This study aimed to understand the effect of molecular-weight distribution on the properties of acid-hydrolyzed waxy maize starches (AH-WMSs) prepared at different acid concentrations and hydrolysis times at 50 °C. A reduction in molecular weight of AH-WMS resulted in increased paste fluidity and light transmittance, as well as decreased sedimentation, amylose‑iodine complex, and pasting viscosity. Freshly prepared AH-WMS viscoelastic gels at 20 % solids showed thixotropy at 25 °C and 50 °C, and both the shear stress and the area of hysteresis loop decreased with decreasing molecular weights. After storage at 4 °C for 24 h, the AH-WMS viscoelastic gels exhibited anti-thixotropy at 25 °C. However, the anti-thixotropy behavior disappeared at 50 °C for those with lower molecular weights. Freshly prepared viscoelastic gels obtained from AH-WMSs with higher molecular weights showed higher values of liquidity, firmness, consistency, cohesiveness, and viscosity at 20 % and 30 % solids. After storage at 4 °C for 24 h, AH-WMS viscoelastic gels at 30 % solids transformed into solid gels, and the gel strength decreased with decreasing molecular weights. AH-WMSs with a similar molecular-weight distribution displayed similar pasting, rheological, and textural properties at high solids.

The objective of this work was to understand the cross-linked waxy wheat starch (WWS) characteristics from thermal properties, pasting properties, and paste rheological behaviors, textural properties, morphology, and freeze-thaw stability. WWS, waxy maize starch (WMS), and waxy tapioca starch (WTS) were cross-linked using sodium trimetaphosphate (STMP) and sodium tripolyphosphate (STPP) with a ratio of 99:1 (w/w) at levels of 0.01%, 0.05%, and 0.1%. WWS had lower gelatinization temperatures and enthalpy change than WMS and WTS, and cross linking had no or little impact on them. With increasing cross-linking levels from 0.01% to 0.1%, the peak viscosity decreased for the WWS, but increased for WMS and WTS, indicating that WWS was more sensitive to STMP/STPP. Cross-linking led to a substantial increase in final viscosity for all waxy starches. WWS cross-linked at 0.05% had the highest final viscosity among three waxy starches cross-linked at all three levels, which was consistent with the highest firmness, consistency, and cohesiveness of the paste and the morphology of swollen granules. Paste from WWS at 0.1% cross-linking showed almost no thixotropy, while all cross-linked WMS and WTS pastes exhibited high thixotropy. WWS had lower syneresis than WMS and WTS before and after cross linking, indicating a better cold storage stability.

As the population of individuals with diabetes and obesity continues to grow, the utilization of resistant starch (RS) in low-glycemic index and low-caloric foods has become more popular. Hydroxypropyl starch (HPS) is a chemically modified starch developed decades ago and has been widely used in both food and non-food applications. HPS with high degrees of substitution has substantial amounts of RS. Meanwhile, it also provides superior textural functionality in foods when comparing with other RSs, such as cross-linked starch and high-amylose starch. Moreover, long-term consumption of HPS has demonstrated certain health benefits, including increased energy expenditure, obesity prevention, and reductions in glycemic response, insulin resistance, and plasma cholesterol levels. Despite these benefits, the mechanism behind the enzymatic resistance of HPS, however, remains unclear. Therefore, the objective of this work is to provide a comprehensive review of the formation of resistant starch in HPS. Through this review, we aim to contribute to a better understanding of HPS for its applications in the food industry.

Professor Dexter French (1918-1981) was an American chemist and biochemist at Iowa State College (University in 1959). He devoted his career to advance knowledge of polysaccharides and oligosaccharides, in particular starch, cyclodextrins, and enzymes. Cyclodextrins are oligosaccharides obtained from starch and are typically cage molecules with a hydrophobic cavity that can encapsulate other compounds nowadays the basis for many industrial applications. Since the 1960s, he has been recognized as an outstanding authority in the field of starches and cyclodextrins and has inspired researchers in laboratories around the world. This review, on the fortieth anniversary of his death, commemorates his remarkable contribution to starch and cyclodextrin chemistry. Firstly, we give an overview of his personal life and career. Secondly, we highlight some of the results on starch and cyclodextrins from Professor French and his group. A third part discusses his impact on the modern chemistry of cyclodextrins and starch.

