Development of quaternary nanocomposites made up of cassava starch, cocoa butter, lemongrass essential oil nanoemulsion, and brewery spent grain fibers

Abstract

We report on production of novel quaternary nanocomposite films based on thermoplastic starch (TPS, 8% w/v) derived from cassava, cocoa butter, (CB, 30% wt.%), and lemongrass essential oil (LEO, 1:1) nanoemulsions reinforced with different concentrations of brewery spent grain (BSG, 5 or 10 wt.%) fibers, by continuous casting. The chemical composition, the morphological, thermal, mechanical properties, film barrier, biodegradability in the vegetable compound, in addition to the application in chocolates, have been widely studied. The addition of CB, LEO, and BSG caused relevant changes in the starch‐based films, such as increased extensibility (from 2.4‐BSG5 to 9.4%‐BSG10) and improved barrier to moisture (2.9 and 2.4 g.mm.kPa−1.h−1.m−2). Contrastingly, the thermal stability of the starch film was slightly decreased. The biodegradability of the herein developed quaternary nanocomposite films was the same as that of TPS films, eliminating concerns on the supplementation with active ingredients that are expected to have some biocidal effect. Despite checking antimicrobial activity only by contact under the biocomposites, chocolates packed with the films were well accepted by consumers, especially the samples of white chocolate stored in the BSG5 biocomposite. Overall, this new approach towards quaternary active, biodegradable films produced in a pilot‐scale lamination unit was successful in either improving or at least maintaining the essential properties of TPS‐based films for food packaging applications, while providing them with unique features and functionalities. Practical Application This contribution relates to new approach toward quaternary films produced in a pilot‐scale lamination unit. It relates to sustainability as it is both biodegradable and based on plant biomass, as well as produced via a clean, through high‐yield process. The four components of the edible films we developed provide it with good in properties performance, as both a passive barrier (i.e. purely physical), and active, related to the sensory attributes of food, essential to be applied in food packaging. The valorization of a BSG also adds to the relevance of our contribution within the circular bioeconomy framework.

Development of a Lemongrass/Silver Nanocomposite for Controlling a Foodborne Pathogen - Escherichia coli

“…Furthermore, the FT-IR spectrum of the LNE alone gives an intense peak from 1671 to 1731 cm −1 which was assigned to the C�O stretch of methyl esterified carboxyl groups, evident of the aromatic group of compounds. 41 As is expected, these intense peaks are also overserved for the two nanocomposites NC1 and NC2 but not for AgNPs. Thielmann et al 42 have confirmed that the presence of citral and limonene groups as evidenced by peaks 1600 and 1735 cm −1 in lemongrass oil are responsible for the antimicrobial activity.…”

“…Stretches at 1650 cm –1 , 1386 cm –1 , and 1074 cm –1 in the spectrum of AgNPs are attributed to CO, O–H, and C–O functional moieties, respectively, confirming a strong interaction between citrate and AgNPs. Furthermore, the FT-IR spectrum of the LNE alone gives an intense peak from 1671 to 1731 cm –1 which was assigned to the CO stretch of methyl esterified carboxyl groups, evident of the aromatic group of compounds . As is expected, these intense peaks are also overserved for the two nanocomposites NC1 and NC2 but not for AgNPs.…”

Advances in biopolymeric active films incorporated with emulsified lipophilic compounds: a review

“…Similarly, Norcino et al 127 observed no effect of copaiba oil nanoemulsions on the biodegradability of pectin films determined by respirometry tests at 28 °C. Mendes et al 128 also did not observe an effect of the incorporation of nanoemulsified lemongrass essential oil on the biodegradability of films based on cassava starch, cocoa butter, and reinforced with brewery spent grain fibers.…”

“…Regarding the effect of emulsions on the biodegradability of active lms, Mendes et al 53 observed that the biodegradability of the cassava starch-based lms determined in vegetal compost (soil) was not qualitatively affected by the addition of lemongrass essential oil emulsions. Similarly, Norcino et al 127 observed no effect of copaiba oil nanoemulsions on the biodegradability of pectin lms determined by respirometry tests at 28 C. Mendes et al 128 also did not observe an effect of the incorporation of nanoemulsied lemongrass essential oil on the biodegradability of lms based on cassava starch, cocoa butter, and reinforced with brewery spent grain bers.…”