Thermal and Rheological Properties of Mung Bean Starch Blends with Potato, Sweet Potato, Rice, and Sorghum Starches

Influence and underlying mechanism of soluble dietary fiber derived from Ganoderma Lucidum-fermented sweet potato residue on the physicochemical-digestive characteristics of wheat starch

Chronic overconsumption of starchy foods has been associated with health risks including cardiovascular diseases and diabetes. Soluble dietary fiber (SDF) presents a promising solution for modifying starch-based food products. In this study, SDF extracted from sweet potato residue (SPR) before and after fermentation with Ganoderma lucidum was incorporated into wheat starch (WS) at varying proportions (0.2 %-0.8 %). Compared with unfermented SDF, the fermented SDF exhibited stronger intermolecular interactions and physical entanglement with WS. As the concentration of fermented SDF increased, the ratio of free water in the gel system increased, while the leaching of amylose (16.64 %-13.68 %), hardness (444-288 g) and chewiness (254.83-170.61) gradually decreased, resulting in the disruption of the WS network structure, increased crystallinity and thermal stability, and inhibition of starch retrogradation. Additionally, the content of resistant starch increased (44.87 %-51.15 %), and the starch digestibility rate decreased. This research furnishes a theoretical foundation for enhancing the resource utilization of SPR and developing functional starch-based foods with improved starch properties and low glycemic index.

Effect of cellulose fibers on the structure, rheological and 3D printing properties of corn starch-based hydrogel ink

In recent years, there has been a lot of study focused on controlling the rheological and 3D printing characteristics of starch-based hydrogels. Rigid cellulose fiber (CF) was employed in this study as a modifier to control the rheology, structure, and 3D printing characteristics of corn starch (CS) hydrogels. The findings demonstrated that CS and CF had a robust hydrogen connection, which facilitated CF's dispersion inside the CS matrix. When CF was present, the CS hydrogel's continuous network structure was destroyed, and its viscosity was greatly decreased. Results from low-field nuclear magnetic resonance (LF-NMR) indicated that the hydrogel system considerably shortened the water's relaxation period. Rheological data revealed that the addition of CF increased the mechanical properties of the CS-CF hydrogel and gave it exceptional self-supporting qualities. CS-CF hydrogel outperformed pure CS hydrogel in terms of 3D printing properties. The appearance and precision of the printed object were measured, and it was discovered that CF2 had satisfactory 3D printing qualities, allowing it to completely recreate the preset model with a printing accuracy of 98.1 %. As a result, this study can serve as a reference for enhancing the rheology and 3D printing performance of starch-based hydrogels.

Amylopectin chain length distributions and amylose content are determinants of viscoelasticity and digestibility differences in mung bean starch and proso millet starch

This study aimed to reveal the underlying mechanisms of the differences in viscoelasticity and digestibility between mung bean starch (MBS) and proso millet starch (PMS) from the viewpoint of starch fine molecular structure. The contents of amylopectin B2 chains (14.94-15.09 %), amylopectin B3 chains (14.48-15.07 %) and amylose long chains (183.55-198.84) in MBS were significantly higher than PMS (10.45-10.76 %, 12.48-14.07 % and 70.59-88.03, respectively). MBS with higher amylose content (AC, 28.45-31.80 %) not only exhibited a lower weight-average molar mass (91,750.65-128,120.44 kDa) and R1047/1022 (1.1520-1.1904), but also was significantly lower than PMS in relative crystallinity (15.22-23.18 %, p < 0.05). MBS displayed a higher storage modulus (G') and loss modulus (G'') than PMS. Although only MBS-1 showed two distinct and discontinuous phases, MBS exhibited a higher resistant starch (RS) content than PMS (31.63-39.23 %), with MBS-3 having the highest RS content (56.15 %). Correlation analysis suggested that the amylopectin chain length distributions and AC played an important role in affecting the crystal structure, viscoelastic properties and in vitro starch digestibility of MBS and PMS. These results will provide a theoretical and scientific basis for the development of starch science and industrial production of low glycemic index starchy food.

Characterization of starch extracted from seeds of Cycas revoluta

Introduction

Starch is major component in the big seeds of Cycas revoluta, however the characteristics of Cycas revoluta remain unknown.

Methods

In this study, the physicochemical and structural properties of two starch samples extracted from Cycad revoluta seeds were systematically investigated, using various techniques.

