Non-volatile taste components and amino acid profile of jengkol (Pithecellobium jiringa) seed flour after steam blanching

Figures & data

Table 1. Scheme of elution gradient for amino acid total

Time (minute)	Solvent A (%)	Solvent B (%)
0	90	10
5.0	50	50
5.2	90	10
7.0	90	10

Table 2. The changes of soluble sugar in jengkol seeds after steam blanching

	Content (ppm)
Soluble Sugars	Without steam blanching	Steam blanching
Galacturonic Acid	227.10	325.63
Maltosa + Rafinosa	156.50	191.63
Glucose	271.80	161.80
Fructose + Galactose	342.70	224.53
Total	998.10	903.59

Table 3. The changes of organic acid in jengkol seeds after steam blanching

	Content (ppm)
Organic Acids	Without steam blanching	Steam Blanching
Oxalic Acid	< 0.158	<0.158
Malic Acid	0.72	0.42
Citric Acid	182.47	65.62
Succinic Acid	1.145.87	82.28
Lactic Acid	259.61	214.57
Total	442.80	362.89

Table 4. Free amino acid levels in without steam blanching jengkol and steam jengkol.

Free amino acids	Content (mg/g dry weight)
	Without steam blanching	Steam jengkol
L-Threonine^a	9.92	14.13
L-Valine^a	0.18	0.33
L-Methionine^a	6.07	4.36
L-Ileucine^a	1.12	0.60
L-Leucine^a	0.55	0.39
L-Phenylalanine^a	4.21	3.25
L-Lysine^a	1.71	0.81
Total	23.76	23.87
L-Aspartic acid^b	1.28	2.15
L-Glutamic acid^b	1.39	1.73
L-Alanine^b	0.15	0.72
L-Serine^b	1.48	1.86
L-Glutamine^b	0.75	0.67
L-Glycine^b	0.99	1.11
L-Tyrosine^b	0.12	0.11
L-Asparagine^b	6.28	5.35
Total	12.46	13.69
L-Histidine^c	1.52	1.62
L-Arginine^c	3.26	5.81
Total	4.78	7.42
Total content	40.99	44.98

^aEssential amino acid

^bNon-essential amino acid

^cSemi-essential amino acid

Table 5. Level of amino acid taste components in without steam blanching and steam jengkol.

Taste components^a	Content (mg/g dry weight)
	Without steam blanching	Steam Jengkol
MSG-like	2.68		3.87
Sweet	12.54		17.82
Bitter	16.92		16.35
tasteless	1.83		0.92
Total	33.96		38.96

^aMSG-like (Asp + Glu); sweet (Thr + Ser + Gly + Ala + Pro); bitter (Val + Met + Ile + Leu + Phe + His + Arg + Trp); tasteless (Cys + Tyr + Lys).

Table 6. Levels of 5′-nucleotide components in without steam blanching and steam jengkol.

5′-Nucleotide^a	Content (mg/g dry weight)
	Without steam blanching	Steam Jengkol
5′-AMP	1.98		1.77
5′-GMP	0.62		0.54
5′-IMP	0.32		0.26
Total	2.92		2.57

Figure 1. Changes of the equivalent umami concentration (EUC) in Jengkol after steam blanching treatment

^aCalculation based on the equation: $\mathrm{Y}=\sum \mathrm{a}\mathrm{i}\mathrm{b}\mathrm{i}+1218\left(\sum \mathrm{a}\mathrm{i}\mathrm{b}\mathrm{i}\right)\left(\sum \mathrm{a}\mathrm{j}\mathrm{b}\mathrm{j}\right)$ of Yamaguchi et al.^[9] where Y is the EUC of the sample (g MSG/100 g); ai is the concentration (g/100 g) of each umami amino acid (Asp or Glu); aj is the concentration (g/100 g) of each umami 5′-nucleotide (5′-IMP, 5′-GMP, 5′-AMP); bi is the relative umami concentration (RUC) for each umami amino acid to MSG (Glu, 1 and Asp, 0.077); bj is the RUC for each umami 5′-nucleotide (5′-IMP, 1; 5′-GMP, 2.3; 5′-AMP, 0.18) and 1218 is a synergistic constant based on the concentration (g/100g) used.

Table 7. The changes of amino acids in jengkol seeds after steam blanching

Amino Acid Groups	Content (% w/w)
	Amino acids	Without steam blanching	Steam Blanching
Essential Amino Acid	Threonine	0.392	0.416
	Valine	0.355	0.379
	Methionine	0.067	0.069
	Isoleucine	0.273	0.286
	Leucine	0.601	0.641
	Phenylalanine	0.489	0.519
	Lysine	1.310	1.108
	Total	3.487	3.418
Non-Essential Amino Acid	Aspartic acid	0.811	0.907
	Alanine	0.548	0.659
	Serine	0.413	0.445
	Glutamine	0.967	0.965
	Glycine	0.363	0.366
	Cysteine	0.031	0.019
	Tyrosine	0.258	0.279
	Proline	1.153	1.116
	Total	4.544	4.756
Semi-Essential Amino Acid	Histidine	0.868	1.011
	Arginine	0.912	0.891
	Total	1.780	1.902
	Total content	9.811	10.076

Table 8. Percentage of amino acids and protein efficiency ratio (PER) in without steam blanching jengkol and steam jengkol.

Parameters	Without steam blanching	Steam Jengkol
Acidic AA, %	18.12		18.58
Basic AA, %	31.49		29.87
Hydrophobic AA, %	36.00		36.41
Uncharged polar, %	15.00		15.14
E/T(%)	35.54		33.92
PER1	2.12		2.36
PER2	2.43		2.63

Note: AA = amino acids, E/T ratio of essential to total amino acids, PER: calculated protein efficiency ratio.

Yamaguchi, S.; Yoshikawa, T.; Ikeda, S.; Ninomiya, T. Measurement of the Relative Taste Intensity of Some L-α-amino Acids and 5ʹ-nucleotides. J. Food Sci. 1971, 36, 846–849. DOI: 10.1111/j.1365-2621.1971.tb15541.x.

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