Progress in the Application of Food-Grade Emulsions

Impact of hydrophilic substances on Ostwald ripening in emulsions stabilized by varied hydrophilic group surfactants

This study investigated the impact of water-soluble substances on Ostwald ripening in emulsions stabilized by surfactants with different head groups (Brij S20 and Tween 60). Adding ≥20% (w/w) corn oil to the oil phase effectively inhibited Ostwald ripening of n-decane emulsions due to compositional ripening. The presence of glucose, maltose, or glycerol in the aqueous phase of the emulsions decreased the Ostwald ripening rate, regardless of emulsifier type. However, the impact of propylene glycol depended on emulsifier type, accelerating Ostwald ripening in Brij S20-stabilized emulsions but having little effect in Tween 60-stabilized emulsions. This effect was mainly attributed to the ability of propylene glycol to alter interfacial characteristics. When emulsions were fabricated with a mixture of n-decane and corn oil, glucose and maltose were still effective in inhibiting Ostwald ripening, but glycerol lost its ability. These results have important implications for formulating emulsion-based delivery systems with enhanced shelf life.

Emerging encapsulation strategies for vitamin A fortification in food sector: an overview

Micro- and nano-encapsulation techniques, such as microfluidization, spray drying, and centrifugal extrusion, have been widely utilized in various industries, including pharmaceuticals, food, cosmetics, and agriculture, to improve the stability, shelf life, and bioavailability of active ingredients, such as vitamin A. Emulsion-based delivery platforms offer feasible and appropriate alternatives for safeguarding, encapsulating, and transporting bioactive compounds. Therefore, there is a need to enrich our basic diet to prevent vitamin A deficiency within a population. This review focused on addressing vitamin A shortages, encapsulation techniques for improving the delivery of vital vitamins A and their food applications. Additionally, more studies are required to guarantee the security of nano-delivery strategies, as they proliferate in the food and beverage sector.

Graphical Abstract

α-tending emulsifiers, microencapsulated improver powder and bakery applications

To date majority of bakery products are manufactured using emulsifiers in paste or gel form that restricts and causes many problems of storage, processing, and handling at the commercial level. Therefore, new developments are required to resolve the issues of the bakery industry. This review discusses the importance of α-tending emulsifiers in the bakery industry and the action of the α-form to produce superior quality products. Further, to produce desired results α-form of emulsifiers blend should be stable and functional at different operating and storage conditions. Emulsifiers in gel or paste form do not maintain the active α-gel phase over a longer storage period. Using emulsifiers blend in powder form can be a solution to all the mentioned difficulties. With the development of new technologies like spray drying and encapsulation has opened new doors to utilize emulsifiers blend in powder form. Few manufactures have tapped this opportunity and have developed improver powder that offers superior quality products as well as processing, storage, and handling benefits and is easy to use. Improver powder maintains its active and functional α-form when stored at ambient temperature. This development also increases the scope of dry premixes in the market and consumers can make products of their choice in the kitchen with minimal effort.

Replacement of milk fat by rapeseed oil stabilised emulsion in commercial yogurt

The incorporation of lipid droplets and further characterization of matrices within dairy products may be possible using such adjacent particles as protein complexes/lipids. Among the range of varied emulsions and their functionalities, great attention has recently focused on the fabrication of high internal phase types. Feasibly, stable alternatives structured with health-beneficial lipids like those derived from plants could replace saturated fatty acids. As a fat replacement strategy, the fate of incorporated HIPE would require some adjustments either with storage stability and/or structural feat for the food matrix. Therefore, the replacement of milk fat by rapeseed oil stabilised emulsion in commercial yogurt was investigated. This involved 25%, 50% and 75% rapeseed oil respectively assigned as low (LIPE), medium (MIPE), and high internal phase emulsion (HIPE). Specifically, emulsions were examined by droplet size, encapsulation, pH, zeta potential, phase separation, and rheology. The fat free yogurt supplemented by HIPE were examined by droplet size, zeta potential, pH, color, sensory, texture and microbiological aspects against positive (regular milk fat) and negative (fat free) yogurt controls. Results showed increasing rapeseed oil contents would form smaller droplet-like emulsions. Within the yogurt matrix however, incorporating HIPE would seemingly reduce oil droplet size without much compromise to bacterial viability, sensory, or texture. Overall, this simple method of lipid alternation shows promise in dairy products.

