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The calls for green biodegradable plastics to replace synthetic ones are continuously growing amidst the current environmental threats. These threats are evident all over the globe as seen from heat waves, floods, earthquakes, glacier melts, etc. This research presents morphological, physical, mechanical, and thermal properties of bioplastics produced from yam and potato tuber peels. This alternative to synthetic plastic materials serves to mitigate the menace posed by plastic waste and hence provides a sustainable environmental solution. Waste yam peels (WYP) and waste potato peels (WPP) were obtained from eateries, then washed, dried, and ground before the starch extraction. The starch was then used to produce bioplastics in the presence of hydrochloric (HCl) and acetic acid. Analysis was carried out on the morphological, qualitative, physical, mechanical, and thermal properties of the material. It was observed that bioplastic produce using HCl was darker than those produced by acetic acid while WYP bioplastics were rougher on the surface than WPP. FTIR spectra also revealed higher peaks in polyester fingerprint bioplastic hence the effect on physical, mechanical, and thermal properties. The bioplastics recorded densities between 1.2 and 1.7 g/cm3; HCl-based bioplastics exhibited denser properties compared to acetic acid based. While WPP bioplastic generally exhibited less water absorption capacity, HCl-based bioplastics also recorded lower water absorption for the same starch. HCl-based bioplastic recorded a higher modulus of elasticity (MOE) compared to acetic-based bioplastic. WPP produced via HCl recorded the highest MOE of 0.09 N/mm2, which is 350% higher than potato and acetic acid. The bioplastics produced exhibited two stages of thermal degradation. The WPP bioplastic exhibited a thermally more stable behavior even though the yam-based bioplastic recorded an earlier onset of thermal degradation. Among the bioplastics produced, WPP-HCl exhibited the best in physical, mechanical, and thermal properties. While all these waste peels bioplastics show promising properties, it gives the bioplastics an advantage in application related to edible foods packaging. [ABSTRACT FROM AUTHOR]

The colours of anthocyanins are sensitive to variations in the pH of the environment. The field of food engineering is seeing a rise in the utilisation of anthocyanins obtained from plants to produce new and active packaging film. A pH-sensitive colorimetric film was developed using anthocyanin recovered from the peel of Phaseolus vulgaris (dark red kidney bean) in conjunction with composite pectin derived from citron peel. Additionally, Anthocyanins could be employed as colorimetric markers to identify food degradation, due to their sensitivity towards pH alterations and the production of ammonia gas. Solvent casting process was used to produce the film which changed from pink to brownish with rising pH due to the ammonia vapour that was produced. The antioxidant and antibacterial abilities of the anthocyanin containing smart films were investigated, and both Escherichia coli and Staphylococcus aureus growth was successfully inhibited. The developed film was characterized for its physical properties such as water solubility, moisture content and swelling index. To examine the structure of the films' surface, scanning electron microscopy (SEM) investigation has been carried out. The film indicator active response to pH fluctuation was demonstrated through tests on samples of chicken meat under various settings, allowing for the real-time monitoring of spoiled foods. This makes monitoring perishable goods, easy, affordable, environmentally friendly and biodegradable pH-sensitive indicator with visible colour change. [ABSTRACT FROM AUTHOR]

A novel organic acid-modified starch and carboxymethyl cellulose (CMC) based films plasticized with glycerol were prepared from unconventional tikhur starch (Curcuma angustifolia) by solution casting. Wet milling was used in the laboratory to extract starch from the tikhur rhizome. Carboxymethyl cellulose, at a concentration of (0.2 g−1 starch dry basis) was blended with the starch to improve its film-forming properties. Three different treatments with varying organic acids (lactic, citric, and acetic acid) with a concentration of 5% w/w of starch (2 ppm) in a film-forming solution were given. The effect of organic acid incorporation on the antibacterial, morphological, structural, thermal, and crystalline properties of developed films was studied. The minimum inhibitory concentration values of the three organic acids against gram-negative (E. coli) and gram-positive (S. aureus) bacteria were measured using the tube dilution method. The MIC results revealed that lactic acid and citric acid are effective against both gram-negative and gram-positive bacteria, while acetic acid showed more effectiveness against gram-negative bacteria (E. coli). MBC results revealed that organic acids have potent bactericidal activity. Citric acid resulted in higher inhibition for gram-positive bacteria (S. aureus) compared to gram-negative bacteria (E. coli.). While acetic acid showed higher inhibition for E. coli. than S. aureus. Lactic acid displayed similar inhibition against both S. aureus and E. coli. Among different organic acids, lactic acid incorporation resulted in a more homogeneous, transparent, and thermally stable film. As evidenced by the micrographs, the lactic acid incorporation resulted in a compact film structure without any visible cracks. While X-ray diffraction showed an increase in crystalline properties due to organic acid modification. In this study, it was indicated that modification with organic acids (polycarboxylic acids) effectively improved the overall properties of developed films depending on the type of organic acid used. The developed films have the potential to replace harmful synthetic films in food packaging. [ABSTRACT FROM AUTHOR]

