GABA and Amino Acids in Tropical and Sub-tropical Fruit of Sapindanceae Family in Thailand

Although fruit is not a major source of amino acids, fruit containing sufficient amounts of amino acids could be a new source. In this study, we compared GABA and amino acid concentrations in selected fruit species of the Sapindanceae family and determined postharvest changes in GABA and amino acid concentrations in rambutan and longan fruit. 18 amino acids, including nine essential amino acids, and GABA were observed. Our results showed variations in GABA and amino acid profiles of different fruit species including Takhro (Schleichera oleosa), Korlan (Nephelium hypoleucum), Chammaliang  (Lepisanthes fruiticosa), Ma huat (Lepisanthes rubiginosa), longan (Dimocarpus longan) cv. Mangkornthong, Rambutan (Nephelium lappaceum) cv. Rongrean, Lychee (Litchi chinensis) cv. Honghuay, Lychee cv. Kom, Lychee cv. Chakapad, and Lychee cv. Sampaokaew. The highest GABA concentration was found in Takhro at concentration of 92 mg/100 g FW. The best amino acid profiles were found in Lychee cv. Sampaokaew and Chammaliang.

A postharvest study measured GABA and amino acid content during a 6-day storage period. GABA levels slightly increased in fruit stored in modified atmosphere packaging at 12 ^o C and fruit stored at room temperature, but fruit quality was diminished in fruit stored at room temperature.  A decrease in aspartic acid content was observed in longan fruit stored at 5 ^oC. All other amino acids remained unchanged in all storage conditions during storage.  GABA concentrations remained relatively constant during 6 days of storage at room temperature and increased by 36% after 6 days of storage at 5 ^oC. Quality of cold stored fruit was greater than that of the control fruit stored at room temperature.

We conclude that GABA and amino acid concentrations depend on species and cultivar, and are also affected by postharvest conditions. Fruit of the Sapindanceae family could be a new source of GABA and amino acids.