Technical Bulletin No. 190 FLAVOR AND AROMA BARRIER PROPERTIES OF EVAL RESINS

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1 Technical Bulletin No. 190 FLAVOR AND AROMA BARRIER PROPERTIES OF EVAL RESINS Generally speaking, the phrase EVAL barrier resins brings to mind a barrier to gases such as oxygen, nitrogen, and carbon dioxide. Protecting food products is increasingly important, especially with the current trend away from product additives. However, protection or barrier mean different things in different situations. In both food and non-food products this can be moisture barrier, light barrier or flexcrack resistance, as well as gas barrier. Now, the area of flavor and aroma barrier is receiving growing attention in the field of plastics packaging. This bulletin will provide a general overview of the outstanding flavor and aroma barrier properties of EVAL resins and films. Flavor Barrier The food industry is becoming increasingly aware of the importance of flavor barriers in containing natural flavors and preventing extraneous flavors from contaminating the product. Some food products are notorious for their ability to absorb extraneous flavors or aromas. No consumer wants potato chips to taste like soap powder or chocolate to smell like onions. In addition, many foods are highly flavored or spicy and the desire is to retain this flavor. Another important flavor consideration is commonly called flavor scalping. This phenomenon is where some plastics, such as polyolefins, selectively absorb certain flavor constituents from the product. The permeation of flavors is difficult to measure quantitatively because they contain many components. Many times, only a simple component of a flavor is measured if a quantitative value must be determined. Gas chromatography and mass spectrophotometric (GC/MS) techniques have been developed that allow the analysis of complex flavors. However, in most cases, the use of organoleptic testing provides reliable and pertinent data at a greatly reduced cost. Test data presented here have been determined by both methods. Tables 1 and 2 show the results of organoleptic testing performed on three complex flavors. The testing was performed by allowing the various film structures to be in contact with the flavors for varying amounts of time ranging from one hour to 35 days. The films were then subjected to a three-minute water wash, and a test panel was used to determine any odor that had been absorbed into the film. EVAL Resin and Film Sales Office 2625 Bay Area Boulevard, Suite 300, Houston, TX 77058; EVAL Manufacturing and R&D Bay Area Boulevard, Pasadena, TX 77507; of 5

2 Table 1 Citrus and Tropical Mix Flavor Film Thickness 1 Hr. 2 Hrs. 15 Hrs. 1 Day 4 Days 35 Days F Series (15µ) A A A A A A E Series (15µ) A A A A A A EF-XL (15µ) A A A A A BO Nylon (15µ) A A B B B B OPP (20µ) B B C C C C PVDC (25µ) A A B B B B LDPE (50µ) D D D D D D Key: A No Detection C Partial Flavor B Faint Flavor D Flavor Clearly Distinguished Table 2 Soft Fruit Mix Flavor Film Thickness 1 Hr. 2 Hrs. 15 Hrs. 1 Day 4 Days 35 Days F Series (15µ) A A B B B B E Series (15µ) A A B B B B EF-XL (15µ) A A B B B B BO Nylon (15µ) A A B B B B OPP (20µ) C C C C C C PVDC (25µ) B B B B C C LDPE (50µ) D D D D D D Key: A No Detection C Partial Flavor B Faint Flavor D Flavor Clearly Distinguished Table 3 indicates the permeation rate of two common flavors, d-limonene, a component in lemon and other citrus flavors, and Methyl Salicylate, used in breath fresheners, winter green and food flavors. The various film structures indicated were subjected to a gelbo flex test (20 times) to simulate shipping and abuse. Table 3 Flavor Permeability (g/m 2. day) 73ºF,0%RH 73ºF,75%RH Structure d-limonene Methyl Salicylate d-limonene Methyl Salicylate A B C D E F Key: A HDPE/Tie/EVOH/Tie/EVA B LDPE/Tie/PA/EVOH/Tie/EVA/Tie/EV0H/PA/Tie/LDPE C PA/Tie/EV0H/PA/Tie/LDPE D LDPE/Tie/EVOH/Tie/LDPE E PP/PE/Tie/PETG/Tie/PP/PE F PVDC ct d OPP of 5

