Higher Gelatinization Temperature Research Articles

Effects of experimental warming on physicochemical properties of indica rice starch in a double rice cropping system

To evaluate the actual response of rice starch physicochemical properties to climate warming, a field warming experiment was conducted with four indica rice cultivars using free-air temperature increase (FATI) facility in a double rice cropping system. FATI facility increased rice canopy temperature by 1.4–2.1 °C during the entire growth period. The responses of starch physicochemical properties to experimental warming were basically consistent for both early and late rice. On average, experimental warming increased the starch relative crystallinity, granule average diameter, and amylopectin average chain length by 14.3%, 6.9%, and 2.4%, respectively. These resulted in starch with lower swelling power, water solubility, and pasting viscosity, but higher gelatinization temperatures and gelatinization enthalpy. Our study indicated that experimental warming affected the rice starch physicochemical properties, and would provide some useful information on how to guide the rice starch end use in food and non-food industries under climate warming.

Physicochemical and Functional Characterization of Potato Starch (Solanum Tuberosum ssp. Andigenum) from the Quebrada De Humahuaca, Argentina

AbstractThe physicochemical properties of starches of 16 Andean potato genotypes from the Quebrada de Humahuaca, Jujuy, are studied and possible applications are evaluated. Moisture, protein, ash, phosphorus, amylose/amylopectin ratio, particle size, swelling power, water absorption index, solubility index, syneresis, turbidity, thermal properties, gelatinization, retrogradation, and their corresponding enthalpies are determined. The analysis of principal components allowed obtaining groups of varieties with similar properties. Four groups of genotypes are obtained: one group is characterized by high gelatinization temperatures, so it can be used for products that require high processing temperatures; the second, with greater swelling power, can be applied in products that require water retention; other can be used in the production of edible film because it has higher amylose content which improves its mechanical properties; the latter is characterized by having a high stability and lower syneresis which indicates it is possible to use in processes that require refrigeration and freezing. The information obtained in this study can be useful for the production of potatoes with differentiated characteristics of their starches and with the possibility to be applied both in food and in non‐food products.

Isolation and physicochemical property of individual parenchyma cells from mealy sweet potato.

This study prepared the dehydrated sweet potato parenchyma cell (SPPC) by isolating intact, individual parenchyma cells (PC) from sweet potato (SP) flesh using pectinase, and compared its chemical compositions, solubility and swelling power, gelatinization, and pasting viscosity to sweet potato starch (SPST) and flour (SPFL). The highest yield of SPPC was achieved when frozen SP whole-tissues were treated with pectin lyase. The majority constituting SPPC was intact, individual PCs fully filled with SPST granules. SPPC possessed lower crude protein and ash contents than SPFL. SPPC revealed lower solubility and swelling power, higher gelatinization temperatures, and lower pasting viscosity than SPST, while it showed lower solubility, higher swelling power, lower gelatinization temperatures, and higher pasting viscosity than SPFL. Overall, SPPC characteristics may result from intact PC walls surrounding clusters of SPPC granules, and SPPC could be considered an alternative to SPFL and SPST for expanding industrial applications of SP.

Retrogradation and Digestibility of Rice Starch Gels: The Joint Effect of Degree of Gelatinization and Storage

Retrogradation affects acceptability of starchy foods; however, it is preferred in some products such as rice noodles. Amylose content, gelatinization temperature, and storage condition were reported to affect retrogradation but with disputed data. The joint effects of these parameters were interested in this study. Rice starch was gelatinized using different temperatures (77, 81, 95, and 121°C) and stored isothermally with temperature cycles for 10 days. Results showed that the most important parameter that affected retrogradation was storage time followed by storage condition and gelatinization temperature. The recrystallization rate constant (k) and Avrami exponent (n) of retrograded starches stored under temperature cycle were higher than isothermal storage. All samples showed similar polymorphs of a mixture of B and V types. High-temperature gelatinized starch gel stored under temperature cycle condition produced higher yield of resistant starch. The study provided useful information on how to apply these parameters to control the retrogradation of starchy foods, especially rice noodle. PRACTICAL APPLICATION: Retrogradation is found to be more prominent at higher gelatinization temperature and longer storage time. Resistant starch produced from retrograded starch depended largely on storage time than storage condition. This finding can be applied to improve rice noodle qualities (by increasing retrogradation) with lower digestibility (by producing higher resistant starch).

