Intelligent double-layer polymers based on carboxymethyl cellulose-cellulose nanocrystals film and poly(lactic acid)-Viola odorata petal anthocyanins nanofibers to monitor food freshness

Nano/micro flexible fiber and paper-based advanced functional packaging materials

Recently, fiber-based and functional paper food packaging has garnered significant attention for its versatility, excellent performance, and potential to provide sustainable solutions to the food packaging industry. Fiber-based food packaging is characterized by its large surface area, adjustable porosity and customizability, while functional paper-based food packaging typically exhibits good mechanical strength and barrier properties. This review summarizes the latest research progress on food packaging based on fibers and functional paper. Firstly, the raw materials used for preparing fiber and functional paper, along with their physical and chemical properties and roles in food packaging, were discussed. Subsequently, the latest advancements in the application of fiber and paper materials in food packaging were introduced. This paper also discusses future research directions and potential areas for improvement in fiber and functional paper food packaging to further enhance their effectiveness in ensuring food safety, quality, and sustainability.

An intelligent myofibrillar protein film for monitoring fish freshness by recognizing differences in anthocyanin (Lycium ruthenicum)-induced color change

A novel smart film MP/BNC/ACN for real-time monitoring of fish freshness was developed using myofibrillar protein (MP) and bacterial nanocellulose (BNC) as film raw materials and anthocyanin (Lycium ruthenicum, ACN) as an indicator. Firstly, the film containing 1 % ACN (MP/BNC/ACN1) was found to have a moderate thickness (0.44 ± 0.01 mm) and superior mechanical properties (tensile strength (TS) = 8.53 ± 0.11 MPa; elongation at break (EB) = 24.85 ± 1.38 %) by determining the physical structure. The covalent, electrostatic, and hydrogen bonding interactions between anthocyanin and the film matrix were identified and confirmed by FT-IR spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscope (SEM) analysis. A comprehensive evaluation concluded that MP/BNC/ACN1 exhibited excellent trimethylamine (TMA) sensitivity (total color difference (ΔE), ΔETMA0-1000 = 4.47-31.05; limit of detection (LOD), LOD = 1.03) and UV stability (ΔE96h = 4.16 ± 0.13). The performance of the films in assessing fish freshness was evaluated, principal component analysis (PCA) and hierarchical cluster analysis (HCA) revealed that MP/BNC/ACN1 (ΔE2-10d = 16.84-32.05) could clearly distinguish between fresh (0-2 d), sub-fresh (4-6 d), and spoiled (8-10 d) stages of fish, which corresponded to the film colors of red, light red, and gray-black. In conclusion, this study addresses the limitation that intelligent films cannot visually discern real-time freshness during fish storage and provides a promising approach for real-time fish freshness monitoring.

Active packaging film of poly(lactic acid) incorporated with plant-based essential oils of Trachyspermum ammi as an antimicrobial agent and vanilla as an aroma corrector for waffles

This study developed active packaging films of Polylactic acid incorporated with the plant-based essential oils of Trachyspermum ammi, T. ammi and Vanilla to package waffles, where the antimicrobial property was provided by T. ammi and its odor was masked by vanilla essential oil. Compared to conventional solvent-cast films of smaller sizes requiring a huge amount of solvents, bigger-size PLA-oil films with lower solvent demand were prepared by tape casting technique with 10, 30, and 50 wt% essential oil blends. Films were studied for their morphological, chemical, mechanical, barrier, and antimicrobial properties. The presence and time-bound release of volatile oils from the films was confirmed by infrared spectroscopy, with a continuous decrease of oils from the films till day 30. The plasticizing effect of oils in films was evidenced by decreased tensile strength and crystallinity. In contrast, an increase in elongation at break and water vapor permeability of oil films were also measured. Finally, when packed in PLA films containing 50 wt% blend of both oils, waffles shelf-life extended up to 30 days compared to 2 days for the neat PLA film, where Vanilla was found effective in masking the unpleasant odor of T.ammi as confirmed by sensory analysis.

