Corn Starch‐Chitosan Proportion Affects Biodegradable Film Performance for Food Packaging Purposes

Abstract

This work proposes an advance towards the scaling of biodegradable films based on corn starch and chitosan, considering the relevant film properties that condition their use for food packaging and their economic feasibility. The influence of corn starch: chitosan (CS:CH) proportion and chitosan molecular weight used in the formulation is also studied. Chitosan (CH) addition improves film forming dispersions (FFDs) stability stored under refrigerated conditions and enhances the film UV barrier properties and elongation at break, however material costs are higher. Films with higher starch content exhibited higher elastic modulus and tensile strength. Water vapor barrier, heat‐sealing capacity, and sealing resistance also increase with the corn starch (CS) proportion in film formulation. Taking into consideration the chitosan type used, the polymer‐plasticiser and polymer‐solvent interactions prevail and led to the development of more flexible materials in film formulations with low molecular weight chitosan (LMW‐CH). Meanwhile, polymer‐polymer interactions also became relevant in those obtained with MMW‐CH leading to resistant films. The obtained results indicate that composite films could be used in food packaging design, with those formulated with 75% CS and 25% medium molecular weight chitosan (MMW‐CH) being a good option considering both the film's properties as well as its economical feasibility.

Antimicrobial Starch‐Based Film for Food Packaging Application

“…Various studies attempted to prepare antimicrobial starch film including synthesis of silver nanoparticle in starch gelatinized medium suspension to fabricate silver nanoparticles coated with starch layer [ 14 ] and casting method of chitosan and starch to obtain active starch film's [ 15 ] due to its simplicity and promising active starch film against microbial attack. However, silver nanoparticles could lead to toxicity issues due to hazardous by product during the synthesis, [ 16 ] while casting method involved the use of concentrated antimicrobial agent due to possibility loss of the agent functionalities during the reaction.…”

Seal materials in flexible plastic food packaging: A review

“…There are other studies on the influences of potential reinforcements in biodegradable films, such as blends with cellulose, chitosan, bagasse particles, natural fibres, graphene oxide and/or nanoparticles 143–153 . Pure corn starch and its blends with amylose, cellulose and methylcellulose achieve maximum seal strength values between 0.2 and 0.4 N.mm −1 at a jaw temperature of 166°C, using an impulse sealer 143 .…”

“…Seal strength of films, using an impulse sealer, of mung‐bean starch, crosslinked with citric acid, are maximum, achieving a value between 0.4–0.5 N.mm −1 , with 3% citric acid content 147 . In blends of corn starch and chitosan, another polysaccharide with good film forming ability, seal strength increases with the proportion of corn starch 153 . Another study checked the seal performance of a blend of potato starch, chitosan and graphene oxide.…”

“…142 There are other studies on the influences of potential reinforcements in biodegradable films, such as blends with cellulose, chitosan, bagasse particles, natural fibres, graphene oxide and/or nanoparticles. [143][144][145][146][147][148][149][150][151][152][153] Pure corn starch and its blends with amylose, cellulose and methylcellulose achieve maximum seal strength values between 0.2 and 0.4 N.mm À1 at a jaw temperature of 166 C, using an impulse sealer. 143 In a study with cassava starch, reinforced with cassava bagasse particles, incorporation of medium sized particles, with a size between 53 and 250 μm, using a vibratory sieve to separate different particle sizes, led to increased seal strength, compared to neat samples or samples with incorporation of small or larger particles.…”

“…147 In blends of corn starch and chitosan, another polysaccharide with good film forming ability, seal strength increases with the proportion of corn starch. 153 Another study checked the seal performance of a blend of potato starch, chitosan and graphene oxide. A maximum seal strength of 0.17 N.mm À1 is achieved with a blend ratio of 75:25 starch:chitosan.…”