Effects of heat pretreatment of wet-milled corn germ on the physicochemical properties of oil

Abstract

Corn germ oil is removed from the milled germ using a conditioning (heating) process, followed by mechanical expelling and/or hexane extraction. In this study, the effect of pretreatment by oven roasting (OR) and microwave (MW) radiation on wet-milled corn germ was investigated. Three OR temperatures (125, 150, and 175 °C) were used with 60 min exposure, and MW pretreatments were established by combining two powers (440 and 800 W) and three pretreatment times (4, 6, and 8 min). The levels of red value, 1,3-diacylglycerol, total diacylglycerol, free fatty acid, and oleic acid increased substantially, while those of triacylglycerol (TAG), linoleic, and linolenic acid decreased significantly following OR. There were no significant differences in TAG compositions following OR and MW treatments. Both heat pretreatments significantly increased the total tocopherol content. δ-Tocopherol showed minimal changes, while β-tocopherol progressively increased after the heat treatments. No significant differences in phytosterols levels were observed among most samples. The MW radiation Proper roasting temperatures or MW radiation times could enrich the content of individual tocopherols and phytosterols, and improve the oxidative stability of oil. The MW radiation tends to be more applicable and sustainable for oil industry to improve the quality of corn germ oil.

Prospects of Maize (Corn) Wet Milling By-Products as a Source of Functional Food Ingredients and Nutraceuticals

“…According to a study, the tocopherols content of oil extracted by Soxhlet extraction using nhexane from unroasted wet-milled corn germ was 59.4 mg/100 g (18). The oil also showed a high γ-Please note that this is an unedited version of the manuscript that has been accepted for publication.…”

Chemical Profiles of Twenty-three Monovarietal Olive Oils Produced in Liangshan Region of China

“…Samples for fatty acid profile were determined following the test procedure described by Zheng et al 14 . Detailed information were provided in the Supplementary material.…”

Chemical Compositions and Oxidative Stabilities of Ginkgo biloba Kernel Oils from Four Cultivated Regions in China

“…The oxidative stability of the kernel oils was determined in terms of the induction period using a Metrohm 892 Rancimat with slight modifications (Zheng et al, 2018b). The oil samples (3 g) were heated to accelerated oxidation at 120 °C in a reaction tube with the cleaned and dried air at 20 L hour −1 bubbled into the hot sample.…”