Recent progress in pectin extraction, characterization, and pectin-based films for active food packaging applications: A review

Prospects of yam (Dioscorea) polysaccharides: Structural features, bioactivities and applications

Yam (Dioscorea) is a tuber crop cultivated for food security, revenue, and medicinal purposes. It has been used to treat diabetes, asthma, diarrhea, and other diseases. The main active ingredients in yam, polysaccharides, are regarded to be the important reason for its widespread applications. Now, a comprehensive review of research developments of yam polysaccharides (YPs) was presented to explore their prospects. We outlined the structural characteristics, biological activities, structure-activity relationships, and potential applications. Around 13 neutral components and 17 acidic components were separated. They exhibited various bioactivities, including immunomodulatory, hypoglycemic, hypolipidemic, antioxidant, gastrointestinal protective, anti-fatigue, and senile disease treatment activities, as well as prebiotic effect. Structure-activity relationships illustrated that unique structural properties, chemical modifications, and carried biopolymers could influence the bioactivities of YPs. The potential applications in medicine, food, and other fields have also been summarized.

Investigation into pectin extraction and technological implementations in the food industry

Pectin, a complex polysaccharide found abundantly in the cell walls of fruits and vegetables, plays a pivotal role in various food applications owing to its unique gelling, thickening and stabilizing properties. As consumer preferences lean towards natural and sustainable ingredients, the demand for pectin as a food additive has surged. This burgeoning interest has prompted a comprehensive exploration into both the extraction methods of pectin from its natural sources and its diverse technological applications in the food industry. The extraction process involves breaking down the plant cell wall to release the pectin. Traditional methods such as hot acid extraction have been widely used, but advances in technology have spurred the development of novel techniques like enzyme-assisted extraction and microwave-assisted extraction. These methods aim not only to enhance the yield and purity of extracted pectin but also to minimize environmental impact and energy consumption. Pectin's versatility has positioned it as a valuable ingredient in the food industry. Its ability to form gels under specific conditions makes it a key component in the production of jams, jellies and fruit preserves. Additionally, pectin acts as a stabilizer in dairy products, prevents syneresis in baked goods and improves the texture of confectionery items. The application of pectin goes beyond its role as a gelling agent; it is also employed in the encapsulation of bioactive compounds, enhancing the functional properties of various food products. © 2024 Society of Chemical Industry.

Impacts of ultrasound-assisted Fenton degradation and alkaline de-esterification on structural properties and biological effects of pectic polysaccharides from Tartary buckwheat leaves

Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn) leaf has abundant rhamnogalacturonan-I enriched pectic polysaccharides, which exert various health-promoting effects. Nevertheless, the potential relationship between the chemical structure and the biological function of pectic polysaccharides from Tartary buckwheat leaves (TBP) remains unclear. Therefore, to bridge the gap between the chemical structure and the biological function of TBP, the impacts of ultrasound-assisted Fenton degradation (UFD) and mild alkaline de-esterification (MAD) on structural properties and biological effects of TBP were systematically studied. Compared with the native TBP (molecular mass, 9.537 × 104 Da), the molecular masses of degraded TBPs (TBP-MMW, 4.811 × 104 Da; TBP-LMW, 2.101 × 104 Da) were significantly reduced by the UFD modification, while their primary chemical structures were overall stable. Besides, compared with the native TBP (esterification degree, 22.73 %), the esterification degrees of de-esterified TBPs (TBP-MDE, 14.27 %; TBP-LDE, 6.59 %) were notably reduced by the MAD modification, while their primary chemical structures were also overall stable. Furthermore, the results revealed that both UFD and MAD modifications could significantly improve the antioxidant, antiglycation, and immunostimulatory effects of TBP. Indeed, TBP's biological effects were negatively correlated to its molecular mass and esterification degree, while positively linked to its free uronic acids. The findings demonstrate that both UFD and MAD modifications are promising techniques for the structural modification of TBP, which can remarkedly promote its biological effects. Besides, the present results are conducive to better understanding TBP's structure-bioactivity relationship.

