Applications and characterization of anti-browning enzymatically modified potato starch (EPS) film associated with chitosan (CTS)/L-Cys/citric acid (CA) on fresh-cut potato slices.

This study explores the influence of incorporating L-cysteine (L-Cys), chitosan (CTS), and citric acid (CA) on the enzymatic modification of potato starch (EPS) films to enhance anti-browning properties. Four types of EPS composite films were evaluated for preserving fresh-cut potato slices at low temperatures to inhibit browning. Their thermal, physiochemical, mechanical, and digestibility properties were assessed. Results indicate that the addition of CTS, CA, and L-Cys improved the anti-browning activity of the EPS films by increasing film thickness and reducing water vapor permeability (WVP), oxygen transmission rate (OTR), ultraviolet (UV) transmittance, and tensile strength (TS). Furthermore, these additives improved the film's microstructure, resulting in reinforced intermolecular interactions, increased elongation at break, heightened crystallinity, enhanced thermal stability, and favorable gastrointestinal digestibility. Overall, EPS/CTS/L-Cys/CA composite films show promise as edible packaging materials with effective anti-browning properties.

Application of poly(L-lactic acid)-based films for equilibrium modified atmosphere packaging of "Kyoho" grapes and its favorable protection for anthocyanins.

Grapes were packaged by different Poly (L-lactic acid)-based packaging films (PLTL-PLEL) and stored at 5 °C for 35 days to investigate the effects of equilibrium modified atmosphere packaging on the quality of "Kyoho" grapes during storage. Changes in physiochemical quality, antioxidant content and senescence of grapes were studied. Furthermore, UPLC-Q-TOF-MS/MS was used to observe and identify key factors influencing the variation of grape anthocyanins under different atmosphere conditions. Alterations in gas components and enzyme activities significantly impacted anthocyanin levels, highlighting oxygen concentration as the primary influence on total anthocyanin levels. The PLTL-PLEL50 packaging resulted in an approximate 5.7% lower weight loss and increased soluble solids by approximately 14.4%, vitamin C, total phenols and flavonoids reaching 60.2 mg/100 g, 8.4 mg/100 g and 7.2 mg/100 g, respectively. This packaging also preserved higher anthocyanin levels, with malvidin-3-glucoside and peonidin-3-glucoside at 0.55 µg/mL and 1.62 µg/mL, respectively, on the 35th day of storage.

High­oxygen-modified atmospheric packaging delays flavor and quality deterioration in fresh-cut broccoli.

The purpose of this study was to investigate the impact of high­oxygen-modified atmospheric packaging (HOMAP) on aroma changes in fresh-cut broccoli during storage and to explore its regulatory mechanisms. The results showed that HOMAP reduced the levels of undesirable aroma substances hexanoic acid, isobutyric acid, cyclopentanone and increased glucosinolate accumulation by inhibiting the expression of arogenate/prephenate dehydratase (ADT), bifunctional aspartate aminotransferase and glutamate/aspartate-prephenate aminotransferase (PAT), thiosulfate/3-mercaptopyruvate Transferase (TST) to reduce the odor of fresh-cut broccoli. HOMAP inhibited the expression of respiratory metabolism related genes 6-phosphate fructokinase 1 (PFK), pyruvate kinase (PK), and NADH-ubiquinone oxidoreductase chain 6 (ND6). In HOMAP group, the low expression of phospholipase C (PLC), phospholipase A1 (PLA1), linoleate 9S-lipoxygenase 1 (LOX1) related to lipid metabolism and the high expression of naringenin 3-dioxygenase (F3H), trans-4-Hydroxycinnamate (C4H), glutaredoxin 3 (GRX3), and thioredoxin 1 (TrX1) in the antioxidant system maintained membrane stability while reducing the occurrence of membrane lipid peroxidation.

Polyphenols functionalized MOF encapsulated BPQDs for synergistic photothermal/photodynamic antibacterial properties and multifunctional food preservation.

Active antibacterial materials play an important role in solving food safety problems caused by pathogen contamination. In this study, a composite active antibacterial material with the synergistic antibacterial effectiveness of photothermal, photodynamic and the surface charge of polyphenols was developed, where the multi-porous polyphenol functionalized metal-organic frameworks (ZIF-8-TA) were used as the framework carrier, and black phosphorus quantum dots (BPQDs) were used as the photosensitive source. The resulted ZIF-8-TA/PBQDs possesses excellent photothermal conversion efficiency (27.92%), photodynamic performance and surface charge, and these factors ensure the outstanding broad-spectrum antibacterial performance (100%). Multifunctional characteristics and excellent biocompatibility endow the materials with vast potential for foodstuff packaging. The results showed that the composite antibacterial film produced by doping ZIF-8-TA/PBQDs into chitosan could effectively prolong the shelf life of foodstuff compared with commercial membrane. The successful implementation of this research provides a new idea for controlling microbial contamination and developing multifunctional antibacterial materials.