Digitalization of Colorimetric Sensor Technologies for Food Safety

Colorimetric sensors play a crucial role in promoting on-site testing, enabling the detection and/or quantification of various analytes based on changes in color. These sensors offer several advantages, such as simplicity, cost-effectiveness, and visual readouts, making them suitable for a wide range of applications, including food safety and monitoring. A critical component in portable colorimetric sensors involves their integration with color models for effective analysis and interpretation of output signals. The most commonly used models include CIELAB (Commission Internationale de l'Eclairage), RGB (Red, Green, Blue), and HSV (Hue, Saturation, Value). This review outlines the use of color models via digitalization in sensing applications within the food safety and monitoring field. Additionally, challenges, future directions, and considerations are discussed, highlighting a significant gap in integrating a comparative analysis toward determining the color model that results in the highest sensor performance. The aim of this review is to underline the potential of this integration in mitigating the global impact of food spoilage and contamination on health and the economy, proposing a multidisciplinary approach to harness the full capabilities of colorimetric sensors in ensuring food safety.

Formulation and application of poly lactic acid, gum, and cellulose-based ternary bioplastic for smart food packaging: A review

In future, global demand for low-cost-sustainable materials possessing good strength is going to increase tremendously, to replace synthetic plastic materials, thus motivating scientists towards green composites. The PLA has been the most promising sustainable bio composites, due to its inherent antibacterial property, biodegradability, eco-friendliness, and good thermal and mechanical characteristics. However, PLA has certain demerits such as poor water and gas barrier properties, and low glass transition temperature, which restricts its use in food packaging applications. To overcome this, PLA is blended with polysaccharides such as gum and cellulose to enhance the water barrier, thermal, crystallization, degradability, and mechanical properties. Moreover, the addition of these polysaccharides not only reduces the production cost but also helps in manufacturing packaging material with superior quality. Hence this review focuses on various fabrication techniques, degradation of the ternary composite, and its application in the food sector. Moreover, this review discusses the enhanced barrier and mechanical properties of the ternary blend packaging material. Incorporation of gum enhanced flexibility, while the reinforcement of cellulose improved the structural integrity of the ternary composite. The unique properties of this ternary composite make it suitable for extending the shelf life of food packaging, specifically for fruits, vegetables, and fried products. Future studies must be conducted to investigate the optimization of formulations for specific food types, explore scalability for industrial applications, and integrate these composites with emerging technologies (3D/4D printing).

Electrospun fiber mats based on chitosan-carrageenan containing Malva sylvestris anthocyanins: Physic-mechanical, thermal, and barrier properties along with application as intelligent food packaging materials

This study aimed to encapsulate Malva sylvestris extract (MSE) into chitosan-carrageenan (CH-KC) fibers using the electrospinning technique and monitor the freshness of silver carp fillets during the refrigerated storage conditions for 8 days. The CH-KC + MSE 4 % fiber mats were red at pH values lower than 3, purple at pH 4-6, dark blue at pH 7, green at pH 8-10, and brown at pH 11-12. The tensile strength, elongation at break, water vapor permeability, oxygen transmission rate, moisture content, and water solubility of fabricated fiber mats were 7.71-11.02 MPa, 13.12 %-30.00 %, 7.35-20.01 × 10-4 g mm/m2 h Pa, 3.81-8.23 cm3/m2 h, 15.74 %-27.34 %, and 3.90 %-7.56 %, respectively. Regarding the potential application of a fabricated indicator for freshness monitoring of silver carp fillets, total viable count, psychrotrophic bacterial count, pH, and total volatile basic nitrogen reached 8.91 log CFU/g, 8.03 log CFU/g, 8.10, and 40.18 mg N/100 g at the end of the study, respectively. Meanwhile, the CH-KC + MSE 4 % fiber mat color changed from white to green. These findings suggest that CH-KC + MSE 4 % fiber mats can be further utilized in the food industry to control the freshness of refrigerated silver carp fillets.

