The relationship between amylopectin fine structure and the physicochemical properties of starch during potato growth

Fine molecular structure and digestibility changes of potato starch irradiated with electron beam and X-ray

The change of digestibility of starch irradiated with different types from the perspective of fine structure is not well understood. In this work, the change of internal structure, molecular weight and chain-length distribution, helical structure, lamellar structure, fractal structure and digestibility of native and treated potato starch with electron beam and X-ray was analyzed. Two irradiations caused the destruction of internal structure, the disappearance of growth rings and increase of pores. Irradiation degraded starch to produce short chains and to decrease molecular weight. Irradiation increased double helical content and the thickness and peak area of lamellar structure, resulting in the reorganization of amylopectin and increase of structure order degree. The protected glycosidic linkages increased starch resistance to hydrolase attack, thereby enhancing the anti-digestibility of irradiated starch. Pearson correlation matrix also verified the above-mentioned results. Moreover, X-ray more increased the anti-digestibility of starch by enhancing ability to change fine structure.

Relationships among Structure, Physicochemical Properties and In Vitro Digestibility of Starches from Ethiopian Food Barley Varieties

Studying diversity in local barley varieties can help advance novel uses for the grain. Therefore, starch was isolated from nine Ethiopian food barley varieties to determine starch structural, pasting, thermal, and digestibility characteristics, as well as their inter-relationships. The amylose content in the varieties significantly varied from 24.5 to 30.3%, with a coefficient of variation of 6.1%. The chain length distributions also varied significantly, and fa, fb1, fb2, and fb3 ranged from 26.3 to 29.0, 48.0 to 49.7, 15.0 to 15.9, and 7.5 to 9.5%, respectively. Significant variations were also exhibited in absorbance peak ratios, as well as thermal, pasting, and in vitro digestibility properties, with the latter two parameters showing the greatest diversity. Higher contents of amylose and long amylopectin fractions contributed to higher gelatinization temperatures and viscosities and lower digestibility. Structural characteristics showed strong relationships with viscosity, thermal, and in vitro digestibility properties. Cross 41/98 and Dimtu varieties are more suitable in functional food formulations and for bakery products. These results might inspire further studies to suggest target-based starch modifications and new product development.

Investigating the evolution of the fine structure in cassava starch during growth and its correlation with gelatinization performance

The evolution of the starch fine structure during growth and its impact on the gelatinization behavior of cassava starch (CS) was investigated by isolating starch from South China 6068 (SC6068) cassava harvested from the 4th to 9th growth period. During growth, the short-range ordered structure, crystallinity as well as particle size distribution of starch were increased. Meanwhile, the starch molecular size and amylopectin (AP) proportion increased, while the proportion of amylose (AM) exhibited a decreasing tendency. The chains of short-AM (X ~ 100-1000) were mainly significantly reduced, whereas the short and medium-AP chains (X ~ 6-24) had the most increment in AP. The solubility, thermal stability, shear resistance, and retrogradation resistance of starch were enhanced after gelatinized under the influence of the results mentioned above. This study presented a deeper insight into the variation of starch fine structure during growth and its influence on gelatinization behavior, which would provide a theoretical basis for starch industrial applications.

Feasibility of replacing waxy rice with waxy or sweet-waxy corn viewed from the structure and physicochemical properties of starches

To explore the feasibility of substituting waxy rice with waxy or sweet-waxy corn, eight varieties of waxy and sweet-waxy corns were selected, including three self-cultivated varieties (Feng nuo 168, Feng nuo 211, and Feng nuo 10). Their starches were isolated and used as research objects, and commercially available waxy rice starch (CAWR) and waxy corn starch (CAWC) were used as controls. X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, rapid viscosity analyzer, and rotational rheometer were used to analyze their physicochemical and structural characteristics. The morphologies of all corn starch granules were generally oval or round, with significant differences in particle size distributions. All ten starches exhibited a typical A-type crystal structure; however, their relative crystallinity varied from 20.08% to 31.43%. Chain length distribution analysis showed that the A/B ratio of Jing cai tian nuo 18 and Feng nuo 168 was similar to that of CAWR. Peak viscosities of corn starches were higher than that of CAWR, except for Feng nuo 10, while their setback values were lower than that of CAWR. Except for Feng nuo 10, the paste transparency of corn starches was higher than that of CAWR (10.77%), especially for Jing cai tian nuo 18 (up to 24%). In summary, Jing cai tian nuo 18 and Feng nuo 168 are promising candidates to replace CAWR in developing various rice-based products.

