Effect of gelatin bloom values on the physicochemical properties of starch/gelatin–beeswax composite films fabricated by extrusion blowing

A comparative study on the structure, physical property and halochromic ability of shrimp freshness indicators produced from nine varieties of steamed purple sweet potato

Nine varieties of purple sweet potato were steamed and used for the production of shrimp freshness indicators. The impact of purple sweet potato's variety on the structure, physical property and halochromic ability of indicators was determined. Results showed different varieties of purple sweet potato had different starch, crude fiber, pectin, protein, fat and total anthocyanin contents. The microstructure, crystallinity, moisture content, water vapor permeability, tensile strength and elongation at break of indicators were affected by crude fiber content in purple sweet potato. The color, transmission and halochromic ability of indicators was associated with the total anthocyanin content in purple sweet potato. Freshness indicators produced from Fuzi No. 1, Ganzi No. 6, Ningzi No. 2, Ningzi No. 4, Qining No. 2 and Qining No. 18 of purple sweet potato were suitable to indicate shrimp freshness. This study provides useful information on screening suitable varieties of purple sweet potato for intelligent packaging.

Gelatin based preservation technologies on the quality of food: a comprehensive review

Gelatin has played a great potential in food preservation because of its low price and superior film forming characteristics. This review provides a comprehensive overview of the latest research progress and application of gelatin preservation technologies (film, coating, antifreeze peptide, etc.), discussing their preservation mechanisms and efficiency through the viewpoints of quality and shelf life of animal and aquatic products as well as fruits and vegetables. It showed that bioactive and intelligent gelatin-based films exhibit antibacterial, antioxidant, water resistance and pH responsive properties, making them excellent for food preservation. In addition, pH responsive properties of films also intuitively reflect the freshness of food by color. Similarly, gelatin and its hydrolysate can be widely used in antifreeze peptides to reduce the mass loss of food during freezing and extend the shelf life of frozen food. However, extensive works are still required to extend their commercial application values.

Composite starch films as green adsorbents for removing benzo[a]pyrene from smoked sausages

Benzo[a]pyrene (BaP), which is emitted during the processing of smoked sausages, accumulates in sausages and poses a serious threat to human health. This study focused on the removal of BaP from sausages and accompanying particulate matter (PM) during the smoking of sausages by films formed by combining corn starch (CS) with K-carrageenan (KC)/sodium alginate (SA). Initially, the effects of different additions of KC and SA on the rheological analysis, thermogravimetric analysis (TGA) and film-forming properties of the composite films were investigated. The BaP reduction capacities of CS-KC and CS-SA composite films in sausage were 41.1%-47.0% and 54.2%-56.5%, respectively, because the three-dimensional mesh structure of the composite films provided a large number of adsorption sites. Finally, kinetic studies demonstrated that BaP control in composite films is mainly achieved by intraparticle diffusion. Therefore, due to its excellent recyclability and biodegradability, composite starch film has a promising application in smoked meat products.

Effects of starch-fatty acid complexes with different fatty acid chain lengths and degrees of saturation on the rheological and 3D printing properties of corn starch

The effect of corn starch-fatty (CS-FA) complexes from varying carbon chain length and degree of unsaturation on the rheological and 3D printing properties of corn CS-FA complex gels. The CS-FA complexes with longer carbon chain lengths and lower saturation enhanced the ability of gels to bind water, promoting the formation of intermolecular hydrogen bonds. The CS-FA complexes inhibit retrogradation and increase the amount of bound water, thereby reducing the structural integrity and transforming the original skeleton structure into a flake-like structure. These changes in gel structure led to lower flow stress and storage modulus for CS-FA gels containing FAs with shorter carbon chain lengths and lower saturation, resulting in reduced "extrusion swelling" of the material and facilitating its extrusion. The decreased "extrusion swelling" of gel improved print line width and printing performance. The CS-FA complex gel-printed product with a 12-carbon chain FA has the greatest printing accuracy, thanks to its moderate G', flow stress, and viscosity. This study provides important information for the CS-FA complexes for the preparation of starch-based 3D printing materials.

Interaction mechanisms of edible film ingredients and their effects on food quality

Traditional food packaging has problems such as nondegradable and poor food safety. Edible films play an important role in food packaging, transportation and storage, having become a focus of research due to their low cost, renewable, degradable, safe and non-toxic characteristics. According to the different materials of edible films substrate, edible films are usually categorized into proteins, polysaccharides and composite edible films. Functional properties of edible films prepared from different substrate materials also vary, single substrate edible films are defective in some aspects. Functional ingredients such as proteins, polysaccharides, essential oils, natural products, nanomaterials, emulsifiers, and so on are commonly added to edible films to improve their functional properties, extend the shelf life of foods, improve the preservation of sensory properties of foods, and make them widely used in the field of food preservation. This paper introduced the classification, characteristics, and modification methods of common edible films, discussed the interactions among the substrate ingredients of composite edible films, the influence of functional ingredients on the properties of edible films, and the effects of modified edible films on the quality of food, aiming to provide new research ideas for the wide application and further study of edible films.

Extrusion-blown oxidized starch/poly(butylene adipate-co-terephthalate) biodegradable active films with adequate material properties and antimicrobial activities for chilled pork preservation

Food safety concerns from spoilage and non-degradable packaging risk human health. Progress made in biodegradable plastic films, but limited study on biomass composite films with favorable morphological, mechanical, and inherent antibacterial properties for fresh meat preservation. Herein, we present a versatile packaging film created through the extrusion blowing process, combining oxidized starch (OST) with poly(butylene adipate-co-terephthalate) (PBAT). SEM analysis revealed even distribution of spherical OST particles on film's surface. FTIR spectra revealed new intermolecular hydrogen bonds between OST and PBAT. While combining OST slightly reduced tensile properties, all composite films met the required strength of 16.5 ± 1.39 MPa. Notably, films with 40 % OST showed over 98 % antibacterial rate against Staphylococcus aureus within 2 h. pH wasn't the main cause of bacterial growth inhibition; OST hindered growth by interfering with nutrient absorption and metabolism due to its carboxyl groups. Additionally, OST disrupted bacterial membrane integrity and cytoplasmic membrane potential. Remarkably, the OST/PBAT film excellently preserved chilled fresh pork, maintaining TVB-N level at 12.6 mg/100 g on day 6, microbial count at 105 CFU/g within 6-10 days, and sensory properties for 8 days. It extended pork's shelf life by two days compared to polyethylene film, suggesting an alternative to a synthetic material.

Starch-gelatin blend films: A promising approach for high-performance degradable food packaging

Packaging plays a vital role in safeguarding food from environmental factors and contamination. However, the overuse and improper disposal of non-biodegradable plastic packaging materials have led to environmental concerns and health risks. To address these challenges, the development of degradable food packaging films is crucial. Biodegradable polymers, including natural biopolymers like starch (ST) and gelatin (GE), have emerged as promising alternatives to traditional plastics. This review focuses on the utilization of ST-GE blends as key components in composite films for food packaging applications. We discuss the limitations of pure ST-GE films and explore methods to enhance their properties through the addition of plasticizers, cross-linkers, and nanoparticles. The blending of ST-GE, facilitated by their good miscibility and cross-linking potential, is highlighted as a means to improve film performance. The review also examines the impact of various additives on the properties of ST-GE blend films and summarizes their application in food preservation. By providing a comprehensive overview of ST-GE hybrid systems, this study aims to contribute to the advancement of sustainable and effective food packaging solutions.

Fabrication of Cellulose Acetate-Based Proton Exchange Membrane with Sulfonated SiO2 and Plasticizers for Microbial Fuel Cell Applications

