## 3 Results and Discussion
### PCA Analysis  
To better visualize the biological characteristics of the rice grains, a PCA biplot is presented along with the explored classification of the data using the Euclidean distance method (Figure 2). The PCA shows the formation of four groups using the variability of five biochemical characteristics of the samples: total phenolic compounds (TPC), antioxidant activity (AA), \(\gamma\)-oryzanol, phytic acid (PA), and total dietary fiber (TDF). The total accumulated inertia is 97.8%, indicating that the first two dimensions are highly significant in explaining the majority of the data variability and precisely evaluating the most important sample locations in the factorial plane. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Source** & **Parameters** & **Concentration (mg/Kg)** \\ \hline \multirow{2}{*}{WRBC} & Cadmium (Cd) & \textless{}0.30 \\  & Arsenic (As) & \textless{}0.55 \\ \hline \multirow{2}{*}{BRBC} & Cadmium (Cd) & \textless{}0.30 \\  & Arsenic (As) & \textless{}0.55 \\ \hline \multirow{2}{*}{WRCC} & Cadmium (Cd) & \textless{}0.30 \\  & Arsenic (As) & \textless{}0.55 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Heavy metals. Figure 2: Principal component analysis. The replicates forming the groups of white rice with biological control (WRBC) and chemical control (WRCC) are the furthest from the represented variables, suggesting that they share similarly low values across the factorial plane. However, they are slightly distant from each other, indicating that they are influenced by the nature of the pest control treatment. On the right side of the plane are the groups of brown rice with biological control (BRBC) and chemical control (BRCC), with the highest values in the entire data distribution, particularly highlighting the levels of PA for the BRBC group. Although whole rice samples exhibit the highest levels of phytotic acid, it is observed that within the same type of rice, samples from grains grown under biological control show higher values. However, for the rest of the nutritional and biochemical properties, chemical control displays slightly higher values (this is also reflected in the Tukey test of Table 1). Biological control elevates PA levels due to the properties of phytotic acid as a natural antioxidant and its role as an intermediate in inositol phosphate metabolism, with derivatives involved in various signal transduction pathways, including the biological stress response, as reported by [PERSON] et al. in 2021 [36]. In addition, the use of biological agents for pest control triggers a basal hypersensitivity response in rice plants, activating genes in the penetration zones that result in the encoding of specialized enzymes [12], increasing the phytotic acid content in rice grains, as it depends on the level of expression of genes associated with limiting enzymes [22]. Figure 1 also shows that the variables TPC, \(\gamma\)-oryzanol, and TDF are grouped together, indicating correlations between these variables, i.e., the increase in the values of these variables follows a similar proportion, as shown in the correlation matrix (Table 2). However, reducing the dimensionality of the data in a biplot shows a different pattern, where a slight independence in the behavior of phytotic acid levels is indicated for brown rice samples coming from plots that employed a biological control; this is also reflected with white rice samples. This is due to the specific and complex role of rice biochemistry involving factors such as control, type, species, or source environment, making some components, such as phytic acid, not necessarily match the metabolic pathway of other components [25; 27]. Finally, the AA levels show a slight separation from the classification group and are located closer to the horizontal plane, indicating a stronger relationship with the first component.