Opto-chemical method for ultra-low oxygen transmission rate measurement

Films formed from cellulose nanofibrils (CNFs) are known to be good barrier materials against oxygen, but they lose this feature once placed in humid conditions. To tackle this issue, we applied an optimized pressing condition under elevated temperature to increase the films’ density and improve their barrier performance. Furthermore, a water barrier coating was employed on the surfaces to control the moisture uptake at high relative humidity (RH). Neat self-standing films of CNF with the basis weight of 70 g/m2 were made through a filtration technique and pressed for 1 hour at 130 °C. The resulting nanostructures were covered on both sides using a water-borne barrier layer. Hot-pressing resulted in a significant reduction in oxygen transmission rate (OTR) values, from 516.7 to 3.6 (cm3/(m2·day)) and to some degree, helped preserve the reduced oxygen transmission at high relative humidity. Introducing 35 g/m2 of latex coating layer on both sides limited the films’ swelling at 90% RH for about 4 h and maintained the OTR at the same level. A finite element model was used to predict the dynamic uptake of water into the systems. The model was found to over-predict the rate of water uptake for uncoated samples but gave the correct order of magnitude results for samples that were coated. The obtained data confirmed the positive effect of hot-pressing combined with coating to produce a film with low oxygen transmission rate and potential to maintain its oxygen barrier feature at high relative humidity.

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A Comparison of Vacuum Packaging Systems and Films on the Physical Characteristics of Beef Cuts

Journal of Milk and Food Technology ◽

10.4315/0022-2747-39.11.740 ◽

1976 ◽

Vol 39 (11) ◽

pp. 740-744 ◽

Cited By ~ 2

Author(s):

S. C. SEIDEMAN ◽

Z. L. CARPENTER ◽

G. C. SMITH ◽

C. VANDERZANT ◽

K. E. HOKE

Keyword(s):

Transmission Rate ◽

Storage Period ◽

Vacuum Packaging ◽

Low Oxygen ◽

Packaging Film ◽

Transmission Rates ◽

Oxygen Transmission Rate ◽

Moisture Vapor ◽

Oxygen Transmission ◽

Reduced Surface

One hundred and fifty beef knuckles, 140 beef ribs, and 60 arm chucks were vacuum packaged by two systems (nozzle and chamber vacuumizing machines) in bags manufactured from films differing in oxygen and moisture vapor transmission rates. Primal cuts in each system were randomly assigned to storage periods of 7, 14, 21, 28, or 35 days. In addition, leaker packages were assigned storage periods of 7, 14. or 21 days. At the termination of each storage period, cuts were evaluated for degree of vacuum, appearance of fat cover, surface discoloration, and total desirability. The combination of a chamber vacuumizing machine and use of a packaging film with a low oxygen transmission rate resulted in superior fat appearance ratings, reduced surface discoloration, and higher total desirability scores. Cuts from leaker packages usually received the lowest ratings for these attributes.

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