{"title":"Microfluidic droplet analysis on heterogeneous interfacial films composed of cyclodextrin and sodium casein where stiff meets soft","authors":"Jie Hou , Hua-Neng Xu","doi":"10.1016/j.foodhyd.2025.111183","DOIUrl":null,"url":null,"abstract":"<div><div>Interfacial films of emulsion droplets often exhibit microheterogeneity due to spatial variations in their local structure. The traditional characterization method on the films with a rheometer remains difficult as it is technically complex and requires numerous steps. Herein, we choose cyclodextrin-oil inclusion complexes (ICs) as stiff units and sodium casein (SC) as soft units to build the heterogeneous films and introduce a flow-focusing microfluidic platform to characterize the heterogeneous films upon snap-off dynamics that allows oil droplets to be aged against aqueous solutions with varying composition. We identify four distinct flow-regimes: threading, jetting, dripping and squeezing, and measure the fluidic pressure boundaries required for droplet generation. We further extract three quantitative parameters of snap-off time, shape-relaxation time and elongation as a function of the cyclodextrin (CD) and SC concentration in the dripping regime. Notably, the snap-off scenario is the form in which interfacial instabilities are manifested, and a composition change in the CD-SC solutions provokes pronounced changes in interfacial properties, which fits well with the interfacial rheology experiments in our previous study. Our results highlight the potential of microfluidic platform in high-throughput characterization of complex interfacial properties for various engineering applications.</div></div>","PeriodicalId":320,"journal":{"name":"Food Hydrocolloids","volume":"164 ","pages":"Article 111183"},"PeriodicalIF":11.0000,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Food Hydrocolloids","FirstCategoryId":"97","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0268005X25001432","RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, APPLIED","Score":null,"Total":0}
引用次数: 0
Abstract
Interfacial films of emulsion droplets often exhibit microheterogeneity due to spatial variations in their local structure. The traditional characterization method on the films with a rheometer remains difficult as it is technically complex and requires numerous steps. Herein, we choose cyclodextrin-oil inclusion complexes (ICs) as stiff units and sodium casein (SC) as soft units to build the heterogeneous films and introduce a flow-focusing microfluidic platform to characterize the heterogeneous films upon snap-off dynamics that allows oil droplets to be aged against aqueous solutions with varying composition. We identify four distinct flow-regimes: threading, jetting, dripping and squeezing, and measure the fluidic pressure boundaries required for droplet generation. We further extract three quantitative parameters of snap-off time, shape-relaxation time and elongation as a function of the cyclodextrin (CD) and SC concentration in the dripping regime. Notably, the snap-off scenario is the form in which interfacial instabilities are manifested, and a composition change in the CD-SC solutions provokes pronounced changes in interfacial properties, which fits well with the interfacial rheology experiments in our previous study. Our results highlight the potential of microfluidic platform in high-throughput characterization of complex interfacial properties for various engineering applications.
期刊介绍:
Food Hydrocolloids publishes original and innovative research focused on the characterization, functional properties, and applications of hydrocolloid materials used in food products. These hydrocolloids, defined as polysaccharides and proteins of commercial importance, are added to control aspects such as texture, stability, rheology, and sensory properties. The research's primary emphasis should be on the hydrocolloids themselves, with thorough descriptions of their source, nature, and physicochemical characteristics. Manuscripts are expected to clearly outline specific aims and objectives, include a fundamental discussion of research findings at the molecular level, and address the significance of the results. Studies on hydrocolloids in complex formulations should concentrate on their overall properties and mechanisms of action, while simple formulation development studies may not be considered for publication.
The main areas of interest are:
-Chemical and physicochemical characterisation
Thermal properties including glass transitions and conformational changes-
Rheological properties including viscosity, viscoelastic properties and gelation behaviour-
The influence on organoleptic properties-
Interfacial properties including stabilisation of dispersions, emulsions and foams-
Film forming properties with application to edible films and active packaging-
Encapsulation and controlled release of active compounds-
The influence on health including their role as dietary fibre-
Manipulation of hydrocolloid structure and functionality through chemical, biochemical and physical processes-
New hydrocolloids and hydrocolloid sources of commercial potential.
The Journal also publishes Review articles that provide an overview of the latest developments in topics of specific interest to researchers in this field of activity.