”

Cucumis melo seed oil: agro‐food by‐product with natural anti‐hyperlipidemic potential

“…The sweet melon seed oil used during the current study also showed a positive/healthy impact on hypercholotrolemia. Moreover, cholesterol management through diet therapy could be the safest strategy as some other scientists have also recommended the safe use of Moringa olifera , 18 dairy products with specific strains of Lactobacillus, 19 watermelon, 20 and coumarins 21 to control hyperlipidemia.…”