Poly (lactic acid)/modified gum arabic (MG)based microcellular composite foam: Effect of MG on foam properties, thermal and crystallization behavior

Influence of 3-chloropropyl) triethoxysilane and pH on the properties of modified guar gum film

Guar gum (GG) as a polymer biopolymer is widely used in the field of bio-based packaging. However, its poor mechanical properties, barrier properties and high viscosity greatly hinder its use as an effective packaging material. Therefore, this study introduced CPTES to improve the mechanical (16.58-27.39 MPa) and tensile properties (26.80 %-30.67 %). The FTIR and XRD results indicated a strong interaction between the biofilm fractions modified by CPTES, CPTES bound to the hydroxyl groups on GG and formed a dense polysiloxane network through adsorption and grafting. OM and AFM reflect a denser and flatter film structure on the surface of the G30 film, which has the best film formation. Based on this, the pH of the solution was further adjusted to reach an alkaline environment, disrupting the intermolecular binding through electrostatic repulsion. The rheological behavior indicates that the viscosity and viscoelasticity of film solution gradually decrease with the increase in pH. OM and AFM results show that the G30/8 film has the best compact properties, while the nonporous compact film structure further improves the mechanical, barrierand and thermodynamic properties of the film. Accordingly, the findings of this study had a certain value for regulating the low viscoelasticity of GG emulsion and enhancing the stability of film formation.

Obtaining poly (lactic acid) nanofibers encapsulated with peppermint essential oil as potential packaging via solution-blow-spinning

The development of active packaging based on biodegradable material and incorporating active compounds, such as essential oil, is a new technique to ensure food safety without harming the environment. In this study, nanofiber mats of poly (lactic acid)/ polyethylene glycol (PLA/PEG) blend incorporated with peppermint essential oil (PO) at different ratios (5-20 % v/w) were produced by solution-blow-spinning (SBS) for potential packaging application. Electron microscopy showed a cylindrical and interlaced morphology for PLA/PEG/PO and a significant increase in the diameter (139-192 nm) of the nanofibers by increasing PO content. All nanofibers showed high thermal stability (278-345 °C) suitable for use in the food industry. Nuclear magnetic resonance (¹³C NMR) spectrum confirmed PO in the nanofibers after SBS. ATR-FTIR spectral analysis supported the chemical composition of the nanofiber mats. PO addition led to obtaining hydrophobic nanofibers, enhancing the contact angle to 122° and decreasing water vapor permeability (60 % reduction compared to the PLA/PEG (3.0 g.mm.kPa^-1.h^-1.m^-2). Although the PLA/PEG/20%PO nanofibers did not show halo formation in 24 h, they effectively extended the strawberries' shelf-life at 25 °C, evidencing PO release over time. It also reduced weight loss (2.5 % and 0.3 % weight loss after 5 days for PLA/PEG and PLA/PEG/20%PO, respectively) and increased firmness (8-12 N) for strawberries packed with the nanofiber mats. It is suggested that PLA/PEG films incorporating PO may be used as an active, environmentally friendly packaging material.

Nanochitosan functionalized hydrophobic starch/guar gum biocomposite for edible coating application with improved optical, thermal, mechanical, and surface property

The current work demonstrates a unique approach of utilizing nanochitosan (NCS) based edible nanomodifier for functionalizing starch (ST)/guar gum (GG) biocomposite with superior packaging properties targeting stringent edible food packaging on fresh cuts. The effectiveness of NCS in terms of structure-property-performance analysis of ST/GG biocomposites was done. The inclusion of NCS to the biocomposites of ST/GG converts its hydrophilic surface nature to hydrophobic (contact angle of ~114°) by modifying the surface features. The addition of NCS improved the thermal stability, where the observed 10% weight degradation of ST biocomposites were ~79.36, ~80.49, and ~186.89 °C for neat ST, ST/GG biocomposites, and ST/GG/NCS (3% w/v) (ST-GG-NCS3), respectively. The observed transparency of ST, ST-GG, and ST-GG-NCS3 were 21, 8, and 48%, respectively in the visible region suggesting consumer preference for transparent packaging materials. The wt% of O, C and N elements in ST-GG-NCS3 as observed by EDX spectra were ~ 50.2, ~47.6, and ~ 2.2%, respectively, which confirm the safety of the materials. Additionally, it is noteworthy to mention that the storage quality in terms of microbial growth, pH change, color attributes, and weight loss are better preserved when used as an edible coating on cut apple fruits.

Silk nanodisc based edible chitosan nanocomposite coating for fresh produces: A candidate with superior thermal, hydrophobic, optical, mechanical and food properties

This paper demonstrates the fabrication of silk nanodisc (SND) dispersed chitosan (CS) based new edible coating as a candidate for superior thermal, hydrophobic, optical, mechanical, and physicochemical properties, which further provide remarkable storage quality for banana fruits. Fabrication of SND is attained following acid hydrolysis of silk fibroin (SF), where the successful nanostructures formulations are analyzed by FESEM, FETEM and XRD analysis delivering disc shaped morphology with amplified crystallinity (~95.0%). The SF has been fabricated from waste muga cocoons using the degumming process. The superior thermal stability of SND compared to SF portray a new era in required heat resistant packaging. The effectiveness of SND is investigated on packaging properties of CS biocomposites including thermal, wettability, mechanical, color, surface morphology, and others. Wettability of SND incorporated CS biocomposite enhanced by ~ 10° suggesting improved hydrophobicity. The edible coatings are a new candidate to improve the shelf life of bananas over 7 days at 25 °C for prevailing original weight, optical property, firmness, and others.

Soybean Meal-Based Wood Adhesive Enhanced by Phenol Hydroxymethylated Tannin Oligomer for Exterior Use

Bio-based adhesives have low water resistance and they are less durable than synthetic adhesives, which limits their exterior applications. In this study, a bio adhesive was developed from soybean meal and larch tannin that was designed for exterior use. Phenol hydroxymethylated tannin oligomer (PHTO) was synthesized and then mixed with soybean meal flour in order to obtain a soybean meal-based adhesive (SPA). The results showed that the moisture absorption rate, residual rate, and solid content of SPA with 10 wt % PHTO (mass ratio with respect to the entire adhesive) were improved by 22.8%, 11.6%, and 6.8%, respectively, as compared with that of pure SPA. The wet shear strength of plywood with SPA with 10 wt % PHTO (boiling in 100 °C water for 3 h) was 1.04 MPa when compared with 0 MPa of pure SPA. This met the bond strength requirement of exterior-use plywood (GB/T 9846.3-2004). This improved adhesive performance was mainly due to the formation of a crosslinked structure between the PHTO and the protein and also PHTO self-crosslinking. The formaldehyde emission of the resulting plywood was the same as that of solid wood. The PHTO-modified SPA can potentially extend the applications of SPAs from interior to exterior plywood.