Development and characterization of W/O/W double emulsion of watermelon rind powder
Karnam Sangwan, Renu Garhwal, Rahul Mehra, Yash Pal, Anuradha Bhardwaj, Varij Nayan, Naveen Kumar, Shiv Kumar, Gülden Gökşen, José M. Lorenzo, Harish Kumar
Abstract
Watermelon rind and seeds are agro-industrial waste, which can be used as a source of polyphenolic compounds and citrulline with several beneficial effects on health. This investigation aimed to evaluate the feasibility of preparation of double emulsions (DEs) encapsulating lyophilized watermelon rind powder (WRP) using watermelon seed oil (WSO) by two-step emulsification method. WRP was added in concentrations of 2%, 2.5%, and 3%, and PGPR, a hydrophobic emulsifier, was added in concentrations of 2%, 3%, and 4% to the oil phase. To maximize the combinations during the preparation of stable DEs, sodium caseinate (SC), pectin, and gum arabic were utilized as emulsifiers and stabilizers in the outer phase at various concentrations (0.5–4%). General emulsion stability was analyzed by determining the emulsion properties, sedimentation stability, droplet size, viscosity characteristics, microscopy, and zeta potential. DEs prepared by the combination of SC at 3% as an emulsifier for the outer phase, PGPR at 4% in the middle oil phase, and WRP at 2.5% in the external phase, exhibited better emulsification properties. DEs of WRP and WSO formulations could be regarded as appropriate food-grade systems.