## 3 Results and Discussion
### PLSR Correlations between Chemical Composition and Sensory Perception  
#### 3.4.1 Chilled Samples  
The flavour perception of juicy and meaty were closely associated with C18:0, SFA, 20:5 (n-3), and n-3 that had positive loadings along Dimension 1. Interestingly, oxidised was negatively correlated with all fatty acids measured in this study (Figure 6a). Similar to [PERSON] et al. [38], medium and long-chain unsaturated fatty acids yielded oxidised and liver-like off flavours. Moreover, [PERSON] and [PERSON] [39] indicated that the majority of SFAs were positively correlated with flavour intensity, tenderness, and juiciness in beef. However, a negative association were observed between flavour intensity, tenderness, and juiciness, and PUFA in Hanwoo steers [40]. The majority of amino acids (isoleucine, phenylalanine, histidine, threonine, glycine, ornithine, aspartic acid, serine) found in this study were correlated to oxidised, browned, and livery flavour that had negative loadings along Dimension 1 (Figure 6a). Similarly, [PERSON], [PERSON], [PERSON], [PERSON], [PERSON] and [PERSON] [21] reported that amino acids such as serine, threonine, valine, leucine, isoleucine, and phenylalanine contributed to brown or roasted attribute. In another study, when three different lamb cuts were subjected  
Figure 6: (a) Correlation biplots of Partial Least Square Regressions (PLSR) models for PEF treated chilled samples representing fatty acids, amino acids, and volatile composition in relation to sensory attributes. (b) Correlation biplots of PLSR models for PEF treated frozen samples representing fatty acids, amino acids, and volatile composition in relation to sensory attributes. VOC codes for Figure 6a correspond to Supplementary Table S2 for chilled samples, and codes in Figure 6b correspond to Supplementary Table S3 for frozen samples. Exploratory variables with VIP less than 1 are omitted for clarity. to high-pressure treatment at 400 MPa and above, attributes such as livery, bromed, and oxidised were mainly associated with the presence of amino acids [25]. The correlation biplot (Figure 6a) of PEF treated chilled lamb samples showed that livery and bromed flavour were closely associated with 3-methyl-butanol, 2-ethylfuran, pyridine, and 3,5-diethyl-2-methyl- pyrazine that had high negative loadings along Dimension 1. The formation of 3-methyl-butanal flavour from the Strecker (Maillard) reaction is commonly related to bromed flavour [41]. The 2-ethylfuran volatile compound mainly resulted from the degradation of lipids, and they are sometimes regarded as markers of lipid oxidation [42]. [PERSON] and [PERSON] [43] found that most of the compounds associated with livery flavour in pork liver were pyrazines. The oxidised flavour was closely associated with 2-ethyl-3-methyl pyrazine that had high negative loadings along Dimension 2. The volatile, 2-ethyl-3-methyl pyrazine has been associated with earthy, oily, and nutty flavour in peanuts [44] and potatoes [45]. A correlation biplot showing how fatty acids, amino acids, and volatile composition were correlated to sensory attributes is shown in Figure 6a. Meaty and juicy attributes that had high loadings along Dimension 1 were separated from livery and bromed that had high negative loadings. Meaty and juicy attributes were associated with the presence of fatty acids. Meaty and juicy are two positive attributes of meat flavour that are correlated with the presence of fatty acids because fats can impact flavour in two ways; oxidation of fatty acids produces carbonyl compounds, which are strong flavour contributors, and fatty acids that can also act as a storage repository for odoriferous compounds, which are released on heating [46]. Fatty acids primarily influence flavour and juiciness [47]. Perceived juiciness is impacted through lubrication by fatty acids and stimulation of saliva during mastication. Volatile flavour compounds have been demonstrated to increase as overall fatty acid content increases.