Polysaccharide-Based Edible Biopolymer-Based Coatings for Fruit Preservation: A Review

Over the last decades, a significant rise in fruit consumption has been noticed as they contain numerous nutritional components, which has led to the rise in fruit production globally. However, fruits are highly liable to spoilage in nature and remain vulnerable to losses during the storage and preservation stages. Therefore, it is crucial to enhance the storage life and safeness of fruits for the consumers. To keep up the grade and prolong storage duration, various techniques are employed in the food sector. Among these, biopolymer coatings have gained widespread acceptance due to their improved characteristics and ideal substitution for synthetic polymer coatings. As there is concern regarding the safety of the consumers and sustainability, edible coatings have become a selective substitution for nurturing fruit quality and preventing decay. The application of polysaccharide-based edible coatings offers a versatile solution to prevent the passage of moisture, gases, and pathogens, which are considered major threats to fruit deterioration. Different polysaccharide substances such as chitin, pectin, carrageenan, cellulose, starch, etc., are extensively used for preparing edible coatings for a wide array of fruits. The implementation of coatings provides better preservation of the fruits such as mango, strawberry, pineapple, apple, etc. Furthermore, the inclusion of functional ingredients, including polyphenols, natural antioxidants, antimicrobials, and bio-nanomaterials, into the edible coating solution matrix adds to the nutritional, functional, and sensory attributes of the fruits. The blending of essential oil and active agents in polysaccharide-based coatings prevents the growth of food-borne pathogens and enhances the storage life of the pineapple, also improving the preservation of strawberries and mangoes. This paper aims to provide collective data regarding the utilization of polysaccharide-based edible coatings concerning their characteristics and advancements for fruit preservation.

Application of bacteriophages in biopolymer-based functional food packaging films

Recently, food spoilage caused by pathogens has been increasing. Therefore, applying control strategies is essential. Bacteriophages can potentially reduce this problem due to their host specificity, ability to inhibit bacterial growth, and extend the shelf life of food. When bacteriophages are applied directly to food, their antibacterial activity is lost. In this regard, bacteriophage-loaded biopolymers offer an excellent option to improve food safety by extending their shelf life. Applying bacteriophages in food preservation requires comprehensive and structured information on their isolation, culturing, storage, and encapsulation in biopolymers for active food packaging applications. This review focuses on using bacteriophages in food packaging and preservation. It discusses the methods for phage application on food, their use for polymer formulation and functionalization, and their effect in enhancing food matrix properties to obtain maximum antibacterial activity in food model systems.

Antifungal efficacy of chitosan extracted from shrimp shell on strawberry (Fragaria × ananassa) postharvest spoilage fungi

The strong demand for biological materials in the food industry places chitosan at the forefront of other biopolymers. The present study aims to evaluate the antifungal properties of chitosan extracted from shrimp shell waste (Parapenaeus longirostris) against post-harvest strawberry (Fragaria × ananassa) spoilage fungi. The physicochemical characteristics (DD, Mw, and solubility) of extracted chitosan were determined. In addition, functional characteristics were studied by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The antifungal effect of chitosan on mycelial growth and spore germination of Aspergillus niger, Botrytis cinerea, Fusarium oxysporum, and Rhizopus stolonifer was evaluated. Yield, degree of deacetylation, molecular weight, and solubility were 21.86%, 83.50%, 180 kDa, and 80.10%, respectively. A degree of deacetylation of 81.27% was calculated from the FTIR spectrum and a crystallinity index of 79.83% was determined from the X-ray diffraction pattern. SEM images of extracted chitosan showed a combination of fibrous and porous structure. At 3% chitosan, mycelial growth inhibition rates of A. niger, B. cinerea, F. oxysporum, and R. stolonifer ranged from 81.37% to 92.70%. At the same chitosan concentration, the percentages of spore germination inhibition of the isolated fungi ranged from 65.47% to 71.48%. The antifungal activity was highly dose-dependent. As a natural polymer, chitosan offers a convincing alternative to synthetic antimicrobials for the post-harvest preservation of strawberries. Its potential lies in its ability to inhibit the growth of spoilage fungi.

