Starch-composition, fine structure and architecture

The concept of resistant starch (RS) has evoked new interest in the bioavailability of starch and in its use as a source of dietary fiber, particularly in adults. RS is now considered to provide functional properties and find applications in a variety of foods. Types of RS, factors influencing their formation, consequence of such formation, their methods of preparation, their methods of estimation, and health benefits have been briefly discussed in this review.

Resistant Starch–A Review

Recent developments in methods and instrumentation have contributed to major advances in our understanding of the fine structure of amylose and amylopectin. The structure of the starch granule slowly unravels with new insight into key structural features. Following a brief presentation of the structural features common to all starches, the most recent findings for the structure of amylose and amylopectin are reported. The organization of different types of chains in amylopectin is discussed with a critical review of the 'cluster' model leading to the presentation of alternative models. The locations of molecular components in the starch granule are described according to a progress structural order. The description of the crystalline components is followed by a presentation of their supramolecular arrangements. The crystalline components comprise platelet nanocrystals which have already been identified and characterized, and other less well characterized 'blocklet components'. The location and state of amylose within the granule is also presented. This comprehensive review aims at distinguishing between those structural features that have received widespread acceptance and those that are still under debate, with the ambition of being educational and to provide stimulation for further fundamental investigation into the starch granule as a macromolecular assembly.

The molecular structures of starch components and their contribution to the architecture of starch granules: A comprehensive review

Starch retrogradation is a process in which disaggregated amylose and amylopectin chains in a gelatinized starch paste reassociate to form more ordered structures. Starch retrogradation has been the subject of intensive research over the last 50 years, mainly due to its detrimental effect on the sensory and storage qualities of many starchy foods. However, starch retrogadation is desirable for some starchy food products in terms of textural and nutritional properties. To better understand the effect of starch retrogradation on the quality of starchy foods, measurement methods of starch retrogradation and factors that influence starch retrogradation have been studied extensively. This article provides a comprehensive review of starch retrogradation including the definition of the process, molecular mechanisms of how it occurs, and measurement methods and factors that influence starch retrogradation. The review also discusses the effect of retrogradation on the in vitro enzyme digestibility of starch. Spectroscopic methods such as FTIR and Raman are considered to be very promising in characterizing starch retrogradation at a molecular level, although more studies are needed in the future.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/1541-4337.12143

Starch retrogradation: a comprehensive review

Methods for the study of starch retrogradation

Formation, analysis, structure and properties of type III enzyme resistant starch

Enzyme-resistant starch. II. Influence of amylose chain length on resistant starch formation

Pea, potato, wheat, and rice starches were annealed for 24 hr. Differential scanning calorimetry data were collected ; pasting characteristics were determined using the Brabender Viscoamylograph and the Newport Scientific Rapid Visco-Analyser (RVA) ; and amylose leaching during heating in the viscoamylograph was examined. Differential scanning calorimetry data showed an increased gelatinization temperature and enthalpy, and a narrower gelatinization temperature range for all starches. Viscoamylograph viscosity curves showed that annealing resulted in an increased peak viscosity (except for potato starch), and an increased viscosity upon cooling. The amount of amylose leached from the granules was not linked to viscosity changes. Less amylose was leached from the granules of annealed pea and potato starches. The amount of solubilized amylose was practically unchanged (slightly decreased) after the annealing treatment for rice starch, whereas annealed wheat starch showed a slightly increased leaching of amylose. Except for pea starch, RVA results were comparable to the results from the viscoamylograph. In a dimethyl sulfoxide (DMSO) and water mixture (92.5 :7.5, w/w), viscosity changes were not consistent for all annealed starches. For annealed pea, wheat, and rice starches, the onset of solubilization occurred at lower temperatures. The increased peak viscosity was attributed to a higher rigidity and resistance to shear of the starch granules. For annealed potato starch, the viscosity was decreased. A higher rigidity and increased resistance to heat and shear of the starch granules are probably the main causes of the viscosity changes due to annealing, both in water and in a DMSO-water mixture.

R. C. Eerlingen

Papers

Formation, analysis, structure and properties of type III enzyme resistant starch

Enzyme-resistant starch. II. Influence of amylose chain length on resistant starch formation

Influence of annealing on the pasting properties of starches from varying botanical sources.

Enzyme-resistant starch. V. Effect of retrogradation of waxy maize starch on enzyme susceptibility.

Acid hydrolysis of native and annealed wheat, potato and pea starches—DSC melting features and chain length distributions of lintnerised starches