Preparation of sodium alginate modified silver-metal organic framework and application in citric acid/PVA antimicrobial packaging.

Silver-metal organic framework (Ag@MOF) has exhibited outstanding antimicrobial activity in antimicrobial applications, and reducing the biotoxicity associated with silver has become a research priority. In this study, Ag@MOF was initially modified with sodium alginate (SA) to form SA-Ag@MOF. The results showed that SA could control the release of Ag+, reducing the release by about 8% at 24 h, and the biotoxicity was significantly reduced. Finally, SA-Ag@MOF was applied as an antimicrobial agent in citric acid-modified PVA film to develop a novel composite antimicrobial film. When added at 2 MIC, the CA3-M2 film can effectively inhibit the growth of E. coli and S. aureus, and the inhibition rate has reached 98%. For white radish packaging applications, CA3-M2 film inhibited the growth of surface microorganisms, while ensuring moisture and tissue hardness to extend shelf-life up to 7 days. Overall, the strategy conceived here can be a theoretical basis for novel antimicrobial packaging.

Antioxidant and antimicrobial extracts from grape stalks obtained with subcritical water. Potential use in active food packaging development.

In order to valorise winemaking grape stalks, subcritical water extraction at 160 and 180 °C has been carried out to obtain phenolic-rich extracts useful for developing active food packaging materials. Red (R) and white (W) varieties (from Requena, Spain) were used, and thus, four kinds of extracts were obtained. These were characterised as to their composition, thermal stability and antioxidant and antibacterial activity. The extracts were incorporated at 6 wt% into polylactic acid (PLA) films and their effect on the optical and barrier properties of the films and their protective effect against sunflower oil oxidation was analysed. Carbohydrates were the major compounds (25-38%) in the extracts that contained 3.5-6.6% of phenolic compounds, the R extracts being the richest, with higher radical scavenging capacity. Every extract exhibited antibacterial effect against Escherichia coli and Listeria innocua, while PLA films with extracts preserved sunflower oil against oxidation.

Integrating detection and degradation of bisphenol A by photocatalytic fuel cell-driven photoelectrochemical sensor.

To ensure food safety and environmental protection, it is crucial to rapidly identify and remove bisphenol A (BPA), a plasticizer commonly used in the inner lining of food containers and beverage packaging. Here, a photocatalytic fuel cell (PFC)-integrated self-powered photoelectrochemical (PEC) sensor is constructed. Unlike conventional single PEC or PFC sensors, this PFC-integrated PEC sensor relies on not only the difference in Fermi energy levels between photoanode and photocathode but also charge accumulation resulted from the oxidation of BPA by photogenerated holes. Consequently, this sensor achieved a remarkable maximum output power (Pmax) of 8.58 µW cm-2, as well as a high sensitivity, wide linear detection range (0.1-200 µM), low detection limit (0.05 µM), great stability, reproducibility, and real sample detection capability. This work integrates PFC and PEC technologies successfully for the rapid identification and efficient removal of BPA.

Nanolignin-containing cellulose nanofibrils (LCNF)-enabled multifunctional ratiometric fluorescent bio-nanocomposite films for food freshness monitoring.

Herein, the nanolignin-containing cellulose nanofibrils (LCNF)-enabled ratiometric fluorescent bio-nanocomposite film is developed. Interestingly, the inclusion of LCNF in the cellulose-based film enhances the detecting performance of food freshness, such as high sensitivity to biogenic amines (BAs) (limit of detection (LOD) of up to 1.83 ppm) and ultrahigh discernible fluorescence color difference (ΔE = 113.11). The underlying mechanisms are the fluorescence resonance energy transfer (FRET), π - π interaction, and cation - π interaction between LCNF and fluorescein isothiocyanate (FITC), as well as the increased hydrophobicity due to lignin, which increases the interactions of amines with FITC. Its color stability (up to 28 days) and mechanical property (49.4 Mpa) are simultaneously improved. Furthermore, a smartphone based detecting platform is developed to achieve access to food safety. This work presents a novel technology, which can have a great potential in the field of food packaging and safety.

Blueberry anthocyanin based active intelligent wheat gluten protein films: Preparation, characterization, and applications for shrimp freshness monitoring.