Impact of starch chain length distributions on physicochemical properties and digestibility of starches

Changing starch structure at different levels is a promising approach to promote desirable metabolic responses. Chain length distribution (CLD) is among the starch structural characteristics having a potential to determine properties of starch-based products. Therefore, the objective of the current review is to summarize recent findings on CLD and its impact on physicochemical properties and digestion. Investigations undertaken to enhance understanding of starch structure have shown clearly that CLD is a significant determining factor in modulating starch digestibility. Enzymatic modifications and processing treatments alter the CLD of starch, which in turn affects the rate of digestion, but the underlying molecular mechanisms have yet to be fully elucidated. Even though advances have been made in manipulating CLD using different methods and to correlate the changes with various functional properties, in general the area needs further investigations to open new awareness for enhancing healthiness of starchy foods.

Effects of dual modification by cationization and acetylation on the physicochemical and structural characteristics of glutinous rice starch

In this research, the effects of cationization, acetylation and dual modification by cationization and acetylation on the physicochemical and structural characteristics of glutinous rice starches were investigated. The rapid viscosity analyzer revealed a substantial increased paste viscosity post modification. Particularly, for dually modified starch, the peak viscosity increased from 3071.67 to 4082.00 cP. The freeze-thaw stability substantially enhanced, with both single cationic and dually-modified starches standing out by exhibiting no water syneresis even at 21 freeze-thaw cycles, while native starch exhibited higher syneresis, up to 74.55 %. Both single cationization and cationization-acetylation destroyed the starch granules, characterized by the roughness and cracks. But, for single acetylation, there was no notable changes on granules' morphology. Fourier transform infrared spectroscopy exhibited notable shifts after modification, both acetylation and dual modification, resulting in a new peak at 1728 cm-1. 13C cross-polarization magic angle spinning nuclear magnetic resonance spectra displayed new peaks at 52-55 and 19-22 ppm following cationization and acetylation, respectively. These structural alterations indicate the successful incorporation of functional groups during modification. Overall, this study provides valuable insights for the industrial utilization of these three modified glutinous rice starches.

Assessment of freeze damage in tuber starch with electrical impedance spectroscopy and thermodynamic, rheological, spectrographic techniques

In this study, we aimed to use electrical impedance spectroscopy (EIS) to assess the freeze-damage level of starches from potato tubers treated with multiple freezing-thawing (FT) cycles. The results showed that the relationship between the physicochemical properties of starches and the impedance characteristics of starch paste is temperature-dependent. As the temperature rises to 70-90 °C, the impedance modules show a significant correlation with the amylose and mineral contents, gelatinization and pasting properties, short-range ordered structure, relative crystallinity, and damage level within the range of 10-1 MHz (p < 0.01). This could be because FT leads to a reduction in amylose and ion content. Compared to a high level of freeze-damaged starch (FDS), a low level of FDS has less amylopectin and more amylose. Additionally, the ions could be typically evenly distributed throughout the unbranched linear amylose structure in starch paste. At the peak gelatinization temperature, the starch paste made from a low level of FDS exhibits a weakened network structure, allowing more unbound water for ion movement and enhancing electric conduction. In conclusion, EIS can predict the damage level and properties of FDS, which can benefit the frozen starchy food industry.

