Physical and techno-functional characterization of passion fruit seed by-products (Passiflora edulis): defatted flour and residual flour after phenolic extraction

Passion fruit seeds (Passiflora edulis), which are discarded by the industry, have
attracted interest as a source of oil and phenolic extracts. These processes offer the
potential for producing byproducts such as defatted flour (DPFSF) and residual
flour(RF) after phenolic extraction. This strategy ensures sustainable production and
consumption, reducing food losses and waste throughout the production and supply
chains. Our objective was to evaluate the physical and technological-functional
characteristics of passion fruit seed byproducts (DPFSF and RF). Three varieties of
yellow passion fruit (Passiflora edulis) were used: FB 300 Araguari, Imperador, and
Gigante Amarelo. The seeds were manually separated from the fruits and dried at 60°C
for 48 hours, ground in a blender, and defatted with n-hexane using a Soxhlet extractor
to obtain DPFSF. This flour was then subjected to a phenolic extraction process using

ethanol:water (70:30, v/v) in a water bath at 70°C for 4 hours. The solid residue from
this process was dried in a forced-air oven (± 40°C) for 4 hours to obtain RF. Color
analysis was performed using the CIELab colorimetric system, along with
measurements of pH, water activity, water solubility, water and oil absorption capacity,
emulsifying activity and emulsion stability, foaming capacity and foam stability, in vitro
protein digestibility by pH-drop, and degree of hydrolysis. The extraction of phenolic
compounds caused significant changes in the physical and technological properties of
the residual flour (RF). The RF exhibited lower lightness (L*=43.34) and a higher a*
value (4.26), indicating darkening and a tendency toward reddish coloration compared
to DPFSF (L*=74.14; a*=1.96). An increase in pH (6.60 vs. 5.37) and a reduction in
water activity (0.43 vs. 0.69) were also observed, which may favor greater
microbiological stability during storage. Regarding technological properties, DPFSF
exhibited higher water absorption capacity (2.07 g/g), emulsifying activity (8.18 m2/g),
and foaming capacity (13.33%), while RF exhibited higher water solubility, especially at
alkaline pH (88.80% at pH 9). As for in vitro protein digestibility and the degree of
hydrolysis, there were no differences among the samples. Thus, DPFSF proved to be
more promising for products that require water retention, foaming, and air incorporation,
such as baked goods, cakes, plant-based beverages, and emulsified meat products,
while RF showed greater potential for applications requiring higher solubility and
stability during storage, such as in instant formulations, powdered beverages, protein
supplements, and dehydrated soups. Therefore, the utilization of these byproducts
represents a sustainable, high-value-added strategy, contributing to the reduction of
agro-industrial waste and the development of functional ingredients for food products.
We would like to thank the funding agencies CAPES, CNPq, FAPEMIG and PPGN-UFV.