Effect of Xanthan Gum and Processing on Shelf Life Extension of Karamae: Karamae Maeparkong, Phatthalung

Abstract

Karamae, a Thai traditional dessert, only lasts 7 to 14 days before becoming harder from retrograded and rancid starch. The purpose of this research was to examine the combined effect of xanthan gum (XN) and processing methods on the extension of Karamae’s shelf life. Karamae processing was used at two levels in a factorial 2×3 completely randomized design. The first method involved adding each ingredient one at a time while using fresh coconut milk (the standard method), and the second method involved doing the same while using boiled coconut milk sweetened with sugar. Two levels of XN content were studied at 0.25, and 0.5% of starch weight. Karamae was preserved in a nylon bag with vacuum condition and oxygen absorbers at room temperature (30 °C) for 49 days. The characteristics of all samples were determined every 7 days. The results revealed that the moisture loss of Karamae (without XN)with and without oxygen absorber dramatically decreased after a 49-day storage at 32 and 36% whereas the sample containing XN displayed a moisture loss of 4-15%. Moreover, the L* and hardness increased (p>0.05) with longer storage times in the second method using 0.5% XN. In addition, after 14 days of storage, the overall preference scores of the standard method processing of Karamae without XN and oxygen absorber significantly reduced (p≤0.05). However, the overall preference scores were lower at 28 days for both methods with 0.5% XN. The findings indicated that the standard method with 0.5% XN showed the highest overall preference scores. As a result, the shelf life of Karamae could be prolonged from 7 days to 28 days of storage time using the combination method of the second method and 0.5% XN.