###### Abstract  
This study aims to obtain protein fractions, such as albumin, globulin, prolamin, and glutelin, from jackfruit leaf flour and protein concentrate (LPC). The protein fractions were characterised based on their protein content, amino acid profile, hydrosolubility, emulsifying, foaming, and thermal properties. The flour and LPC are mainly composed of prolamin and glutelin, respectively. The glutelin fractions presented a higher protein content and amino acid profile, featuring elevated leucine, valine, and glutamic acid levels. The glutelin fraction of LPC exhibited the highest hydrosolubility (27.7-88.6%), while globulin fractions displayed the lowest values (0.0-25.9%). The prolamin fraction of LPC showed higher foaming capacity (113.3%) and foaming stability (95.55%). The better emulsifying activity index (53.2 m\({}^{2}\)/g) and emulsion stability index (82 min) were observed in the glutelin fraction (LPC). The globulin (flour and LPC) and prolamin (flour) fractions had the highest glass transition, denaturation temperatures, and low enthalpy values. Therefore, the functional and thermal properties depend on amino acid composition and protein content. The glutelin and prolamin fractions of LPC could be used as emulsifying and foaming (respectively) agents based on vegetable proteins. LPC protein fractionation proved instrumental in obtaining proteins with superior functional properties compared to flour ones. Artocarpus heterophyllus; agro-industrial by-products; green biomass; plant protein; osborne fraction; emulsifier; glass transition temperature +
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LPC is a sustainable alternative source of animal-based protein and vital phytochemicals with nutritional and pharmacological effects. The production of the LPC, whether directly or indirectly, strongly supports sustainability and circular economy concepts, providing reassurance about the environmental benefits of this approach [7]. LPCs derived from the green biomass of lucerne (_Medicago sativa_), spinach (_Spinacia oleracea_) [8], moringa (_Moringa oleifera_) [9], and _Azolla pinmata_[10] are potential sources of edible protein. Thus, they are promising nutraceuticals or ingredients of functional and health-promoting foods. Green leaves from jackfruit (_Artocarpus heterophyllus_ [PERSON]) cultivation are a significant source of plant protein in Nayarit, Mexico. The leaves are generated during tree pruning as agro-industrial by-products. Jackfruit LPC was obtained from this biomass but had low solubility. However, the use of enzymatic hydrolysis has significantly improved the functionality of this LPC, opening new possibilities for its utilisation [11]. Enzymatic hydrolysis offers advantages such as high sensitivity, reproducibility, low production costs, and environmental friendliness compared to other protein modification methods. While these benefits apply to most plant-based proteins, optimising the process conditions, including the type of enzyme, concentration, hydrolysis time, and protein source, is crucial for obtaining improved protein ingredients. If not correctly optimised, enzymatic modification could lead to unintended negative changes, such as reduced techno-functionality, lowered nutritional quality, and loss of desirable taste and texture [12]. Moreover, enzymatic hydrolysis has significant drawbacks for sample preparation, such as long sample treatment times and low analyte recoveries. Protein fractionation provides a versatile alternative approach for enhancing the functionality of LPC. Plant protein fractionation yields albumins, globulins, prolamins, and glutelins and is adaptable to various plant sources. The solubility of these protein classes is a critical factor in creating emulsions and is crucial in the formation of suitable covalent complexes with polysaccharides, which is necessary for food formulation [13]. Each protein fraction class varies depending on the plant source, offering diverse functional properties for food applications [14]. In that sense, [PERSON] et al.