The present invention aims to provide extracts or beverages containing 2,5-piperazinedione,3,6-bis(phenylmethyl)-,(3S,6S)&mdash；, which is a useful substance with an improving effect on learning motivation, in an easy-to-ingest form and at a high concentration. Extracts or beverages whose ratio between the content of 2,5-piperazinedione,3,6-bis(phenyl-methyl)-,(3S,6S)&mdash； (unit: &mu；g/100 g) and Brix(Bx) is 6 (&mu；g/100 g)/Bx or more can be ingested continuously over a long period of time as foods and beverages useful for improvement of learning motivation.本發明之課題在於提供一種以容易飲用之形態含高濃度之具有改善學習意願作用的有用物質之2,5-哌嗪二酮，3,6-雙(苯基甲基)-，(3S,6S)-的萃取精華液或飲料。解決上述課題之方法係2,5-哌嗪二酮，3,6-雙(苯基甲基)-，(3S,6S)-含量(單位：μg/100g)與布裏克氏糖度(Bx)之比為6(μg/100g)/Bx以上之萃取精華液或飲料，其係香味、口感佳，甚至外觀亦佳。又，作為對學習意願之改善有用的飲食品而言，可長期地持續攝取。