White-salted noodles are prepared, stored and consumed in various ways. However, relationships among cooking and storage conditions on nutritional functionality are not fully understood. The manuscript elucidates the mechanism of formation of resistant starch (RS) leading to slower digestion rate of variously cooked (boiled, steamed, stir-fried, fried and microwave heated) noodles followed by storage under different conditions (-18, 4 and 25 degrees C for 4, 24 and 48 h). RS content of noodles stored at 25 degrees C was higher than noodles stored at 4 degrees C, which was consistent with increases in the degree of crystallinity during storage. We showed that the residual moisture content primarily facilitated the mobility of starch chains and contributed towards the increase in RS associated with the decrease of enzyme susceptivity of noodles after storage. Evidence that supramolecular organization (helical structure and crystallinity) had a more pronounced effect than the macroscopic structure such as compactness or bulk density was also provided.

Noodles are widely consumed in China, which can be cooked in different ways. The effects of different cooking methods (boiling, steaming, microwave heating, stir-frying and frying) on the resistance starch (RS) content and digestive properties (digestion rate, digestibility and estimated glycemic index (eGI) value) of noodles were investigated. The RS content was greatly affected by the cooking time, and it was varied when the noodles were optimally cooked using different cooking methods. The RS contents of the microwaved and stir-fried noodles were relatively high (0.59%–0.99%), but it was lower (0.43%–0.44%) in the boiled and steamed noodles. Microwaved noodles showed the slowest digestion rate and the lowest eGI. Due to the limited water within fried noodles, none RS was found in the fried noodles, whereas stir-fried noodles showed RS5 formation from the XRD and DSC results. Compared with boiled and steamed noodles, the microwaved noodles showed a more compact morphology without porous holes on the surface, whereas fried noodles showed irregular morphology. The results indicated that the digestive properties of noodles made with the same ingredients can be greatly altered by using different cooking methods, and the digestive properties of different cooked noodles are worthy of confirmation using in vivo analysis.

Sheet-extruded films from the blends of hydroxypropylated normal corn starch (HP) and native normal corn starch (NS) at weight ratios of 100:0, 90:10, 70:30, 50:50, 30:70, and 0:100 were prepared and characterized. Glycerol and water were added as plasticizers at 11 and 27% starch weight, respectively. The highest tensile strength (TS) and longest elongation to break (EB) for dry films were observed at 70:30 HP: NS ratio, which was 25.76 MPa, and 3.97%, respectively. However, TS and EB of this 70:30 blend extruded starch film exhibited low resistance upon wetting for 10s. The film TS and EB were reduced to 13.26 MPa and 3.35%, respectively. Addition of 0.5% (wt/wt starch) succinic acid (SA) as a cross-linker to 70:30 HP: NS starch blend before film extrusion positively affected both TS and EB of films upon wetting; rather higher TS (16.64 MPa) and EB (4.85%) values were observed, which indicated improvement in water resistance of the films. Sheet-extruded films from 70:30 HP: NS blends resulted in improved dry strength, and upon cross-linking with SA, improved wet strength as well. The films had smooth and compact structure, which was explained by esterification/transesterification reactions promoted by SA, and confirmed by Fourier-transform infrared spectroscopy analysis. Practical Applications Manufacturing packaging films from biological sources, as well as coating materials, would be beneficial to the environment along with wider applications. Biobased packaging materials include both edible coatings and edible films along with primary and secondary packaging materials, and could also have non-food applications. They are derived from renewable sources and are potentially biodegradable through composting (which is a technique for waste management). Hydroxypropylation of starch results in wider functionality, and sheet-extrusion can result in more flexible and transparent films. Blends of 70:30 HP: NS resulted in stronger sheet-extruded films; testing of both dry and wet strengths of films indicated its suitability for both as edible coating (wet application), and other dry coatings/ films. These blend film can be an alternative to synthetic packaging films within their limitations.

紫苏籽油具有很好的食用及保健功能,将其制成稳定的可涂抹乳液可增加其应用的多样性.本文利用β-环糊精的乳化特性,通过高速均质法将紫苏籽油制成 Pickering乳液,观察乳液的微观结构、测定其粒度和 Zeta 电位,研究体系添加糖、盐、黄原胶以及 PH值对乳液稳定性的影响,并对其黏皮特性进行了初步测定.结果表明,紫苏籽油经β-环糊精乳化后可形成稳定的水包油型 pickering乳液,油滴呈标准球形,粒径在数十纳米范围;外水相添加5％蕉糖或 0.5％黄原胶可增加、添加食盐则降低乳液的崭度及稳定性,酸性条件不利于乳液的稳定;流变特性结果显示,环糊精稳定的紫苏籽油乳液为剪切变稀的假塑性流体,在 25～80 ℃条件下乳液呈现类似奶油状特性.

