## 3 Results and Discussion  
### The Yield of Protein and the Amino Acid Composition  
The moisture (8.64%), protein (24.06%), lipid (8.01%), ash (19.39%), and carbohydrate (29.92%) content of the feedstock material was previously reported [2]. The protein yield from jackfruit leaves increased as the intensity did (Table 1). The higher yield (58.0 \(\pm\) 2.4%) was obtained at 1080 W and 15 min. The yields obtained using HIU were between three and eight times higher than those obtained using the same source by the maceration process (1 N HCl) and by UAE (42 kHz for 20 min) [6]. Previously, it was reported that by increasing the power from 100 to 400 W, the extraction yields of pecan proteins were enhanced from 20.5 to 45.5%. However, increasing the power to 500 W decreased the yield of pecan proteins to under 25% [21]. In other studies, as the power increased, it was possible to obtain a decrement in protein extraction linked to protein denaturation, owing to hydrolysis or aggregation related to the formation of disulfide bridges through the oxidation of sulfur-containing amino acids in the protein, induced by hydroxyl-free radicals generated at a high ultrasound (US) power [10; 21]. The high yields linked to HIU are related to the energy input during the extraction process, which can lead to a higher yield of proteins. The increased energy input and disruption of the solid matrix can accelerate the release of compounds, owing to the enhancement of mass transport, resulting in a higher extraction rate [10]. Regarding the temperature during the extraction process, the initial temperature of the samples was 22 \(\pm\) 2 \({}^{\circ}\)C; after the treatments, an increase of 5 \(\pm\) 2 \({}^{\circ}\)C was observed, without exceeding 60 \({}^{\circ}\)C. The total temperature increment was less than 7 \({}^{\circ}\)C in all treatments. This behavior indicates that the processing was carried out under adequate temperature conditions. Temperature increments up to 60 \({}^{\circ}\)C that are caused by HIU could negatively affect the protein structure [22]. The composition of the proteins obtained from jackfruit with an intensity of 1080 W was assessed by GC-MS. Using this technique, 15 of the 20 amino acids (AA) were identified in the proteins from jackfruit leaves, of which seven (Val, Leu, Ile, Met, Thr, Phe, and Lys) corresponded to essential amino acids (EAAs, Table 2). These EAAs were reported in the proteins and modified proteins of jackfruit leaves that were obtained by maccarations and UAE [6]. However, the concentration of the EAAs obtained by HIU was significantly higher (approximately six times higher). Using emerging technologies such as HIU to valorize agro-waste is an important alternative method for providing proteins to malnourished populations. The protein concentrations in this study ranged from 22 to 58% for dry weight. Thus, the protein content in jackfruit leaves is 1.2-3.4 times higher than that of beef (17.4%), fish (19.2-20.6%), and chicken (19-24%) and is 1.23 times higher than that of entire eggs (47%) [23]. This makes jackfruit leaves a concentrated and efficient source of high-quality protein with a similar content of EAAs to _Arthospira_ sp., a microalga that has been called a \"superfood\" by the World Health Organization. The proteins of this microalga can have eight of the nine EAAs in concentrations of 10 to 55 mg of each amino acid per gram of powder [24].