Fillers improve the thermal stability and mechanical properties of bio-plastics. This research aims to synthesize and characterize biodegradable film from mango seed kernel starch reinforced with micro-pottery clay using glycerol as a plasticizer. The mango seed kernel starch was extracted and characterized in terms of solubility (75.01 ± 0.35%), swelling power (22.3 ± 0.24%), moisture content (10.33 ± 0.21%), ash content (0.41 ± 0.13%), and yield of starch (19.97 ± 0.021%). Pottery clay to starch ratios of 0, 5, 7, and 10% w/w, and glycerol to starch ratios of 0, 25, 30, and 35% w/v were evaluated. The film was analyzed for its physicochemical properties such as tensile strength, thickness, transparency, and biodegradability. Furthermore, the surface functional groups, morphology, and thermal properties of the film were analyzed using FT-IR, SEM, 3D optical surface profiler, and TGA. The control film has a tensile strength of 3.33 ± 0.008Mpa whereas the tensile strength of the reinforced film is 7.66 ± 0.012 MPa. The maximum biodegradation rate of the film is 74.38 ± 0.012 at 35% glycerol concentration. Increasing the amount of glycerol increased the solubility of the biodegradable film due to its strong affinity towards water molecules. Glycerol increases film thickness and reduces its transparency. The microstructure results indicate that clay particles are homogeneously dispersed with reduced surface roughness of reinforced films compared to the control. The mango seed kernel starch film reinforced with 5% pottery clay and 25% glycerol was selected based on tensile strength, thermal stability, and biodegradability properties. In summary, the addition of glycerol and pottery clay significantly affects the physicomechanical and thermal properties of films. [ABSTRACT FROM AUTHOR]

In this study, a simple pH-colorimetric film was developed to detect the spoilage of pasteurized milk. The biosensor was fabricated by incorporating the pH-sensitive anthocyanins (AC) extracted from blue pea (Clitoria ternatea L.) flower into a starch-based edible film. The color responses of both AC aqueous extracts and edible films incorporated with different AC concentrations towards different pH buffers (pH 2–11) were measured using Ultraviolet–visible (UV–Vis) spectrophotometer and colorimeter, respectively. Based on the results, there were significant differences (p < 0.05) for both total color changes (∆E) and L*a*b color system of the pH-sensitive edible film in different pH buffers. It indicated that the AC incorporated edible films were able to exhibit color changes over a wide range of pH. The potential application of the pH-sensitive film in spoilage detection was then carried out. Color changes of the film in commercial pasteurized milk were measured at predetermined intervals (24, 48, and 72 h) under storage conditions of 25 °C. Meanwhile, milk samples were collected for the microbiological test [total plate count (TPC)]. Results showed that the pH-sensitive films were able to detect pH changes of pasteurized milk which was associated with milk spoilage with visually observable color changes from deep blue to a light blue and showed a significant ∆E (p < 0.05) of 19.95 ± 0.009. The ∆E of the films in spoilage detection has a significant correlation with the pH changes of milk (R = − 0.9932) and TPC with a desirable coefficient (R = 0.9918). Therefore, the pH-sensitive edible film can provide a highly sensitive and non-destructive way of monitoring the food quality or spoilage without creating safety issues in the food industry. [ABSTRACT FROM AUTHOR]

