Enhancement Effect of Chitosan Coating on Inhibition of Deoxynivalenol Accumulation by Litsea cubeba Essential Oil Emulsion during Malting

The purpose of this work was to study the enhancement effect of chitosan coating on inhibition of deoxynivalenol (DON) accumulation by Litsea cubeba essential oil emulsion during malting. Firstly, the primary emulsion suitable for malting process was screened and the improvement effect of chitosan coating on the properties of primary emulsion was studied. On this basis, chitosan-based Litsea cubeba essential oil emulsion was applied to malting processing. The results showed that the primary emulsion of Litsea cubeba essential oil had good antifungal properties and a minimal effect on the germinability of barley compared with other primary emulsions. The addition of chitosan can improve the physical stability and antifungal ability of the emulsion and reduce the effect of the emulsion on barley germination. When 100 g of chitosan-based Litsea cubeba essential oil emulsion (40 mg/g) was applied to the malting process, the germination rate of barley was 87.7% and the DON concentration of finished malt was reduced to 690 μg/kg, which was 20.9% lower than that of the control. Meanwhile, the other indexes of malt produced by secondary emulsion treatment (after adding chitosan) increased significantly compared with those of malt produced by primary emulsion. This study was of great significance for the application of emulsion to inhibit the accumulation of mycotoxin during malting.

A Microstructural Study of the O/W Primary Emulsion on the Formation of Oil-in-Water-in-Oil Multiple Emulsion

Aim: This study aimed to investigate the influence of the preparation process and composition on the microstructure of the O/W primary emulsions and the corresponding impact on the formation of oil-in-water-in-oil (O/W/O) multiple emulsions. Objectives: Multiple emulsions were prepared by a two-step emulsification method and the microstructure was characterized by the microscope. Methods: The primary emulsion was prepared by four kinds of preparation methods, which including both high-energy and low-energy emulsification, and then the primary emulsion was re-emulsified by stirring in the outer phase. Result: Through the theoretical investigation and the corresponding verification experiments of the interfacial film, the geometric reason for that the O/W/O multiple emulsion was relatively difficult to prepare has been found. The microstructure of O/W particles was more obvious, and the particle size were smaller with the increase of the hydrophilic emulsifier amount which was beneficial to the formation and stability of O/W/O structures. However, the excess emulsifier existed in the water phase could interfere the stability of the W/O interface. Moreover, the viscosity of inner oil phase had a large influence on the formation of O/W/O emulsion by affecting the particle size of the primary emulsion and the dynamic equilibrium between the inner and outer oil phase. Conclusion: It can be concluded that fine multiple emulsions formed when the particle size of the primary emulsion was moderate since the large particles would breaking through the outer interface membrane and small particles would combining with the outer oil phase due to the Ostwald ripening.

Influence of Process Parameters on the Characteristics of Hydrophilic Drug-Loaded Microparticles through Double Emulsion Solvent Evaporation Technique

The purpose of this study was to investigate the influence of process parameters on the characteristics of microparticles using double emulsion solvent evaporation method for encapsulation of hydrophilic drug. Donepezil hydrochloride (DPH), a reversible cholinesterase inhibitor, was selected as a model hydrophilic drug. Prior to conducting an experiment, the target particle size of microparticles was set at approximately 200 μm. The investigated process parameters include pH of outer water phase, stirring time, polymer amount, and volume of outer water phase. The results showed that DPH-loaded microparticles was successfully prepared in two steps. In the first step, the primary emulsion was prepared by dissolving DPH in distilled water before emulsifying in dichloromethane (DCM) containing different amounts of poly(butylmethacrylate-co-2-dimethylaminoethyl-methacrylate-co-methyl-methacrylate) (PBM-DM-MM) using ultrasonic probe. In the second step, the primary emulsion was emulsified in polyvinyl alcohol (PVA) solution by overhead stirrer to prepare double emulsion. After solvent evaporation, the microparticles were collected by centrifugation and washed with distilled water. Based on the statistical analysis, stirring time, polymer amount and volume of outer water phase were the main significant parameters influencing particle size of microparticles.

Effect of pH on the stability of W1/O/W2 double emulsion stabilized by combination of biosilica and Tween-20

Indonesia is amongst agricultural countries whose majority of the population consume rice as their staple food. Rice rice production tends to increase year by year followed by the increasing of their byproducts such as rice husks. The majority of rice husk waste has been generally thrown away by burning on site which cause pollution and may negatively impact on the environmental sustainability. In fact, rice husk waste contains of about 20% silica which potentially be used as emulsion stabilizers. Biosilica could stabilize the interface between water and oil due to their hydrophilicity and hydrophobicity characteristics in nature. However, their wettability was greatly influenced by pH. In this experiment, the effect of pH of the outer continuous phase (W2) was investigated. The primary emulsion (W1/O) was prepared by mixing a 40% water phase containing gelatin 3% w/w relative to the aqueous phase and Tween-20 of 1.1% w/w relative to the primary emulsion with the remaining oil phase for 5 minutes. The primary emulsions were then dispersed into the aqueous phase (W2) of various pH (2; 3; and 5.7) by using a mixture of Tween-20 and biosilica as emulsifiers. The result showed that the most stable double emulsion was obtained upon the acidic pH of 2. There was no differences between the stability of double emulsion prepared at pH 2 and that of pH 3 after 7 days. However those prepared without pH adjustment (5.7) tended to be instable in the long-term. This implied that acidic pH would increase the packing density of biosilica in the interfaces thus enhancing the barrier properties of the droplets against coalescences. A stable food grade double emulsion would be very beneficial to develop low-fat emulsion products in various food applications. Furthermore, the inner aqueous phase could be used as a vehicle to encapsulate bio-active agents such as nutrients or antioxidants for the advancement of developments of functional food products.