Contents lists available at ScienceDirect Food Hydrocolloids journal homepage: www.elsevier.com/locate/foodhyd Genipin-crosslinked ovotransferrin particle-stabilized Pickering emulsions as delivery vehicles for hesperidin Zihao Wei, Yujia Cheng, Jieyu Zhu, Qingrong Huang * Department of Food Science, Rutgers University, 65 Dudley Road, New Brunswick, NJ, 08901, United States ARTICLE INFO Keywords: Genipin Ovotransferrin particles High internal phase pickering emulsion Microstructure Rheological property Hesperidin bioaccessibility ABSTRACT The present work aimed to fabricate genipin-crosslinked ovotransferrin (OVT) particle-stabilized Pickering emulsions as delivery vehicles for hesperidin. Nearly monodisperse ovotransferrin colloidal particles were prepared by employing genipin crosslinking, and reaction mechanism for the crosslinking of ovotransferrin with genipin was proposed. Genipin-crosslinked OVT particles were found to be efficient Pickering stabilizers at different oil fractions, and high internal phase Pickering emulsions (oil fraction φ = 0.75) with emulsified phase volume fraction of 100% could be solely stabilized by these particles. Visual observation and microscopic image indicated that genipin-crosslinked OVT particle-stabilized high internal phase Pickering emulsion (particle concentration c = 2.0 wt%, oil fraction φ = 0.75) was stable during one-month storage at room temperature. Optical microscopy and rheological measurements revealed that microstructures and rheological properties of genipin-crosslinked OVT particle-stabilized Pickering emulsions were dependent on both protein particle con- centration and internal oil phase volume fraction. Genipin-crosslinked OVT particle-stabilized high internal phase Pickering emulsions were also stable at various pHs (2.0–4.0) and ionic strengths (0–200 mM). Optical microscopy showed that increase of pH or ionic strength resulted in a slight decrease in emulsion droplet sizes. In vitro digestion study showed that these OVT particles-stabilized high internal phase Pickering emulsions could improve both extent of lipolysis and hesperidin bioaccessibility significantly. 1. Introduction Pickering emulsions have various advantages such as promotion of controlled and sustained drug release, targeted nutraceutical delivery as well as outstanding stability, thus Pickering emulsions have been widely applied in food, pharmaceutical and cosmetic fields (Marto, Ascenso, Simoes, Almeida, & Ribeiro, 2016; Wei & Huang, 2019a, 2019b; Xiao, Li, & Huang, 2016a). Formation of Pickering emulsions can be affected by solvent properties (ionic strength, pH, etc.), and modification of Pickering stabilizers helps to regulate physicochemical properties of Pickering emulsions (Bertolino, Cavallaro, Lazzara, Milioto, & Parisi, 2017; Lazzara et al., 2018). High internal phase Pickering emulsions refer to Pickering emulsions with dispersed phase volume fraction above 0.74 (Cameron, 2005; Ikem, Menner, & Bismarck, 2008). High internal phase Pickering emulsions are called gel emulsions due to highly viscous nature, and high internal phase Pick- ering emulsions can be employed as templates to synthesize porous polymers (Cameron, 2005). However, application of high internal phase Pickering emulsions is associated with some challenges. It has already been reported that phase inversion of high internal phase Pickering emulsions may occur, leading to deterioration of emulsion stability (Binks & Lumsdon, 2000). In addition, although high internal phase Pickering emulsions can be stabilized by chitin nanocrystals, gliadin colloidal particles and functionalized silica particles, the types of emulsifiers for stabilization of high internal phase Pickering emul- sions are still limited (Hu et al., 2016; Ikem et al., 2008; Perrin, Bizot, Cathala, & Capron, 2014). Hence, more research efforts are required to develop eligible emulsifiers to stabilize high internal phase Pickering emulsions perfectly. Protein colloidal particles such as zein or kafirin particles have proved to be effective Pickering emulsifiers (de Folter, van Ruijven, & Velikov, 2012; Xiao, Wang, Gonzalez, & Huang, 2016b). Anti-solvent precipitation is a major method to fabricate protein particles for pro- lamins (de Folter et al., 2012; Xiao et al., 2016b), and protein–protein crosslinking technique can be utilized to synthesize protein particles for many other proteins (Gerrard, 2002). Glutaraldehyde is a common protein–protein crosslinker due to excellent grafting efficiency and low cost, but adverse health effects of glutaraldehyde have hindered its application (Takigawa & Endo, 2006). Biocompatible crosslinkers should be discovered as substitutes of glutaraldehyde. As a natural https://doi.org/10.1016/j.foodhyd.2019.04.008 Received 6 February 2019; Received in revised form 8 March 2019; Accepted 2 April 2019 * Corresponding author. E-mail address: qhuang@sebs.rutgers.edu (Q. Huang). Food Hydrocolloids 94 (2019) 561–573 Available online 03 April 2019 0268-005X/ © 2019 Elsevier Ltd. All rights reserved. T