71A-24 |
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K. L. DANGARAN, Dairy Processing and Products, USDA-ERRC, 600 East Mermaid Lane, Wyndmoor, PA 19038 and J. M. Krochta, Dept. of Food Science and Technology, Univ. of California-Davis, 1 Shields Ave., 237 Cruess Hall, Davis, CA 95616. WPI/sucrose films have excellent oxygen-barrier properties, are highly glossy, and are durable. Unfortunately, WPI/sucrose films deteriorate over time due to sucrose crystallization; however, the extent that the sucrose crystallization affects appearance, barrier, and tensile properties has not been quantified. Past studies have shown that crystallization inhibitors can slow the rate of sucrose crystallization in WPI films. It was hypothesized that the addition of crystallization inhibitors to WPI/sucrose films would slow the loss of desirable film properties. The objective of this study was to quantify the effect of sucrose crystallization on gloss, oxygen permeability (OP), and tensile properties of WPI film over time. The effect of crystallization inhibitors on film properties was also measured. The inhibitors investigated were raffinose and lactose. Four film formulations were studied—a control formulation of WPI/sucrose, two formulations containing the inhibitors, and a negative control of WPI/glycerol. Films were stored in 53% relative humidity at constant temperature. Properties were measured periodically following ASTM methodologies for gloss, oxygen transmission, and tensile properties of films. As expected, no significant changes were seen in the properties of WPI/glycerol films, because no plasticizer crystallization took place. However, after 14 days of storage, the WPI/sucrose control films were dull and too brittle to test OP and tensile properties. The lactose inhibitor maintained the flexibility of the films an additional week. The raffinose inhibitor prevented changes in film properties for 28 to 42 days, depending on the property being tested. Results indicate raffinose was the more effective sucrose-crystallization inhibitor for extending the life of the WPI/sucrose films. Gloss and oxygen permeability properties remained unchanged for 42 days. The limiting factor was the reduction of film durability due to sucrose crystallization.
Session 71A, Dairy Foods: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |