Changes in Quality of Cold-Pressed Rapeseed Oil with Sinapic Acid Ester-Gelatin Films during Storage

Abstract

In recent years, cold-pressed rapeseed oil (CPRO) has become an attractive health-beneficial product and a promising alternative to olive oil. However, a high level of unsaturated fatty acids renders a CPRO more susceptible to oxidative deterioration. Therefore, the effect of new gelatin strips with polyvinyl alcohol (GEL-PVA) and sinapic acid esters (ethyl sinapate—ESA; octyl sinapate—OSA, and cetyl sinapate—CSA) on the oxidative stability, antioxidant activity (AA), and total phenolic content (TPC) in CPRO samples was analyzed during accelerated storage. In addition, the antioxidant properties of the GEL-PVA films loaded with sinapic acid esters were studied. Interestingly, the CPRO stored in an amber glass marasca bottle containing GEL-PVA-ESA strips for 14 days had the highest AA, while the antioxidant potential was the lowest for oil without film strips. Furthermore, oil samples stored in bottles containing GEL-PVA-ESA and GEL-PVA-OSA strips for 14 days had higher antioxidant properties than the AA and TPC in fresh CPRO. Moreover, synchronous fluorescence (SF) spectroscopy and excitation-emission matrix (EEM) fluorescence spectroscopy were applied for the evaluation of changes in the main fluorescent components in CPRO samples during the accelerated storage. Overall, this study revealed that GEL-PVA films incorporated with sinapic acid esters enhanced the antioxidant potential of CPRO and delayed oxidative degradation by releasing amphiphilic antioxidants into the oil.

The Application of Phenolic Acids in The Obtainment of Packaging Materials Based on Polymers—A Review

“…Sinapic acid (( 2E )-3-(4-Hydroxy-3,5-dimethoxyphenyl)prop-2-enoic acid, SA) also known as sinapinic acid, is a small, naturally occurring hydroxycinnamic acid. It possesses 4-hydroxyl and 3,5-dimethoxy substitution in the phenyl group of cinnamic acid [ 22 , 23 ]. Sinapic acid is widely used due to its antioxidant, anti-inflammatory, antibacterial properties and anxiolytic-like effects.…”

“…Sinapic acid is widely used due to its antioxidant, anti-inflammatory, antibacterial properties and anxiolytic-like effects. It occurs in rye, fruits, and vegetables, and it is one of the main phenolic compounds of canola and rapeseed [ 22 , 23 ]. While sinapic acid is a common acid in the plant kingdom and is widely used in various applications, reports about its use as a modifier for biopolymers are uncommon.…”

“…D. Rabiej-Kozioł et al studied changes in the quality of rapeseed oil with sinapic acid ester–gelatin/poly(vinyl alcohol) films during storage [ 23 ]. They prepared gelatin/poly(vinyl alcohol) active films with the addition of three sinapic acid esters: ethyl sinapate, octyl sinapate, and cetyl sinapate.…”

“…The authors studied the antioxidant activity and the thickness of films. Based on their results, the addition of each sinapic acid ester resulted in a significant enhancement of the antioxidant activity of the gelatin/poly(vinyl alcohol) films [ 23 ]. Additionally, it was clearly visible that the addition of sinapic acid esters resulted in a significantly increased thickness of the films in comparison with the gelatin/poly(vinyl alcohol) non-modified samples.…”

“…Additionally, it was clearly visible that the addition of sinapic acid esters resulted in a significantly increased thickness of the films in comparison with the gelatin/poly(vinyl alcohol) non-modified samples. The authors also observed that the carbon chain length of esters added to the film affected their thickness: a longer chain of ester resulted in an increased thickness of films [ 23 ].…”