From Seed to Function: Biophysical Dynamics, Functional Behavior, and Thermal Characteristics of Protein Fractions From Baobab Fruit Seeds

ABSTRACT

Proteins derived from underutilized plant resources are gaining increasing attention as sustainable alternatives for functional food systems. In this study, proteins from baobab ( Adansonia digitata L.) fruit seeds were isolated and systematically fractionated to elucidate their structure–function relationships. A protein isolate was obtained from defatted baobab seed flour with a yield of 50.40% and high protein purity (89%). A separate sequential extraction of the same defatted flour generated four classical seed protein fractions, namely albumin, globulin, glutelin, and prolamin, which were comprehensively characterized for physicochemical, thermal, and functional properties. Distinct apparent isoelectric points (ca. pH 3.5–6.0) were associated with characteristic pH‐dependent aggregation and solubility behavior. The protein isolate exhibited minimum solubility (ca. 45%) near pH 4 and maximum solubility of ca. 90% under alkaline conditions, reflecting charge‐regulated intermolecular interactions. Differential scanning calorimetry revealed pronounced differences in thermal stability among fractions, with denaturation temperatures ranging from 74.48°C (albumin) to 106°C (prolamin), while the isolate showed the highest stability ( T _d  = 116.23°C). Functional analyses demonstrated strong interfacial and hydration properties. The isolate exhibited the highest emulsifying activity (69.3%), foaming capacity (68.10%), water absorption capacity (142%), and oil absorption capacity (62.51%), indicating favorable interfacial and hydration behavior. Amino acid profiling revealed a nutritionally favorable composition, particularly a high lysine content (59.10 mg g ⁻¹ protein), which is advantageous for complementing lysine‐deficient cereal proteins. Collectively, these results demonstrate that baobab seed proteins combine favorable nutritional quality with desirable techno‐functional attributes, highlighting their potential as multifunctional ingredients for plant‐based food formulations.