This work aimed to compare the potential application of anthocyanins extracted from jabuticaba fruit (Plinia cauliflora) and purple sweet potato (Ipomoea Batatas L.) peels as potential raw materials to manufacture colorimetric indicator films. The effect of anthocyanin source on morphology, thickness, moisture content, hydrophobicity, solubility in water, chemical structure, thermal properties, color, and opacity of films was analyzed. Furthermore, color change of films when exposed to controlled visible light and their application to monitoring meat freshness at three temperatures (− 20, 4, and 20 °C) was studied. Anthocyanins from both agri-food wastes increased the molecular spacing in the polymer chains, increasing thickness values and decreasing the thermal stability of the films. However, this effect was more evident when anthocyanins from purple sweet potato peels were used. The other physicochemical properties of colorimetric films were not altered with the presence of anthocyanins. Both colorimetric indicator films showed visible changes from red color to blue color when used to monitor meat freshness at the proposed storage temperatures. Based on physicochemical and colorimetric results, jabuticaba peel is an interesting agri-food waste to manufacture colorimetric indicator films for the food packaging sector. [ABSTRACT FROM AUTHOR]

BACKGROUND Fish spoilage leads to an increase in the pH value of the fish. A colorimetric pH indicator can be used to monitor fish spoilage and has been exploited in intelligent packaging because of its simplicity, practicality and low cost. The aim of this study was to develop two pH‐indicator films comprising starch (S), tara gum (TG), polyvinyl alcohol (PVA) and anthocyanins extracted from blueberry peel and the films were then used to monitor the freshness of tilapia fillets during storage at 25 and 4 °C. RESULTS: The ultraviolet‐visible (UV‐visible) spectra and color of anthocyanins changed within pH 2–10. Fourier‐transform infrared spectroscopy, UV‐visible spectrophotometry and scanning electron microscopy certified that blueberry peel extract (BPE) had been introduced into the S/PVA and TG/PVA matrices. Visual color changes in the films occurred at pH 2–8. A freshness application test was conducted in tilapia fillets stored at 4 and 25 °C, and visual color changes in the films were observed. The TG/PVA/BPE film had a greater color difference (ΔE) from pink and transparent to dark yellow at 25 °C and to dark purple at 4 °C than ΔE of S/PVA/BPE film, which sufficiently correlated with the change of total volatile base nitrogen (TVB‐N) and total aerobic counts (TACs) of fillets. CONCLUSION: It can be concluded that the color changes of TG/PVA/BPE films were corresponded with TVB‐N and TAC values of tilapia fillets, which presented great potential as a visual package label to monitor fish freshness at ambient and chilled temperatures. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

In the present study, 0.5–1.5% silica powder, from sugarcane waste ash, was incorporated into corn and potato starch bioplastics doped with sodium silicate solution to improve the properties of elongation at break and increase the thermal resistance of the bioplastics. The starch-based bioplastics were produced by casting and characterized by color analyses, transparency, opacity apparent, humidity, thickness, tensile strength, elongation at break, FTIR, DSC, SEM, and biodegradation assay. The addition of 0.5% of silica powder improved the elongation at break of the corn starch-based bioplastics. The sample CS5-P0.5 presented the highest percentage of elongation at the break among the studied samples, increased from 59.2% (without silica powder) to 78.9% (with silica powder). For potato starch bioplastic the addition of 0.5% of silica powder did not improve elongation at break but increased the thermal resistance. Increased until 17 °C for PS5-P0.5 sample and until 11 °C for PS7.5-P0.5 sample. The bioplastics of potato starch were biodegraded in 5 days, and those of corn starch took almost 40 days. Silica powder inhibited the growth of fungi in starch bioplastics. [ABSTRACT FROM AUTHOR]

This work aimed to study the effect of modified cassava starches, and PVA grade on the properties of biodegradables sheets produce with starch/PVA blends by an extrusion-calendering process; using native starch, distarch phosphate, acetylated distarch phosphate, acetylated distarch adipate or oxidized starch; PVA with 88% and 98% hydrolysis degrees (HD), and glycerol as a plasticizer. The sheets had tensile strength, Young's modulus, and elongation that ranged from 1.0 to 6.8 MPa; 3.2 to 16.2 MPa and 130 to 443%, respectively. Sheets produced with higher HD PVA had better mechanical properties, independent of starch type. Materials produced with all starch types presented similar response for the same PVA, except those with oxidized starch, that had the poorer mechanical properties. All the sheets were visually homogeneous and had good processability. Sheets produced with higher HD PVA (98%) had better mechanical properties and higher crystallinity than those produced with lower HD PVA (88%) because the higher the HD, the higher the number of hydroxyl groups, which leads to a better interaction with the starch. The biodegradable sheets can be produced on an industrial scale because they have adequate mechanical properties and use well-known industrial techniques. [ABSTRACT FROM AUTHOR]