The aim of this study was to prepare active intelligent gluten protein films using wheat gluten protein (WG) and apple pectin (AP) as film-forming matrices, and blueberry anthocyanin extract (BAE) as a natural indicator. SEM and FT-IR analyses demonstrated the successful immobilization of BAE in the film matrix by hydrogen bonding interactions and its compatibility with WG and AP. The resultant WG-AP/BAE indicator films demonstrated notable antioxidant activity, color stability, barrier qualities, pH and ammonia response sensitivity, and mechanical properties. Among them, WG-AP/BAE5 exhibited the best mechanical properties (TS: 0.83 MPa and EB: 242.23%) as well as the lowest WVP (3.92 × 10-8 g.m/m2.Pa.s), and displayed high sensitivity to volatile ammonia. In addition, WG-AP/BAE5 showed a color shift from purplish red to green to yellowish green, demonstrating the monitoring of shrimp freshness in real time. Consequently, this study offers a firm scientific foundation for the development of active intelligent gluten protein films and their use in food freshness assessments.

Starch as a smart, cheap, and green gatekeeper for the controlled release of propyl gallate from antioxidant biodegradable packaging films.

Oxidative rancidity of food products and massive consumption of plastic packaging have put the necessity in manufacturing novel antioxidant biodegradable packaging films. A comprehensive investigation was conducted on starch/poly(butylene adipate-co-terephthalate) (PBAT) antioxidant blown films, in which starch acted as a gatekeeper for the controlled release of propyl gallate (PG). PG was well integrated into the matrices and bound to starch molecules by hydrogen bonding. All films showed strong anti-ultraviolet performance, and higher oxygen barrier than the traditional polyethylene film. Increasing starch proportions promoted the swelling of films and the release of PG, thereby causing higher antioxidant activity at the same contact time to free radical solutions. Similar polarity made PG prone to partition and rapid migration into the food simulants with higher ethanol concentration and the high-fat-content peanut butter. The film with 20:80 w/w starch/PBAT proportion and 3% w/w PG content effectively suppressed the oxidation of peanut butter within 300-day storage. Findings demonstrated this strategy for manufacturing starch/PBAT antioxidant films as a long-term active packaging in food industry.

Chemically tailored graphite oxide nanoparticles for improving material properties of canola protein-based films.

Canola protein obtained from canola meal, a byproduct of the canola industry, is an economical biopolymer with promising film-forming properties. It has significant potential for use as a food packaging material, though it possesses some functional limitations that need improvement. Incorporating nanomaterials is an option to enhance functional properties. This study aims to produce canola protein films by integrating GO exfoliated at several oxidation times and weight ratios to optimize mechanical, thermal, and barrier properties. Oxidation alters the C/O ratio and adds functional groups that bond with the amino/carboxyl groups of protein, enhancing the film properties. Significant improvement was obtained in GO at 60 and 120 min oxidation time and 3% addition level. Tensile strength and elastic modulus increased 200% and 481.72%, respectively, compared to control. Control films showed a 37.57 × 10-3 cm3m/m2/day/Pa oxygen permeability, and it was significantly reduced to 5.65 × 10-3 cm3m/m2/day/Pa representing a 665% reduction.

Hydrophobic polyethylene film prepared by film blowing process for preservation of fried shrimp rolls.

Hydrophobic coatings have wide applications, but face challenges in food flexible packaging in terms of poor adhesion and inadequate wear resistance. Health hazards and poor adhesion drive the search for novel hydrophobic coatings substitutes. Here, we introduced rationally synthesized carnauba wax-SiO2 microspheres as a component to composite polyethylene (PE) film construction, and created a wear-resistant hydrophobic composite PE film via the blown film technique. The resultant hydrophobic composite film demonstrated an enhanced water contact angle from 86° to above 100°, coupled with favorable mechanical properties such as wear resistance, tensile strength and effective barrier performance against water vapor and oxygen. Upon implementation in the preservation of a Cantonese delicacy, Chaoshan fried shrimp rolls, it was observed that at 25 °C, the carnauba wax-SiO2-PE composite packaging film extended the shelf life of the product by 3 days compared to pure PE film.

Properties and application of antioxidant and antibacterial composite films based on methylcellulose and spine grape pomace fabricated by thermos-compression molding.

