ABSTRACT
As food packaging evolves, consumer interests are shifting from traditional to intelligent food packaging systems. Intelligent packaging includes active components that display changes in a visual or interactive form perceivable by consumers. This offers real-time monitoring of the quality and shelf life of the packaged food and enhances transparency. For example, pH-sensitive natural pigment-based films change color in response to variations in pH levels, enabling the film/labels to reflect alterations in the acidity or basicity of the food inside the package. Natural pigments like anthocyanins, curcumin, betalains, chlorophyll, and carotenoids have been comprehensively reported for developing biodegradable pH-sensitive films of starch, protein, chitosan, and cellulose. Natural pigments offer great compatibility with these biopolymers and improve the other performance parameters of the films. However, these films still lack the strength and versatility of petroleum-based synthetic plastic films. But these films can be used as an indicator and combined with primary packaging to monitor freshness, time-temperature, and leak for muscle foods, dairy products, fruits and vegetables, and bakery products. Therefore, this review provides a detailed overview of pH-sensitive pigments, their compatibility with natural polymers, their role in film performance in monitoring, and their food packaging applications.
ABSTRACT
The study aimed at the development of elephant foot yam starch (EFYS) based edible film through blending of Xanthan (XG) and agar-agar (AA). Film thickness and density increased with increase in concentration of hydrocolloids and the respective highest value 0.199 mm and 2.02 g/cm3 were found for the film possessing 2% AA. The film barrier properties varied with hydrocolloids and the lowest value of water vapour transmission rate (1494.54 g/m2) and oxygen transmission rate (0.020 cm3/m2) was observed for the film with 1% XG and 1.5% AA, respectively. Mechanical and thermal properties also improved upon addition of hydrocolloid. Highest tensile strength (20.14 MPa) and glass transition temperature (150.6 °C) was observed for film containing 2% AA. Fourier transform infrared spectroscopy demonstrated the presence of -OH, C-H, and C=O groups. The change in crystallinity was observed through peak in X-ray diffraction analysis, which increased with increase in the hydrocolloids' concentration.
ABSTRACT
Limited studies have been reported on the interaction of elephant foot yam (EFY) starch and hydrocolloids. Hence the present study investigated the effect of hydrocolloids (agar-agar, AAG and xanthan gum, XG) concentration (0.5, 1, 1.5 and 2%) on pasting, rheological, thermo-functional and morphological properties of EFY starch. The increase in concentration reduced the swelling index and enhanced the solubility. Peak, holding, break down and set back viscosity was highest at 2% XG than AAG. Dynamic storage modulus (G') was higher than loss modulus (Gâ³) within frequency range with an increase in hydrocolloids concentration. Pasting temperature reduced from 77.20 to 49.7⯰C (AAG) and 77.20 to 61.56⯰C (XG). FTIR exhibited differences in peak absorbance and broadness of OH and CO stretching at 3400-3200â¯cm-1 and 1260-1000â¯cm-1 upon hydrocolloids' addition. Increased AAG concentration reduced the peak temperature of gelatinization and retrogradation of EFY starch. The effect of hydrocolloids and their concentrations on the higher binding of EFY starch molecules and crystallinity has also been supported by SEM images. These results show that EFY starch with hydrocolloids can be used as a thickener. Its good binding ability may be explored for the possible applications in bakery industry and for the development of edible packaging film.
