Influence of homogenization process and formulation on physicochemical attributes of pumpkin pulp (Cucurbita moschata) and modified starch suspensions of hawthorn yam (Dioscorea rotundata).

Background: Physicochemical stability is a key factor that determines the shelf life of colloidal systems and it is influenced by process conditions and formulation. The aim of the research was to evaluate the effect of homogenization process conditions and formulation on physicochemical attributes of suspensions of pumpkin pulp (Cucurbita moschata) and hawthorn yam (Dioscorea rotundata) starch (OSAYS) modified with 2-octenylsuccinic anhydride (E/Z) (OSA). A response surface methodology with a central composite experimental design was used to evaluate the effect of the independent variables: total solids contributed by the pumpkin pulp (TSPP) (3.5-3.8% w/w), OSAYS content (1-2% w/w) and homogenization time (t_hom) (6-10 min), on the dependent variables: viscosity (μ), moisture (X_w), pH, color coordinates (L*, a*, b*), volume arithmetic mean diameter (D_[3,4]), surface arithmetic mean diameter (D_[2,3]), zeta potential (|ζ|), spectral stability index (R) and antioxidant capacity [2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) methods]. Suspensions were prepared in a colloid mill equipped with a cooling jacket and operating at 466 × g.

Results: The suspensions were physicochemically stable, conferred mainly by the synergy between the μ and the repulsive forces of the colloidal system (negative ζ), even though the attractive forces were significant (relatively high D_{[2, 3]} and D_{[3, 4]}).

Conclusion: Experimental optimization of the suspensions defined the independent variables: TSPP: 3.8%, OSAYS: 1.39%, t_hom: 6 min, as: μ: 154.4 cP, X_w: 94.3%, pH: 4.3, L*: 61.8, a*: 6.2, b*: 30.8, D_[3,4]: 1321.9 μm, D_[2,3]: 731.9 μm, R: 0.660, ABTS: 88.6 μm Trolox and DPPH: 0.79 mg Trolox mL^-1. © 2025 Society of Chemical Industry.