Effects of glycerol and storage relative humidity on the properties of kudzu starch‐based edible films

Abstract

Kudzu (Pueraria lobata) starch films were prepared using glycerol as plasticizer. The effects of glycerol (0,10,20,30, and 40% of dry starch) and storage relative humidity (RH, 53, 75, and 100%) on molecular interactions, crystalline structural characterizations, and thermal stabilities of the films were investigated using Fourier transform-infrared (FT-IR) spectra, XRD, and thermogravimetry and DTA (TG-DTA). The results showed that kudzu starch could form intermolecular hydrogen bonds with glycerol and water molecules, and increasing RH could enhance the sensibility of C-O bonds in C-O-C groups to glycerol. The addition of glycerol promoted the formation of B-type and V-type crystal structure in plasticized film, whereas increasing RH impeded V-type crystal structure. Thermal stability decreased slightly as glycerol content and RH increased. Moreover, anti-plasticization was found from TG-DTA spectra and water sorption isotherms at low water activities. Furthermore, water vapor permeability (WVP) and mechanical properties of the films were also studied. The WVP values increased with increasing glycerol content and RH, and the lowest value was about 3.15 Â 10 À11 g m À1 s À1 Pa À1for 20% glycerol plasticized film at 50% RH. The puncture strength of kudzu starch film ranged from 1.31 to 10.86 N and deformation ranged from 4.10 to 5.15 mm.

Effect of plasticizer type and concentration on physical properties of biodegradable films based on sugar palm (arenga pinnata) starch for food packaging

“…As observed, the unplasticized SPS film shows a large amorphous area with crystalline peaks Fig. 7 Zhong and Li (2014) who suggested that peak 2θ at 17°e xhibited the formation of double-helical B-type crystalline. The X-ray diffraction patterns of unplasticized SPS films are similar to that of films containing glycerol (G-and GSplasticized films).…”

“…Furthermore, it can be seen that the intensity of diffraction peaks increased as glycerol concentration increased from 0 to 45 % for G-and GS-plasticized films. Zhong and Li (2014) who studied the effect of glycerol on the properties of Kudzu starch films found that crystallinity of the films was enhanced as glycerol concentration increased from 0 to 40 %. Bergo et al (2008) also reported similar results regarding the crystallinity of cassava starch films with glycerol content from 0 to 45 %.…”

Mechanical and microstructural properties of sugar palm (Arenga pinnata Merr.) starch film: Effect of aging

“…The higher glycerol-containing extruded material takes up more water during storage. Therefore, increases the rate of retrogradation [19].…”

Effect of Plasticizer Type and Concentration on Tensile, Thermal and Barrier Properties of Biodegradable Films Based on Sugar Palm (Arenga pinnata) Starch

“…Thus, starch has attracted a great deal of interest as a potential alternative to conventional plastics for packaging applications. Several studies have investigated the development and characterization of starch based films from corn [4,[6][7][8], potato [9][10][11][12][13], cassava [14][15][16][17][18][19][20], banana [21], yam [22,23], pea [1], sago [24][25][26], rice [27][28][29][30], maize [31][32][33][34], Kudzu [35] and agar [36][37][38][39]. According to Sahari et al [40] sugar palm starch is also a potential biopolymer material for making biodegradable films.…”

“…On the contrary, the addition of plasticizers decreases film mechanical resistance. The type and concentration of plasticizer employed has significant effect on the physical, thermal, mechanical and barrier properties of films [35,[50][51][52]. The most common plasticizer utilized for starch based films are polyols such as glycerol and sorbitol, amongst many others.…”