# Effects of Phenolic-Rich Extracts from Castanea sativa Mill. Wood Processing Byproducts on the Development of Compostable Polylactic Acid-Based Materials with Antioxidant and Antibacterial Properties

## TL;DR

This paper explores using chestnut wood byproducts to create compostable, antioxidant, and antibacterial polylactic acid films for sustainable packaging and biomedical uses.

## Contribution

The study introduces a novel use of Castanea sativa wood byproducts to enhance polylactic acid films with antioxidant and antibacterial properties.

## Key findings

- CSW extract added to PLA films showed strong antioxidant activity, with 96% DPPH radical scavenging at 3% concentration.
- PLA films with CSW extract exhibited antimicrobial effects against Staphylococcus aureus and Bacillus cereus.
- The films remained compostable, disintegrating over 90% within 14 days under controlled conditions.

## Abstract

In a circular economy framework, valorizing agro-industrial
waste
into high-performance active materials is crucial for sustainable
packaging and biomedical innovative applications. This study reported
the design, development, and characterization of multifunctional polylactic
acid (PLA)-derived films obtained by extrusion, incorporating PLA
with an extract from Castanea sativa Mill. wood (CSW) by-products. The phenolic profile of the extract
was identified through HPLC-DAD-MS analysis, highlighting the presence
of gallic acid, ellagic acid, and hydrolyzable tannins as vescalagin
and castalagin. TGA analysis evidenced thermal stability till 250
°C according to the extrusion process. Interestingly, CSW extract
exhibited in vitro antimicrobial properties against
Gram-positive relevant bacterial strains (MBC from 0.5% to 1.0% w/v).
Finally, active films (PLA_1CSW, PLA_3CSW, and PLA_5CSW) were prepared
by extruding PLA with CSW extract at 1, 3, and 5%, w/w, respectively.
Mechanical characterization of these films showed that tensile strength
and modulus remained comparable to neat PLA, while elongation at break
decreased with increasing CSW content. Antioxidant assays showed dose-dependent
DPPH radical scavenging activity, reaching a value of 96% for PLA_3CSW.
PLA_5CSW revealed strong antimicrobial performance against Staphylococcus aureus and Bacillus
cereus. For all formulations, overall migration into
food simulant remained below EU limits (<10 mg/dm2)
and, according to ISO 20200:2016, disintegration under controlled
composting conditions reached >90% within 14 days. These findings
revealed the potential of CSW extract in the production of sustainable,
compostable, and bioactive PLA-based films, according to a sustainable
transition following circular economy principles in the food and biomedical
sectors.