Synergistic Effect of Laccase and Sugar Beet Pectin on the Properties of Concentrated Protein Emulsions and Its Application in Concentrated Coconut Milk.

Pusen Chen,Weijun Chen,Haiming Chen,Shan Jiang,Qiuping Zhong,Wenxue Chen

doi:10.3390/molecules23102591

Abstract

Concentrated coconut milk (CCM), a raw material from coconut products, is extremely unstable because of its high oil content (>30%). In this study, three model emulsions—primary emulsions stabilized by coconut proteins only, secondary emulsions stabilized by the conjugation of sugar beet pectin (SBP) and coconut protein, and laccase-treated secondary emulsions—were prepared to investigate the effects of different factors (coconut proteins, coconut proteins + SBP, laccase-treated emulsions) on the stability of model emulsions and the application of this method to real CCM. The stability of the emulsions was evaluated based on their interfacial tension, zeta potential, particle size distribution, rheological properties, and the assembly formation of SBP and coconut protein at the oil–water interface. Results showed that addition of SBP or laccase can increase the viscosity and reduce the interfacial tension of the emulsion, and the effect was concentration dependent. Zeta potential of the emulsion decreased with the increase of protein (from −16 to −32 mV) and addition of SBP (from −32 to −46 mV), and it was reduced when laccase was added (from −9.5 to −6.0 mV). The secondary emulsion exhibited the narrowest particle size distribution (from 0.1 to 20 μm); however, laccase-catalyzed secondary emulsions showed the best storage stability and no layering when the laccase content reached 10 U/100 g. Confocal laser scanning microscopy (CLSM) revealed that protein was adsorbed on the oil–water interface and SBP distributed in the continuous phase could undergo oxidative crosslinking by laccase. These results show that the stability of the concentrated emulsion can be effectively improved by adding SBP and laccase.

Highlights

IntroductionConcentrated emulsions are widely used in the cosmetics, personal care, oil recovery, and food industries to provide desired properties (smooth and soft texture, uniformity, stability, viscosity, moisture retention, and high carrying capacity) of particular products (e.g., creams, mayonnaise, and lotions) and to reduce storage and transportation costs [1]
Concentrated emulsions are widely used in the cosmetics, personal care, oil recovery, and food industries to provide desired properties of particular products and to reduce storage and transportation costs [1]
This section describes the interfacial tension between coconut oil and a solution containing groups in sugar beet pectin (SBP) could be adsorbed onto the surface of coconut protein, a solution containing coconut protein and SBP, and a solution containing emulsion droplets, decreasing the interfacial tension between the water and oil phases

Summary

Introduction

Concentrated emulsions are widely used in the cosmetics, personal care, oil recovery, and food industries to provide desired properties (smooth and soft texture, uniformity, stability, viscosity, moisture retention, and high carrying capacity) of particular products (e.g., creams, mayonnaise, and lotions) and to reduce storage and transportation costs [1]. The increasing customer demand for natural over synthetic ingredients and the rapid growth of functional foods requiring “green” additives represents an opportunity to use bioemulsifiers extracted from natural resources. The use of proteins, polysaccharides, and their mixtures as bioemulsifiers is becoming increasingly important due to their high versatility and environmental acceptability [4]. Few applications for Pickering emulsions have been found for commercial food products

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