Developing a hybrid composite polymer membrane with desired functional and intrinsic properties has gained significant consideration in the fabrication of proton exchange membranes for microbial fuel cell applications. Among the different polymers, a naturally derived cellulose biopolymer has excellent benefits over synthetic polymers derived from petrochemical byproducts. However, the inferior physicochemical, thermal, and mechanical properties of biopolymers limit their benefits. In this study, we developed a new hybrid polymer composite of a semi-synthetic cellulose acetate (CA) polymer derivate incorporated with inorganic silica (SiO₂) nanoparticles, with or without a sulfonation (-SO₃H) functional group (sSiO₂). The excellent composite membrane formation was further improved by adding a plasticizer (glycerol (G)) and optimized by varying the SiO₂ concentration in the polymer membrane matrix. The composite membrane's effectively improved physicochemical properties (water uptake, swelling ratio, proton conductivity, and ion exchange capacity) were identified because of the intramolecular bonding between the cellulose acetate, SiO₂, and plasticizer. The proton (H⁺) transfer properties were exhibited in the composite membrane by incorporating sSiO₂. The composite CAG-2% sSiO₂ membrane exhibited a higher proton conductivity (6.4 mS/cm) than the pristine CA membrane. The homogeneous incorporation of SiO₂ inorganic additives in the polymer matrix provided excellent mechanical properties. Due to the enhancement of the physicochemical, thermal, and mechanical properties, CAG-sSiO₂ can effectively be considered an eco-friendly, low-cost, and efficient proton exchange membrane for enhancing MFC performance.

Structural characteristics and gel properties of pectin from citrus physiological premature fruit drop

This study is the first to extract and characterize pectin from citrus physiological premature fruit drop. The extraction yield of pectin reached 4.4 % by acid hydrolysis method. The degree of methoxy-esterification (DM) of citrus physiological premature fruit drop pectin (CPDP) was 15.27 %, indicating it was low-methoxylated pectin (LMP). The monosaccharide composition and molar mass test results showed CPDP was a highly branched macromolecular polysaccharide (β: 0.02, Mw: 2.006 × 10⁵ g/mol) with rich rhamnogalacturonan I domain (50.40 %) and long arabinose and galactose side chain (32.02 %). Based on the fact that CPDP is LMP, Ca²⁺ was used to induce CPDP to form gels. Textural and rheological tests showed that the gel strength and storage modulus of CPDP were higher than commercial citrus pectin (CP) used in this paper due to the lower DM and rich neutral sugar side chains of CPDP. Scanning electron microscope (SEM) results showed CPDP had stable gel network structure.

Beeswax: A review on the recent progress in the development of superhydrophobic films/coatings and their applications in fruits preservation

Recently, the design and fabrication of bio-inspired superhydrophobic materials using natural lipid additives such as beeswax (BW) have aroused great attention in food packaging as they can minimize the transfer rate of water molecules and have effective moisture barriers. This review discusses the recent progress in the design and fabrication of BW-containing edible films/coatings (e.g., emulsion and blend films, bilayer materials, bionanocomposites, and antimicrobial materials) and their potential applications on the postharvest life and quality attributes of various fruits. Incorporation of BW into polysaccharides- and proteins-based emulsion films effectively improved their hydrophobicity, water vapor, and UV/visible light barrier properties, as well as the film tensile properties. The addition of nanoparticles to BW-based polymeric matrices often results in improved physico-mechanical properties. BW coatings have been also applied to prolong the shelf-life of various climacteric fruits, however, optimization of the wax concentration can be further investigated to develop targeted food storage systems.

Development of antimicrobial gelatin-ulvan-beeswax composite films: Optimization of formulation using mixture design methodology

A new generation of antimicrobial film was developed by incorporation of ulvan extracted from Ulva intestinalis into gelatin from common carp scale and its water sensitivity was reduced with addition of beeswax. Optimum composition of gelatin (0-100%w/w), ulvan (0-100%w/w) and beeswax (0-10%w/w) for achieving composite films with minimum water solubility (S) and water vapor permeability (WVP) and maximum tensile strength (TS), elongation at break point (EAB) and antibacterial effect on E. coli (EC) were investigated using mixture design methodology. Both pure gelatin and ulvan films and their composites had relatively good mechanical and optical properties. Addition of ulvan to gelatin produced composite films with good antibacterial properties but water resistance of all the films was weak. Addition of beeswax up to ∼5 % improved the water resistance and mechanical properties of the films without jeopardizing their antibacterial properties. The final optimum formulation with a desirability of 0.709 was achieved as 52.18 % of gelatin, 40.83 % of ulvan and 6.97 % of beeswax resulting in a minimum possible S (40 %) and WVP (1.86 10^-10 g/ms Pa) and maximum possible TS (6.23 MPa) and EAB (89 %) with good EC (7.66 mm). Finally, good mechanical, thermal and microstructural properties of the optimum composite film was confirmed. Altogether, a combination of ulvan and beeswax can be a promising solution for development of gelatin films with both antimicrobial properties and lower water sensitivity.

