Chitosan-Starch Films with Natural Extracts: Physical, Chemical, Morphological and Thermal Properties

Abstract

The aim of this study is to analyze the properties of a series of polysaccharide composite films, such as apparent density, color, the presence of functional groups, morphology, and thermal stability, as well as the correlation between them and their antimicrobial and optical properties. Natural antioxidants such as anthocyanins (from cranberry; blueberry and pomegranate); betalains (from beetroot and pitaya); resveratrol (from grape); and thymol and carvacrol (from oregano) were added to the films. Few changes in the position and intensity of the FTIR spectra bands were observed despite the low content of extract added to the films. Due to this fact, the antioxidants were extracted and identified by spectroscopic analysis; and they were also quantified using the Folin-Denis method and a gallic acid calibration curve, which confirmed the presence of natural antioxidants in the films. According to the SEM analysis, the presence of natural antioxidants has no influence on the film morphology because the stretch marks and white points that were observed were related to starch presence. On the other hand, the TGA analysis showed that the type of extract influences the total weight loss. The overall interpretation of the results suggests that the use of natural antioxidants as additives for chitosan-starch film preparation has a prominent impact on most of the critical properties that are decisive in making them suitable for food-packing applications.

Influence of Green Tea and Basil Extracts on Cassava Starch Based Films as Assessed by Thermal Degradation, Crystalline Structure, and Mechanical Properties

“…The latter behavior was also observed in the derivative curves (Figure 5B). Significant weight loss at the same range of temperatures was also reported by other authors for starch films prepared with natural extracts, as a consequence of the earlier thermal degradation of the extracts compared with that of starch …”

Effects of Carvacrol, Thymol and essential oils containing such monoterpenes on wound healing: a systematic review

“…The monoterpenes account for about 90% of the EO and are endowed with a wide range of biological and pharmacological properties . Carvacrol and thymol are monoterpenes widely found in essential oils of the genus Origanum . These isomers of position (Figure ) have several antibacterial and antifungal activities and also anti‐inflammatory and analgesic effects.…”

“…[8,9] Carvacrol and thymol are monoterpenes widely found in essential oils of the genus Origanum. [10] These isomers of position ( Figure 1) have several antibacterial and antifungal activities [11] and also anti-inflammatory [12] and analgesic [13] effects. These properties make these compounds strong candidates for the development of products for tissue repair.…”

Effects of the addition of ultrasound‐pulsed gelatin to chitosan on physicochemical and antioxidant properties of casting films

“…However, this biopolymer has displayed certain limitations in the mechanical and antioxidant properties of its cast films . Studies of chitosan based material characterization have shown that the addition of polymers such as starch, gelatin and natural extracts have improved antioxidant and physicochemical properties . For example, blending biopolymers such as chitosan and collagen from jumbo squid byproducts produced films with enhanced mechanical properties due to an increase in the percentage of elongation and a decrease in the elastic modulus of the films, and these effects were related to the interactions between polymers …”

“…2,3 Studies of chitosan based material characterization have shown that the addition of polymers such as starch, gelatin and natural extracts have improved antioxidant and physicochemical properties. 4,5 For example, blending biopolymers such as chitosan and collagen from jumbo squid byproducts produced films with enhanced mechanical properties due to an increase in the percentage of elongation and a decrease in the elastic modulus of the films, and these effects were related to the interactions between polymers. 2,6 One green technology that, in recent years, has been used for the improvement of the functional properties of proteins is high-intensity ultrasound.…”