Nisin release from films is affected by both protein type and film-forming method

Effects of protein type (wheat or corn) and film-forming method (casting or heat-pressing) on films were evaluated for the retention of biologically active nisin (Nisaplin) and release of activity into water at four different temperatures (5, 25, 35 and 45 degreesC. Nisin activity was measured using the agar diffusion method against Lactobacillus plantarum 1752. Cast corn zein (CCZ) and cast wheat gluten (CWG) films retained 12.1% (8.1 x 10(4) IU/g film) and 15.8 % (1.1 x 10(5) IU/g film) of the original activity after film formation, respectively. Heat-pressed corn zein (HPCZ) and heat-pressed wheat gluten (HPWG) films retained 6.5 % (4.3 x 10(4) IU/g film) and 7.4% (4.9 x 10(4) IU/g film) of the original activity after film formation, respectively. The maximum nisin activity found migrating into water at any sampling time was 561 IU/ml (CCZ), 1058 IU/ml (CWG), 309 IU/ml (HPCZ), and 478 IU/ml (HPWG). (C) 2003 Elsevier Ltd. All rights reserved.