Enhancing Thermal Stability and Bioaccesibility of Açaí Fruit Polyphenols through Electrohydrodynamic Encapsulation into Zein Electrosprayed Particles

Abstract

The açaí fruit (Euterpe oleracea Mart.) is well known for its high content of antioxidant compounds, especially anthocyanins, which provide beneficial health properties. The incorporation of this fruit is limited to food products whose processing does not involve the use of high temperatures due to the low thermal stability of these functional components. The objective of this work was the encapsulation of açaí fruit antioxidants into electrosprayed zein, a heat-resistant protein, to improve their bioavailability and thermal resistance. First, the hydroalcoholic açaí extract was selected due to its high polyphenolic content and antioxidant capacities, and, subsequently, it was successfully encapsulated in electrosprayed zein particles. Scanning electron microscopy studies revealed that the resulting particles presented cavities with an average size of 924 nm. Structural characterization by Fourier transform infrared spectroscopy revealed certain chemical interaction between the active compounds and zein. Encapsulation efficiency was approximately 70%. Results demonstrated the effectiveness of the encapsulated extract on protecting polyphenolic content after high-temperature treatments, such as sterilization (121 °C) and baking (180 °C). Bioaccesibility studies also indicated an increase of polyphenols presence after in vitro digestion stages of encapsulated açaí fruit extract in contrast with the unprotected extract.

Phenolic compounds: current industrial applications, limitations and future challenges

“…to protect them from thermal degradation during sterilization and baking processes. 55 In particular, anthocyanin co-pigmentation has been shown to be an efficient way to achieve stability; molecular interaction of anthocyanins with other compounds leads to the accumulation of acyl in the pyran ring, which reduces the sensitivity of this flavonoids to the nucleophilic attack of water, consequently preventing anthocyanins from forming chalcones and losing their colour. Co-pigmentation of anthocyanins with phenolic acids, catechin and β-cyclodextrin has been proposed to increase the thermal stability and colour intensity of these compounds.…”

Uniaxial and Coaxial Electrospinning for Tailoring Jussara Pulp Nanofibers

“…Remarkably, the most thermally stable ones increase their commercial interest for scaling-up process and industrial applications, since food production often require heating steps [ 29 ]. Lyophilized açaí fruit extract, possessing a high concentration of anthocyanins, presented an early degradation that started at approximately 100 °C, with maximum degradation at 162.5 °C [ 30 ]. These decomposition bands are visible only for the V4 sample ( Figure 3 e) in the region of the thermogram between 72 and 144 °C (thermal decomposition region of anthocyanins and açai extract, respectively), which is further supported the FTIR results.…”

Microencapsulation of Anthocyanins—Critical Review of Techniques and Wall Materials

“…Dicastillo et al [63] employed an electrohydrodynamic process for the encapsulation of açaí fruit extract into zein electrosprayed particles. The formation of ultrathin fibers was reported while applying zein (20% w/v).…”