Quality assessment of Indian rice varieties, evaluation of its relationship with their Glycemic index

The preference for a particular rice quality trait varies regionally, with the shift of choice towards better quality varieties. The qualitative properties namely amylose content, gelatinization temperature, hardness and Glycaemic Index (GI) were studied. Eight rice varieties (Basmati, Non-Basmati, Parboiled) 1121 Mini Sella Mogra (1121 MSM), Mini Sella Mogra (MSM), Noorjahan Basmati (NB), White Sella Dubar (WSD), Golden Sella (GS), Parmal Sella (PSe), Parmal Silky (PSi), Hari Bhari Parmal Sella (HBPS) were selected. Amylose content were highest in WSD (41 ± 0.05%) and PSe (40.99 ± 0.02%). Onset temperature during gelatinization was high in NB (98.28 ± 0.28 °C) and PSe (95.54 ± 0.47 °C). PSe showed the highest positive cycle peak in texture profile analysis (hardness 3900 ± 41 g) while least in PSi (1300.09 ± 0.64 g). GI was lowest of WSD and PSe (GI ~ 41). A positive correlation was found between amylose content, hardness and gelatinization temperature, which inversely related to GI. Principal Composition Analysis (PCA) has generated PC1 (55.68%) and PC2 (26.26%), the two principal components describing total 82.12% of data distribution. The Agglomerative hierarchical clustering divided all the samples into three clusters (C1–C3), based on percentage contribution. PSe was found to be best with high amylose percentage (40.99 ± 0.02%), high onset gelatinization temperature (95.54 ± 0.47 °C), maximum hardness (3900 ± 41 g) and low GI (GI ~ 41).

Exploring the functionality of starches from corms and cormels of Xanthosoma sagittifolium

SummaryXanthosoma sagittifolium, belonging to the araceas family, represents an attractive alternative as a starch source. Nevertheless, as a rhizome plant two differentiated parts could be distinguished named corms and cormels." by "However, the rhizome of Xanthosoma sagittifolium has two differentiate parts named corms and cormels of Xanthosoma. Granules morphology, composition, hydration properties, pasting/thermal behaviour, as well as gelling performance were assessed. Scanning Electron Microscopy (SEM) revealed different morphology, granules were organised as aggregates in starch isolated from corms. Corms starch displayed lower hydration properties, lower apparent viscosity during heating and cooling and higher gelatinisation temperatures than cormels starch. Gels from corms starch showed less syneresis than cormels starch, but no significant differences were observed regarding their hardness. Therefore, the part of the araceas plant from which the starch is extracted must be always defined, because significant differences in their functionality are ascribed to their morphological origin.

Physicochemical properties of starches from vitreous and floury endosperms from the same maize kernels

Starches were isolated from vitreous and floury endosperms from the same kernels, and their physicochemical properties were investigated to reveal their differences. Starch from vitreous endosperm had more surface indentations, larger granule size, and higher contents of protein, amylose and damaged starch than that from floury endosperm. Both starches from vitreous and floury endosperms exhibited A-type crystalline structure, but starch from vitreous endosperm had lower relative crystallinity and lamellar peak intensity than that from floury endosperm. Starch from floury endosperm had higher gelatinization temperature and enthalpy but lower gelatinization temperature range and percentage of retrogradation than that from vitreous endosperm. Native starch from floury endosperm was more resistant to enzyme hydrolysis than that from vitreous endosperm. Gelatinized and retrograded starches had similar digestion properties between starches from vitreous and floury endosperms. Principal component analysis indicated that starches from vitreous and floury endosperms had significant differences in their physicochemical properties.

Effect of milling methods on the properties of rice flour and gluten-free rice bread

The properties of rice flour are very important for making gluten-free rice bread. In this study, rice flour was prepared using different milling methods (wet-milling, cyclone-milling and ultrafine-milling) to investigate their effect on the properties of gluten-free rice bread. The milling method was found to significantly affect the damaged starch content, state of the starch granule, gelatinization temperature and absorption enthalpy of rice flour (p < 0.05). The starch granules of flour prepared by wet milling had a high integrity, low damaged starch content (2.80 g/100 g), high gelatinization temperature, and high values of absorption enthalpy and gel strength compared to ultrafine-milling and cyclone-milling methods. As the deformation of the starch in the rice grains decreased, the amount of completely gelatinized starch granules in the bread decreased, with its specific volume also decreasing from 3.1 to 1.2 mL/g. Increase in starch damage content was observed to decrease the specific volume of bread, consequently increasing the hardness of bread. Also, uneven pores were observed, and the number and size of internal pores decreased. This indicated that wet-milled rice flour with a low content of damaged starch and higher starch granules integrity produced better gluten-free rice bread.

