Comparative Study of Chemical Compositions and Antioxidant Capacities of Oils Obtained from 15 Macadamia (Macadamia integrifolia) Cultivars in China

Abstract

The planting area of macadamia in China accounted for more than one third of the world’s planted area. The lipid compositions, minor components, and antioxidant capacities of fifteen varieties of macadamia oil (MO) in China were comparatively investigated. All varieties of MO were rich in monounsaturated fatty acids, mainly including oleic acid (61.74–66.47%) and palmitoleic acid (13.22–17.63%). The main triacylglycerols of MO were first time reported, including 19.2–26.1% of triolein, 16.4–18.2% of 1-palmitoyl-2,3-dioleoyl-glycerol, and 11.9–13.7% of 1-palmitoleoyl-2-oleoyl-3-stearoyl-glycerol, etc. The polyphenol, α-tocotrienol and squalene content varied among the cultivars, while Fuji (791) contained the highest polyphenols and squalene content. Multiple linear regression analysis indicated the polyphenols and squalene content positively correlated with the antioxidant capacity. This study can provide a crucial directive for the breeding of macadamia and offer an insight into industrial application of MO in China.

Optimization of hydration method for efficiently separating high‐quality oils from macadamia seed kernels

“…Moreover, hydration method was found to be superior to hot pressing in terms of production of oil rich in fat‐soluble biaoactive compounds ( p < .05). The bioactive compounds in the crude oil (without refining) extracted by solvent determined in this study were in the range of that from several varieties of macadamia nuts which were reported to have 1569.50–2064.54 mg/kg phytosterols, 27.9–53.1 mg/kg α‐tocotrienols as well as 91.15–268.08 mg/kg squalene and 126–359 μmol TE/kg antioxidant activity (Shuai et al, 2021). The variation of fat‐soluble bioactive compounds may be caused by difference in such factors as varieties and growing conditions.…”

Characterization of a novel squalene‐rich oil: Pachira macrocarpa seed oil

“…The phytosterols were determined according to the method described by Shuai et al. (2021). Phytosterols were determined by a GC system (Agilent 7890A, Agilent Technologies, USA) installed with a DB‐5MS capillary column (30.0 m × 0.25 mm × 0.25 µm) and an FID (Agilent Technologies, USA).…”

Chemistry and Functionality of Cold-Pressed Macadamia Nut Oil

“…The macadamia nut, which belongs to the Proteaceae family, is native to Australia [15]. At the maturity stage, the nut is approximately 2.6 cm in length and 2.7 cm in width, and it consists of the husk, shell, and kernel [13,16].…”

“…Although the area of macadamia nut production slightly increased (18%) in Australia from 2010 to 2016, the industry production almost doubled within the same period, recording an average industry production rate of 2.8 tons per hectare [19]. In China, macadamia nuts were introduced in the 1970s from Australia, and to date, it is one of the fastest producers of nuts globally [15]. Macadamia nut is a lucrative crop in Malawi, which is ranked the seventh top producer of nuts, valued at USD 35 million.…”

“…Tocotrienols are found in higher concentrations in CPMO than tocopherols. Moreover, they are more powerful antioxidants than tocopherols and show better cholesterol-lowering and anti-cancer properties [15]. The α-tocotrienol (15.91-46.83 µg/g) was the most abundant followed by γ-tocotrienol (9.04-22.23 µg/g) and δ-tocotrienol (3.00-17.66 µg/g) [14].…”