The Araucaria angustifolia seed, named pinhão, has a high content of carbohydrates, and it is considered an unconventional starch source. Its coats are rich in phenolic compounds, which can be easily extracted with some solvents. This study presents a method of aqueous and ethanolic extraction of phenolic compounds from pinhão coats and its incorporation into corn and pinhão starches. Thermogravimetry, differential scanning calorimetry, X-ray powder diffractometry, Fourier-transform infrared spectroscopy and field emission gun-scanning electron microscopy were applied to evaluate the thermal, structural and morphological properties of starches. The control samples were prepared under the same conditions, with deionised water and ethanol/water 55:45 v/v, without extracts. Starches incorporated with both extracts showed lower thermal decomposition temperatures than the native ones. The gelatinization enthalpy (ΔHgel) of corn starch decreased after incorporation with extracts. The ΔHgel of native pinhão starch was 7.3 J g−1. A higher ΔHgel was observed after treatment with ethanolic extract, while the aqueous extract caused a decrease in this value. Treatments did not change the diffraction patterns but change the relative crystallinity (RC) of starches, except to the samples treated with ethanol/water 55:45 v/v that maintained RC similar to the native ones. There was a good correlation of FTIR data with RC and ΔHgel. After incorporation with ethanolic extract, the pinhão starch showed superficial peeling. No change was observed in morphological characteristics for the other samples. Results indicate that there is an interaction between the phenolic compounds of the pinhão coats and the starch. [ABSTRACT FROM AUTHOR]

It is evermore imperative to develop green processes and products due to the environmental and health problems facing modern society. Thus, the aims of this study were as follows: to use HPLC-MS to identify and quantify the phenolic compounds in Amazon Curcuma longa L. starch; to develop a bioactive starch film and to characterise its phenolic compounds (HPLC-MS) and antioxidant capacity (DPPH, ABTS and ORAC), as well its thickness and granular structure (SEM), mechanical (tensile strength and elongation at break) and colour (CIE-lab scale: L*, a*, b*) properties. HPLC-MS revealed eight major phenolic compounds in the C. longa starch and six in its film. The starch and the film from C. longa had high levels of antioxidant capacity, 65-92% (as measured by DPPH and ABTS). Furthermore, C. longa exhibited a smooth structural surface and strong resistance to tensile force, as well as maintaining its elasticity as measured by mechanical assays (tensile strength and elongation at break). Based on the obtained results a novel biodegradable starch film was obtained applying a single matrix, the Amazon Curcuma longa L. starch. [ABSTRACT FROM AUTHOR]

In this study, hollow microparticles were produced with polymethylsilsesquioxane/chitosan/bovine hydroxyapatite/hexagonal boron nitride (PCBB) polyblend using single-nozzle electrospinning method. Also, hollow microparticles are loaded with amoxicillin (AMX) and their drug delivery capabilities have been studied according to a treatment of osteomyelitis disease. The morphology, chemical groups, particle size, antimicrobial activity, and AMX drug release were systematically studied using scanning electron microscopy (SEM), optical microscopy, Fourier transformation infrared spectroscopy (FTIR), hollow microparticle size measurements, antimicrobial activity test, and UV spectroscopy. In vitro biocompatibility was analyzed with human bone osteosarcoma (U2OS) cell line. This present work can help in the design of a drug delivery platform for antimicrobial effect and bone repair at the same time for osteomyelitis disease treatment. [ABSTRACT FROM AUTHOR]

Technological advances have led to increased constraints regarding food packaging, mainly due to environmental issues, consumer health concerns, and economic restrictions associated therewith. Hence, food scientists and technologists are now more focused on developing biopolymer packages. Starch satisfies all the principal aspects making it a promising raw material for edible coatings/films. Modified starch has grabbed much attention, both at the academic as well as at the industrial level, because these films exhibit dramatic improvement in filming properties without involving any significant increase in cost of production. Various methods, additives used, and recent advances in the field of starch film production are discussed in detail in this review, which also provides an overview of the available information along with recent advances in modified starch film packaging. [ABSTRACT FROM AUTHOR]