**3. Results and discussion**

In total, 28 volatiles were detected by HS-SPME-GC-MS. Among them, 15 were identified in var. minor and 22 in var. major; accounting for 98.3% and 95.4% of total emission, respectively. The flavor constituents were divided into five chemical classes, including monoterpenes hydrocarbons (MH), sesquiterpenes hydrocarbons (STH), apocarotenes (AP), non-terpenes derivatives (NTD), and oxygenated monoterpenes (OM). Faba bean var. major emitted 61.4% of NTD, 19.4% of MH, 9.3% of OM, 4.8% of AP, and 0.6% of STH volatiles. On the other hand, 64.7% of NTD, 27.9% of MH, 3.4% of STH, 1.2% of OM, and 1.1% of AP were detected in the bouquet of the minor cultivar (**Table 1**). This data is in accordance with the studies of *Khrisanapant* [18] and Rajhi et al. [10]. Indeed, these authors demonstrated that NTD group was the major chemical class in legumes.

#### **3.1 Non terpenes derivatives constituents (NTD)**

The individual volatile profiles of both cultivars are summarized in **Figure 2**. NTD volatiles identified in this study were: 5 aldehydes (heptanal, nonanal, decanal, undecanal, and dodecanal), 5 alkanes (*n*-dodecane, *n-*undecane, *n*-tridecane, *n*-tetradecane, and *n*-pentadecane), esters (butyl butyrate and ethyl octanoate), one phenol (phenol), 1 phenone (acetophenone), alcohol (phenylethyl alcohol), and hydrocarbon (naphthalene). The most abundant chemical group was aldehyde; including nonanal, which has a fat, citrus, and green flavor, decanal which is soap, orange peel and tallow like aroma, and undecanal, which has a waxy type of flavor. These chemicals were emitted by var. minor (8.2%, 2.6%, and 0.6%, respectively) and var. major (7.6%, 5.6%, and 0.9%, respectively). The heptanal aldehyde, which has a strong fruity odor [19], was registered only in the individual profile of var. major (7.1%). However, the dodecanal aldehyde, which has a soapy type of odor [19], was only found in the volatile bouquet of var. minor (0.3%). These results are in good agreement with a previous investigation of volatile


#### **Table 1.**

*Chemical classes percentage of volatiles compounds in major and minor faba bean seeds.*

*Monotoring the Aroma Compounds of* Vicia faba *L var. Major and var. Minor DOI: http://dx.doi.org/10.5772/intechopen.106922*

#### **Figure 2.**

*NTD volatile compounds identified in faba bean var. minor and var. major.*

compounds of other legumes, in particular soybeans, mung beans, cowpeas, peas, chickpeas, orange lentils and adzuki beans [18, 20, 21].

Alkanes were the second dominant class in the NTD volatiles. Among the detected alkanes, two constituents were emitted by both cultivars: the *n-*tridecane and *n*-tetradecane (**Figure 2**). *n*-undecane and *n*-pentadecane were registered in the emission profile of var. major (1.6% and 2.6%, respectively). However, the alkane *n*-dodecane was characterized in the individual profile of var. minor. The high content in alkanes, was also previously reported by Oomah et al. [20] for different types of *P. vulgaris*. Their abundance legume seeds may be explained by the occurrence of lipid peroxidation, which causes the formation of the characteristic aroma of dry pulses, since alkanes are mainly obtained from oxidative reaction of lipids [11, 20].

Two esters were identified using the HS-SPME-GC-MS: the butyl butyrate, which has a fruity odor [19], is emitted by major and minor cultivars (6.3% and 12.4%, respectively), and the ethyl octanoate, presented a strong fruity and flowers odor [19], was found only in the bouquet of the latter one (2.5%). The NTD phenol was emitted by var. minor with a percentage identification of 27.4%.

This result agrees with that of Mebazaa et al. [22] and Ramadan et al. [23]. In their study on black, dark red kidney and pinto beans, Oomah et al. [20] demonstrated that the volatile profiles of studied *P. vulgaris* pulses were rich in aldehydes, alkanes, esters, and ketones.

#### **3.2 Oxygenated monoterpenes**

Seven constituents belong to the oxygenated monoterpenes were detected in both cultivars using HS-SPME-GC-MS. Among them five such as camphor, borneol, menthol, carvone, and bornyl acetate were appeared in the emission profile of var. major (2.8%, 0.9%, 1.7%, 1.3%, and 2.6%, respectively). However, the minor cultivar emitted much more α-terpineol (1%) and verbenone (0.2%) (**Figure 3**).

#### **Figure 3.**

*OMT volatile compounds identified in faba bean var. minor and var. major.*