Sheet‐extruded films from the blends of hydroxypropylated normal corn starch (HP) and native normal corn starch (NS) at weight ratios of 100:0, 90:10, 70:30, 50:50, 30:70, and 0:100 were prepared and characterized. Glycerol and water were added as plasticizers at 11 and 27% starch weight, respectively. The highest tensile strength (TS) and longest elongation to break (EB) for dry films were observed at 70:30 HP: NS ratio, which was 25.76 MPa, and 3.97%, respectively. However, TS and EB of this 70:30 blend extruded starch film exhibited low resistance upon wetting for 10s. The film TS and EB were reduced to 13.26 MPa and 3.35%, respectively. Addition of 0.5% (wt/wt starch) succinic acid (SA) as a cross‐linker to 70:30 HP: NS starch blend before film extrusion positively affected both TS and EB of films upon wetting; rather higher TS (16.64 MPa) and EB (4.85%) values were observed, which indicated improvement in water resistance of the films. Sheet‐extruded films from 70:30 HP: NS blends resulted in improved dry strength, and upon cross‐linking with SA, improved wet strength as well. The films had smooth and compact structure, which was explained by esterification/transesterification reactions promoted by SA, and confirmed by Fourier‐transform infrared spectroscopy analysis. Disciplines Agricultural Science | Food Chemistry | Food Processing | Human and Clinical Nutrition | Systems and Integrative Engineering Comments This accepted article is published as Kim, H.Y., Lamsal, B., Jane, J.L., Grewell, D., Sheet‐extruded films from blends of hydroxypropylated and native corn starches, and their characterization. Journal of Food Process Engineering (accepted on June 30,2019); 2019, e13216. Doi:10.1111/jfpe.13216. Posted with permission. This article is available at Iowa State University Digital Repository: https://lib.dr.iastate.edu/fshn_hs_pubs/29

Starch plays a significant role in the texture, stability, appearance, and nutritional value of food products. A comprehensive understanding of chemical compositions, structures, and functional properties of starch is crucial for proper utilization of this important ingredient to develop high-quality and nutritious foods. In this chapter, structures of major components (amylose and amylopectin) and minor components (including intermediate components, endogenous lipids and proteins, and phosphate monoesters) present in starches of different crop varieties are reviewed. Organization of the aforementioned components in semicrystalline starch granules is also discussed. Impacts of the chemical compositions and structures of various components on the functional properties of starch, including gelatinization, pasting, gelling, and retrogradation/syneresis, are covered, relating to the performance of different starches in food products and other applications.

This study aimed to understand the physicochemical characteristics of sweet potato starch following spray-drying and extrusion processes for desirable applications. Spray-dried starch showed formation of agglomerates and decreased in average granular size from 16.5 μm of the native starch granules to 14.1 μm. Spray-drying reduced the percentage crystallinity from 25.3 to 22.6% and showed a slight decrease in the molecular weight of amylopectin from 3.1 to 2.6 × 108 g mol−1. In addition, changes in the pasting and gelatinization properties, higher final viscosity (454.4 RVU), and less enthalpy change (8.73 J g−1) were reported after spray-drying. Thus, spray-drying resulted in partially gelatinized starch, which can be selected for making more viscous products. Extruded sweet potato starch displayed an amorphous structure, showed total loss of crystallinity, and significant reduction in molecular weight of amylopectin to 0.41 × 108 g mol−1, reflecting complete gelatinization of starch granules during extrusion. Extruded starch showed significant changes in pasting properties, including a display cold viscosity (9.4 RVU). Therefore, extruded starch was suitable for products that require quick solubility and a low final viscosity. Thus, the spray-drying and extrusion processes produce sweet potato starches with particular characteristics that can be used for different and potential applications in industries.