Comparative studies on physicochemical properties, starch hydrolysis, predicted glycemic index of Hom Mali rice and Riceberry rice flour and their applications in bread

Physicochemical properties, predicted glycemic index (pGI) and bread qualities of a non-pigmented white rice flour (Hom Mali, HM) and a pigmented rice flour (Riceberry rice flour, RB) were investigated. In the present study, RB (15.3% amylose) contained higher total polyphenolics, anthocyanins, and ferric reduction activity power than HM (21.3% amylose). RB had lower swelling power and higher gelatinization temperatures. In addition, RB contained higher levels of beneficial resistant starch (RS) and lower levels of slowly digestible starch (SDS) with medium pGI. RB provided slower glucose release than HM. The pasting characteristics showed that peak and final viscosity, trough and setback value, and breakdown of RB was lower than HM. RB bread had lower cohesiveness, gumminess, chewiness and adhesiveness than HM bread. Furthermore, RB bread demonstrated lower starch hydrolysis and pGI than HM bread. These findings suggest that anthocyanin-rich RB could be used as an alternative food ingredient for gluten-free bread.

Substitution of wheat flour with highly enzyme-resisted cassava starch and its effect on starch digestibility and quality of breads

The aim of this research was to investigate changes in flour characteristics, bread quality, in vitro and in vivo starch digestibility and glycemic index (GI) values of breads with 10%, 20% and 30% of a mixture of highly enzyme-resisted cassava starch (HRCS) and vital gluten (9:1, w/w) substitution for wheat flour. The composite flours had higher gelatinization temperatures and lower maximum, trough, final, breakdown and setback viscosities than did the wheat flour. The composite flours also had higher water holding capacity and lower swelling index as compared to the wheat flour. The specific volumes of loaves with HRCS substitution reduced substantially, while hardness and gumminess values of loaves escalated remarkably. Resistant starch (RS) contents of substituted breads remarkably enhanced, whereas blood glucose response in mice and GI values of the substituted breads significantly reduced along with raising amounts of HRCS substitution. Moreover, increase in the percentage of HRCS and vital gluten supplementation up to 20% did not significantly impact on the sensorial profile of breadcrumbs including color, appearance, odor and flavor, texture and overall acceptability. As a result, HRCS can be substituted for wheat flour up to 20% in breadmaking to improve human health benefits with satisfied bread quality.

Detection and analysis of rice quality characters in Southern Henan glutinous rice germplasm resources

Southern Henan is rich in germplasm resources of glutinous rice, which is an important genetic resource bank for breeding new varieties of glutinous rice. The detection and analysis of rice quality characters in Southern Henan glutinous rice germplasm resources can provide scientific basis for the breeding and application of new high-quality glutinous rice varieties. In this study, 13 representative glutinous rice varieties in the south of Henan Province were selected as the experimental materials, and their main quality indexes, such as appearance quality, milling quality, cooking and eating quality, and nutritional quality, were detected and classified by using near-infrared grain analyzer combined with biochemical and physical-chemical analysis techniques and methods Analysis. The results showed that the chalkiness rate of 13 typical glutinous rice germplasm resources was not up to the national standard of high quality rice, except for the three glutinous rice varieties of Heixiangnuo 334, Xingengnuo 631 and Jugengnuo-GB-5; In terms of gelatinization temperature, the gelatinization temperature of Jugengnuo-GB-5 was the lowest, which belongs to the national first-class high-quality rice. Except that the alkali dissipation value of three glutinous rice varieties is less than 3 (high gelatinization temperature), other glutinous rice varieties are all of medium low gelatinization temperature; In terms of taste value, among the 13 glutinous rice varieties tested, Yanggengnuo 1 had the highest (92.23%) and Jugengnuo-GB-5 had the lowest (34.86%); Among the 13 glutinous rice varieties tested, except Yanggengnuo 1, the protein content was 9.09%, other glutinous rice varieties were less than 9.00%, and the variation range was between 6.32% to 9.09%; The content of free fatty acids was different among the varieties. The highest content was Heixiangnuo 1926, its free fatty acid content was 31.66%, the lowest content was Heixiangnuo 193, which was 17.30%; As for the milling quality, except the brown rice rate of Heixiangnuo 334 and the whole milled rice rate of Heixiangnuo 193, the processing quality of other glutinous rice varieties all reached the national standard of high quality rice. Among them, Yanggengnuo 1 has higher milled rice rate, whole milled rice rate and taste value, and the overall performance is better. There are abundant variations in appearance quality, milling quality, cooking and eating quality, nutritional quality and other main quality indexes of Southern Henan glutinous rice germplasm resources, which provide important information for the cultivation of new high-quality glutinous rice varieties in the later stage.

