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

Abstract

Natural extracts are investigated as plasticizers of starch–glycerol biobased films for food coating applications. For this purpose, films with cassava starch, glycerol, and distilled water with and without green tea or basil extracts are obtained by solvent casting. The plasticizing effect of the extracts is confirmed from the films crystalline structure, thermal degradation behavior, glass transition temperature, and tensile properties. Increased mobility of starch chains is the result of a strong interaction between extract components and starch molecules. The Kohlrausch–Williams–Watts (KWW) theoretical modeling, used for the first time to determine the effect of antioxidant components in starch films, also confirms the plasticizing effect of either green tea or basil extracts. In addition, the original luminosity of the starch film is not compromised by the incorporation of the extracts. Moreover, a delay in the starch retrogradation is achieved, making the film more durable and hence, very promising to be used as food coating.

Collagen films, cassava starch and their blends: Physical–chemical, thermal and microstructure properties

“…Regarding the second, third and fourth stages of degradation, the T2 film presented two endothermic events, and one exothermic event, attributed to total evaporation of free water and loss of bound water in the film matrix, and/or the decomposition of fractions of glycerol and sucrose. Similar results were reported by Jaramillo et al 59 in cassava starch films containing green tea and basil extracts. This study demonstrated that thermal degradation of glycerol fractions can occur between 180°C and 280°C.…”

“…For the T2 cassava starch film, a characteristic peak of a semi‐crystalline structure was observed at 2Ɵ = 18.2°. According to Jaramillo et al, 59 it may be associated with the peak of high‐density amylose. Another peak, however wider, can be observed around 21.4°, and it may be associated with the beginning of crystallization of amylopectin, which is slower when compared to amylose, and happens during film storage.…”

Bioactive food coating: A review

“…Jamróz et al 98 reported that green tea extract incorporated in furcellaran–gelatin films created a bioactive film with both enhanced antioxidant and antimicrobial activities. Similar results have been reported for films made of chitosan, 99 gelatin, 100 alginate 101 and starch 102 . Black tea extract has also been used in order to increase the antioxidant activity of HPMC and starch films 103,104 …”

“…Similar results have been reported for films made of chitosan, 99 gelatin, 100 alginate 101 and starch. 102 Black tea extract has also been used in order to increase the antioxidant activity of HPMC and starch films. 103,104 Wei et al 105 reported the incorporation of anthocyanins from purple sweet potato into gellan gums edible films.…”

Preparation and Performance Characterization of a Composite Film Based on Corn Starch, κ-Carrageenan, and Ethanol Extract of Onion Skin

“…CS/κC films had three diffraction peaks at 2θ = 17.7°, 2θ = 19.7°, and 2θ = 22.1°. The diffraction peaks at 2θ = 17.7° and 19.7 were due to the recrystallization of amylose and amylopectin during the storage of the starch composite films [ 28 ]. After adding the EEOS, the diffraction peak at 2θ = 17.7° decreased with the addition of EEOS.…”