Natural Deep Eutectic Solvent-Assisted Pectin Extraction from Pomelo Peel Using Sonoreactor: Experimental Optimization Approach

Valorization of Food Waste: Utilizing Natural Porous Materials Derived from Pomelo-Peel Biomass to Develop Triboelectric Nanogenerators for Energy Harvesting and Self-Powered Sensing

Food waste is an enormous challenge, with implications for the environment, society, and economy. Every year around the world, 1.3 billion tons of food are wasted or lost, and food waste-associated costs are around $2.6 trillion. Waste upcycling has been shown to mitigate these negative impacts. This study's optimized pomelo-peel biomass-derived porous material-based triboelectric nanogenerator (PP-TENG) had an open circuit voltage of 58 V and a peak power density of 254.8 mW/m2. As porous structures enable such triboelectric devices to respond sensitively to external mechanical stimuli, we tested our optimized PP-TENG's ability to serve as a self-powered sensor of biomechanical motions. As well as successfully harvesting sufficient mechanical energy to power light-emitting diodes and portable electronics, our PP-TENGs successfully monitored joint motions, neck movements, and gait patterns, suggesting their strong potential for use in healthcare monitoring and physical rehabilitation, among other applications. As such, the present work opens up various new possibilities for transforming a prolific type of food waste into value-added products and thus could enhance long-term sustainability while reducing such waste.

An eco-friendly extraction method to obtain pectin from passion fruit rinds (Passiflora edulis sp.) using subcritical water and pressurized natural deep eutectic solvents

This work evaluated the efficiency of Subcritical Water Extraction (SWE) and Pressurized Natural Deep Eutectic Solvents (P-NaDESs) under different temperatures (100, 120, 140 and 160 °C) in obtaining pectin from Passion Fruit Rinds (PFR) and its residual biomass (PFR - UAPLE), and compare the results with those of Conventional Extraction (CE). The highest pectin yields, 19.1 and 27.6 %, were achieved using P-NaDES (Citric Acid:Glucose:Water) at 120 °C for PFR and its PFR-UAPLE, respectively. Regarding the Degree of Esterification (DE), pectin obtained with SWE and CE had DE below 50 %, while with P-NaDES (Citric Acid: Glucose:Water), DE was above 50 %. Higher Molecular Weights (MW) (98 and 81 kDa) were obtained with SWE and P-NaDES from PFR compared to PFR-UAPLE and CE. Galacturonic acid was the most abundant (74 to 78 %) monosaccharide obtained by SWE. In terms of morphology, water extraction provided pectin with more uniform textures, whereas extraction with acidified mixtures led to more heterogeneous surfaces. Overall, comparing SWE and P-NaDES, the obtained pectins differed in terms of monomeric composition, MW and DE. These results indicate that pectins obtained by both methods can have different applications depending on their structural characteristics.

NADES assisted integrated biorefinery concept for pectin recovery from kinnow (Citrus reticulate) peel and strategic conversion of residual biomass to L(+) lactic acid

The present study aims to establish an integrated strategy for valorization of kinnow peel waste. A total of ten natural deep eutectic solvents (NADESs) were exploited for extraction of pectin. The highest yield of pectin enriched material was reported 35.66 % w/dw using choline chloride-Maltose based NADES. The extraction process parameters and chemical composition of NADES influenced the yield and different associated physico-chemical attributes of the pectin enriched material. All the recovered pectin enriched materials found to be composed of low methoxy pectin (degree of methylation: 18.41-40.26 %) and galacturonic acid (GalA) content was in range of 67.56-78.22 %. The Principal Component Analysis (PCA) was used to categorise isolated pectin enriched materials based on similarities and differences. The liquid fraction upon pectin extraction presented a considerable amount of fermentable sugar which was further utilized for lactic acid production by microbial intervention. The microbial strain Lactobacillus amylophilus GV6 was exploited for lactic acid fermentation where the highest yield reached 55.59 g/L. A sustainable and straight-forward biorefinery concept was developed for extraction of pectin enriched material and lactic acid production from kinnow peel waste with potential application in food and biotechnological sectors.

