## 3 Results and Discussion
### Volatile Analysis
#### 3.2.1 Effects of Storage, PEF Processing, and Cuts on Volatile Composition
The alcohol, 1-hexanol (1), derived from hexanal reduction, was present in the shoulder cut sample at significantly lower levels as compared to other cuts. In contrast, chilled rib cut had a lower concentration of 2-methyl propanal as compared to other cuts. Generally, thiophenes, sulphur containing compounds, and furans can contribute to meat-like aromas that have exceptionally low odour threshold values [16]. Overall, storage for 7 days led to the production of more volatiles compared day 0 samples. Increased volatile production with increased storage period can be a result of lipid oxidation as the ability of unsaturated fatty acids to oxidize plays an important role in the flavour development during cooking [19]. [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON] and [PERSON] [6] also reported that TBARS values (between 0.06 and 0.12 mg MDA/kg) of fresh beef samples increased (although below the critical level that contributes to rancidity) with increased lipid oxidation after 7 days of storage. PEF-Treated Frozen Samples  
Similar to chilled samples, F1 differentiated control frozen samples from PEF processed frozen samples when stored for 7 days. In addition, F2 differentiated the frozen samples in terms of effects of storage. Figure 4b explained 77.56% variance and showed that samples subjected to PEF treatment were separated along F1 from control samples. Negative scores along F1 were correlated with PEF processed samples stored for 7 days. Most frozen lamb cuts that were subjected to both PEF and 7 days storage were closely associated with 2,3-octanedione (2), 2-heptanone (3), hexanal (8), heptanal (9), 2-ethylfuran (12), pyridine (15), 3,5-diethyl-2-methyl-pyrazine (20), dimethyl disulphide (22), and dimethyl trisulphide (24). In contrast to chilled samples, frozen-thaured PEF treated samples stored for 7 days were not mainly dominated by pyrazines. The volatile compound, 2,3-octanedione, can be derived from the heating and breaking down of linoleic acid [20]. [PERSON], [PERSON], [PERSON] and [PERSON] [18] reported that 2,3-octanedione had an oxidized fat and warmed-over flavour, which is derived from lipid oxidation. This result can be explained by higher lipid oxidation in frozen-thaured cuts. Since, sulphur volatile compounds are derived from sulphur containing amino acid degradation [16], freezing condition and longer storage may have accelerated protein degradation in meat. The presence of more sulphur volatile compounds in aged meat may also be due to the increased concentration of cysteine during storage [21]. Frozen samples that were subjected to PEF treatment and 7-day storage period were also associated with aldehydes like hexanal (8) and heptanal (9). In terms of cuts, significantly higher level of hexanal and heptanal was present in frozen-thauredrump cut and shank cut, respectively. Positive scores along F1 were correlated with control frozen samples that were stored for 7 days. Control samples that were subjected to 7 days storage were shown to be associated with 2-nonanone (4), 2-methyl-butanal (7), nonanal (11), 2-pentylfuran (14), pyrrole (16), methyl-pyrazine (17), 2-ethyl-3-methyl-pyrazine (18), 3-ethyl-2,5-dimethyl-pyrazine (19), thiophene (21), and 2-furanmethanethiol (23). In this study, the frozen thawed topside sample had a significantly higher level of methyl-pyrazine (17), 2-ethyl-3-methyl-pyrazine (18), and 3,5-diethyl-2-methyl-pyrazine (20) than other cuts (except knuckle and rib). Moreover, large amounts of 2-furanmethaneniol (23) were also present in the meat sample, with the frozen-thawed loin and rump cuts having significantly higher levels of this compound compared to shoulder and shank cuts. The volatile, 2-furanmethaneniol (furfuryl mercaptan), was reported to be formed from the breakdown of ribose via the Maillard reaction [22]. It possesses roast, nutty, burnt, and meaty notes, which contribute to cooked goat and chicken aroma [14; 16].