3 Table 4 and Figure 1 indicate the permeation and sorption rate respectively of d-limonene in various films. Table 4 d-limonene Permeation Films Permeation (g.mil/100 in 2. day) F Series EVOH E Series EVOH HDPE 61.9 LDPE 77.4 EVA (VAc: 5%) 98.0 EVA (VAc: 7%) Polypropylene C, 65% RH Page 3 of 5

4 Aroma Barrier Where food products are concerned, aroma barrier is somewhat analogous to flavor barrier. Food products must be protected from outside aromas in the distribution chain, grocery store, and home. Other food and non-food products such as garlic, agricultural chemicals, pesticides, insecticides, or perfumes can be highly aromatic. In this case, the desire is to retain the aroma in the package and not let it escape into the surrounding environment. As with flavor permeation, aroma permeation can be determined by sensory evaluation or gas chromatography. Table 4 shows the results of sensory evaluations for various aromas packaged in a variety of film structures. The numbers represent the time it takes the aroma to permeate the package at room temperature. Aroma Permeation PVDC ct d Structure LDPE OPP/PE PET/PE Nylon F Series/PE EF-XL/PE Thickness (µ) (50) (20/50) (20/50) (15) (15/50) (15/50) Orange Essence Strawberry Essence Curry Powder Garlic Powder Coffee Powder Linalol Geraniol Prenyl Benzoate Methyl Ionone Key: 1--<1 Hr. 3--<1 Week 5-->2Weeks 2--<Day 4--<2 Weeks Table 5 compares the permeation rate of various film structures for other common aromas. Table 5 Aroma Permeation Days to Leakage Thickness Vanillin Menthol Piperonal Camphor Film Construction (mils) (Vanilla) (Peppermint) (Heliotropin) PET/F Series/PE 0.5/0.6/ >30 OPP/F Series/PE 0.7/0.6/ >30 27 >30 PET/F Series 0.5/0.6 >30 >30 30 >30 ON/F Series 0.6/0.6 2 > PET/PE 0.5/ >30 ON/PE 0.6/ PVDC ct d PET/PE 0.6/2.0 7 > PVDC ct d/opp/pe 0.7/ PVDC ct d PET Note: Values in the table above indicate the number of days until leakage through the package is detected. The greater the values, the higher the fragrance preservation. Page 4 of 5

5 Table 6 shows actual permeation rates, as measured by gas chromatography, for the following aromas: Allyl Sulfide: Garlic Food type (croutons, snacks, salad dressing) Acetic Acid: Vinegar Food type (cheddar cheese, snacks, condiments) Ethyl Phenyl Acetate: Used in soaps and floral fragrances Beta-Pinene: Used in household cleaners Ethyl Acetate: Food flavorings (citrus, berry, coconut, coffee, chocolate, honey) Menthol: Chewing gum, creme de menthe, peppermint Table 6 Aroma Permeability (g/m hrs. 100 C, 75% RH) Allyl Acetic Ethyl Phenyl Beta Ethyl Film Sulfide Acid Acetate Pinene Acetate Menthol HDPE/Nylon/EVA < < (1.25 mil) HDPE/EVOH/EVA < >0.002 > < (1.25 mil) LDPE/Nylon/EVOH/ > < Nylon/LDPE (1.4 mil) PP/PET/PP > >0.09 >0.005 > (1.0 mil) PVDC Ct d OPP < < < (1.0 mil) Regulatory Approvals EVAL resins and films meet the requirements of the U.S. Food and Drug Administration for direct food contact applications under 21CFR, part Similar approvals have been granted by the Canadian Ministry of Health. These approvals allow the use of EVAL resins and films to prevent flavor scalping as well as the absorption of aromas into the package layers. All information contained herein is presented in good faith and without warranty. EVAL Company of America accepts no liability for damage or loss resulting from the use or misuse of this information. Page 5 of