CHANGES ON NON VOLATILE TASTE COMPOUNDS OF FRESH AND STEAMED Leucaena leucocephala SEEDS POWDER

NUR AINI MAHMUDAH, Dr. Ir. Supriyadi, M.Sc.

2019 | Tesis | MAGISTER ILMU DAN TEKNOLOGI PANGAN

Biji petai cina (Leucaena leucocephala) memiliki karakter rasa yang unik yakni gurih, manis, dan sedikit pahit. Studi ini mengkaji pengaruh perlakuan steam blanching terhadap komponen rasa pada bubuk biji petai cina, serta perubahan fisik dan kimiawi. Steam blanching (pengukukusan) selama 5 menit memberikan pengaruh positif terhadap peningkatan nilai kecerahan (L) dari 62.42 menjadi 63.26. Namun, secara kimiawi terdapat efek negatif terhadap penurunan nilai protein kasar sebanyak 12 persen. Berdasarkan evaluasi senyawa-senyawa rasa pada bubuk biji petai cina, diketahui bahwa nilai komponen gula maltose dan rafinosa bubuk biji petai cina segar cenderung lebih rendah dibandingkan pada bubuk biji petai cina kukus, sedangkan nilai glukosa cenderung meningkat. Asam-asam organik, mineral, dan komponen nukleotida inosine-monophosphate (IMP) mengalami kecenderungan penurunan pada bubuk biji petai cina kukus, sementara kandungan asam-asam amino bebas cenerung naik. Nilai konsentrasi ekivalen umami (KEU) bubuk biji petai cina segar dan kukus secara berurutan yaitu 0.62 g MSG/100 g db and 0.60 g MSG/100 g db. Diantara senyawa-senyawa rasa pada kedua sampel bubuk biji petai cina, asam organik (asam suksinat dan asam sitrat) merupakan komponen dominan berdasarkan nilai taste active value (TAV), kemudian komponen mineral (P, Mg, K, Ca, Na), asam-asam amino bebas (asam glutamat, serin, histidin, arginin, alanin, methionin), dan gula (glukosa).

Leucaena leucocephala seeds are known to have a unique taste like a combination of savory, sweet, and slightly bitter. This study investigated the effect of steam blanching on the taste compounds of L. leucocephala seeds powder, along with its physical and chemical properties. Steam blanching for 5 minutes gave a positive effect on the appearance of Leucaena leucocephala powdered seeds, shown by increased brightness value from 62.42 to 63.26. But, it had a negative effect on the chemical properties by decreased crude protein content of steamed seeds powder for about 12 percent. Evaluation of the taste compounds by sugar components resulted that maltose and raffinose in the fresh seeds powder tended to be lower than in the steamed one, but the glucose was tended to be higher. The content of organic acids, minerals, and 5'-nucleotide compound (IMP) in the steamed L. leucocephala seeds powder tended to decrease, but free amino acids content in the steamed seeds powder were increased. Equivalent umami concentration (EUC) value from each fresh and steamed seeds powder delivered a number of 0.62 g MSG/100 g db and 0.60 g MSG/100 g db respectively. Among the taste compounds identified in powdered L. leucocephala seeds, organic acids (especially succinic acid and citric acid) were the most responsible to the taste formation of powdered L. leucocephala seeds by taste active value (TAV) evaluation. Then followed by minerals (P, Mg, K, Ca, Na), free amino acids (glutamic acid, serine, histidine, arginine, alanine, methionine), and sugar (glucose).

Kata Kunci : Leucaena leucocephala, steam blanching, taste compounds, equivalent umami concentration, taste active value