Ultrasound-Assisted Preparation of Brazil Nut Oil-in-Water Emulsions Stabilized by Arabic Gum

Abstract

The objective of this work is to evaluate the stability of Brazil nut oil emulsions with gum Arabic using ultrasound-assisted homogenization. The emulsions were prepared in a completely randomized design varying the time (2 and 4 min) and the ultrasound power (30 and 40%). The physicochemical properties of the emulsions (pH, conductivity, turbidity, zeta potential, surface tension, rheology and optical microscopy) were evaluated after the homogenization process and 4 hours later. The results showed that more energetic homogenization processes (longer duration and higher ultrasound power) favored the physicochemical properties, keeping the emulsions more stable. Thus, Brazil nut oil emulsions prepared with ultrasound-assisted showed good physic-chemical characteristics that can guarantee good emulsion stability during spray drying, guaranteeing efficiency and protection of the physical and chemical properties of the Brazil nut oil.

Physicochemical characteristics and survivability of Lactobacillus paracasei encapsulated by a gum arabic-pectin mixture as wall material and added to fresh panela cheese

“…Generally, the higher the absolute value of ζ-potential (>±30 mV), the stronger the electrostatic repulsions and the more stable the emulsion (Xiong et al, 2019). Conversely, lower ζ-potential values (<±30 mV), such as those observed in this study (-20 mV), may confirm the steric mechanism as dominant in the stability of the emulsion (Sena et al, 2019). This steric mechanism in the gum arabic gum/pectin, confirmed by the negative charge of ζ-potential may be possibly due to the carboxylic acid and anionic behaviour of gum arabic and pectin biopolymers due to carboxylic acid content in their structure, which gives them a negative charge (Timilsena et al, 2016).…”

“…The values of ζ-potential refer to which of the two types of mechanisms is responsible for the stability of the emulsion. The steric mechanism comprises the adhesion of the emulsifier to the surface of droplets, and the electrostatic mechanism is associated with the electrostatic repulsion of the surface charges of the particles (Sena et al, 2019). Generally, the higher the absolute value of ζ-potential (>±30 mV), the stronger the electrostatic repulsions and the more stable the emulsion (Xiong et al, 2019).…”

“…The pH is an important factor to maintain emulsion stability since its variation may indicate chemical changes and a subsequent emulsion destabilization. Generally, emulsions have pH values between 2.5-7.5 and any change outside these values is considered an effect of system instability (Sena et al, 2019).…”

“…The generation of small droplets trough high energy homogenization processes increases the surface tension due to presence of frictional forces between the droplets caused by the large surface area. Conversely, a decrease of surface tension may induce the accumulation of emulsion droplets at the air/emulsion interface (cream) (Yang et al, 2018;Sena et al, 2019). The surface tension of pure water at 25 ºC is 72.4 mN m −1 and compared to this, the emulsifying agents such as pectin contribute to decrease this value to obtain a more stable emulsion.…”

Nanoencapsulation of Vitamin D3 by the Emulsion Inversion Point Method for Enrichment of Coconut Yogurts

“…Brazil nut is therefore the best-known food source of selenium among plant-based foods, essential for proper thyroid and immune functions . Some of the biological properties of BNO are its antioxidant and anti-inflammatory activity, which could reduce some risk factors related to cancer and cardiovascular diseases and improve cognitive functions. − …”