Physicochemical, Thermal, Structural and Pasting Properties of Unconventional Starches from Ginger (Zingiber officinale) and White Yam (Dioscorea sp.)

Abstract Ginger and white yam starches were investigated and compared with maize starch. Proximal composition, thermogravimetry, differential scanning calorimetry, microscopy, colourimetry, X-ray powder diffractometry and pasting profile were analysed. The unconventional starches presented higher protein and ash contents than the maize starch, that had the highest thermal stability. Higher gelatinisation temperatures were reported for ginger starch, and the enthalpy of the unconventional starches were similar. The maize starch presented the lowest gelatinisation values. For the corn starch the granules were polygonal and smaller than the unconventional starches, and oval shapes and larger diameters were found for the ginger and yam starches. The unconventional starches presented less brightness and a greater tendency to red and yellow. The maize and ginger starches had A-type diffraction patterns, while the white yam starch had a C-type pattern. The highest relative crystallinity was observed for the ginger starch and there were small differences between the yam and maize starches. Higher peak viscosity and final viscosity and lower pasting temperature were observed for the yam starch. Ginger starch showed the highest shear and stability of heating glue, so may be used in products processed under high temperatures; and yam starch can be used in acidic foods that require high viscosities.

고아밀로스 쌀 품종 전분의 분자구조적, 열적특성 및 유화제 첨가에 의한 아밀로스-지질 복합체 형성

Purpose: The present study assessed molecular structural and thermal properties of rice starches with high amylose content and their ability to form amylose-lipid complexes with various emulsifiers. Methods: Rice starches from four cultivars (Dodamssal, Bukkyoung, Saegoami, and Saemimyeon) were analyzed for amylose and amylopectin molecular structure using high performance liquid chromatography (HPLC), thermal properties, amylose-lipid complex formation with various emulsifiers using differential scanning calorimeter (DSC), and in vitro starch digestibility. Results: Among the four starches, Dodamssal, which has significantly higher amylose content and longer branched chains of amylopectin than the other three starches, showed significantly different thermal properties, amylose-lipid complex formation, starch digestibility based on high starch pasting and gelatinization temperature, high amylose-lipid complex dissociation enthalpy, and high resistant starch content. Bukkyoung and Saegoami were not significantly different molecular structure and exhibited similar thermal characteristics, amylose-lipid complex formation, and starch digestibility. Conclusion: Differences in the molecular structures of amylose and amylopectin for the four starches significantly influenced the starch pasting and gelatinization characteristics, the amylose-lipid complex formation by various emulsifiers, and the in vitro starch digestibility. Dodamssal could be a potential source for effective amylose-lipid complex formation, which may contribute to enhancing type 5 RS.

A comparative study of mango seed kernel starches and other commercial starches: the contribution of chemical fine structure to granule crystallinity, gelatinization, retrogradation, and pasting properties

Mango seed kernels (MSK) are the waste from mango processing plants; but they still contain valuable nutrients. In this study, the physicochemical properties of starches isolated from seed kernels of three Thai mango cultivars (Namdokmai, Kaew, and Chokanan), mainly used in the industry, were characterized and compared with those of other commercial starches namely tapioca, corn, low-, and high-amylose rice. MSK starches possessed a smooth-oval shape granule with average diameter of 12.90–13.20 µm. They were higher in lipid (0.53–0.55%) and amylose (31.50–33.12%) than other starches. Amylopectin and amylose of MSK starches had a relatively low molecular weight. Amylopectin of MSK starches had higher proportion of B1 and B2 chains but lower proportion of A chain than those of other starches. These chemical properties contributed to changes in value of following properties of MSK starches: higher crystallinity (40.20–41.30%), higher gelatinization temperature (78.13–82.39 °C) and enthalpy (17.32–19.45 J/g), higher pasting temperature (81.6–84.4 °C) and peak viscosity (356.2–423.8 rapid viscoanalyzer units). Amylopectin of MSK starches also retrograded to a higher extent than that of other starches. Based on their physicochemical properties, MSK starches; especially Kaew cultivar, could be a potential source of resistant starch; particularly of RS2.

