Physicochemical Properties of Starch from Aroids of North East India

Figures & data

Table 1 Chemical composition of aroid corms on dry weight basis; shape and size of starch granules

Aroids	A. paeonifolius	X. caracu	C. esculenta	X. sagittifolium
Moisture content (%)	9.5 ± 1.4	10.2 ± 0.85	11.2 ± 0.74	12.2 ± 1.2
Total ash content (%)	1.2 ± 0.9	1.5 ± 0.5	1.3 ± 0.6	1.2 ± 0.8
Apparent amylose content (%)	12.54 ± 0.6	12.84 ± 0.8	17.54 ± 1.2	18.25 ± 0.54
Total amylase content (%)	14.24 ± 2.1	16.6 ± 3.4	22.4 ± 4.5	20.4 ± 1.6
Lipid content with chloroform: methanol	0.05 ± 0.01	0.04 ± 0.02	0.04 ± 0.01	0.06 ± 0.01
Lipid content with n-propanol: water	0.01 ± 0.005	0.02 ± 0.01	0.02 ± 0.008	0.03 ± 0.01
Lipid content with HCl hydrolysis	0.13 ± 0.02	0.2 ± 0.04	0.09 ± 0.02	0.17 ± 0.05
Starch damage (%)	4.54 ± 0.24	1.42 ± 0.14	2.17 ± 0.08	2.54 ± 0.11
Enthalpy of gelatinization (J/g)	14.5 ± 1.24	16.4 ± 0.54	12.5 ± 1.41	13.2 ± 0.89
Water binding capacity (%)	86.2 ± 4.5	82.1 ± 5.1	87.7 ± 3.5	79.5 ± 4.3
Total carbon content (%)	62.35 ± 9.2	70.18 ± 11.2	80.53 ± 14.5	80.84 ± 15.5
Total oxygen content (%)	37.75 ± 5.6	29.73 ± 12.3	11.74 ± 5.2	14.69 ± 5.2
Granule size (μm)	5–12	1.25–2.21	0.71–1.25	2.1–2.84
Granule shape	Polygonal	Polygonal	Polygonal	Polygonal
Fissures	Absent	Absent	Absent	Absent
Concentric rings	Absent	Absent	Absent	Absent
Starch content (%, fresh wt.)	10.23 ± 0.44	14.15 ± 0.58	14.81 ± 0.60	12.36 ± 0.50
Total phosphorus content (mg/100 gm) from EDX	0.08 ± 0.05	0.04 ± ND	0.07 ± 0.02	0.05 ± 0.04
Relative degree of the crystallinity (%)	48.84	46.91	35.77	41.30
α-amylase hydrolysis (%)	30.49 ± 0.3	42.54 ± 1.5	56.15 ± 1.9	36.04 ± 1.4

Figure 1 Scanning electron microscopic images of purified aroid starch granules showing their granule size and morphology.

Figure 2 X-ray diffraction patterns of four aroid starches. (a) A. aeonifolius, (b) C. esculenta, (c) X. sagittifolium, and (d) X. caracu.

Figure 3 FT-IR patterns of the purified aroid starches along with commercial starch from Merck (India) showing their purity: (a) A. aeonifolius, (b) X. caracu, (c) C. esculenta, (d) X. sagittifolium, (e) Starch soluble (Merck). (Continued)

Table 2 DSC analysis data of the aroid and commercial starch

Sl No.	Aroids	To (°C)	Tc (°C)	Tp (°C)	ΔH (mJ/gm)
1	Starch soluble	57.42 ± 2.44	72.44 ± 1.87	70.49 ± 2.63	9,122.00 ±237
2	A. paeonifolius	95.94 ± 3.15	112.77 ± 1.28	104.22 ± 2.77	95,326.66 ± 543
3	X. caracu	97.55 ± 2.1	106.50 ± 3.31	103.49 ± 3.89	14,660.00 ± 238
4	X. sagittifolium	85.44 ± 3.85	118.01 ± 3.33	102.40 ± 3.15	24,083.33 ± 349
5	C. esculenta	95.45 ± 3.19	118.01 ± 2.84	106.97 ± 2.64	44,000.00 ± 455

Figure 4 Effect of temperature on amylose leaching in aroid starches: A. paeonifolius, ◊; X. sagittifolium, ×, X. caracu, □; C. esculenta, Δ.

Figure 5 Acid hydrolysis of the aroid starches with respect to time (days): A. paeonifolius, ◊; X. sagittifolium, ×; X. caracu, □; C. esculenta, Δ.