Free Amino Acid and Reducing Sugar Composition of Pandan (Pandanus amaryllifolius) Leaves

Abstract

Pandan leaves are commonly used to flavor desserts in Southeast Asia. The key aroma compound in pandan, 2-acetyl-1-pyrroline (ACPY), probably forms through Strecker degradation during cooking. This study investigated the composition of free amino acids and reducing sugars that could be precursors of ACPY in pandan leaves. Fresh pandan leaves contained 2.38 mg/g fructose and 1.77 mg/g glucose. Major free amino acid in pandan was glutamic acid (0.41 mg/g). Proline, a precursor of ACPY in fragrant rice, was at 0.12 mg/g. Pandan samples were heated at 100 ^oC for 10 min at pH 7.0. Aroma impact compounds in heated pandan were ACPY and 3-methyl-2(5H)-furanone. In this experiment, glutamic acid, proline, ornithine, fructose and glucose were added to pandan samples separately. Addition of glutamic acid, proline, and ornithine increased ACPY and generated 4-vinylphenol and 3-ethyl-4-methyl-1H-pyrrole-2,5-dione that were not normally detected in heated pandan samples. Addition of fructose and glucose did not affect ACPY concentrations but decreased in 2-ethyl-5-methyl furanone.