Characterization of young bamboo culm starch from Dendrocalamus asper.

The search for new and natural ingredients has been stimulated by the food and non-food industries, and the fresh young bamboo culm of Dendrocalamus asper emerges as promising for industrial production due to its composition with >10% of starch. So, this study aimed to characterize starch, extracted in aqueous solution, from three different parts (bottom, middle and top) of the young bamboo culm of D. asper (SB, SM and ST, respectively). Morphological and physicochemical characteristics of the young bamboo culm starches were evaluated, besides thermal properties, and the obtained data were evaluated by ANOVA and Scott-Knot test (p < 0.05). The starches presented pale yellow coloration, with high luminosity (L* > 89), and lower index in the red region. SEM images showed compound granules, which under polarized light exhibit a Maltese cross. The starches presented polyhedral shape and small size with an average diameter of 5.4 μm. All the samples presented low moisture (7.0 g/100 g), protein (2.0 g/100 g), lipid (0.3 g/100 g) and ash (1.0 g/100 g) contents. ST and SB showed apparent amylose content similar to starches from cereals and isolated from bamboo seeds. This agress to molecular size distribution of starch chains, since the SB, SM and ST presented amylopectin levels higher than those of amylose, as well as normal starches. The chain length of amylopectin presented the main peak at DP 12-13 and the second on at DP 43, similar to cereals like wheat, rice and barley. Its chain has higher proportion of short chains, which corroborates with the A-type polymorph presented. Concerning about thermal properties, all the samples presented high gelatinization temperature (>78 °C) and low enthalpies values (<6.35 J·g-1), which indicates the greater molecular organization. The gelatinization temperatures of gelatinized starches were lower than the native ones. The physicochemical and thermal characteristics of the obtained starches corroborate with the success of the extraction, which keep the starch granule native, and were similar to those of other starches already used in food and non-food products.

Structural and physicochemical properties of heat moisture treated and citric acid modified acha and iburu starches

Starches extracted from acha (Digitaria exilis) and iburu (Digitalia iburua) were subjected to heat moisture treatment and citric acid modification. Successful applications of the treatments are expected to promote commercial utilization of the starches from these underutilized crops and improve the economy and livelihood of stakeholders along their value chains. Granules of the starches from the two cereal grains were polyhedral in shape. Generally, modifications led to the clustering of the polyhedral of the starches granules. Indentations were observed on the surfaces of citric acid modified (CAM) starches. This could be due to the weathering effect of acid hydrolysis. Modification methods employed did not affect the characteristic type-A crystal polymorph of the native starches. The starches generally exhibited single prominent peaks at (2ϴ) 16 and 24, and a doublet at 17-19. Crystallinity index of the starches ranged from 27.01-27.84% for acha and 29.01–30.47% for iburu. FTIR analysis and high peak gelatinization temperatures of the starches suggested heterogeneity in the matrices. CAM starches of the two grains remained in liquid form throughout the pasting cycle. Acha starches are lighter and whiter in color. All the starch samples exhibited promising functional properties that could place them as good materials for different industrial uses. Results of this study further exposed the potentials of acha and iburu starches for food and pharmaceutical applications.

Characterization of rice physicochemical properties local rice germplasm from Tana Toraja regency of South Sulawesi

The research about the characterization of physicochemical properties from local rice germplasm of Tana Toraja’s Regency, South Sulawesi aims to determine the physicochemical properties of rice as a parameter to indicate the quality of cooking. Local varieties categorized as germplasm that needs to be protected for future varietal improvement.In this research, the researchers used seven varieties of local rice. The parameters analyzed including physicochemical properties of amylose content, protein content, gel consistency, and gelatinization temperature. Percentage of amylose content ranged from 2 to 18 %. Pare Bumbungan and Pare Lalodo are categorized as waxy rice and Pare Ambo, Pare Bau, Pare Kobo, Pare Rogon and Pare Tallang are categorized as low amylose content. The percentage of protein content ranged from 7.3 to 9.5 %. Gelatinization temperature of rice showed high gelatinization temperature. Pare Bumbungan, Pare Kobo, Pare Lalodo, and Pare Rogon are categorized as soft gel consistency (˃50 mm). Pare Ambo, Pare Bau and Pare Tallang are categorized as medium gel consistency (36-50m). Pare Rogon and Pare Kobo are two kinds of rice varieties according to the quality of cooking criteria for consumers in Indonesia.

