Comparative study on thermo-mechanical, structural and functional properties of pectin extracted from immature wasted apples and commercial pectin

Pectin yield of 22.22 ± 0.98 % (dry basis) was achieved from prematurely dropped Golden Delicious apples, having a light orange hue (hue value: 78.08 ± 0.04) and an overall color difference (ΔE) of 9.92 ± 0.01 compared to commercial pectin (CP). Extracted AP exhibited a lower equivalent weight (725.24 ± 29.73) and higher methoxy content (8.36 ± 0.28 %) in contrast to CP. However, a similar degree of esterification of 71.57 ± 0.79 and 70.55 ± 0.59 %, was observed in AP and CP respectively. Apple pectin demonstrated slight lower galacturonic acid (GalA) content of 68.10 ± 3.94 % in comparison to 72.31 ± 4.62 % of CP, which was further corroborated by reduced intensity in FTIR fingerprint region (912-1025 cm-1). Morphology revealed a sheet-like cloudy appearance indicating a significant presence of associated sugars whereas X-ray diffraction highlighted the highly amorphous nature of AP. AP and CP solutions (3-9 %) displayed a shear-thinning flow and viscoelastic behavior where the loss (G') moduli dominated over the storage moduli (G"). Owing to high degree of esterification, galacturonic acid content (>65 %) that aligns with commercial standards and viscoelastic behavior, the extracted AP holds promise for potential utilization in commercial applications. This study underscores the potential for sustainable utilization of prematurely dropped apples through pectin extraction, contributing to valorization of the wasted bioresource.

Cellulose nanocrystals reinforced chitosan/titanium dioxide bionanocomposite with enhanced interfacial compatibility: Fabrication, characterization, and application in fresh-cut apple slices

This research aimed to investigate the feasibility of using a bionanocomposite made of chitosan, CNC, and TiO2 nanoparticles to package freshly sliced apples. At the outset, the effect of varying concentrations of CNC (1, 5, and 10 %) and TiO2 (1, 3, and 5 %) on the mechanical, thermal, and water sensitivity characteristics of the chitosan bionanocomposite was studied. Among different combinations, the bionanocomposite containing 10 % CNC and 3 % TiO2 displayed significant enhancements compared to neat chitosan film. Notably, it exhibited a substantial increase in tensile strength (78.2 %), glass transition temperature (26.7 %), and melting temperature (30.0 %) compared to neat chitosan film. Additionally, it demonstrated reduced WVP (27.8 %), FWS (44.4 %), and SR (50.7 %). These improvements were attributed to the synergistic interactions among chitosan, CNC, and TiO2 nanoparticles through hydrogen and oxygen bonding, corroborated by spectral changes in the material. The photocatalytic degradation of ethylene and microbes by UV-A (intermittent) activated TiO2 contained in the developed bionanocomposite was confirmed by the retention of acceptable quality and radical scavenging activity (70 % retention) of fresh-cut apple slices up to 11 days. The developed bionanocomposite can thus preserve the quality of ethylene-producing horticultural produce.

A review on the effect of micro- and nano-plastics pollution on the emergence of antimicrobial resistance

The recent upsurge in the studies on micro/nano plastics and antimicrobial resistance genes has proven their deleterious effects on the environmental and human health. Till-date, there is a scarcity of studies on the interactions of these two factors and their combined influence. The interaction of microplastics has led to the formation of new plastics namely plastiglomerates, pyroplastics. and anthropoquinas. It has long been ignored that the occurrence of microplastics has become a breeding ground for the emergence of antimicrobial resistance genes. Evidently microplastics are also associated with the occurrence of other pollutants such as polyaromatic hydrocarbons and pesticides. The increased use of antibiotics (after Covid breakout) has further elevated the detrimental effects on human health. Therefore, this study highlights the relation of microplastics with antibiotic resistance generation. The factors such as uncontrolled use of antibiotics and negligent plastic consumption has been evaluated. Furthermore, the future research prospective was provided that can be helpful in correctly identifying the seriousness of the environmental occurrence of these pollutants.

Process Optimization for Development of Guar Gum-Based Biodegradable Hydrogel Film Using Response Surface Methodology

In the current study, a guar-gum-based biodegradable hydrogel film was prepared using an initiator (potassium persulfate), crosslinker (N-N methyl bis acrylamide), and plasticizer (glycerol) for packaging of fruits and vegetables. The effect of independent variables (initiator, crosslinker, and plasticizer) on the biodegradation (% wt. loss), color difference (ΔE), hardness (N), swelling index (%), and transparency (%) of the film was studied using Box-Behnken design, random surface methodology (RSM). The results showed significant effects on all the abovementioned parameters, and it was observed that the developed model was accurate, with a prediction error of only -3.19 to 2.99%. The optimized formulation for the preparation of hydrogel film was 0.15% initiator, 0.02% crosslinker, and 2.88% plasticizer exhibiting satisfactory biodegradability, color difference, hardness, swelling index, and transparency. Results showed that a guar-gum-based biodegradable hydrogel film has adequate physical, optical, and biodegradable properties and can be successfully utilized in the food packaging industry.

Microwave irradiation assisted intensive and quick delignification of lignocellulosic biomass, and confirmation by spectral, morphological and crystallinity characterization

The purpose of this work was to use a microwave-assisted technique to improve and accelerate lignin removal from rice straw biomass. Using a Box-Behnken experimental design, the effect of four critical process parameters, viz. microwave power (480-800 W), irradiation time (4-12 min), bleaching solution concentration (0.4-3.0 %), and bleaching time (1-5 h) on the delignification (%) was investigated, and the process was optimised using response surface methodology. The experimental data best fitted a quadratic model with an R² of 0.9964. The optimized value of process parameters (in aforementioned sequence) was found to be 671 W, 8.66 min, 2.67 %, and 1 h respectively, for the best delignification of 93.51 percent.The absence of lignin peaks (1516 and 1739 cm^-1) was corroborated by deconstructed morphological structure and higher crystallinity in the optimised delignified sample (53.7 %).