The effect of high pressure processing on the morphology of polyethylene films tested by differential scanning calorimetry and X‐ray diffraction and its influence on the permeability of the polymer

This study investigated the influence of high‐pressure processing on the morphology and permeability of low‐density polyethylene (LDPE) films used for food packaging. This was done by monitoring the crystallinity, melting temperature (T_m), and oxygen transmission rate (OTR) of the materials before and after the pressure treatments. A first set of pouches made from the LDPE films were filled with 95% ethanol then pressured at 200, 400, 600, and 800 MPa for 5 and 10 min at 25 and 75°C. The crystallinity and T_m of the films were measured using differential scanning calorimetry (DSC). X‐ray diffraction (XRD) was also used to determine the crystallinity. A second set of LDPE pouches were similarly made but a half of them were filled with 95% ethanol and the other half filled with distilled water. These second set of pouches were pressured at 200, 600, and 800 MPa then their OTR tested. Results of the DSC experiments showed that the T_m increased with increasing pressure intensity but the crystallinity changes were not detectible. The XRD method on the other hand, showed significant (P < 0.05) crystallinity increases with increasing pressure treatments. The gas permeability analyses showed decreasing OTR's with increasing high‐pressure intensity treatments. The OTR in the pouches filled with the 95% ethanol was slightly lower than that of the pouches filled with water. These findings allowed us to better anticipate the behavior of LDPE films used to package high‐pressure processed foods. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effect of High Pressure Processing on the Thermal and Mechanical Properties of Polyethylene Films Measured by Dynamical Mechanical and Tensile Analyses

This study investigated the influence of high pressure processing on the thermal and mechanical properties of low‐density polyethylene (LDPE) films used for food packaging. This was carried out by monitoring the thermal and mechanical properties of the materials before and after the pressure treatments. Pouches made from the LDPE films were pressured at 200, 400 and 800 MPa for 5 and 10 min at 25 and 75°C. The storage and loss moduli, tensile strength and elongation at break and yield of the film samples were then measured using dynamic mechanical analysis (DMA) and an Instron® Universal Tester (Canton, MA, USA), respectively. The DMA was performed at ?130 to 85°C, whereas the tensile and elongation analyses were carried out at room temperature. Results of the DMA experiments showed that the storage modulus increased with increasing pressure intensity. The tensile analysis showed that the tensile strength increased but the elongation decreased with increasing pressure treatment. Copyright © 2013 John Wiley & Sons, Ltd.     

High-performance liquid chromatography and gas chromatography to set the analysis method of stearoyl lactylate,a food emulsifier

Food Science and Biotechnology - Stearoyl lactylates (SLs, E481/E482) and their sodium and calcium salts are emulsifiers commonly used as food additives. This study was performed to set the...     

The Influence of High‐pressure Processing on the Migration of Irganox 1076 from Polyethylene Films

This study investigated the influence of high‐pressure processing (HPP) on the migration of Irganox 1076 from low‐density polyethylene films to 10 and 95% ethanol as food simulants. Pouches made from the low‐density polyethylene films were pressured at 600 and 800 MPa for 5 min at 25 and 75 °C. Control samples were not high‐pressure processed. The mass transfer of Irganox 1076 from the films towards the ethanol was monitored over a 40‐day period and quantified using a high‐performance liquid chromatography method. The results showed a lower level of Irganox migration from the films to the ethanol at lower when compared with higher pressure treatments. At the processing temperature of 75 °C, the migration appeared higher when compared with the samples treated at 25 °C. The migration in the HPP samples was higher than that of the controls. The results of this study showed that HPP at higher temperatures caused a higher level of chemical migration from polyethylene when compared with samples not treated by this technique. Copyright © 2013 John Wiley & Sons, Ltd.     

Preparation and properties of sodium bicarbonate‐incorporated LDPE films with deodorizing function for kimchi packaging

Volatile compounds produced during the fermentation of kimchi result in a sour taste and unpleasant odor. Here, we evaluated the utility of sodium bicarbonate (baking soda) as a natural deodorant in kimchi packaging. Baking soda decomposed into sodium carbonate, which showed superior deodorizing effects at 180°C, and aroma patterns were altered after deodorizing treatment with baking soda and heat‐treated baking soda. Moreover, the numbers of off‐odor compounds were decreased when using baking soda or heat‐treated baking soda. In addition, the acetic acid removal rate increased with heat treatment of baking soda. Notably, the external shape and color of baking soda particles were not affected by heating. It was observed that an increase in the content of baking soda in the low‐density polyethylene (LDPE)/baking soda composite films enhanced deodorizing effects. Finally, sensory evaluation confirmed that odor decreased with increased baking soda content. The findings demonstrate the potential value of baking soda and LDPE/baking soda composite films in kimchi packaging and reduction of off‐odors.