Effects of biochar coupled with chemical and organic fertilizer application on physicochemical properties and in vitro digestibility of common buckwheat (Fagopyrum esculentum Moench) starch

Common buckwheat starch, a functional ingredient, has wide food and non-food applications. Excessive chemical fertilizer application during grain cultivation decreases quality. This study examined the effects of different combinations of chemical fertilizer, organic fertilizer, and biochar treatment on the physicochemical properties and in vitro digestibility of starch. The amendment of both organic fertilizer and biochar was observed to have a greater impact on the physicochemical properties and in vitro digestibility of common buckwheat starch in comparison to organic fertilizer amendment solely. The combined application of biochar, chemical, and organic nitrogen in an 80:10:10 ratio significantly increased the amylose content, light transmittance, solubility, resistant starch content, and swelling power of the starch. Simultaneously, the application reduced the proportion of amylopectin short chains. Additionally, this combination decreased the size of starch granules, weight-average molecular weight, polydispersity index, relative crystallinity, pasting temperature, and gelatinization enthalpy of the starch compared to the utilization of chemical fertilizer alone. The correlation between physicochemical properties and in vitro digestibility was analyzed. Four principal components were obtained, which accounted for 81.18 % of the total variance. These findings indicated that the combined application of chemical fertilizer, organic fertilizer, and biochar would improve common buckwheat grain quality.

Structural, functional and mechanistic insights uncover the role of starch in foxtail millet cultivars with different congee-making quality

Ten foxtail millet cultivars with different congee-making quality were investigated for relationships between starch structures, functional properties and congee-making qualities. Swelling power, pasting peak viscosity (PV) and setback (SB), gel hardness and resilience, and gelatinization onset (T_o), peak (T_p) and range (R) temperature were correlated with congee-making performance significantly. Good eating-quality cultivars with these parameters were in the range of 15.41-18.58 %, 3095-3279 cp, 1540-1745 cp, 430-491 g, 0.47-0.57, 64.43-65.28 °C, 69.97-70.32 °C and 23.38-24.52 °C, respectively. Correlation analysis showed that amylose, amylopectin B₂ chains and A₂₁ were essential parameters controlling the functional properties. Amylose molecules with linear molecular morphology would cause crystal defects and a wide range of molecular weight distribution. Additionally, they were more prone to re-association, which influenced the PV, SB, T_o, T_p and gel hardness. B₂ chains impacted the gelatinization temperature range (R), gel resilience and swelling behavior by affecting the alignment of double helices and the size of starch particles and pores. Starch with more binding sites of bound water (A₂₁) tended to leach from the swelling granules easily and contributed to higher values of PV. The content of amylose, B₂ chains and A₂₁ of good eating-quality cultivars were 16.19-18.46 %, 11.60-11.69 % and 96.50-97.02 %, respectively.

Preparation and characterization of debranched starches: Influence of botanical source and debranching time

The influence of botanical source (waxy corn, glutinous rice, tapioca and potato), either based on crystallization or morphology, and the debranching time (6-48 h) on the physicochemical properties of debranched starches (DBSs) were systematically investigated. The divergence of depolymerization among different botanical sources within same hydrolysis time suggested that the debranching treatment was not only depending on the molecular profile and crystalline structure, but also related with the granular size and morphology of native starches. Fourier transformation infrared spectroscopy (FT-IR), X-ray diffraction (XRD), differential scanning calorimetry (DSC) suggested that long-term debranching reaction produced DBSs with improved degree of crystallization and reduced iodine binding capacity. Simulated in-vitro digestion assay showed that the proportion of digestive fractions from different botanical originated DBSs differed greatly. Additionally, prolonging the debranching time yielded increased level of resistant starch. The study may provide guidance for exploring DBSs with various molecular weight to fulfill their tailored applications.

Relationship among gelatinization, retrogradation behavior, and impedance characteristics of potato starch

In this study, the physicochemical properties of potato starch from different varieties were investigated. Furthermore, the relationships among gelatinization, retrogradation behavior, and impedance characteristics of potato starch gels were evaluated by texture analysis, low-field nuclear magnetic resonance spectroscopy, and electrical impedance spectroscopy. The results indicated amylose content was positively correlated with setback viscosity, and negatively correlated with T_o and ΔH. In addition, impedance values of potato starch gels differed in a frequency-dependent manner. Notably, higher frequencies resulted in low diffusion of ions in prepared gels, which combined with the concentration of mobile ions in free water, led to a gradual decrease in impedance module. Compared with phase values, impedance module showed high correlation with gelatinization parameters (T_o, T_p, and T_c) and viscosity parameters (peak temperature and setback viscosity), more notably at frequencies below 100 Hz. In this context, the electric current flowed through mobile ions that interacted with bound water attached to the starch molecules at lower voltage frequencies, and were repressed by the formation of an ordered and compact gel network during retrogradation. Collectively, these results indicate that impedance spectroscopy can be potentially used as an efficient and reliable method to predict gelatinization and retrogradation behavior of potato starch.

