Amir Rezaei; Masoud Rezaei; Mahdi Alboofetileh
Abstract
[1]Introduction: Nowadays, pH indicator has engrossed wide attention because of its eligibility to monitoring shelf life. Intelligent packaging is authoritative of detecting, sensing, tracing, recording and communicating properties to provide information is communicated directly through color changes. ...
Read More
[1]Introduction: Nowadays, pH indicator has engrossed wide attention because of its eligibility to monitoring shelf life. Intelligent packaging is authoritative of detecting, sensing, tracing, recording and communicating properties to provide information is communicated directly through color changes. In the meantime, natural anthocyanins are non-toxic, water- soluble and safe dye that are indicator to pH change. Anthocyanins are a large group of natural dyes. Some natural anthocyanin, such as anthocyanin extracted from mulberry, black bean, blueberry and violet basil (Ocimum basilicum) are used to spoilage monitoring. In present study, an intelligent pH-indicator film based on Arabic gum- Carboxymethyl cellulose incorporated with Violet basil (Ocimum basilicum. L) Anthocyanin was prepared and its properties including structural, physical, mechanical, thermal, antioxidant activity and color sensitivity to changing pH and ammonia gas were evaluated. Materials and methods: For this purpose, at first anthocyanin of Violet basil was extracted and its color reactions were investigated. In next step, the extracted anthocyanin was added to Arabic gum- Carboxymethyl cellulose at different concentrations (40, 60 and 80 mg/100 g film formation solution) and their properties were evaluated. Results and discussion: The results of FTIR and XRD tests showed that the extracted anthocyanin was successfully dissolved in the composite film. Addition of anthocyanin to film matrix led to increasing the WVP and antioxidant activity and decreasing the water contact angle, elongation at break (EB) and thermal properties. The tensile strength value of the prepared films increased from 19 to 23.64 MPa with increasing anthocyanin content from 0 to 60 mg/100 g film solution; but, it decreased with further increase of the anthocyanin content. Exposing the indicator films to ammonia gas and different pHs led to changing the color changes from red to yellow. These color variations of films were consistent with the color changes of the anthocyanin solution. This result indicates that the films prepared sensitive to pH change, and observed different color in films as the solution is changed from acidic to alkaline because causes its structural changes. The structure of anthocyanin is yellow salt ions in acidic solutions, is converted to quinoidal in weak alkaline solutions, and becomes unstructured in high pH solutions.In this study, pH indicator films were prepared based of Carboxymethyl cellulose and Arabic gum containing violet basil anthocyanin. The developed films are non-toxic and biodegradable and provide visible color response. Based on these results can be concluded that the indicator film prepared in present study could be used as intelligent food packaging for visual evolution of freshness/spoilage in food products
Food Technology
Amir Rezaie; Masoud Rezaei; Mahdi Albooftileh
Abstract
Introduction: Films with appropriate mechanical properties and low permeability are very important for food packaging. Natural polymers have gained increasing attention for the development of biodegradable films due to the environmental problems caused by petroleum-based polymers. Carboxymethyl cellulose ...
Read More
Introduction: Films with appropriate mechanical properties and low permeability are very important for food packaging. Natural polymers have gained increasing attention for the development of biodegradable films due to the environmental problems caused by petroleum-based polymers. Carboxymethyl cellulose (CMC) is a linear polysaccharide that exhibited good film forming properties. Gum Arabic (GA) is another polysaccharide that can be used for preparing the edible and biodegradable films. However, several studies have shown that biopolymers like CMC and GA films have high water vapor permeability and poor mechanical properties in moist conditions. One of the strategies that can be used for improving the properties of biopolymers films is blending the different polymers and formation the composite films. Various studies on the preparation of biocomposite films have been performed, however, to the best of our knowledge, studies on combinations of the CMC and AG have not been reported yet. Thus, the main objectives of this study were to prepare CMC/AG composite films using solvent casting method and investigate the effect of different CMC/AG blending ratio on the physical (water vapor permeability (WVP), water contact angle (WCA), color, opacity and light-barrier properties), mechanical and thermal properties. Furthermore, in order to determine the structural characteristics of the films, fourier-transform infrared spectroscopy (FT-IR) and x-ray diffraction (XRD) measurements were also performed. Material & Method: The CMC and AG solutions were prepared by dissolving 1 g in 100 mL of distilled water at 45 °C for 24 h under magnetic stirring. The prepared solutions were then blended in different proportions (75:25, 50:50, and 25:75). After mixing, glycerol (0.3% w/w) was added as a plasticizer and the solution was stirred for 15 min. The prepared solutions were poured into a glass plate, then dried at 45 °C for 24 h in the oven. Finally, the properties of CMC, GA and composite films were determined. Result and Discussion: In this study, biodegradable films composed of CMC and AG were successfully prepared. Results showed that some properties of the composite films were greatly influenced by addition of AG. So that, WVP of films was decreased significantly in the blend films and the lowest WVP was observed in the 25:75 (AG: CMC) films (p < 0.05). The films hydrophobicity was significantly increased from 41.33o to 61.10o by addition of AG to the CMC films (p < 0.05). With increasing the ratio of AG, the tensile strength (TS) of blend films decreased. Opacity and light transmission of the composite films increased and decreased, respectively with increasing the AG ratio. The differential scanning calorimetry (DSC) test demonstrated that the thermal properties of blend films improved with increasing the AG content. The FT-IR analysis indicated that new interaction was generated between the components of the blend films. Generally, it can be concluded that blending the AG and CMC can improve some of the physico-mechanical properties of the blend films
