# Polycyclic Aromatic Hydrocarbons in Popcorn Corn Varieties and Popcorns
## 1 Introduction  
_Zea mays_ ssp. _Everta_ is a widespread corn cultivar, one of the oldest commodities known to humans. The kernel consists of the endosperm, pericarp, and germ, with the endosperm being the most important part in popping corn [1]. The corn cultivar, moisture content in the kernel, storage conditions, type of packaging, etc., all affect the quality of popping popcorn produced in microwave ovens [2]. The grain bursts at temperatures of 150-200 \({}^{\circ}\)C, during which the water from the grain changes into steam. It then transforms the endosperm into a white hollow mass of increased volume. At higher pressure, the heated steam converts the soft starch into a gelatinous material. Due to the increase in pressure in the pericarp, the grain bursts. [PERSON] et al. [3] state that the first pop has the greatest influence on the popping volume. Approximately 96% of popping occurs at approximately 180 \({}^{\circ}\)C, while, at lower temperatures, the popping decreases [4]. At the moment that the grain bursts, the water is overheated. This property leads to the expansion of the grain when the pericarp bursts [5]. The optimal share of moisture in the grain for popping is 10 to 15%. If the moisture content is lower, there is not enough water in the grain, whose steam can create pressure and lead to the complete cracking of the grain. At high moisture content, the pericarp weakens and causes the grain to burst before the appropriate pressure is reached [6]. The maximum bursting potential is realized if the popcorn kernel reaches full maturity, and kernel moisture is the key to optimal bursting. The product created by popping the kernels is called popcorn. The origin of polycyclic aromatic hydrocarbons (PAHs) is commonly any type of pyrolytic process, such as incomplete wood burning (or other organic matter). Fires,volcanic eruptions, and carbonization cause the PAHs to end up in the environment [7; 8; 9]. They can differ by the number of fused rings, and thus can be of lower molecular weight (2-4 rings) (LMW-PAHs) and higher molecular weight (more than 4 rings) (HMW-PAHs). PAHs are lipophilic molecules and acknowledged as health deteriorators [10; 11; 12] due to their presence in various foods and beverages. PAHs are designated as persistent organic pollutants (POPs) and are commonly found in different commodities. Crops are usually contaminated via soil, water, or air, since PAHs are ubiquitous and highly mobile, thus representing a serious environmental threat [13; 14; 15]. According to [PERSON] et al. [16], plants have the ability to secrete enzymes and transform or biodegrade PAHs in soil. In doing so, some plants show more effectiveness in the biodegradation of PAHs than other species. Foods, especially processed samples, are complex materials for analysis. Usually, analytes have to be separated from the matrix. Since PAHs are lipophilic molecules, upon extraction, they merge with the lipid constituents and have to be purified. Thus, a number of different approaches have been developed to aid the removal of lipid components from the matrix. They involve solid or liquid extractions or liquid-liquid extraction methods, pressurized liquid extraction, or even supercritical fluid extraction. After purification, the partition methods, such as solid-phase extraction or solid-phase microextraction, follow. At the end, analytical determination is usually performed by applying liquid chromatography (LC), ultra-high-performance LC (UHPLC), or gas chromatography (GC) with different detectors. Recent studies employ comprehensive techniques such as GC \(\times\) GC or LC \(\times\) LC. A deeper overview of extraction and analytical methods can be found in excellent review papers [17; 18; 19]. Current reports indicate that data on PAHs in cereals are lacking. Not many researchers have dealt with PAHs in cereals. However, some of them have been determined in breakfast cereals and bread [20] and dried maize grain samples [21]. According to [PERSON] et al.