Comparative Analysis of Physicochemical and Functional Properties of Pectin from Extracted Dragon Fruit Waste by Different Techniques

Dragon fruit peel, often discarded, is a valuable source of commercial pectin. This study investigates different extraction methods, including cold-water (CW), hot-water (HW), ultrasound (US), and novel enzyme extraction (xylanase: EZX), to extract pectins from dragon fruit peel and compare their characteristics. The pectin yield ranged from 10.93% to 20.22%, with significant variations in physicochemical properties across methods (p < 0.05). FTIR analysis revealed that extraction methods did not alter the primary structural configuration of the pectins. However, molecular weights (Mws) varied significantly, from 0.84 to 1.21 × 103 kDa, and the degree of esterification varied from 46.82% to 51.79% (p < 0.05). Monosaccharide analysis identified both homogalacturonan (HG) and rhamnogalacturonan-I (RG-I) pectic configurations in all pectins, predominantly comprising galacturonic acid (77.21-83.12 %mol) and rhamnose (8.11-9.51 %mol), alongside minor side-chain sugars. These properties significantly influenced pectin functionalities. In the aqueous state, a higher Mw impacted viscosity and emulsification performance, while a lower Mw enhanced antioxidant activities and promoted the prebiotic function of pectin (Lactis brevies growth). This study highlights the impact of extraction methods on dragon fruit peel pectin functionalities and their structure-function relationship, providing valuable insights into predicting dragon fruit peel's potential as a food-grade ingredient in various products.

Hot-air drying vs. lyophilization of sugar beet flakes for efficient pectin recovery and influence of extraction conditions on pectin physicochemical properties

This study assessed the influence of drying pretreatment and extraction conditions (type of acid and particle size of plant material) on the yield and physicochemical properties of pectin from sugar beet flakes resulted as by-product of sugar beet processing in the sugar industry. The results indicated that the drying conditions (hot-air drying and lyophilization) affected the extraction yield, the chemical composition of pectin, its color, degree of methylation and acetylation, molecular weight, and its rheological and emulsifying properties. The best results for pectin yield (16.20%), galacturonic acid content (91.19 g/100 g), degree of methylation and acetylation (66.93 and 23.87%), and molecular weight (3.89 × 105 g/mol) were obtained when sugar beet flakes were pretreated by hot-air drying, and the extraction was made with citric acid using plant material with particle sizes of 125-200 μm. This pectin also had high emulsion activity (51.42%) and emulsion stability (88.03%). The FT-IR spectra were similar, while pectin thermal behavior was affected by the drying pretreatment and extraction conditions. The results of this study showed that from this by-product of the sugar industry it can be extracted high quality pectin with rheological and emulsifying properties that are superior to commercial citrus and apple pectin.

Advancing Food Preservation: Sustainable Green-AgNPs Bionanocomposites in Paper-Starch Flexible Packaging for Prolonged Shelf Life

In the pursuit of enhancing food packaging, nanotechnology, particularly green silver nanoparticles (G-AgNPs), have gained prominence for its remarkable antimicrobial properties with high potential for food shelf-life extension. Our study aims to develop corn starch-based coating materials reinforced with G-AgNPs. The mechanical properties were examined using a uniaxial tensile tester, revealing that starch coated with the highest G-AgNPs concentration (12.75 ppm) exhibited UTS of 87.6 MPa compared to 48.48 MPa of control paper, a significant (p < 0.02) 65% increase. The assessment of the WVP showcased a statistical reduction in permeability by up to 8% with the incorporation of the hydrophobic layer. Furthermore, antibacterial properties were assessed following ISO 22196:2011, demonstrating a strong and concentration-dependent activity of G-AgNPs against E. coli. All samples successfully disintegrated in both simulated environments (soil and seawater), including samples presenting G-AgNPs. In the food trial analysis, the presence of starch and G-AgNPs significantly reduced weight loss after 6 days, with cherry tomatoes decreasing by 8.59% and green grapes by 6.77% only. The results of this study contribute to the advancement of environmentally friendly packaging materials, aligning with the UN sustainable development goals of reducing food waste and promoting sustainability.

Development and characterization of films from Campomanesia xanthocarpa and commercial citrus pectins with different degrees of methyl-esterification

In this study, pectins from commercial citrus and isolated from gabiroba (Campomanesia xanthocarpa) fruits, were obtained with different degrees of methyl-esterification (DM) and applied in the films. The DM ranged from 0 % to 62.5 % and the gradual de-esterification process was confirmed by mono-dimensional analysis (1H NMR). In order to investigate the influence of DM values in pectin film properties, PCP (DM: 62.5 %); PCP-5 (DM: 37.4 %); PCP-15 (DM: 19.1 %), and a fully de-esterified sample PCP-35 (DM: 0 %) were selected. The functional properties of the films clearly showed that the DM and cross-linking process are necessary to obtain a material with water resistance. Furthermore, pectin isolated from the fruits of gabiroba was purified (GW-Na, DM: 51.9 %) and partially de-esterified (GW-Na-5, DM: 37.1 %). These pectins were used, for the first time, in development of films and the physical and mechanical properties were compared with films made with PCP and PCP-5 samples. GW-Na and GW-Na-5 films presented suitable properties, with reduced solubility reduced (57.1 and 26.2 %), high degree of swelling (2.14 and 2.26), low flexibility (18.05 and 6.11 MPa), respectively. High strength and rigidity (99.36 and 1040.9 MPa), for both films (GW-Na and GW-Na-5) were demonstrated, similar to that obtained by analyzed citrus pectin.

The reduce of water vapor permeability of polysaccharide-based films in food packaging: A comprehensive review

Polysaccharide-based films are favored in the food packaging industry because of their advantages of green and safe characters, as well as natural degradability, but due to the structural defects of polysaccharides, they also have the disadvantages of high water vapor permeability (WVP), which greatly limits their application in the food packaging industry. To break the limitation, numerous methods, e.g., physical and/or chemical methods, have been employed. This review mainly elaborates the up-to-date research status of the application of polysaccharide-based films (PBFs) in food packaging area, including various films from cellulose and its derivatives, starch, chitosan, pectin, alginate, pullulan and so on, while the methods of reducing the WVP of PBFs, mainly divided into physical and chemical methods, are summarized, as well as the discussions about the existing problems and development trends of PBFs. In the end, suggestions about the future development of WVP of PBFs are presented.

Production of PVA-chitosan films using green synthesized ZnO NPs enriched with dragon fruit extract envisaging food packaging applications

In this work, the PVA-chitosan composite packaging films doped with biomass-fabricated zinc oxide nanoparticles (ZnO NPs) and dragon fruit waste extract (DFE) were developed for potential use in food packaging applications. ZnO NPs were synthesized using a sustainable method employing C. sinensis waste extract as a reducing agent. Chitosan and PVA were blended in a specific ratio (1: 1 w/w) to obtain a film-forming solution, into which the ZnO NPs and dragon fruit waste extract were incorporated. The resulting solution was cast into films, which were characterized using various analytical techniques. Mechanical properties, water solubility, and thermal stability of the films were also evaluated. The results demonstrated that the incorporation of green ZnO NPs and dragon fruit waste extract enhanced the mechanical strength and thermal stability of the films while reducing water vapor permeability. Moreover, the films exhibited biocidal and excellent 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging properties, indicating their use in the food packaging sector. The production of these films offers a practical approach to produce bioactive food packaging materials. The use of plant extract and waste material as reducing agents can reduce the overall cost of production while providing added benefits, such as antioxidant and antibacterial properties.

Polyphenol-Enriched Pectin from Pomegranate Peel: Multi-Objective Optimization of the Eco-Friendly Extraction Process

A multi-objective optimization was performed using response surface methodology to obtain a high-value-added product, pectin enriched in polyphenols, from pomegranate peel. For this purpose, a green extraction technique that combines citric acid and ultrasound was carried out considering three variables: time, pH, and temperature. The extraction procedure was optimized using the Box-Behnken design, these being the most suitable conditions, with an extraction time of 34.16 min, a pH of 2.2, and a temperature of 89.87 °C. At this point, the pectin yield was 31.89%, with a total retained polyphenol content of 15.84 mg GAE/g pectin. In addition, the water activity, ash content, equivalent weight, methoxyl content, and degree of esterification were determined for the pectin obtained at the optimal point. This study demonstrates that polyphenol-enriched pectin can be obtained from pomegranate peel via an eco-friendly and efficient method, and that it presents similar properties to commercial pectin, preserving its quality and with potential use as an ingredient or food supplement with a high nutritional value. This work contributes to developing sustainable strategies to valorize pomegranate agro-industrial waste and produce high-value functional ingredients.

