###### Abstract  
Faba leaves are an unusual vegetable which contain not only a range of functional phytochemicals, but also certain undesirable flavors, which limit their consumption. In this study, several cooking methods (microwaving, roasting, steaming, and boiling), which are expected to reduce the odd flavors, were evaluated in terms of both health benefit effects and odd flavor factors, including antioxidant activities and the content of non-volatile and volatile organic compounds (VOCs). A cooking time of 5 min was selected because of the high content of \(\iota\)-dopa (\(\sim\)3,4-dihydroxyphenylalanine) and aim of reducing the undesirable flavors of the cooked faba leaves. Microway and steaming significantly increased the \(\iota\)-dopa content by 24% and 19%, respectively. Roasting specifically increased the content of flavonoids, exhibiting a 28% increase of kaempfer-3-O-arabinoside-7-O-thamoside, representatively, whereas boiling decreased about 50% of most phytochemicals evaluated. Microwaying and steaming treatments significantly increased the antioxidant activities. The \(\iota\)-dopa content and antioxidant activities of the processed faba leaves were strongly positively correlated with either an \(R^{2}\) = 0.863 of DPPH radical scavenging activity or an \(R^{2}\) = 0.856 value of ABTS radical scavenging activity, showing that \(\iota\)-dopa was a key antioxidant. All cooking methods potentially improved the flavor of the cooked faba leaves compared with that of the fresh leaves, because they significantly reduced the contents of VOCs such as alcohols, aldehydes, and ketones. These VOCs were the main components (\(>\)90%) in the fresh leaves. Adverse aromatic hydrocarbons were newly formed by the microwaving treatment, typically producing \(p\)-\(x\)ylene, which is known to be a harmful dose-dependent compound, but they were not detected in leaves processed by the other cooking methods; therefore, although microwaving efficiently increased antioxidant activity, the chemical safety of the aromatic hydrocarbons produced need further study. d 2020 April 2020 27 May 2022 2020 April 2020 27 May 2022 27  
antioxidant contributors in faba leaves [3]; however, the chemical synthesis of \(\iota\)-dopa is time-consuming and expensive, and involves the use of toxic compounds [7]. Consuming natural \(\iota\)-dopa from enriched plant resources such as faba leaves has thus become important as far as health benefits are concerned. Faba leaves are also rich sources of flavonoids. [PERSON] et al. [8] have reported that kaempfer is the main aglycone of the various types of flavonoid, and it forms various glycosides in different cultivars of faba leaves. A study by [PERSON] et al. [3] reported that the total flavonoid content of the faba leaf varies with its maturity, with young leaves (66.96 mg of catechin equivalent/g dry weight) possessing more than 1.5 times as many flavonoids as old leaves. The health benefits of flavonoids regarding antioxidant, anti-inflammatory, anti-diabetic, and other health-promoting properties have been widely reported [9; 10]. Although faba leaves are excellent sources of phytochemicals with various bioactivities, their consumption is often limited because of the presence of undesirable flavors. The volatile organic compounds (VOCs) in faba leaves are considered to be responsible for their grassy smell, which has been widely reported as being related to the plant's defense system [11; 12]. No studies seem to have identified the major contributors causing this unattractive grassy smell among the various VOCs, or how to remove them and thereby promote the better use of this agricultural waste in people's daily diets. As mentioned above, faba leaves are consumed either fresh or after domestic cooking. Several studies have reported on the effects of domestic cooking on the variation in composition and bioactivity of leafy vegetables, concluding that they are significantly affected not only by the cooking methods and degree of processing, but also by the plant species and cultivars [13; 14; 15].