The Peruvian carrot and cassava starches were processed by spray-drying and extrusion processes. The amylose content, molecular weight of amylopectin, morphology, granule size, crystalline fraction, and thermal and pasting properties were investigated and compared with those native starches. The spray-dried starches showed reduction on molecular weight of amylopectin and reduction on crystallinity. This process caused change in surface granules as folds and wrinkles, and consequence reducing in granule size, when compared to native starch. There were partial gelatinization of spray-dried starches, with the development of viscosity at room temperature. The Peruvian carrot starch was most susceptible by spray-drying process. Extruded starch showed great reduction on molecular weight and complete degradation on crystalline fraction. The surface morphology of these starches showed a melting mass, due to the fully gelatinization. With these unique properties induced by both processes, the possibilities of industrial applications of these starches are significantly increased.

This study aimed to investigate impacts of milling methods on ethanol production using an uncooked dry‐grind (cold fermentation) process and characterize residual starch in the distiller's dried grains (DDG) coproduct. Four corn lines with different chemical compositions were ground with cyclone, ultra‐centrifugal, or hammer mills equipped with a screen of 0.5 mm opening and used for the cold fermentation process. Greater starch hydrolysis and ethanol yield were obtained from cyclone‐milled corn, resulting from larger damaged starch contents and smaller particle sizes of the ground corn. Corn grains and ground corn after five‐month storage showed less starch hydrolysis than the freshly ground counterpart. Residual starch (2.8–8.0%) with large proportions of intact amylopectin contents (up to 42.5%) was found in the DDG from all types of milling. The results suggested that the entrapment of starch granules in ground corn and a low activity of amylolytic enzymes at a high ethanol concentration were accountable for the remaining of starch in the DDG.

Important characteristics of solvent-cast films prepared with modified high amylose corn starch were compared. The hydroxypropylation of high amylose corn starch with propylene oxide at 3-12% (w/w starch basis) and glycerol as plasticizer reduced film brittleness. Increasingly intact and transparent films with higher elongation at break (E) were obtained with higher concentrations of propylene oxide- E increased from 37.55 to 63.37% for 3 and 12% propylene oxide, respectively. However, corresponding tensile strength (TS) of the films decreased from 15.98 MPa to 8.85 MPa. Plasticizer types (glycerol, sorbitol, xylitol, and mixtures of glycerol/sorbitol or glycerol/xylitol) and contents (10-25%, w/w of starch) strongly affected the film formation and characteristics of hydroxypropylated high amylose corn starch. The hydroxypropylation with 6% (w/w) propylene oxide (6HPHACS) and 20% (w/w) glycerol resulted in optimal cast-films, based on both appearance and mechanical properties. These films exhibited better flexibility with adequate tensile strength and water vapor permeability. (C) 2016 Elsevier B.V. All rights reserved.

This study aimed to understand effects of adding corn oil (CO) and soy protein (SP) to corn starch on the physicochemical properties and digestive rates of annealed starch complex and mechanisms of interactions between corn starch (CS), CO and SP. Binary and ternary blends were prepared using CS mixed with CO (10%, dsb) and/or SP (10%, dsb) and incubated in a water bath at 50°C for 14h. Results showed that more agglomerates of the granules were in the ternary blends. With the addition of CO and/or SP, the CS displayed a decreased pasting temperature, an increased peak viscosity and a decreased enthalpy change of amylose-lipid complex dissociation. The CO can reinforce but SP hinder the annealing phenomenon. Results also showed that CO decreased retrogradation of CS, whereas SP increased it. The digestibility studies showed that the addition of CO and SP decreased the content of rapidly digestible starch and increased the sum of slowly digestible starch and resistant starch contents. SP displayed more impact on the digestibility of the ternary blends than CO. The physical barrier of CO, and amylose-lipid complex and protein-starch matrix can provide resistance to starch digestion.

Brazilian pine seeds (Araucaria angustifolia) or pinhao are popularly consumed in South America as a seasonal food. Pinhao of seven accessions were supplied by Brazilian Agricultural Research Corporation (Embrapa/Forestry) germplasm bank. Starch was isolated from those seeds and characterized. Structures and functional properties of starch, including amylose content, molecular weight (M-w) and gyration radius of amylopectin, amylopectin branch chain-length distribution, thermal and pasting properties, and in vitro digestibility were studied. The samples had significant differences on structures and functional properties. The pinhao starch consisted of considerable amounts of slowly digestible starch (SDS) and resistant starch (RS). Results obtained from this study are useful for developing new applications for pinhao, which is a promising ingredient for the health/nutraceutical food industry. (C) 2016 Elsevier Ltd. All rights reserved.