Vegetable Lignocellulosic Residues and Chitosan as Valuable Resources in the Superabsorbent Bio-aerogel Development for Food Conservation

Abstract

Superabsorbent bio-aerogels were developed from TEMPO-oxidized cellulose nano bers (isolated from vegetables lignocellulosic residues) and two different commercial chitosan reactants (low and high molecular weight) by polyelectrolyte complex formation at room temperature. Three different thickness values were considered, and two different aging times were employed, thus leading to twelve different bio-aerogels samples. Remarkably, no crosslink agents nor organic solvents were used. All the developed materials were characterized and deeply studied. The bio-aerogels components were strongly interacting through hydrogen bonding, leading to highly porous and stable materials able to absorb high amounts of water and soybean oil. Then, the speci c tests to visualize the material's potential use as food absorbent pads showed: i) they were able to absorb simulated food exudates under a speci c pressure in higher quantities (≈ 4000%) than some commercial pads (≈ 1600%); ii) the materials have low to moderate antibacterial activities exposing better reduction effectiveness for Listeria monocytogenes than for Salmonella typhimurium; and iii) the antioxidant properties were in general low. In the light of all the results achieved, the bio-aerogels prepared from H-CH with an aging time of 24 h and whose thickness was around 2.1 mm (H-10g-24) were selected as the most appropriate for the desired application. 1.0-IntroductionConsumers criteria to buy a certain product have evolved over time. People have different ways to satisfy the same need since their intrinsic history and speci c consumption behavior, as well as the social in uences under which they are immersed, determine their wants. In this sense, buying a food product in many cases not only implies paying attention to the good's both price and quality, but it is also necessary to take notice about the product's precedence, freshness, safety, packaging, and environmental impact characteristics, among many others. Several of the above-mentioned characteristics have a close relation one with each other and, from some decades up to now, have been attracting increasing attention . For example, meat products have incorporated absorption pads as part of their packaging to entrap their possible exudates and, thus, to avoid visible drip or blood as well as undesired bad odors. Furthermore, some pads contain active compounds able to delay microbial growth and, at the same time, to extend the food shelf life (Yao et al. 2021). However, these pads are usually made of synthetic polymers making them harmful to the environment due to their non-biodegradable nature. Then, the moving towards equally useful, bio-based, and environmentally friendly food packaging materials is highly desired.The extraction of biopolymers from residue involves various positive ecological impacts, such as the reduction of i) residues accumulation due to its exploitation; ii) the use of non-renewable resources; and iii) non-biodegradable packaging waste. It is important to remark that this practice is not com...

Revalorization of Yerba Mate Residues: Biopolymers-Based Films of Dual Wettability as Potential Mulching Materials

“…The temperature at which each degradation rate is fastest, T max , is clearly observed in the DTGA curves, ( Figure 7 b) being 327, 364, 207, 207 and 287 °C for the bilayer material, the hydrophobic layer, the hydrophilic layer, TO-YCNF and CH films, respectively. CH and the hydrophobic layer both presented thermal events in accordance with those previously observed [ 51 , 59 , 60 , 61 ]. On the other hand, TO-YCNF and the hydrophilic layer presented the same T max value, which is smaller than others reported for TO-CNF prepared from cotton stalks (near 230 °C) and from a vegetable residue mixture (two main events with similar intensities at 234 and 291 °C) [ 51 , 62 ].…”

“…Then, TO-YCNF was prepared from the bleached pulp, and it was fully characterized ( Table 2 ). The nanofibrillation yield (61%) was similar to others obtained when a mixture of vegetable residues was employed as starting raw material for TO-CNF, whereas the optical transmittance (52%) was smaller than in the mentioned study [ 51 ]. The transmittance of the CNF suspension (T 800 ) is directly related to the nanofibrillation degree: as the nanofibrillation yield decreases, the optical transmittance diminishes due to the poor light dissipation achieved by the fibers [ 38 ].…”

“…The interaction of the anions on the fibers’ surface with the external nearest area is high since the CD value is 1492 µeq/g, indicating the effectiveness of the TEMPO-mediated oxidation treatment for the introduction of carboxyl groups. The obtained value is higher than the one observed for similar TO-CNF obtained from different vegetable residues [ 51 , 53 , 54 ]. The specific surface of the TO-YCNF (634 m 2 /g) is higher than the one reported for other TO-CNF, whilst the CC (190 µeq/g) value is intermediate, thus revealing the success of the TEMPO-mediated oxidation treatment [ 51 , 53 , 54 ].…”

“…The specific surface of the TO-YCNF (634 m 2 /g) is higher than the one reported for other TO-CNF, whilst the CC (190 µeq/g) value is intermediate, thus revealing the success of the TEMPO-mediated oxidation treatment [ 51 , 53 , 54 ]. Regarding the fibers’ morphology, their length (798 nm) is between other values reported for TO-CNF prepared by the same procedure from a mixture of vegetable residues (614 nm) and wheat straw (1033 nm), whereas their diameter is smaller (3.94 nm) than the one observed in the mentioned cases (5–6.81 nm) [ 51 , 53 ].…”

“…The hydrophobic layer was first prepared from a PLA solution (1.5 wt% in Ethyl Acetate) by being cast (20 mL) in a Petri dish. Once the PLA film was air-dried, the hydrophilic layer was built onto it by pouring the CH/TO-YCNF mixture prepared based on the experience of our previous studies [ 51 ]. For this, equal mass quantities (15 g) of a CH solution (1.0 wt% in acetic acid 1 v / v %) and the TO-YCNF suspension were mixed during 3 min at 10,000 RPM in an Ultra-Turrax homogenizer (IKA T18 digital Ultra Turrax, Wilmington, NC, USA).…”