Exploring carbohydrate extraction from biomass using deep eutectic solvents: Factors and mechanisms

Deep eutectic solvents (DESs) are increasingly being recognized as sustainable and promising solvents because of their unique properties: low melting point, low cost, and biocompatibility. Some DESs possess high viscosity, remarkable stability, and minimal toxicity, enhancing their appeal for diverse applications. Notably, they hold promise in biomass pretreatment, a crucial step in biomass conversion, although their potential in algal biomass carbohydrates extraction remains largely unexplored. Understanding the correlation between DESs' properties and their behavior in carbohydrate extraction, alongside cellulose degradation mechanisms, remains a gap. This review provides an overview of the use of DESs in extracting carbohydrates from lignocellulosic and algal biomass, explores the factors that influence the behavior of DESs in carbohydrate extraction, and sheds light on the mechanism of cellulose degradation by DESs. Additionally, the review discusses potential future developments and applications of DESs, particularly extracting carbohydrates from algal biomass.

Structure and Applications of Pectin in Food, Biomedical, and Pharmaceutical Industry: A Review

Pectin is a biocompatible polysaccharide with intrinsic biological activity, which may exhibit different structures depending on its source or extraction method. The extraction of pectin from various industrial by-products presents itself as a green option for the valorization of agro-industrial residues by producing a high commercial value product. Pectin is susceptible to physical, chemical, and/or enzymatic changes. The numerous functional groups present in its structure can stimulate different functionalities, and certain modifications can enable pectin for countless applications in food, agriculture, drugs, and biomedicine. It is currently a trend to use pectin to produce edible coating to protect foodstuff, antimicrobial bio-based films, nanoparticles, healing agents, and cancer treatment. Advances in methodology, use of different sources of extraction, and knowledge about structural modification have significantly expanded the properties, yields, and applications of this polysaccharide. Recently, structurally modified pectin has shown better functional properties and bioactivities than the native one. In addition, pectin can be used in conjunction with a wide variety of biopolymers with differentiated properties and specific functionalities. In this context, this review presents the structural characteristics and properties of pectin and information on the modification of this polysaccharide, its respective applications, perspectives, and future challenges.

Special Issue: Green Sustainable Chemical Processes

Sustainable chemical process engineering results from applying the principles of green chemistry or sustainable chemistry to chemical process engineering [...]

Use of Ionic Liquids and Deep Eutectic Solvents in Polysaccharides Dissolution and Extraction Processes towards Sustainable Biomass Valorization

A shift to a bioeconomy development model has been evolving, conducting the scientific community to investigate new ways of producing chemicals, materials and fuels from renewable resources, i.e., biomass. Specifically, technologies that provide high performance and maximal use of biomass feedstocks into commodities with reduced environmental impact have been highly pursued. A key example comprises the extraction and/or dissolution of polysaccharides, one of the most abundant fractions of biomass, which still need to be improved regarding these processes' efficiency and selectivity parameters. In this context, the use of alternative solvents and the application of less energy-intensive processes in the extraction of polysaccharides might play an important role to reach higher efficiency and sustainability in biomass valorization. This review debates the latest achievements in sustainable processes for the extraction of polysaccharides from a myriad of biomass resources, including lignocellulosic materials and food residues. Particularly, the ability of ionic liquids (ILs) and deep eutectic solvents (DESs) to dissolve and extract the most abundant polysaccharides from natural sources, namely cellulose, chitin, starch, hemicelluloses and pectins, is scrutinized and the efficiencies between solvents are compared. The interaction mechanisms between solvent and polysaccharide are described, paving the way for the design of selective extraction processes. A detailed discussion of the work developed for each polysaccharide as well as the innovation degree and the development stage of dissolution and extraction technologies is presented. Their advantages and disadvantages are also identified, and possible synergies by integrating microwave- and ultrasound-assisted extraction (MAE and UAE) or a combination of both (UMAE) are briefly described. Overall, this review provides key information towards the design of more efficient, selective and sustainable extraction and dissolution processes of polysaccharides from biomass.