Fabrication of multifunctional ethyl cellulose/gelatin-based composite nanofilm for the pork preservation and freshness monitoring

In this study, an active and intelligent nanofilm for monitoring and maintaining the freshness of pork was developed using ethyl cellulose/gelatin matrix through electrospinning, with the addition of natural purple sweet potato anthocyanin. The nanofilm exhibited discernible color variations in response to pH changes, and it demonstrated a higher sensitivity towards volatile ammonia compared with casting film. Notably, the experimental findings regarding the wettability and pH response performance indicated that the water contact angle between 70° and 85° was more favorable for the smart response of pH sensitivity. Furthermore, the film exhibited desirable antioxidant activities, water vapor barrier properties and also good antimicrobial activities with the incorporation of ε-polylysine, suggesting the potential as a food packaging film. Furthermore, the application preservation outcomes revealed that the pork packed with the nanofilm can prolong shelf life to 6 days, more importantly, a distinct color change aligned closely with the points indicating the deterioration of the pork was observed, changing from light pink (indicating freshness) to light brown (indicating secondary freshness) and then to brownish green (indicating spoilage). Hence, the application of this multifunctional film in intelligent packaging holds great potential for both real-time indication and efficient preservation of the freshness of animal-derived food items.

Development of pH-responsive intelligent and active films based on pectin incorporating Schiff base (Phenylalanine/syringaldehyde) for monitoring and preservation of fruits

This study aimed to develop pectin-based films by incorporating Schiff base compounds (SPS) synthesized by phenylalanine and syringaldehyde. The SEM images showed good compatibility between SPS and pectin matrix. The interaction of SPS and pectin matrix was analyzed by FTIR and XRD. Results indicated that the cross-linking effects between SPS and pectin matrix improved the thermal stability, water resistance and light shielding ability of the films. The incorporation of SPS in the films scavenged more than 80% of DPPH and ABTS free radicals, exhibited sustained antimicrobial ability against S. aureus, E. coli and B. cinerea, and showed significant color changes as pH-responsive films. Especially, the intelligent active coating/films inhibited the quality deterioration of cherry tomatoes and fresh-cut mangoes, and monitored the freshness of fresh-cut mangoes during storage. Therefore, the SPS/PE films have a potential application in maintaining fruit quality and monitoring the freshness of fresh-cut fruit.

Recent advances in carboxymethyl cellulose-based active and intelligent packaging materials: A comprehensive review

Researchers have concentrated on innovative approaches to increase the shelf life of perishable food products and monitor their quality during storage and transportation as consumer demand for safe, environmentally friendly, and effective packaging develops. This comprehensive review aims to provide an overview of recent developments in carboxymethyl cellulose (CMC) chemical synthesis and its applications in active and intelligent packaging materials. It explores various methods for modifying cellulose to produce CMC and highlights the unique properties that make it suitable for addressing packaging industry challenges. The integration of CMC into active packaging systems, which helps reduce food waste and enhance food preservation, is discussed in depth. Furthermore, the integration of CMC in smart sensors and indicators for real-time monitoring and quality assurance in intelligent packaging is examined. The chemical synthesis of CMC and strategies to optimise its properties were studied, and the review concluded by examining the challenges and prospects of CMC-based packaging in the industry. This review is intended to serve as a valuable resource for researchers, industry professionals, and policymakers interested in the evolving landscape of CMC and its role in shaping the future of packaging materials.

Anthocyanin-Loaded Polymers as Promising Nature-Based, Responsive, and Bioactive Materials

Anthocyanins are a specific group of molecules found in nature that have recently received increasing attention due to their interesting biological and colorimetric properties that have been successfully applied in several fields such as food preservation and biomedicine. Consequently, reviews devoted to a general overview of these flavonoids have proliferated in recent years. Meanwhile, the incorporation of anthocyanins into polymeric systems has become an interesting strategy to widen the applicability of these molecules and develop new smart and functional polymers in the above cited areas. However, anthocyanin-based polymers have been scarcely reviewed in the literature. Accordingly, this review aims to be a systematic summary of the most recent approaches for the incorporation of anthocyanins into macro-, micro-, or nanostructured polymers. Moreover, this work describes the fundamentals of the applicability of smart anthocyanin-based polymers and offers an updated review of their most interesting applications as sensors, biological regulators, and active materials.