Improving properties of thermoplastic starch films by incorporating active extracts and cellulose fibres isolated from rice or coffee husk

Abstract

Hydrothermal (60 min, 180ºC) extracts and cellulose fibres from coffee and rice husks were obtained to be incorporated into corn starch films, in order to improve the film functional properties as food packaging material and confer them active properties. Extracts exhibited antioxidant properties (EC 50 : 5.37-5.29 mg extract solids/mg DPPH) and antibacterial activity against Listeria innocua and Escheriquia coli (MIC values: 35-45 and 34-35 mg extract solids/mL, respectively). The active extracts improved tensile properties of the starch films; elastic modulus increased by about 350% and films become less stretchable. The cellulosic fibres from both residues were more 2 effective as reinforcing agents in films containing extract solids than in net starch films. Extracts also provoked 30 % reduction in the WVP of starch films and 50-85 % reduction in the oxygen permeability, depending on their amount in the films, but no effect of cellulose fibres was observed on barrier properties.

Coffee By-Products and Their Suitability for Developing Active Food Packaging Materials

“…The lipid fraction may derive from the cherry skin cutin and also from silverskin partially removed during the dehusking process [ 27 ]. CH are rich in phenolic compounds (13 mg g −1 of GAE), mainly caffeic and chlorogenic acids [ 58 ]. The paucity of data available shows that for the valorization of CH, much more research is required.…”

Polysaccharide and Protein Films with Antimicrobial/Antioxidant Activity in the Food Industry: A Review

“…The extracts demonstrated antioxidant activity (5.37-5.29 mg extract solids/mg DPPH • ). Starch films with the addition of coffee husk showed greater antioxidant activity than films with rice husks [18]. Sunflower husk extract was also added to the starch films and its addition caused an increase in antioxidant activity.…”

Opportunities for the Use of Brazilian Biomass to Produce Renewable Chemicals and Materials

“…The films showed good protection against Listeria innocua and Escherichia coli , a reduction in oxygen permeability and an enhancement in tensile strength. These materials are therefore very promising for use in food packaging [205] …”

“…The coffee husk can be incorporated into polypropylene to improve its tensile strength and thermal stability and reduce the melt flow rate by 50 %. [205] Cellulose, along with antioxidant and bactericide compounds can be extracted from coffee husk, which can thereafter be incorporated into thermoplastic starch films. The films showed good protection against Listeria innocua and Escherichia coli, a reduction in oxygen permeability and an enhancement in tensile strength.…”

“…These materials are therefore very promising for use in food packaging. [205] Alkaline hydrolysis can allow the isolation of bioactive compounds such as flavones, glycosides, alkaloids and terpenoids from coffee husk lignin. These compounds show antiinflammatory, bactericide, cardiovascular protective, blood sugar regulative and anti-tumour properties.…”