Effect of sugarcane bagasse on thermal and mechanical properties of thermoplastic cassava starch/beeswax composites

The demand for biodegradable material has been an important issue, especially in food packaging applications. Among many biodegradable materials, starch biopolymer has been recognised as a completely biodegradable material that can be produced from various plants. It is one of the richest resources that are renewable, biodegradable, and available at low cost. However, starch biopolymers are often associated with poor mechanical properties. Hence, the main objective of this study is to evaluate the mechanical and thermal characteristics of sugarcane bagasse fibre (SBF) reinforced thermoplastic cassava starch (TPCS), which was prior modified with beeswax (BW). It was found that the mechanical properties such as tensile, flexural, and impact strength have improved significantly with the incorporation of SBF loading into the TPCS/BW matrix. The highest tensile strength (12.2 MPa) and modulus (2222.6 MPa) were exhibit by sample with 20 wt% SBF loading and further increment of fibre led to decrease in the strength of the materials. The thermal properties showed that higher SBF loading resulted in improved thermal stability of the material, i.e., higher glass transition and melting temperature than the polymer matrix. Overall, SBF has shown good potential as a reinforcing material which is able to improve the functional characteristics of TPCS/BW as a new potential biodegradable material.

Effects of beeswax emulsified by octenyl succinate starch on the structure and physicochemical properties of acid-modified starchfilms

This work aimed to develop a novel strategy to modulate the distribution of beeswax in acid-modified starch films via tuning octenyl succinate starch (OSS) ratios and to elucidate their structure-property relationships. The apparent viscosity and storage modulus of the film-forming solution decreased with the increase of OSS ratio. Attenuated total reflectance-fourier transform infrared (ATR-FTIR) spectroscopy revealed that the hydrogen bond in the film-forming network was cleaved with the presence of OSS. Scanning electron microscope (SEM), atomic force microscope (AFM), and X-ray diffraction (XRD) demonstrated that OSS ratio had an obvious effect on the formation and distribution of beeswax crystal particles. Uniform distribution of beeswax effectively enhanced the hydrophobicity and water barrier properties of films and performed preferable elongation at break but at the expense of tensile strength and optical properties. The films with higher OSS ratio (>12 %) presented higher thermal stability. This study provides new information on the rational design of emulsified films to obtain desirable physicochemical properties by tuning the distribution of beeswax.

Synthesis, Characterization, and Optimization Studies of Starch/Chicken Gelatin Composites for Food-Packaging Applications

The indiscriminate use of plastic in food packaging contributes significantly to environmental pollution, promoting the search for more eco-friendly alternatives for the food industry. This work studied five formulations (T1–T5) of biodegradable cassava starch/gelatin films. The results showed the presence of the starch/gelatin functional groups by FT-IR spectroscopy. Differential scanning calorimetry (DSC) showed a thermal reinforcement after increasing the amount of gelatin in the formulations, which increased the crystallization temperature (Tc) from 190 °C for the starch-only film (T1) to 206 °C for the film with 50/50 starch/gelatin (T3). It also exhibited a homogeneous surface morphology, as evidenced by scanning electron microscopy (SEM). However, an excess of gelatin showed low compatibility with starch in the 25/75 starch/gelatin film (T4), evidenced by the low Tc definition and very rough and fractured surface morphology. Increasing gelatin ratio also significantly increased the strain (from 2.9 ± 0.5% for T1 to 285.1 ± 10.0% for T5) while decreasing the tensile strength (from 14.6 ± 0.5 MPa for T1 to 1.5 ± 0.3 MPa for T5). Water vapor permeability (WVP) increased, and water solubility (WS) also decreased with gelatin mass rising in the composites. On the other hand, opacity did not vary significantly due to the films’ cassava starch and gelatin ratio. Finally, optimizing the mechanical and water barrier properties resulted in a mass ratio of 53/47 cassava starch/gelatin as the most appropriate for their application in food packaging, indicating their usefulness in the food-packaging industry.

