Effect of Packaging Materials on Adsorption of Orange Juice

Summary Packaging materials used in liquid foods are glass, metal, paper, synthetic plastics, but the largest amount of plastic packaging. This is mainly due to its low energy consumption, high stability, low storage, and low transportation costs, but the packaging materials are a headache for the absorption of flavors contained in juice drinks. Studies have shown that polyester can lose 40% of the limonene in the orange juice, and the lower the depth of the juice, the stronger the adsorption capacity of the packaging material on volatile substances. There are four steps in the process of dilute adsorption of flavor substances into synthetic plastics: adsorption on the surface, adhesion, inhalation, and diffusion.
Polypropylene (PP) and Polyester (PE) are commonly used in aseptic packaging linings. Suelyn is interposed between polypropylene or polyester and aluminum foils. The study of the adsorption of flavors in various packaging materials can help Producers try to reduce the adsorption of flavors on packaging materials. Taking orange juice as an example here, the change trend of the adsorption time of the typical aromatic components in orange juice and the adsorption temperature is studied through several packaging materials. The different influences of packaging materials on the aromatic substances in orange juice are analyzed to reduce the flavor of the packaging materials on the juice. Change.
Through experiments, we can see that, from the analysis of the changes of three aromatic components in orange juice at different temperatures, the effect of temperature on the adsorption rate is not very obvious. From the change of sweet orange oil before and after extraction, the recovery of extracted oil can be seen. The rate can basically reach more than 97%.
The effect of packaging materials on the adsorption of aroma components From the adsorption of several packaging materials in the following figure, LDPE has the strongest ability to adsorb the fragrance components, which is related to its larger amorphous phase area and lower crystallization, and the adsorption of aromatic substances. The diffusion occurs mainly in the amorphous phase region, and the presence of a solid platelet in the crystalline region prevents the diffusion of molecules. Terpenoids are regions of the amorphous phase where lipophilicity is relatively easy to diffuse into the polymeric packaging material. The crystallinity in S is lower and adsorption is weaker. S contains a low level of covalent bonds with Zn2+ carboxyl groups, which changes the lipophilic nature of the polymer surface. The adsorption rates of HDPE and PP are also lower, mainly because their crystalline polymers are harder than LDPE and S and are more resistant to the diffusion of aromatic substances. Limonene is recognized as a solvent for the other component carrier into the amorphous phase of the polymer, and its lipophilicity also facilitates diffusion into the interior of the packaging material. The entering of the limonene into the packaging material also causes the solvent of the packaging material. , And its lipophilicity is also conducive to diffusion to the packaging material, and the inside of the packaging material will also cause the expansion of the packaging material. Adsorption causes changes in the physical properties of the LDPE polymer surface. From this it can be seen that the nature of polymers and aromas is a guarantee of maintaining the quality of packaging and products. HDPE and PP are suitable packaging materials for orange juice.
Adsorption rate of several packaging materials (%)

Thus, the packaging material is an important factor affecting the flavor of the juice. With the wide application of aseptic packaging equipment, plastic materials are increasingly used in the packaging of juice beverages, but different types of plastics have the problem of adsorption of aromatic substances to varying degrees. In the selection of packaging materials, it is necessary to consider safety and non-toxicity on the one hand, and on the other hand to consider whether the adsorption of the flavor is small. ("Milk, Drink, Packing Special")