Methylcellulose (MC)/grape pomace (GP) films, plasticized with either glycerol (GLY) or cinnamon essential oil (CEO), were prepared by thermo-compression molding and characterized. Compared to the GLY-plasticized MC50/GP50 films, a considerable increase in TS and YM values of CEO-plasticized films was observed, rising from 9.66 to 30.05 MPa, 762 to 1631 MPa, respectively. Moreover, the water vapor barrier, surface hydrophobic properties, and antioxidant/antibacterial activities of CEO-plasticized films remarkedly improved with increasing CEO content from 5 to 15% w/w. From scanning electron microscopy, phase separation between GP and the MC/GLY mixture were evident for GLY-plasticized MC/GP films. On the other hand, the CEO-plasticized films showed compact morphologies, attributable to the formation of hydrogen bonding and π-π stacking interaction. Preliminary shelf-life study on showed that fresh chicken wrapped with the CEO-plasticized MC/GP films exhibited lower TVB-N, TBARS, and TVC values than the unwrapped control samples, during 7 d storage at 4 °C.

Enzymatically green-produced bacterial cellulose nanoparticle-stabilized Pickering emulsion for enhancing anthocyanin colorimetric performance of versatile films.

To enhance the colorimetric performance of anthocyanin (Ant), a konjac glucomannan (KGM)-based multifunctional pH-responsive indicator film was fabricated by introducing enzymatically prepared bacterial nanocellulose (EBNC) stabilized camellia oil/camellia essential oil Pickering emulsion (BCCE). Specifically, optimized enzymatic hydrolysis time (36 h) was determined based on the particle size and microstructure. Then BCCE (containing 0.4% EBNC) was incorporated into Ant-containing KGM, and the novel active indicator film (KGM-Ant-BCCE) was constructed. Films with varying BCCE concentrations (3%-11%) exhibited enhanced UV shielding, thermal stability, mechanical strength, water vapor and oxygen permeability, hydrophobicity, and antioxidant performance. The pronounced color change of KGM-Ant-BCCE indicated its potential for visually detecting shrimp freshness. Moreover, the biodegradability (25 days) confirmed the environmentally benign property of the film. In summary, incorporating green-produced EBNC nanoparticle-stabilized BCCE offers an innovative pathway to improve the color indication capability of polysaccharide-based smart packaging.

High-performance carboxymethyl starch/PVA based intelligent packaging films engineered with Cu-Trp nanocrystal as functional compatibilizer.

A spindle-like Cu-based framework (Cu-Trp, Trp = L-Tryptophan) nanocrystal with ammonia-responsiveness was fabricated via simple aqueous solution approach, and it was subsequently explored as a functional compatibilizer of carboxymethyl starch/polyvinyl alcohol (CMS/PVA) blend toward constructing high-performance intelligent packaging films. The results showed that incorporation of Cu-Trp nanocrystal into CMS/PVA blend resulted in significant promotions regarding to the compatibility, mechanical strength (42.92 MPa), UV-blocking (with UV transmittance of only 2.4%), and water vapor barrier effectiveness of the blend film. Besides, the constructed CMS/PVA/Cu-Trp nanocomposite film exhibited superb long-term color stability, favorable antibacterial capacity (over 98.0%) toward both E. coli and S. aureus bacteria, as well as color change ability under ammonia environment. Importantly, the application trial confirmed that the CMS/PVA/Cu-Trp nanocomposite film is capable of visually monitoring shrimp spoilage during storage. These results implied that the CMS/PVA/Cu-Trp nanocomposite film holds tremendous potential as an intelligent active packaging material.

Microscopic Raman-based rapid detection of submicron/nano polypropylene plastics in tea and tea beverages.

Polypropylene (PP) is suitable for a broad range of applications and represents the most extensively utilized plastic in food packaging. Micro- and nano-PP plastics are prevalent categories of microplastics (MPs). However, the majority of MPs particles currently utilized in laboratory studies are man-made polystyrene (PS) spheres, and there has been limited research on micrometer- and nanoscale PP plastic particles. This study aims to employ a top-down approach in crafting micro/nanoparticle (M/NPs) models of PP particles, ensuring their enhanced relevance to real-world environments. Micro/nano PP particles, featuring a negatively charged particle size ranging from 203 to 2101 nm, were synthesized through variations in solution concentration and volume. Simultaneously, the devised MPs model was employed to develop a Raman-based qualitative and quantitative detection method for micro/nano PP particles, considering diverse sizes and concentrations. This method integrates Raman spectroscopy and microscopy to measure PP particles with varying sizes, utilizing the coffee ring effect. The Limit of detection (LOD) for 203 nm PP reached 31.25 µg/mL, while those for 382-2101 nm PP were approximately 3.9 µg/mL. The method underwent quantitative analysis by introducing 203 nm PP nanospheres into real food media (i.e., tea beverages, tea leaves), revealing a minimum LOD of approximately 31.25 µg/mL.