Application of Gelatin in Food Packaging: A Review

Owing to the increasing environmental concerns and requirements for high-quality foods, edible films and coatings (based on proteins, polysaccharides, natural phenolic active substances, etc.) are being developed as effective alternatives to traditional plastic packaging. Gelatin is extracted from collagen. It is an ideal material for food packaging due to its versatile advantages such as low price, polymerization, biodegradability, good antibacterial and antioxidant properties, etc. However, gelatin film exists poor waterproof and mechanical properties, which limit its developments and applications in food packaging. Previous studies show that pure gelatin can be modified by adding active ingredients and incorporating them with bio-polymers to improve its mechanical properties, aiming to achieve the desirable effect of preservation. This review mainly shows the preparation and molding ways of gelatin-based edible films and the applications of gelatin modified with other biopolymers. Furthermore, this review provides the latest advances in gelatin-based biodegradable packaging and food applications that exhibit outstanding advantages in food preservation.

Effect of palm wax on the mechanical, thermal, and moisture absorption properties of thermoplastic cassava starch composites

Thermoplastic starch is a potentially sustainable and biodegradable material. However, it possesses some limitations in terms of mechanical performance and high moisture sensitivity. In this current work, the characteristics of thermoplastic cassava starch (TPCS) containing palm wax at various loading were evaluated. TPCS was prepared via hot pressing by varying the ratios of palm wax (2.5, 5, 10, and 15 wt%). Next, characterization via scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR), mechanical, water solubility, thickness swelling and moisture absorption tests, were conducted on the samples. The findings showed that incorporating starch-based thermoplastics with palm wax has remarkably improved mechanical characteristics of the thermoplastic blends. Besides, the morphology of the samples demonstrated irregular and rougher cleavage fracture after palm wax addition. FT-IR indicated the existence of intermolecular interaction between TPCS and palm wax with the intermolecular hydrogen bonds that existed between them. The thermal stability of TPCS has improved with rising palm wax content. The incorporation of 15 wt% palm wax resulted in the lowest moisture absorption value among the samples. Overall, the developed TPCS/palm wax with improved mechanical and moisture resistance characteristics has the potential to be used as biodegradable materials.

Thermoplastic starch/beeswax blend: Characterization on thermal mechanical and moisture absorption properties

Cassava starch has acquired many attentions owing to its ability to be developed as thermoplastic cassava starch (TPCS) where it can be obtained in low cost, making it to be one of alternatives to substitute petroleum-based plastic. An attempt was made to investigate the thermal, mechanical and moisture absorption properties of thermoplastic cassava starch blending with beeswax (TPCS-BW) fabricated using hot moulding compression method in the range of beeswax loading from 0, 2.5, 5 to 10 wt%. Addition of beeswax has significantly reduced tensile strength, elongation and flexural strength while improving tensile modulus and flexural modulus until 5 wt% beeswax. Incorporation of 10 wt% beeswax has successfully produced the lowest value of moisture absorption and water solubility among the bio-composite which might be attributed to the beeswax's hydrophobic properties in improving water barrier of the TPCS-BW bio-composite. Furthermore, the addition of beeswax resulted in the appearance of irregular and rough fractured surface. Meanwhile, fourier transform infrared (FT-IR) spectroscopy presented that incorporation of beeswax in the mixture has considerably improve hydrogen bonding of blends indicating good interaction between starch and beeswax. Hence, beeswax with an appropriate loading value able to improve the functional properties of TPCS-BW bio-composite.

Preparation of bio-based cellulose acetate/chitosan composite film with oxygen and water resistant properties

Plastic pollution has inspired the preparation of environmentally friendly bio-based plastics that can replace petroleum-based plastics. Herein, a composite film with oxygen and water resistant properties was prepared by a fluidized bed method, employing bio-based cellulose acetate (CA) as raw material, glycerol as a plasticizer, and chitosan and silica as additives. The addition of 15% chitosan greatly reduced the oxygen transmission rate of the CA film by 83.5%, and increased the tensile stress and tensile strain of the composite membrane, reaching 26.5 MPa and 22.2%, respectively. The deposition of silica particles is able to compensate for the undesired increase in the hydrophilicity caused by the addition of chitosan, and tune the hydrophilic nature of the surface of the CA/CS films to the hydrophobic nature, which is desirable for water-resistant applications. The prepared composite film displays good oxygen and water resistant properties and can be used for food packaging and related applications.

