Quality and Antioxidant Properties of Cold-Pressed Oil from Blanched and Microwave-Pretreated Pomegranate Seed

Abstract

The present research studied the influence of blanching and microwave pretreatment of seeds on the quality of pomegranate seed oil (PSO) extracted by cold pressing. Pomegranate seeds (cv. Acco) were independently blanched (95 ± 2 °C/3 min) and microwave heated (261 W/102 s) before cold pressing. The quality of the extracted oil was evaluated with respect to oxidation indices, refractive index, yellowness index, total carotenoids content, total phenolic content, flavor compounds, fatty acid composition, and 2.2-diphenyl-1-picryl hydrazyl (DPPH) and 2.2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging capacity. Blanching and microwave pretreatments of seeds before pressing enhanced oil yield, total phenolic content, flavor compounds, and DPPH and ABTS radical scavenging capacity. Although the levels of oxidation indices, including the peroxide value, free fatty acids, acid value, ρ-anisidine value, and total oxidation value, also increased, and the oil quality conformed to the requirements of the Codex Alimentarius Commission (CODEX STAN 19-1981) standard for cold-pressed vegetable oils. On the other hand, blanching and microwave heating of seeds decreased the pomegranate seed oil’s yellowness index, whilst the refractive index was not significantly (p > 0.05) affected. Even though both blanching and microwave pretreatment of seeds added value to the cold-pressed PSO, the oil extracted from blanched seeds exhibited lower oxidation indices. Regarding fatty acids, microwave pretreatment of seeds before cold pressing significantly increased palmitic acid, oleic acid, and linoleic acid, whilst it decreased the level of punicic acid. On the contrary, blanching of seeds did not significantly affect the fatty acid composition of PSO, indicating that the nutritional quality of the oil was not significantly affected. Therefore, blanching of seeds is an appropriate and valuable step that could be incorporated into the mechanical processing of PSO.

Evaluation of dry microwave and hot water blanching on physicochemical, textural, functional and organoleptic properties of Indian gooseberry (Phyllanthus emblica)

“…The observed YI value of HW blanched sample was higher than MW blanched and raw sample due to the longer exposure of the samples to thermal treatment that might have linked to enzymatic reaction [ 27 ]. Similar results in increase in YI after blanching were reported in pomegranate seeds [ 28 ].…”

Assessing the concentration of conjugated fatty acids within pomegranate seed oil using quantitative nuclear magnetic resonance (qNMR)

“…The cold press oil machine used works on the principle of extracting the oil by pressing the seeds in the worm screw. Precipitating and removing the obtained crude oil from the residue resulted in cold‐pressed PSO 29 . The commercial PSOs were purchased from stores in Kocaeli Providence of Turkey.…”

“…Precipitating and removing the obtained crude oil from the residue resulted in cold-pressed PSO. 29 The commercial PSOs were purchased from stores in Kocaeli Providence of Turkey. The pomegranates were of the Eski Hicaz, Gazipasa Cekirdeksiz, Hicaz Cekirdeksiz, and Yeni Hicaz.…”

Effect of some Cultivation Factors and Extraction Methods on Terminalia Catappa L. Seed Oil

“…The temperature of the outlet oil in this method was in ranges of room temperature to 50 °C. The previous studies showed that the cold pressing could maintain the higher bioactivity compound concentration than the solvent extraction or the hot pressing in seed oils [19][20][21]. In our study, the dried seeds (1 kg) were frozen at -18 °C for 24 hours before extracting oil with a screw presser (YF-J503, Zhengzhou Yuhuo, China).…”