Structural and Functional Properties of Slowly Digestible Starch from Chinese Chestnut

Abstract The structural and functional properties of slowly digestible starch (SDS) modified using pullulanase and prepared from chestnut starch were studied. The modified chestnut starches had 41.9 % SDS, which was higher than native chestnut starches (6.51 %) and cooked chestnut starches (18.6 %). The hydrolysis rate of the modified starches was 74.1 %. Scanning electron microscopy showed that the modified starch granules had a large surface area with signs of cracks and dents, and the cross-sections showed hollow internal structures. X-ray diffraction indicated that the crystallisation of the starch changed from the Cb-type to the V-type, although it retained a few C-type characteristics. Compared with native chestnut starch, the modified starches have a higher gelatinisation temperature using differential scanning calorimetry; and the texture profile analysis hardness, chewiness, cohesiveness, and gumminess of modified starch gels decreased significantly, while adhesiveness increased. When debranched using pullulanase there was a decreased solubility, swelling power, and freeze-thaw stability of the modified starches. These findings suggest that pullulanase modification changed the in vitro digestibility and crystalline structure of the modified starches.

Production, physicochemical and sensory characterization of cocoyam mixed flours and pastes (achu)

Colocasia esculenta L. Schott and Xanthosoma sagittifolium L. Schott are two tropical tubers species commonly referred as cocoyams. Colocasia esculenta tuber is usually used for the preparation of achu (smooth paste food), but not always available. This work is aimed at evaluating the effect of mixing two cocoyam flours on the physicochemical and sensory characteristics of precooked composite flours and achu. In this respect, a factorial design was realized. This factorial design was 2 varieties of Xanthosoma sagittifolium (white-flesh and red-flesh) coded as WX and RX and 5 levels of substitutions (0, 25, 50, 75 and 100%) in the Colocasia esculenta (Ibo coco) coded as IC. Precooked flours showed significant (p < 0.05) differences in the contents of ash (2.09 ± 0.33 to 4.21 ± 0.03%), fiber (1.33 ± 0.04 to 1.57 ± 0.43%), total sugar (71.12 ± 0.85 to 74.02 ± 1.42%), starch (47.26 ± 0.95 to 66.59 ± 1.09%), proteins (3.20 ± 0.14 to 4.35 ± 0.07%) and total oxalate (0.41 ± 0.16 to 0.82 ± 0.11%). The water absorption capacity and water solubility index also shown a significant difference (p < 0.05). The highest gelatinization temperature, final viscosity, setback, and consistency during the heating time were recorded for Xanthosoma sagittifolium flours, meanwhile the peak viscosity and breakdown indexes were higher in Colocasia esculenta flour. It was also observed that there was least difference (p < 0.05) in the overall acceptability (4.54 ± 1.96 to 5.74 ± 1.40) of the sensory attributes of reconstituted achu by the participants. Elsewhere, the results revealed that more than 35% of the participants like very much the achu made from cocoyam flour mixtures while 44.65% of them just like it. These results indicate the potential of Xanthosoma sagittifolium precooked flours for substituting Colocasia esculenta flour at varying proportions in achu making.

The Importance of Surface-Binding Site towards Starch-Adsorptivity Level in α-Amylase: A Review on Structural Point of View.

Starch is a polymeric carbohydrate composed of glucose. As a source of energy, starch can be degraded by various amylolytic enzymes, including α-amylase. In a large-scale industry, starch processing cost is still expensive due to the requirement of high temperature during the gelatinization step. Therefore, α-amylase with raw starch digesting ability could decrease the energy cost by avoiding the high gelatinization temperature. It is known that the carbohydrate-binding module (CBM) and the surface-binding site (SBS) of α-amylase could facilitate the substrate binding to the enzyme's active site to enhance the starch digestion. These sites are a noncatalytic module, which could interact with a lengthy substrate such as insoluble starch. The major interaction between these sites and the substrate is the CH/pi-stacking interaction with the glucose ring. Several mutation studies on the Halothermothrix orenii, SusG Bacteroides thetaiotamicron, Barley, Aspergillus niger, and Saccharomycopsis fibuligera α-amylases have revealed that the stacking interaction through the aromatic residues at the SBS is essential to the starch adsorption. In this review, the SBS in various α-amylases is also presented. Therefore, based on the structural point of view, SBS is suggested as an essential site in α-amylase to increase its catalytic activity, especially towards the insoluble starch.