Extending the storage life of some fruits by using Pullulan produced from locally isolate Aureobasidium pullulans

Extending the storage life of some fruits by using Pullulan produced from locally isolate Aureobasidium pullulans

  • محمد عبد الرزاق الصوفي
Keywords: storage life, fruits, Pullulan, Aureobasidium pullulans.

Abstract

Six isolates of A. pullulans were collected from many sources including Hibiscus sabdariffa (Roselle), old Roofs of houses and bathroom surface that referred as Ap ros1, Ap or2, 3, 4 and Ap bs5, 6 respectively, all these isolates were identified based on morphological characteristics and nutritional physiology profiles, all were able to utilize various carbon and nitrogen sources such as glucose, xylose, sucrose, maltose, ammonium sulfate, ammonium nitrate and ammonium chloride, also they showed positive test for starch and amylase, while α-cellulose, ethanol, and methanol were could not be assimilated and could not grow in 0.05% cycloheximide, the other tests referred to different results among isolates, the Ap ros1 isolate from Hibiscus sabdariffa (Roselle) was selected for production of pullulan.

           Four bacterial strains of two gram (+) and two gram (-) were chosen for the tests. The effect of pullulan coating on bacterial growth was observed in all tested strains, it was 63, 65, 70 and 75% for Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Salmonella typhimuram respectively.

The weight loss of uncoated peach was 3.2, 4.8, 6.1, 7, 7.2, 8.3 and 9.1%, while in coated peach with 10% pullulan were 3.1, 4.5, 5.8, 6.2, 6.8, 7.9 and 8.9%, and in coated peach with 20% pullulan were 2.9, 3.8, 4.1, 4.6, 5.8, 6.4 and 7.6%, when these samples are stored at 3, 6, 9, 12, 15, 18 and 21 days respectively that stored at 25°C, and when uncoated and coated peach with 10 and 20% pullulan stored at 4°C . The weight loss in uncoated peach was 0.01, 0.06, 0.16, 0.23, 0.35, 0.46, 0.6, 0.68, 0.73 and 0.75%, while in coated peach with 10% pullulan were 0.01, 0.05, 0.12, 0.16, 0.2, 0.3, 0.5, 0.58, 0.64 and 0.71%, and in coated peach with 20% pullulan were 0.015, 0.02, 0.04, 0.08, 0.1, 0.12, 0.18, 0.3, 0.46 and 0.5%, when these samples are stored at 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 days respectively.

The weight loss of uncoated pear was 1.4, 2, 2.6, 4.4, 5.5, 6.4 and 7.2%, while in coated peach with 10% pullulan were 1.2, 1.6, 2, 2.4, 4.3, 5.2 and 6.6%, and in coated peach with 20% pullulan were 0.8, 1, 1.4, 1.6, 3, 4.6 and 5.4%, when these samples are stored at 3, 6, 9, 12, 15, 18 and 21 days respectively that stored at 25°C, and when uncoated and coated pear with 10 and 20% pullulan that stored at 4°C. The weight loss is 0.02, 0.07, 0.14, 0.16, 0.3, 0.33, 0.44, 0.45, 0.52 and 0.54%, while in coated peach with 10% pullulan were 0.02, 0.06, 0.11, 0.16, 0.21, 0.3, 0.36, 0.38, 0.44 and 0.46%, and in coated peach with 20% pullulan were 0.01, 0.05, 0.08, 0.09, 0.1, 0.16, 0.19, 0.24, 0.26 and 0.28%, when these samples are stored at 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 days respectively.

Author Biography

محمد عبد الرزاق الصوفي

Mohammed A. Al-Soufi

Published
2019-12-31