An ammonia-sensitive fluorescence sensor based on polyvinyl alcohol-graphene quantum dots/halloysite nanotubes hybrid film for monitoring fish freshness.

A fluorescent hybrid film composed of nitrogen-doped graphene quantum dots (N-GQDs) loaded on halloysite nanotubes (HNTs) (N-GQDs/HNTs nanocomposite) as a sensitive element and polyvinyl alcohol (PVA) as a film-forming matrix was designed for freshness detection. The PVA-N-GQDs/HNTs hybrid film exhibited significantly enhanced fluorescence attributed to the loading of N-GQDs onto the surface of HNTs through electrostatic interactions and hydrogen bonding, effectively reducing their aggregation. The fluorescence of the hybrid film could be quenched by ammonia via photoinduced electron transfer (PET), with good linearity in the range of 20 ppm to 500 ppm ammonia and a limit of detection (LOD) of 0.63 ppm. In addition, the hybrid film was applied to monitor the freshness of seawater fish and freshwater fish stored at refrigeration and room temperature to evaluate the practicality of this approach. The developed hybrid film showed promise for nondestructive and on-site monitoring of fish spoilage.

Development of dual-channel starch-based film incorporated with betanin@ß-cyclodextrin inclusion complex and berberine for indicating shrimp freshness.

In this study, the ß-cyclodextrin encapsulated betanin (BET@ß-CD) with improved thermal stability and retention as well as the berberine (BBR) with aggregate induced luminescence effect were incorporated into corn amylose (CA) biomatrix to develop colorimetric/fluorescent dual-channel smart film. Results shown that the added functional components were uniformly distributed in the film matrix. The high tensile strength (78.87%), low water solubility (31.15%) and water vapor permeability (1.24 × 10-10 g Pa-1 s-1 m-1) of the film predicted its acceptable stability. It was worth mentioning that the film displayed excellent responsiveness to volatile ammonia (0.025-25 mg/mL) with at least 4 times recyclability. Application experiment demonstrated that the film can achieve macroscopic dynamic monitoring of the freshness of shrimps stored at 25 °C, 4 °C, -20 °C under daylight (red to yellow) and UV light (yellow-green to blue-green). Thus, the study suggests an attractive and effective strategy for constructing dual-mode smart packaging materials for food freshness detection.

Edible thermochromic beads from flavonoid, fatty acid, and lecithin for smart packaging.

Enzymatic browning and microbial growth are two natural phenomena that occur when fruits and vegetables are exposed to abnormal conditions, i.e., temperatures in the range of 12-22 °C, leading to their spoilage. Controlling the temperatures during the supply chain aims to optimize the product's shelf life. Irreversible thermochromic beads were fabricated using a simple extrusion technique containing fatty acid, lecithin, and anthocyanin solution-alginate. The pigmentation durability was adjusted based on electrostatic interactions, as evidenced by the reduction in dye leaching in the case of the produced bead at pH = 6 to less than 0.007 after 45 min. Characterization shows that the chosen combination of fatty acids and the quinonoid molecule is useful for producing thermochromic beads, with a color change at 12 °C-22 °C, from blue to purple. Using the prepared thermochromic beads in the supply chain of fresh-cut salad and brussels sprouts showed a great result for monitoring their freshness after 21 ± 1 min.

Corncob-derived biodegradable packaging films: A sustainable solution for raspberry post-harvest preservation.

Plastic food packaging, with its harmful migration of microplastics and nanoplastics into food, presents significant ecological imbalance and human health risks. In this regard, using food and agricultural byproducts as packaging materials reduces environmental and economic concerns and supports their sustainable management. Herein, cellulosic residue from corncob was employed as a renewable source for developing biodegradable packaging films. It was solubilized in ZnCl2 solution, crosslinked with Ca2+ ions, and plasticized with sorbitol to form films and used to improve the shelf-life of raspberries. The optimized film possesses water vapor permeability, tensile strength, and elongation at break of 1.8(4) x10-10 g-1 s-1 Pa-1, 4.7(1) MPa, and 15.4(7)%, respectively. It displays UV-blocking and antioxidant properties and biodegrades within 29 days at 24% soil moisture. It preserves raspberries for 7 and 5 more days at room temperature and refrigeration conditions, respectively, compared to polystyrene film. Overall, more value addition could be envisioned from agricultural residues to minimize post-harvest losses and food waste through biodegradable packaging, which also aids in mitigating plastic perils.