Manufacture of low-benzo(a)pyrene sesame seed (Sesamum indicum L.) oil using a self-designed apparatus.

Ji Yoon Yi,Hui Ju Kim,Myong-Soo Chung

doi:10.1371/journal.pone.0173585

Abstract

The aim of this study was to lower benzo(a)pyrene (BaP) contents in sesame seed oil (SSO) during manufacture by using a self-designed apparatus, to determine its optimal conditions, and to analyze antioxidants in SSO which might be related to BaP content reduction. Washing and spin-drying steps reduce exogenous BaP contamination, and the reduced moisture in seeds lowered BaP content in final SSO. A ventilation system in the roasting step inhibits BaP formation and reabsorption, followed by a controlled compression step. The optimal condition, a single washing cycle with 2-min spin-drying, 1350-rpm ventilation, and a single compression cycle, reduced the BaP content in SSO to 2.93 μg/kg, where the raw seeds had been spiked with 10-μg/kg BaP. Total phenolic contents showed a reversal pattern to the distribution of BaP contents. Sesamol and sesamolin were quantified by a high performance liquid chromatography-ultraviolet detector, and it was suggested that sesamol which is a strong antioxidant might have prevented BaP formation during the roasting step. This study enabled the commercial production of low-BaP SSO, and the data could be used in further investigations of the BaP content reduction mechanism with quantitative chemical analysis of the SSO composition.

Highlights

Benzo(a)pyrene (BaP) is a carcinogenic polycyclic aromatic hydrocarbon (PAH) found in various foodstuffs, such as meats, seafoods, dairy products, cereals, grains, fruits, vegetables, breads, and beverages (Fig 1) [1,2,3]
The washing step is necessary to eliminate dirt, dust, and some BaP attached to raw SS, while poorly controlled processing conditions lead to an elevated BaP content in sesame seed oil (SSO), which is produced during the roasting step due to the increased moisture content of SS
The application of one or two cycles of washing process did not produce any significant differences in the reduction effects on BaP in SSO compared to unwashed ones: the BaP contents were reduced to 3.13, 2.93, and 4.79 μg/kg in SSO for no, one, and two cycles of washing, respectively

Summary

Introduction

Benzo(a)pyrene (BaP) is a carcinogenic polycyclic aromatic hydrocarbon (PAH) found in various foodstuffs, such as meats, seafoods, dairy products, cereals, grains, fruits, vegetables, breads, and beverages (Fig 1) [1,2,3]. It was reclassified as an IARC Group 1 carcinogen in 2012, which means that it is carcinogenic to humans [4]. It has been reported that food processing methods involving thermal treatments such as smoking, roasting, grilling, toasting, and broiling result in the formation of BaP [3,8,9]. Since many vegetable oils are produced using thermal processes and are lipophilic, BaP is found in various types of vegetable oils [10,11,12]

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