The Effect of Starch Isolation Method on Morphological and Physicochemical Properties of Zagros Oak (Quercus brantii var. Persica) Starch

Abstract

This study aimes to compare the physicochemical and functional properties of Zagros acorn (Quercus brantii) starches isolated by various methods: wet‐milling (acid‐concentration: 1800, 2000, and 2200 ppm; WME‐A, WME‐B, and WME‐C), enzyme‐assisted (2, 4, and 6 h; EAE‐A, EAE‐B, and EAE‐C), freeze‐thaw (UAE‐A), ultrasound‐assisted (15 and 30 min: UAE‐B and UAE‐C), and lactic acid‐assisted (24, 32, and 48 h: LAE‐A, LAE‐B, and LAE‐C). The extracted starch is tannins‐free and forms a paste with low turbidity (1.35% (WME‐A/B) to 1.92% (UAE‐C) and acceptable yield (39.1% (WME‐B) to 23.07% (UAE‐C)). The amylose content significantly varies between 17.7% (AAE‐C) and 18.13% (EAE‐A). Starches isolated by WME‐B follows, and EAE‐B methods exhibits the highest swelling power (SP) and solubility besides the lowest syneresis. The range of viscosity is between 892.33 (WME‐B) and 593.33 (UAE‐C) cP (p < 0.05). The morphology of the granules varies depending on the isolation method. FTIR‐spectra of various starches show almost similar profiles. The results provide valuable insights about the differences in physicochemical properties of Zagros acorn starch isolated by various methods to choose appropriate applications of these un‐conventional starch. Overall, WME‐B is suggested as a simple and economical method, while the EAE‐B is an environmentally friendly method.

Modification of Acorn Starch Structure and Properties by High Hydrostatic Pressure

“…Commercial starch granules occur in a range of shapes, as shown in Figure 1 A, ranging from round, oval, and semicircular to triangular and trapezoidal–triangular, including granules with irregular shapes. Acorn starch granules were found to be round, oval, and semi-circular in shape, with some granules being triangular or trapezoidal–triangular in shape ( Figure 1 B–E), as reported in the literature [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ]. Aside from the shape, commercial and acorn starch granules had a smooth surface without cracks and/or fissures, but a few granules had pits ( Figure 1 A–E) [ 14 , 17 , 19 , 20 , 21 ].…”

“…Acorn starch granules were found to be round, oval, and semi-circular in shape, with some granules being triangular or trapezoidal-triangular in shape (Figure 1B-E), as reported in the literature [14][15][16][17][18][19][20][21][22]. Aside from the shape, commercial and acorn starch granules had a smooth surface without cracks and/or fissures, but a few granules had pits (Figure 1A-E) [14,17,[19][20][21]. Pressurization did not affect the shapes and morphology of acorn starches of both Q. pyrenaica and Q. robur species, as previously observed for lily, chestnut, rice, and maize starches up to 500 MPa [9,23].…”

“…The amylose contents of Q. pyrenaica (P0.1/t20; 53.2 ± 0.5%) and Q. robur starches (R0.1/17.4; 58.2 ± 0.1%) were similar to those reported for Q. rotundifolia (53.7–54.5%) and Q. suber (57.9–59.4%) starches, respectively [ 35 ]. However, they were higher than those reported for Q. ilex (25.8%) [ 36 ], Q. palustris (31.4%) [ 18 ], Q. serrata (27.1%) [ 37 ], Q. suber (24.4%) [ 38 ], Q. calliprinos (29.2%) [ 39 ], Q. suber (34.4%) [ 36 ], Q. acutissima (30.6%) [ 15 ], Q. ilex (31%) [ 40 ], and Q. wutaishanica (31.4%) [ 16 ], Q. ilex (39.0%) [ 41 ], Q. pubescens (19.5%) [ 36 ], Q. rotundifolia (41.7%) [ 42 ], Q. leucotrichophora (15.6%) [ 14 ], Q. brantii (~18%) [ 21 ], Q. coccifera (36%) [ 40 ], and Q. suber (48.9%) [ 42 ] starches. The mechanical forces created during pressurization may have led to the cleavage of covalent bonds along the polymeric chains.…”

“…The solubility and swelling power values of Q. pyrenaica (P0.1/t20; 2.36 ± 0.18–17.82 ± 0.18% and 6.40 ± 0.10–16.83 ± 0.03 g/g, respectively) and Q. robur (R0.1/17.4; 1.46 ± 0.19–19.71 ± 0.14% and 6.53 ± 0.09–16.75 ± 0.60 g/g, respectively) starches diverged from those of Q. brantii (9.7% and 24.5 g/g, respectively) [ 20 ], Q. fabri (0.26–4.87% and 0.024–0.14 g/g, respectively) [ 22 ], Q. brantii (60–65% and 0.26–0.27 g/g, respectively) [ 21 ], Q. rotundifolia (9.1 g/g) [ 42 ], Q. suber (9.0 g/g) [ 42 ], and Q. ilex (0.2–14.0% and 8.95–13 g/g, respectively) [ 41 ].…”

Effect of Olive Pomace Fiber on the Baking Properties of Wheat Flour and Flat Bread (Barbari Bread) Quality

“…The supernatants were mixed with 95% ethanol (fourfold volumes) for 2 h at room temperature. The residues were washed with 100% ethanol and dried to obtain SDF [21][22][23]. Based on our experiments, the yield of olive pomace fiber was 92.12% in which 21.68% of this fiber was SDF (moisture content: 5:55 ± 0:06%, protein content: 2:13 ± 0:05, and ash content: 0:46 ± 0:06), and 70.44 of ODF was IDF (moisture content: 3:34 ± 0:12%, protein content: 3:19 ± 0:04, and ash content: 5:38 ± 0:23).…”