Introduction
Oil–bearing crops include those whose fruits (or mesocarps), seeds, and nuts are worth for the edible or industrial oils to extracted. The Food and Agriculture Organization of the United Nations (FAO) listed 21 oil crops, which collectively yield an annual production of world oilseed for about 100 million tons (Athar and Nasir, 2005). Vegetable oils have progressively supplanted animal oils as a major source of dietary fat, leading to oil crop production becoming one of the prevailing forms of world agriculture. Oil crops contain diverse array that strengthen nutritional value of human diet, with the oils generated by such crops being especially good sources of tocopherol and thus promoting the balanced intake of vitamin E (Athar and Nasir, 2005; Kornsteiner et al., 2006). Peanuts, most fundamental food crop in the world, where China, India, and the United States are top three peanuts worldwide producers (Arya et al., 2016). The peanuts pods ripen approximately 150 days after the seeds planted. With mechanized reaping, the whole peanut plant, including the seed pods, are removed from the soil before being dried (sun or hot–air) and then seed shelling (Arya et al., 2016; Nawade et al., 2018). Peanuts easily lipid oxidize and decompose during storage and transportation due to their high–fat level (>50%), and this influence their nutritional, agricultural and edible safety importance (Chukwumah et al., 2007; Liu et al., 2018; Hu et al., 2019; Xie et al., 2019).
The cooking methods used with edible oils differ in terms of the temperature, duration, and the amount of oil used. Vegetable oils are important constituents of the daily diet of most people, although the actual intake of such oils differs considerably depending on the cooking methods used. The World Health Organization (WHO) has identified three important factors for determining the nutritional value of oils: I) the presence of antioxidants; II) the ratio of saturated fatty acids (SFA), mono–unsaturated fatty acids (MUFA), and poly–unsaturated fatty acids (PUFA); and III ) the essential fatty acid ratio (Hashempour–Baltork et al., 2016). Relatedly, the WHO has recommended a ratio of 1:1.5:1 for SFA:MUFA: PUFA and a ratio of 1:5~10 for α– linolenic acid (omega–3): linoleic acid (omega–6) in people’s dietary intake. Vegetable oils are high in MUFA and, as part of a low–cholesterol diet, have been found to lead to reduced cardiovascular disease (CVD) risk, in addition to potentially improving serum lipid profiles, decreasing LDL oxidation, and exerting a cardioprotective effect (Hashempour–Baltork et al., 2016; Chen et al., 2008). The antioxidant components in vegetable oils is composed of hydrocarbons, carotenes, tocopherol, phytosterols, and triterpenes, the minor constituents of various vegetable oils are associated with medicinal qualities and thus can be useful in preventing or delaying the onset of chronic diseases and promoting health (Chen et al., 2008; Alasalvar and Bolling, 2015; Ghosh et al., 2017).
Organic solvent extraction (mostly using petroleum ether, petroleum benzene, and hexane) and mechanical pressing are two conventionally used commercial methods in producing vegetable oils. However, the residual solvent remains of the former process can cause environmental safety issues and neurological damage, while mechanical pressing provides only a low yield of oils (Mingyai et al., 2018; Yang et al., 2018). To increase the extractability of oil, several destructive pretreatments need to be performed. Cold‐pressed oils are generated with no refining process and have good flavor, stable quality, and are high in bioactive components, qualities which have led them to be regarded as excellent food oils by consumers (Yang et al., 2018). Roasting, grinding, and pressing have been the key steps in peanut oil processing. Recent research findings, however, have given mind to the enhancement of substitute processing techniques for oil production and flavor. Roasting constitutes a critical processing stage that affect the color, composition, conversion to bioactive compounds, and or ganoleptic qualities of the extracted oils, as well as their oxidative stability (Chang et al., 2016; Taş and Gökmen, 2017; Różańska et al., 2019). Research has shown, for example, that roasting increases the oxidative stability of sesame oil, with no oxidation being observed for 50 days after roasting (Rostami et al.,2014).
Insufficient information regarding edible oils has made it increasingly difficult for consumers to choose oils for purchase. Traditional peanut oil preparation focuses on the relationship between roasting temperature and aroma but ignores thermal-oxidative degradation and active substance. In this study, peanuts were roasted at different temperatures (120, 140, and 160℃) to determine how those roasting temperatures affect the chemical properties related to the quality of the oils generated. We investigated various quality indices and the oxidative stability of the generated peanut oils, as these factors have received increasing attention as edible oils have been increasingly recognized as a necessary source of antioxidant components in a healthy balanced diet. Relatedly, the obtained data should be useful for deepening the understanding of the chemical profile, in addition to providing scientific evidence for enhancing the human diet qualities. Moreover, this present work may serve as a worth reference for future complementary studies aimed at evaluating the beneficial effects of vegetable oils on human health.