Water Susceptibility and Mechanical Properties of Thermoplastic Starch–Pectin Blends Reactively Extruded with Edible Citric Acid

Abstract

IntroductionEco-friendly materials has emerged as one of the most reliable and promising solutions for the food and drug packaging next generation [1][2][3] . In this context, thermoplastic starch (TPS) 4-11 and pectin [12][13][14][15] are promising bases for polymers manufacture due to their wide availability, low cost, renewable character and ability of being produced using traditional processing techniques used in the plastics industry, such as extrusion.TPS and pectin polymer blends have been successfully developed resulting in good mechanical properties and oxygen barrier properties polymers [16][17][18][19][20][21] , especially regarding high methoxyl pectin. Furthermore, the association between cationic TPS and pectin has also been examined in various studies 22,23 . Cationic starch and high methoxyl pectin may interact favourably with one another due to the cationic nature of TPS and the anionic nature of the high methoxyl pectin. According to Prado and Matulewicks 24 , the combination of cationic polysaccharides with anionic polymers can lead to interpolyeletrolyte complexes (IPECs) with hydrogel like structures, with the possibility of producing a hydrogel physically cross-linked with in natura sources molecules. Such possibility has a great impact in developing food contact polymers, once conventional crosslinking processes usually uses toxic compounds, such as epichlorohydrin [24][25] .Reactive extrusion has been successfully applied to TPS polymers 1 and has resulted in more flexible and less brittle TPS materials 5,26-29 when compared to similar TPS materials obtained by conventional extrusion. However, few studies have investigated reative extrusion under edible acids and fewer have examined the use of reactive extrusion on cationic starch bio-based polymers 15 and even less have studied high methoxyl pectin polymers or pectin-starch composites and neither are information about such polymers mechanical or barrier performance. Cationic and in natura starches were added to pectin in order to evaluate both starches polymers water susceptibility and mechanical properties, when blended by reactive extrusion with pectin in presence of citric acid. Besides of the edible and nontoxic characteristics of citric acid, its utilization is justified also due to pectin ability in forming gel at low pH (normally using citric acid), in presence of high temperature [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] . Materials and Methods MaterialsIn natura (not modified) (NM) and cationic (C) corn starch materials were obtained from Unilever Brasil Alimentos Ltda and Corn Products Brazil, respectively. The cationic starch (FH5804) was substitution degree of 0,036% and an Pectin and starch are edible, non-toxic, biodegradable and obtained from renewable sources. Also have the benefit to be easily cross-linked producing hydrogels. Reactive extrusion with edible citric acid and cross linking interactions was evaluated on extruded thermoplastic in natura and cationic starch-pectin blends. Materials w...

EffectofWaterLoadingonTheChemicalStructureand Mechanical Properties of Thermoplastic Tapioca StarchFilm

“…In curve (a), C-O-C and C-O-H asymmetric stretch was equally seen to have distinct intensities in all the curves and a downward shift was equally noticed from 1021 cm -1 in curve (a) to 1019 and 1007 cm -1 in curve (b) and (c) respectively. These changes signify the intermolecular hydrogen bond interactions between the starch ether group and OH group of the water molecules [20]. There is a CH2 and CH3 bending vibrations seen between 1465 and 1355 cm -1 on the starch films.…”

Polysaccharides for Biodegradable Packaging Materials: Past, Present, and Future (Brief Review)

“…Thus, Lopez et al [ 117 ] stated that the introduction of chitosan into thermoplastic starch reduced growth of S. aureus and E. coli at contact. One more polysaccharide used in blends with starch for production of biodegradable materials is pectin [ 125 , 126 , 127 , 128 ]. These polymers obtained under reactive extrusion can lead to formation of materials with interesting nontoxic and differentiated properties [ 125 ].…”

“…One more polysaccharide used in blends with starch for production of biodegradable materials is pectin [ 125 , 126 , 127 , 128 ]. These polymers obtained under reactive extrusion can lead to formation of materials with interesting nontoxic and differentiated properties [ 125 ].…”

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