No abstract

The agroindustrial residue from the production of acerola pulp is rich in residual vitamin C. Thus, aiming its extraction and stabilization, this work proposed the nanoparticle (NP) encapsulation via ionic gelation with subsequent preparation of nanocomposites (NC) film based on galactomannan matrix. NP were characterized and their stabilities were evaluated under different storage conditions (incidence of light, temperature and oxidizing atmosphere). The results by Dynamic Light Scattering (DLS) and Scanning Electron Microscopy (SEM) indicated homogeneous morphology, spherical shape and size of ~220 nm. Regarding the stability, the UV-visible spectrophotometric analysis showed a much lower degradation rate for encapsulated vitamin C, resulting in more than 30% of preservation compared with the non-encapsulated systems at the end of 15th day of storage. In agreement, the NC films also resulted in preservation of vitamin C mainly for the test in high temperature, which maintained about 80% of the initial concentration, whereas in the non-encapsulated condition this value fell to 45%. The morphological analysis of these films by SEM indicated good distribution of the NP in the galactomannan matrix. Thus, the results indicate the feasibility of using the encapsulation method to stabilize vitamin C extracted from the agroindustrial residue of acerola.

Traditional packaging was developed to act as a protective barrier against the external environment. It was also designed to interact as little as possible with the packaged food (Khaneghah et al., 2018).However, these characteristics are no longer sufficient for new consumers, increasingly concerned and demanding environmentally friendly, healthy, sophisticated products that provide greater food security (Bhargava et al., 2020). Over the years, the need for new materials that extend the shelf life of food has emerged (Bhargava et al., 2020;Khaneghah et al., 2018). As a result, a new packaging concept emerged as active packaging.

Given the potentiality of nanoparticles (NP) to load substances as active principle of drugs, cosmetics and food, there is interest in increasing its production. Particularly in the agroindustrial area, the byproducts are source of functional compounds that must be stabilized by encapsulation, for example, to allow its application. Considering the amount of generated byproducts, it is necessary to understand the encapsulation synthesis in a high scale dimension. In this way, the active compounds vitamin C (from the byproduct of the acerola processing) and polyphenols (from the byproduct of grape processing) were nanoencapsulated into chitosan NP at three reactional volumes: 0.1; 1.0 and 10.0 dm3. The NP were characterized for yield, particle size, morphology, encapsulation efficiency and release profile. In general, the increase in scale did not influence these parameters. It is found a close similarity for NP size value between the 0.1 and 10.0 dm3 reactional volumes. For example, for the blank control, the size was 155±6 and 227±118 nm respectively for 0.1 and 10.0 dm3 reactional volumes. Similarly for the encapsulated acerola byproduct extract (373±44 and 400±83 nm) and ascorbic acid (279±29 and 217±29 nm). For the encapsulated skin grape extract, the size decreased sharply from 1040 to 308 nm. The yield per volume ratio was about 1.3 mg cm-3. Additional analysis for NP with encapsulated skin grape extract, by Scanning Electronic Microscopy, showed uniformly distributed spherical structures and the release profile was similar for all reactional volumes. Thus, the system is suitable for scale-up for NP production.

Biodegradable polymeric blends have been widely studied due to their potential of reducing pollution caused by non-biodegradable materials. The research described here describes a polymer blend that benefits both from the abundance of arrowroot starch (AS) and the good mechanical properties of poly(vinyl alcohol) (PVA). Glycerol (GLY) was used in different proportions as a plasticizer. The addition of GLY improved the mechanical properties of the blends, increasing the elongation at break up to 667%. On the other hand, the GLY addition adversely affected other properties, increasing the water vapor permeability (WVP), solubility and hydrophilic characteristics and reducing the thermal stability and the crystallinity index. The AS/PVA blend without GLY addition showed better physical-chemical properties, having strong chemical interaction between the two kinds of polymeric chains (according FTIR analysis) and a homogeneous morphology (SEM morphological analysis). In general, decreasing the AS content improved the mechanical and WVP properties, the film becoming less hydrophilic. In conclusion, the AS/PVA blends cast films, with or without GLY, are biodegradable materials suitable for packaging applications.