Search

In this study, blue corn extract (BCE) was added to a corn starch, polyvinyl alcohol (PVA) based smart packaging indicator film. Characterization of physical properties of films by tensile test and color difference test. The color changes of BCE and corn starch/PVA/BCE composite films were investigated in the pH range of 1–14. Scanning electron microscopy images showed good compatibility of BCE with the substrate. BCE significantly increased the tensile strength, elongation at break and water content of the films (p < 0.05). The corn starch/PVA/BCE films had good color stability. The addition of BCE had no significant effect on film thickness (p < 0.05). The corn starch/PVA/BCE film underwent a significant change from red to dark purple during the film application for the preservation and storage of tilapia. The results showed that this pH sensitive film has the potential to indicate the shelf life of tilapia. Practical Application: Smart pH indicator films were prepared by mixing different ratios of blue corn extract with corn starch/PVA substrates. The effects of different ratios of BCE on the physical properties and pH sensitivity of the composite membranes were investigated. During the storage of tilapia, the composite membranes showed a clear change from red to dark purple. [ABSTRACT FROM AUTHOR]

The pH-sensitive films were developed by adding Kadsura coccinea (KC) extract to chitosan (CH), gelatin (GL), and sodium alginate (SA) matrix. Due to abundant anthocyanin content, KC could change its colors with changing pH value. The KC extract could significantly increase the thickness, water vapor barrier property (WVP), mechanical property, UV–vis light barrier property, mechanical properties, and antioxidant capacity of the films. However, the KC extract could considerably reduce moisture content and thermal behavior of the films. The CH-KC film had best oxidation resistance. The GL-KC film had best ultraviolet light transmission and thermal properties. The SA-KC film had best WVP and mechanical properties. Fourier transform infrared spectroscopy revealed the molecular interaction between polymer matrix and KC extract. Moreover, CH-KC, GL-KC, and SA-KC films were intelligent and showed significant color changes in different buffer solutions, but the effect of the GL-KC film was most obvious. The GL-KC films can be used as food active and intelligent packaging, especially for monitoring the freshness of meat and seafood with pH changes at room temperature. [ABSTRACT FROM AUTHOR]

In this research, pH-sensitive films were prepared based on gelatin, chitosan, and nanocellulose as film matrix, anthocyanins from hawthorn (Crataegus scabrifolia) fruit (0, 10, 15, and 20%) as natural pigments. The films were evaluated by thickness, moisture content, swelling property, water vapor permeability, mechanical property, UV–Vis light barrier property, microstructure, and color stability of films. The color of hawthorn fruit extract was distinctly different from pH 1 to pH 14. Scanning electron microscope analysis confirmed the biocompatibility between film matrix and hawthorn fruit extract. Fourier transform infrared spectra confirmed the structural changes in polymer matrix and anthocyanins. Furthermore, the pH-sensitive film showed evident color changes from red–purple (fresh), light grey (use soon), to yellow-green (spoiled) when applied to indicate the freshness of shrimp stored under 4 ± 1 °C, before the TVB-N value slowly increased to exceed the limit value (20 mg/100 g) on day 6. The results suggested that the developed films could be used to indicate the changes of food quality. [ABSTRACT FROM AUTHOR]

Black ear mushroom (Auricularia auricula) is an important genus of cultivated mushroom, which contains health benefits. Incorporating black ear (BE) mushroom into brown rice by extrusion changed the physicochemical, and more importantly, the nutritional characteristics of the extrudates. With increased incorporation of BE mushroom in the extrudates in vitro starch digestion of the different extrudates revealed significantly reduced starch digestion, suggesting a lower glycaemic index. In addition, incorporation of BE in brown rice extrudates increased the total phenolic concentration of the samples, which led to higher % scavenging effect against free-radicals in DPPH assay. In the ORAC assay for anti-oxidant activity, BE powder exhibited the highest anti-oxidant activity, followed by 10% BE and 15% BE, and 5% BE extruded products. The extruded brown rice control exhibited the lowest antioxidant activity. Inclusion of black ear mushroom was shown to improve the nutritional qualities of the food product illustrating the connection between plant bioactive ingredients and human health. [ABSTRACT FROM AUTHOR]

In this study, poly( l-lactide) (PLA) films were fabricated by melt processing and the plasticizing effect of hexadecyl lactate (HL) (0, 5, 7.5, 10, and 12.5 wt% on PLA were investigated by scanning electron microscopy (SEM), differential scanning calorimetry, thermogravimetric analysis, tensile, transparency, and water vapor permeability tests. The SEM analysis revealed that PLA with 10 wt% HL appeared uniform with extra small bumps, confirmed the interaction between PLA and HL. The thermal analysis revealed a glass transition temperature of 57.4 °C for neat PLA film, but the addition of HL elicited a decrease in the temperature of the peak (43.8 °C). The incorporation of plasticizer into PLA resulted in the increase of elongation at break, as well as the decrease of tensile strength and tensile modulus. Even though a decrease in transparency was recorded, the PLA/HL blend films appeared transparent by visually observation. The water vapor permeability of PLA/HL blend films increased with the increase of HL. The PLA/HL blend films could effectively extend the shelf-life of fresh-cut pears as the commercial low density polyethylene films. The results indicated that the properties of PLA films can be modified with the addition of HL and PLA/HL blend films could serve as an alternative as food packaging materials to reduce environmental problems associated with synthetic packaging films. [ABSTRACT FROM AUTHOR]

Poly(lactic acid)/poly(trimethylene carbonate) (PLA/PTMC) films incorporated with cinnamaldehyde (0, 3, 6, 9, and 12 wt%) were prepared by solvent casting and characterized by physical, mechanical, and antimicrobial properties. SEM analysis revealed that the surface of film became rougher with certain porosity when cinnamaldehyde was incorporated into the PLA/PTMC blends. Cinnamaldehyde acted as plasticizers which reduce the intermolecular forces of polymer chains, thus improving the flexibility and extensibility of the films. Differential scanning calorimetry showed that the crystallinity of PLA phase decreased by the presence of cinnamaldehyde in the composite films. Water vapor permeability of films increased with the increase of cinnamaldehyde loading. However, the active PLA/PTMC/cinnamaldehyde composite films showed adequate barrier properties for food packaging application. Incorporation of cinnamaldehyde to the PLA/PTMC polymer matrix improved the antimicrobial activity of active packaging films. These results indicated that the best compromise between mechanical, barrier, thermal, and antimicrobial properties could be achieved by the addition of 9 wt% cinnamaldehyde into PLA/PTMC blends. [ABSTRACT FROM AUTHOR]