## 3 Results and Discussion
### Integrated Metabolomics and Flavoromics of Germinated Sacha Inchi Seeds
Amino acids increased up to 6 DAG, except for valine and isoleucine, which reduced at 4 DAG. Glycine, isoleucine, proline, and leucine levels changed from 0 DAG to 8 DAG. Some organic acids (phosphoric, succinic, malic, and 2-aminoadipic acids) significantly increased during germination, while citric acid decreased. Citric and malic acids are major organic acids with high abundance in the TCA cycle. A similar trend of citric acid decrease and malic acid increase is seen in barley [33]. The increase in succinic acid during germination, an intermediate product of the TCA cycle, can improve the TCA cycle rate [31]. Figure 4B presents changes in volatile compounds in sacha inchi seeds at different germination times. A number of volatile compounds developed during germination, which may be related to the macronutrient composition of the seeds. Macronutrients such as starch and protein have a strong affinity to flavor compounds and can trap them through reversible hydrogen bonding and hydrophobic interactions, holding a higher polarity aroma than inclusion complexes. During germination, starch and protein are hydrolyzed into small molecules by \(\alpha\)-amylase and protease, respectively. Trapped flavor compounds can be released throughout germination [34; 35; 36]. We identified 35 volatile compounds, \(\sim\)25.7% at 0 DAG and \(\sim\)60% at 6 DAG and 8 DAG. The largest groups were alcohols (34%), aldehydes (25.7%), and volatile acids (22.8%). At 0 DAG, aceton and (E,E)-3,5-ocatolen-2-one displayed the highest concentration, which contributed woody/creamy and earthy/green pepper odors. The highest levels of hexanal, (E)-2-hexanal, and 1-octent-3-ol developed at 4 DAG, associated with green pea, grass, and mushroom odors. At 6 DAG and 8 DAG, 6 alcohols, 5 aldehydes, and 8 volatile acids were detected: 1-penten-3-ol, 1-pentanol, 3-hexen-1-ol, (Z)-2-heptenal, and 2-octen-1-ol are associated with green, beany, and grassy odors, providing rancid and off-flavors. Aldehydes and alcohols are derived from LOX activity and oxidation of fatty acids and generally cause rancidity [37]. These compounds are formed during LOX-mediated degradation of polyunsaturated fatty acids [38; 39] and are expected to directly correlate with the quality attributes of final germinated seeds. The observed acidity of germinated sacha inchi seeds could be a significant technical difficulty in producing germinated products, mainly due to the increase in volatile acids at the final stages of germination. Germinated brown rice [17] and germinated chickpea, lentil, and yellow pea [9] also show increased hexanoic, heptanoic, octanoic, and nonanoic acids at the final stages of germination; however, these have a low odor threshold (<1). The changes influence this phenomenon in lipid degradation in sacha inchi seeds during germination [40]. Upon germination, the concentration of certain pleasant flavors in sacha inchi seeds increased, such as a soy-sauce-like odor and a peach flavor, which indicated furfural and 2(3H)-furanone,5-ethyldihydro, respectively. Figure 5 shows the relation of all metabolites and flavor compounds during germination of sacha inchi seeds. Flavor compounds were mainly related to the lipid composition. FAMEs had a strong positive correlation (r > 0.7) with alcohols, ketones, butylrolactone, and pyrazine-2-methoxy-3-(1-methylethyl). However, FAMEs had a strong negative correlation (r < -0.7) with aldehydes, volatile acids, 2(3H)-furanone,5-ethyldihydro, and pyridine. In general, lipolysis and lipid oxidation produce rancidity and sourness attributed to aldehydes, alcohols, and volatile acids during germination [41]. During germination, volatile acids are formed via the lipolysis pathway. Aldehyde and alcohol formation during germination is correlated with the oxidation of oleic, linoleic, and linoleic acids as the main substrates through LOXs. These aldehydes and alcohols provide rancid and off-flavors to germinated sacha inchi seeds [42].