A Two-Step Approach to Orange Peel Waste Valorization: Consecutive Extraction of Pectin and Hesperidin

Citrus consumption translates into large amounts of residue, the disposal of which is associated with environmental issues and high costs. Current trends in citrus waste focus on the extraction of highly valued bioactive compounds via single-compound extraction. There is a lack of knowledge on how these methodologies can be introduced into extraction schemes of bioactive compounds, maximizing the residue potential and reducing its amount. The present work aimed to address this issue by designing a consecutive extraction of pectin and hesperidin from orange peel waste. A novel method for extraction and precipitation of hesperidin with an eco-friendly approach is also presented. After neutral pretreatment, pectin extraction was conducted under acidic conditions, followed by hesperidin extraction with a drastic pH change. Pectin had a high AUA content (66.20 ± 1.25%), meeting the criteria for use in the food industry. The best-tested conditions for hesperidin extraction (30 min, 70 °C, 1:10 (w/v)) provided a yield of 1% and a purity of 84%. The designed extraction scheme shows the potential of citrus waste as a source of bioactive compounds of good quality and high interest in the food industry while following the principles of green chemistry and circular economy.

Application of Tannic Acid and Fe3+ Crosslinking-Enhanced Pectin Films for Passion Fruit Preservation

In this work, the role of tannic acid (TA) and Fe3+ in crosslinking pectin (PE) to enhance its physicochemical properties was investigated. Specifically, PE/TA/Fe3+ composite films were prepared using the solution casting method, and the UV-blocking properties, transparency, water content, physico-mechanical properties, antioxidant properties and degradability of the PE composite films were investigated. The microstructure of the PE composite films and the interactions between the contained components were analyzed using FTIR, X_crystal diffraction and SEM scanning electron microscopy. The results showed that the addition of TA and Fe3+ can significantly improve the UV barrier properties and antioxidant properties of PE films. Meanwhile, Fe3+ could form a metal phenol network with TA and crosslink with the PE film, which makes the structure of the PE film denser and thus significantly reduces the water vapor permeability of the PE film. In addition, this work also indicated that the PE composite coatings have a favorable preservation effect on passion fruit, which leads to the lowest weight loss rate and wrinkle index of the passion fruit within 7 days of storage and shows good appearance quality and commercial value. This work indicates that the addition of tannic acid and Fe3+ significantly improved the mechanical and barrier properties of pectin films, and the composite pectin coating extended the shelf life of passion fruit.

A Comprehensive Review on Significance and Advancements of Antimicrobial Agents in Biodegradable Food Packaging

Food waste is key global problem and more than 90% of the leftover waste produced by food packaging factories is dumped in landfills. Foods packaged using eco-friendly materials have a longer shelf life as a result of the increased need for high-quality and secure packaging materials. For packaging purposes, natural foundation materials are required, as well as active substances that can prolong the freshness of the food items. Antimicrobial packaging is one such advancement in the area of active packaging. Biodegradable packaging is a basic form of packaging that will naturally degrade and disintegrate in due course of time. A developing trend in the active and smart food packaging sector is the use of natural antioxidant chemicals and inorganic nanoparticles (NPs). The potential for active food packaging applications has been highlighted by the incorporation of these materials, such as polysaccharides and proteins, in biobased and degradable matrices, because of their stronger antibacterial and antioxidant properties, UV-light obstruction, water vapor permeability, oxygen scavenging, and low environmental impact. The present review highlights the use of antimicrobial agents and nanoparticles in food packaging, which helps to prevent undesirable changes in the food, such as off flavors, colour changes, or the occurrence of any foodborne outcomes. This review attempts to cover the most recent advancements in antimicrobial packaging, whether edible or not, employing both conventional and novel polymers as support, with a focus on natural and biodegradable ingredients.