## 3 Results and Discussion
### GC-MS/MS Analysis of Volatile Compounds in Lamb Patties
Afterwards, the free iron could promote interaction between substrates of unsaturated fatty acid and oxidants [33]. As a result of this interaction, aldehydes and alcohols appear as the most abundant volatiles in cooked lamb [13]. Other natural components that are present in muscle tissue such as hydrogen peroxide and ascorbic acid can also result in lipid oxidation promoting reactive oxygen species (ROS) formation or acting as catalysts. Grilled lamb meat profile is created by the Strecker aldehydes, 2-methylbutanal and 3-methylbutanal [34]. However, we did not find these compounds in our samples. Linolenic acid (C18:3) degradation during cooking was reported to form benzaldehyde in cooked meat. This is consistent with our results as we observed that benzaldehyde was present in the grilled samples as well as in other electrical cooking methods but not in open-charcoal-grilled samples; however, the content was lower in charcoal-grilled samples. The results of our study show heptanoic acid was the highest in infrared- and superheat-cooked samples with 9.96 \(\upmu\)g/g and 4.16 \(\upmu\)g/g, respectively, and hexanoic acid in charcoal- and electric-barbecue-grilled samples was found to be 3.35 \(\upmu\)g/g and 6.59 \(\upmu\)g/g, respectively. The report suggested that benzaldehyde produced burnt sugar and almond special flavour during processing [35]. Heating promotes rapid polyunsaturated fatty acid oxidation which produces a higher amount of free radicals capable of attacking those fatty acids less sensitive to oxidization such as oleic acid promoting the formation of aldehydes such as nonanal, octanal and heptanal [36]. Hexanal is the most important aldehyde compound in cooked samples representing between 87.30% and 90.80% of total aldehydes in the cooked meat. This finding is consistent with some studies which found that hexanal was the major aldehyde in the meat of cooked lamb [33] and goat [25] meat. However, we did not find this compound in our grilled or roasted samples. Hexanal and 1-octen-3-ol are derived from the decomposition of C18:2n-6 fatty acid (linoleic acid) [34]. The cooking treatments of the present study most likely degraded linoleic acid further, thus, producing new volatiles and decreasing the hexanal content in the cooked lamb. Hexanal has been more related to raw meat. Ref. [37] proposed the ratio of hexanal to nonanal as an indicator of raw lamb meat freshness and overall quality. A study by [13] on cooked lamb chop samples showed the detection of 74 volatiles identified by gas chromatography. The formation of these aromatic compounds is dependent on the concentration of lipids, amino acids and carbohydrates in raw meat [38]. Different chemical reactions utilize these substrates upon cooking with different methods and, most importantly, upon cooking conditions [39]. The most important and abundant odorant compounds found were hexanal, 2-ethyl-1-hexanol, 1-octene-3 ol and octanal in cooked lamb and also consistent with other studies [14; 40]. According to results by [23], hexanal was abundant in amount followed by benzyl alcohol, 1-octen-3-ol, nonanal and 2,3-octanedione with more than 1000 ng/g in samples from the burning charcoal lamb samples. Associating gas chromatography data with odour and flavour is difficult. Few studies have quantified the contribution of these compounds to lamb flavour. Ref. [30] using partial least-squares models, reported that lamb flavour is the result of a complex balance among different odour-active volatile compounds. They observed that lamb flavour was positively correlated with the aroma concentration of 2-phenoxyylethanol, acids and dimethylpyrazines and negatively correlated with Strecker derivatives, alkenals and alkaloids. Recently, Ref. [41] identified the key odorants in traditional Chinese grilled mutton shashlik cooked on open carbon fire with or without suet (mutton fat) brushing during grilling. They identified a total of 57 odorants, which predominantly included pyrazines, sulphur-containing compounds and aliphatic aldehydes.