Sorption of ethyl acetate and d‐limonene in poly(lactide) polymers

Abstract

Poly(lactide) (PLA) polymers have garnered increased attention in the last few years as food packaging materials because they are environmentally friendly polymers. As the production of PLA increases and price per pound drops, PLA is becoming a growing alternative as a green food packaging material. In this research, the organic vapor barrier properties of commercially available PLA polymers were studied. Gravimetric sorption tests in PLA films were carried out, and the diffusion (D), solubility (S) and permeability (P) coefficients for ethyl acetate and d-limonene in PLA were determined. For ethyl acetate, values of P = 1.22 × 10 −17 kg m m −2 s −1 Pa −1 , D = 2.63 × 10 −15 m 2 s −1 , and S = 4.62 × 10 −3 kg m −3 Pa −1 ) at 45 • C and a partial pressure of 12 654 Pa were obtained. For d-limonene, no trace was detected after 21 days of testing at 45 • C and 258 Pa, which indicates a permeability coefficient lower than 9.96 × 10 −21 kg m m −2 s −1 Pa −1 . Poly(lactide) polymers demonstrated good aroma barrier to ethyl acetate and d-limonene, and will most likely be good aroma barriers. PLA is not likely to promote flavor loss by either permeation or scalping.

Barrier properties of poly(lactic acid) and its morphological changes induced by aroma compound sorption

“…The results at an activity of 0.5 are of the same order of magnitude as the results of Auras et al 16 who measured, using a different experimental set-up, a solubility coefficient of 6.17 × 10 −3 kg m −3 Pa −1 at 30…”

“…15 The barrier properties of PLA against aroma compounds have been the subject of only a few studies to date. 14, 16 Auras and co-workers 16 showed that PLA has an excellent performance against limonene, a hydrophobic aroma compound found in orange juice. However, more hydrophilic molecules, such as ethyl acetate, a booster and enhancer for fruit aroma often present in high quantity, can be sorbed to an approximately twofold greater extent in the hydrophilic polyester PLA in comparison to PET, polypropylene (PP) and low-density polyethylene (LDPE).…”

Novel PET Nanocomposites of Interest in Food Packaging Applications and Comparative Barrier Performance With Biopolyester Nanocomposites

“…The reason for the latter counterintuitive behavior in the water permeability behavior could be related to the inherent MMT clay hygroscopicity. Previous studies reported that the PET limonene permeability is about 0.0000048 Â 10 À13 kg Á m/s Á m 2 Á Pa when measured at 238C and 40 Pa [7]. The reason for the large disagreement with the limonene permeability data could be related to the different origins of the two samples (extruded vs. un-oriented compression molded specimens) and the fact that the polymer grade, the test conditions used, and the differences in partial pressure used for testing were largely different.…”

Characterization of PLA-limonene blends for food packaging applications

“…Is the most abundant monocyclic monoterpene in nature and represents more than 90% of orange peel oil, being the most important residue in the citrus industry [12]. The limonene diffusion through packaging has been widely studied in different food contact materials such as polyethylene (PE) [13], low density polyethylene (LDPE) [14], high density polyethylene (HDPE), polystyrene (PS) [15] and PLA [15,16]. Furthermore, the sorption of aroma compounds through packaging materials have been reported recently by Salazar et al, (2012) [17], who found a plasticization effect of PLA films by aroma compounds after the sorption studies.…”