Whether properties of PS-WPI blended films are intermediate to properties of the pure PS and WPI film depends on the particular PS and specific property. In the case of MC or HPMC with WPI, the blended films reflect the higher TS of the PS and lower OP of the WPI.

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. V

Four % (wt ⁄ wt) aqueous solutions were prepared at corn starch:methylcellulose:whey protein isolate (CS:MC:WPI) ratios of 2:2:2, 1:2:3, 2:1:3, 2:2:0, 1:2:0 and 2:1:0. Glycerol (gly) was used as a plasticiser at CS-MC-WPI:gly ratios of 2:1, 2.5:1 and 3:1. CS-MC-WPI blend films were stronger than CS-WPI films and had lower oxygen permeability (OP) than MC-WPI films. The highest tensile strength (TS) of blend films was 8.01 ± 3.41 MPa, at CS:MC:WPI ratio of 2:2:0 and CS-MC-WPI:gly ratio of 3:1. Lowest OP value was 45.05 ± 7.24 cm 3 lm m )2 per day kPa )1 , at CS:MC:WPI ratio of 2:2:2 and CS-MC-WPI:gly ratio of 3:1. OP values were predictable based on relative amounts of components. However, TS and elastic modulus properties of the CS-MC-WPI blend films did not reflect the relative amounts of the components. All of CS-MC-WPI films were translucent indicating some degree of immiscibility among the CS, MC and WPI. These results indicate the influence of complex molecular interactions among the components.

No abstract

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.