Properties of potato starch as influenced by microwave, ultrasonication, alcoholic-alkali and pre-gelatinization treatments

The present study was framed to develop modified potato starch by various physical (microwave treatment, ultrasonication, pre-gelatinization) and chemical (alcohol-alkali) methods. Both native and modified starches were characterized on the basis of physicochemical, functional, and morphological attributes. Compared to native potato starch, modified starches exhibited improved water absorption capacity and water solubility index. The particle size of the starches was found to be in the range of 10.01-10.36 μm with negative zeta potential values. FTIR results revealed that modification in the peaks is attributed to the change in the structural configuration and re-organization of the microstructure between molecules of the starch during the treatments. The results of X-ray diffraction suggested that the typical peaks varied to a little extent with modifications and relative crystallinity was decreased for all treated starches. SEM Micrographs revealed the complete structural changes and irregularities in pre-gelatinized and chemically modified starches, whereas other modification methods maintained the structural integrity of starch granules. An increase in pasting temperature of modified starches represented a higher resistance to swelling and rupture, whereas rheologically, starches exhibited non-newtonian behavior with the shear-thinning property. Thus, the characteristics of modified starches will assist in the selection of potato starch for better applications in the food industry.

Studying the Role of Potato Powder on the Physicochemical Properties and Dough Characteristics of Wheat Flour

Potato flour (PF) is rich in health-promoting compounds that can improve the nutritional benefits of food products after blending with wheat flour. However, the incorporation of PF may influence the processing characteristics of mixed powders and the quality properties of products. In this study, the physicochemical properties, processing characteristics, and structures of mixed powders and their corresponding doughs with different PF content (0%, 10%, 20%, 30%, 40%, 60%, 80%, and 100%) were investigated. The addition of PF dramatically increased the fiber content from 0.09 to 1.10 g·kg^-1 but diluted the protein in wheat flour. The peak and final viscosity of mixed powders decreased (from 5111.00 to 1806.33 cP and 5195.33 to 2135.33 cP, respectively) with an increase in PF fraction. The incorporation of PF significantly increased gelatinization temperature. The rapidly digestible starch decreased from 30.48% to 19.67%, and resistant starch increased from 16.93% to 41.84% when the PF content increased from 0% to 100%. The water absorption, stability time, and development time decreased with an increase in PF levels. The G' and G″ of the dough decreased as the addition amount of PF increased, while tan δ presented a complex change tendency. Due to the decrease in protein content in the mixed powders, the addition of PF in wheat flour notably decreased the Hm values of doughs and total carbon dioxide volume produced during fermentation. Additionally, the SH and S-S contents decreased with an increase in PF fraction. Scanning electron microscopy results showed that when the PF content reached up to 80%, a poor and discontinuous gluten framework was formed in the dough. Results showed that PF affected the processing characteristics and gluten structures of wheat dough and was related to the interaction or competition for water molecules between protein and starch, as well as potato starch and wheat starch. Thus, the results of the present study can provide insights into the optimal level of addition of PF during the development of potato-based food products.

The Process of Pasting and Gelling Modified Potato Starch with LF-NMR

Currently, society expects convenience food, which is healthy, safe, and easy to prepare and eat in all conditions. On account of the increasing popularity of modified potato starch in food industry and its increasing scope of use, this study focused on improving the physical modification of native starch with temperature changes. As a result, it was found that the suggested method of starch modification with the use of microwave power of 150 W/h had an impact on the change in starch granules. The LF-NMR method determined the whole range of temperatures in which the creation of a starch polymer network occurs. Therefore, the applied LF-NMR technique is a highly promising, noninvasive physical method, which allows obtaining a better-quality structure of potato starch gels.