Lipid emulsion structure, digestion behavior, physiology, and health: a scoping review and future directions

Research investigating the effects of the food matrix on health is needed to untangle many unresolved questions in nutritional science. Emulsion structure plays a fundamental role in this inquiry; however, the effects of oil-in-water emulsion structure on broad metabolic, physiological, and health-related outcomes have not been comprehensively reviewed. This systematic scoping review targets this gap and examines methodological considerations for the field of relating food structure and health. MEDLINE, Web of Science, and CAB Direct were searched from inception to December 2022, returning 3106 articles, 52 of which were eligible for inclusion. Many investigated emulsion lipid droplet size and/or gastric colloidal stability and their relation to postprandial weight-loss-related outcomes. The present review also identifies numerous novel relationships between emulsion structures and health-related outcomes. "Omics" endpoints present an exciting avenue for more comprehensive analysis in this area, yet interpretation remains difficult. Identifying valid surrogate biomarkers for long-term outcomes and disease risk will be a turning point for food structure research, leading to breakthroughs in the pace and utility of research that generates advancements in health. The review's findings and recommendations aim to support new hypotheses, future trial design, and evidence-based emulsion design for improved health and well-being.

Stability and Digestive Properties of a Dual-Protein Emulsion System Based on Soy Protein Isolate and Whey Protein Isolate

The stability and digestive properties of a dual-protein emulsion consisting of soy protein isolate (SPI) and whey protein isolate (WPI) have been systematically studied. The results showed that the particle size and viscosity of the dual-protein emulsion system decreased continuously with the increase in WPI, and this might be related to the large amount of electric charge on the surface of the emulsion droplets. Dual-protein emulsions with ratios of 3:7 and 5:5 showed the highest emulsion activity, while emulsion stability increased with the increase in WPI. The thicker adsorption layer formed at the interface might have contributed to this phenomenon. After in-vitro-simulated digestion, the emulsion droplet particle size increased substantially due to the weakened electrostatic repulsion on the droplet surface, especially for the intestinal digestion phase. Meanwhile, WPI accelerated the release of free fatty acids in the digestion process, which played a positive role in the nutritional value of the dual-protein emulsion. In accelerated oxidation experiments, WPI also improved the antioxidant properties of the dual-protein emulsion system. This study will provide a new insight and necessary theoretical basis for the preparation of dual-protein emulsions.

Improvement of Oxidative Stability of Fish Oil-in-Water Emulsions through Partitioning of Sesamol at the Interface

The susceptibility of polyunsaturated fatty acids to oxidation severely limits their application in functional emulsified foods. In this study, the effect of sesamol concentration on the physicochemical properties of WPI-stabilized fish oil emulsions was investigated, focusing on the relationship between sesamol-WPI interactions and interfacial behavior. The results relating to particle size, zeta-potential, microstructure, and appearance showed that 0.09% (w/v) sesamol promoted the formation of small oil droplets and inhibited oil droplet aggregation. Furthermore, the addition of sesamol significantly reduced the formation of hydrogen peroxide, generation of secondary reaction products during storage, and degree of protein oxidation in the emulsions. Molecular docking and isothermal titration calorimetry showed that the interaction between sesamol and β-LG was mainly mediated by hydrogen bonds and hydrophobic interactions. Our results show that sesamol binds to interfacial proteins mainly through hydrogen bonding, and increasing the interfacial sesamol content reduces the interfacial tension and improves the physical and oxidative stability of the emulsion.