Recent advances in utilization of pectins in biomedical applications: a review focusing on molecular structure-directing health-promoting properties

The numerous health benefits of pectins justify their inclusion in human diets and biomedical products. This review provides an overview of pectin extraction and modification methods, their physico-chemical characteristics, health-promoting properties, and pharmaceutical/biomedical applications. Pectins, as readily available and versatile biomolecules, can be tailored to possess specific functionalities for food, pharmaceutical and biomedical applications, through judicious selection of appropriate extraction and modification technologies/processes based on green chemistry principles. Pectin's structural and physicochemical characteristics dictate their effects on digestion and bioavailability of nutrients, as well as health-promoting properties including anticancer, immunomodulatory, anti-inflammatory, intestinal microflora-regulating, immune barrier-strengthening, hypercholesterolemia-/arteriosclerosis-preventing, anti-diabetic, anti-obesity, antitussive, analgesic, anticoagulant, and wound healing effects. HG, RG-I, RG-II, molecular weight, side chain pattern, and degrees of methylation, acetylation, amidation and branching are critical structural elements responsible for optimizing these health benefits. The physicochemical characteristics, health functionalities, biocompatibility and biodegradability of pectins enable the construction of pectin-based composites with distinct properties for targeted applications in bioactive/drug delivery, edible films/coatings, nano-/micro-encapsulation, wound dressings and biological tissue engineering. Achieving beneficial synergies among the green extraction and modification processes during pectin production, and between pectin and other composite components in biomedical products, should be key foci for future research.

Natural Antimicrobials as Additives for Edible Food Packaging Applications: A Review

Edible packaging is a swiftly emerging art of science in which edible biopolymers like lipids, polysaccharides, proteins, resins, etc., and other consumable constituents extracted from various non-conventional sources are used alone or imbibed together. Edible packaging with antimicrobial components had led to the development of the hypothesis of active packaging which safeguards the quality of foods as well as health of consumers. Natural antimicrobial agents (NAMAs) like essential oils from spices, bioactive compounds derived from vegetables and fruits, animal and microorganism derived compounds having antimicrobial properties can be potentially used in edible films as superior replcement for synthetic compounds, thus serving the purpose of quality and heath. Most of the natural antimicrobial agents enjoy GRAS status and are safer than their synthetic counterparts. This review focuses on updated literature on the sources, properties and potential applications of NAMAs in the food industry. This review also analyzes the biodegradability and biocompatibility and edibility properties of NAMAs enriched films and it can be concluded that NAMAs are better substitutes but affect the organoleptic as well as the mechanical properties of the films. Despite many advantages, the inclusion of NAMAs into the films needs to be investigated more to quantify the inhibitory concentration without affecting the properties of films and exerting potential antimicrobial action to ensure food safety.

Effects of microwave treatment on the stability and antioxidant capacity of a functional wheat bran

A functional wheat bran (FWB) was obtained from wheat grains that were rich in wheat aleurone. The effects of the microwave (MW) power (2.5, 5.0, 7.5, and 10.0 kW) and treatment time (15, 30, 60, 90, and 120 s) on the moisture and free fatty acid (FFA) content, lipase activity, and antioxidant activity of the FWB were investigated. The purpose of this study is to stabilize the FWB against lipid oxidation and rancidity and as much as possible to retain its antioxidant activities. MW treatment significantly decreased the FFA content, moisture content, and lipase activity of the FWB. Moreover, MW treatment significantly increased the total phenolic content (TPC) and antioxidant activity of the FWB without drastically altering its color. MW treatment at 7.5 kW and 120 s was found to be optimal for stabilizing the FWB and increasing its antioxidant activity. The stabilized FWB was proven to be far more stable than the control FWB during storage. Thus, MW treatment is an effective stabilization method for the storage and utilization of FWB. Additional research is needed for the exact mechanism of the decrease of FFA content and increase of antioxidant activity of FWB induced by MW treatment.