Effect of defatting on starch structure and physicochemical properties

Absolute Quantitative Lipidomics Reveals Different Granule-Associated Surface Lipid Roles in the Digestibility and Pasting of Waxy, Normal, and High-Amylose Rice Starches

Granule-associated surface lipids (GASLs) and internal lipids showed different lipid-amylose relationships, contents, and distributions, suggesting their differing biological origins and functions, among waxy, normal, and high-amylose rice starch. The GASL content mainly depended on the pore size, while internal lipids regulated starch biosynthesis, as indicated by correlations of internal lipids with the chain length distribution of amylopectin and amylose content. Of the 1346 lipids detected, 628, 562, and 408 differentially expressed lipids were observed between normal-waxy, high-amylose-waxy, and normal-high-amylose starch, respectively. After the removal of GASLs, the higher lysophospholipid content induced greater decreases in the peak and breakdown viscosity and swelling power, while the highest digestibility increase was found with the highest triacylglycerol content. Thus, different GASL compositions led to different digestibility, swelling, and pasting outcomes. This study sheds new light on the mechanism of the role of GASLs in the structure and properties of starch, as well as in potential modifications and amyloplast membrane development.

Relation between textural attributes and surface leachate structural and compositional characteristics of cooked rice

The objective of this study was to evaluate the leachate and textural characteristics of cooked rice, and the correlations between the leachate properties and texture attributes were also investigated. Cooked waxy rice had much higher total solids and amylopectin amount in leachate than the normal and high-amylose rice. For all varieties, the amylopectin chain length of the leachate was similar, excluding Dodam cultivar. The rheological characteristics of the leachate solutions were highly dependent on the amylopectin amount of the leachate. Regarding the textural characteristics, Dodam had the highest hardness and the lowest adhesiveness. The principal component analysis showed substantial differences in leachate and textural characteristics of Korean cooked rice according to its amylose content. The adhesiveness was positively and negatively correlated with amylopectin amount of leachate and the proportion of long amylopectin chains, respectively. These results indicated that the leachate characteristics of cooked rice significantly influenced its textural attributes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01446-3.

Starch aided synthesis of giant unilamellar vesicles

Synthesis of giant unilamellar vesicles (GUVs) of charged and uncharged lipids at physiological salt concentration is presented using the starch hydrogel method as an example of the gel assisted synthesis method. The swelling of the gel is assisted by the presence of a high amount of amylopectin in starch and yields giant-sized vesicles, which are unilamellar in nature. This method holds promise since starch is a commonly available cheap bio-compatible material. This work indicates that native starch yields vesicles of better size range as compared to the acid-treated starch. It is demonstrated that contrary to the common belief, pre-hydration of bilayers is not critical to the success of this method. The synthesis of GUVs in physiological salt concentrations is possible since the salt does not produce any osmotic effect on its own. At low starch concentration, the size of the vesicles is found to correlate with the swelling factor. The conjugate effect of the starch concentration and ion leads to the change in the swelling factor of the gel and thereby influence the size and architecture of the vesicles. Also, interactions between starch and lipid play an important role in the formation of the giant vesicles.

Lipid Binding of Fresh and Stored Formulated Wheat Breads. Relationships with Dough and Bread Technological Performance

Lipid binding in fresh and stored soured started breads formulated with nonfat [sodium carboxymethylcellulose (CMC), hydroxypropylmethylcellulose (HPMC), fungal α-amylase-and fat–monoglycerides (MGL), diacetyl tartaric acid ester of mono-diglycerides (DATEM) and sodium stearoyl lactylate (SSL)] additives were determined. Results were correlated with dough and bread technological performance during breadmaking and storage. A preferential binding of the added SSL to the starch with a concomitant displacement of endogenous polar lipids from starch to gluten was observed. Monoglycerides partly bound to the starch and partial remained in the pool of free lipids with displacement of endogenous polar lipids from gluten to starch and free fractions. Addition of DATEM induced similar changes as SSL in association pattern and as MGL in polar lipid translocation. Hydrocolloids showed preferential bindings to the gluten (CMC) and to the starch (HPMC) respectively, associated to a significant displacement of endogenous neutral gluten-bounded lipids to the starchy fraction (CMC) and to a significant release of both starch- and gluten-bonded lipids (HPMC). Addition of α-amylase promoted both a release of endogenous bonded lipids and a binding of glycolipids to the starch whereas the sourer starter induced disaggregation of the starch– and gluten–lipid complexes. Suitable trends in bread lipid parameters for high fermentative power, delayed starch gelatinization, edible fresh bread and reduced bread staleness corresponded to high values of neutral lipids of bonded fractions and high total glycolipid content achieved by the incorporation of SSL and/or CMC into dough formulation.

Physicochemical and functional characteristics of lentil starch

The physicochemical properties of lentil starch were measured and linked up with its functional properties and compared with those of corn and potato starches. The amylose content of lentil starch was the highest among these starches. The crystallinity and gelatinization enthalpy of lentil starch were the lowest among these starches. The high amylose: amylopectin ratio in lentil starch resulted into low crystallinity and gelatinization enthalpy. Gelatinization and pasting temperatures of lentil starch were in between those of corn and potato starches. Lentil starch gels showed the highest storage modulus, gel strength and pasting viscosity than corn and potato starch gels. Peleg's model was able to predict the stress relaxation data of these starches well (R(2)>0.98). The elastic modulus of lentil starch gel was less frequency dependent and higher in magnitude at high temperature (60 °C) than at lower temperature (10 °C). Lentil starch is suitable where higher gel strengthened pasting viscosity are desired.

Internal structure and physicochemical properties of corn starches as revealed by chemical surface gelatinization

The organization of amylose and amylopectin within starch granules is still not well elucidated. This study investigates the radial distribution of amylose and amylopectin in different corn starches varying in amylose content (waxy corn starch (WC), common corn starch (CC), and 50% and 70% amylose corn starches (AMC)). Corn starches were surface gelatinized by 13 M LiCl at room temperature to different extents (approximately 10%, 20%, 30%, and 40%). The gelatinized surface starch and remaining granules were characterized for amylose content, amylopectin chain-length distribution, thermal properties, swelling power (SP), and water solubility index (WSI). Except for the outmost 10% layer, the amylose content in CC increased slightly with increasing surface removal. In contrast, amylose was more concentrated at the periphery than at the core for 50% and 70% AMC. The proportion of amylopectin A chains generally decreased while that of B1 chains generally increased with increasing surface removal for all corn starches. The gelatinization enthalpy usually decreased, except for 70% AMC, whereas the retrogradation enthalpy relatively remained unchanged for CC but increased for WC, 50% and 70% AMC with increasing surface removal. The SP and WSI increased with increasing surface removal for all corn starches, with WC showing a significant increase in SP after the removal of the outmost 10% layer. The results of this study indicated that there were similarities and differences in the distribution of amylose and amylopectin chains along the radial location of corn starch granules with varying amylose contents. More amylose-lipid complex and amylopectin long chains were present at the periphery than at the core for amylose-containing corn starches.