Results

The amylose contents of the two samples were 34.3 % and 35.5%, respectively. The spherical-truncated shaped starch granules possessed A-type crystallinity, and had an average diameter less than 15 μm. Compared to most commonly consumed cereal and potato starch, Cycad revoluta starch showed distinctive characteristics. For physicochemical properties, in the process of gelatinization, the Cycad revoluta starch showed similar viscosity profile to starches of some potato varieties, but Cycad revoluta starch had higher gelatinization temperature. Upon cooling, Cycad revoluta starch formed harder gels than rice starch. For structure, the molecular weight (indexed by Mw, Mn and Rz values), branching degree and the branch chain length distribution were determined.

Discussion

The results suggested that Cycad revoluta starch were different in structure from the main-stream starches. Notable differences in some starch traits between the two samples were recorded, which could be attributed to environmental factors. In general, this study provides useful information on the utilization of Cycad revoluta starch in both food and non-food industries.

Structural, physicochemical and rheological properties of starches isolated from banana varieties (Musa spp.)

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High starch content in green banana can be extracted for industry and avoid waste.

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Banana starch from Tanzania was rich in amylose and resistant starch.

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Banana starch paste presented great structural stability.

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Banana starch had potential to produce edible films and replace chemical binder.

Banana starches were isolated from five banana varieties in Tanzania to analyze the proximate composition, structure, physicochemical and rheological properties. The amylose content of banana starches was 29.92 ± 0.17 %–39.50 ± 0.08 % and the resistant starch content of cooked banana starches ranged from 44.74 ± 1.72 % to 55.43 ± 1.52 %. Banana starch granules presented irregular shapes with particle size of 21.73 to 24.67 μm and showed B-type or C-type crystalline patterns with crystallinity of 36.69 % to 41.83 %. The solubility and the swelling power were 2.5 ± 0.42 %–4.4 ± 0.57 % and 11.27 ± 0.04 %–12.48 ± 0.71 %, respectively. Mzuzu and Malindi starches possessed lower gelatinization temperature. The high gelatinization peak viscosity (2248 ± 67–2897 ± 71 cP), low breakdown (556 ± 7–960 ± 41 cP) and low setback (583 ± 29–864 ± 118 cP) indicated banana starch could replace chemically cross-linked starch for applications that require stable viscosity. The rheological analysis showed that banana starches exhibited shear thinning behavior and had great processing adaptability. The results all above will provide basic data for the development and utilization of banana starch.

Thermal and pasting properties and digestibility of blends of potato and rice starches differing in amylose content

In this study, waxy or normal potato starches (WPS or NPS) were blended with waxy, low-amylose or high-amylose rice starch (WRS, LARS or HARS) in different ratios (100:0, 80:20, 60:40, 40:60, 20:80 and 0:100). Pasting profiles of blends were additively between those of the component starches separately except for some mixtures of WRS and potato starches. Twin or even three gelatinization peaks were observed for potato-WRS or potato-HARS blend, while only one peak was observed in potato-LARS blend. Addition of WRS enhanced the nutritional profile of blends containing WPS by decreasing the rapidly digestible starch level. Microscopy revealed that addition of WRS was beneficial for the development of dense and compact structure of gels of blends compared with their counterparts, which may be because few amylose chains leached to inhibit the interaction between swollen potato and rice starch granules. Besides, peak, trough, breakdown and final viscosity as well as gelatinization enthalpy showed significantly negative correlations with amylose leaching. Non-additive behaviours were observed for properties, but more independent behaviour was observed between potato starch and LARS or HARS. Results suggested that properties of blends of potato and rice starches differing in amylose content varied through different extents of amylose leaching.

The multi-scale structure, thermal and digestion properties of mung bean starch

Identification and selection one special variety mung bean for lower GI food is very useful, however, the fundamental study for mung bean starch is still insufficient to meet its demand. In this study, four varieties of mostly planted mung bean in China were selected as model materials. The multi-scale structure of mung bean starch was characterized by SEC, HPAEC, XRD, SAXS, and SEM. SEC and HPAEC give the amylose contents, amylose and amylopectin fine structure of mung bean starch. Mung bean starch from XRD spectrum display C_A type semi crystallinity. The crystalline lamellar thickness from SAXS curves were 7.34-7.60 nm. DSC indicated that the peak gelatinization temperature is at 67 °C-68 °C. Resistant starch in mung bean disappears rapidly after cooking, although the amount of slowly digested starch was still more than half of the total starch. Since the gene backgrounds of the mung bean starch samples are very close, there was no obvious difference in their molecular and aggregated state structure, and the digestion properties were similar, too. Unique SEC and HPAEC profiles of starch chain length distribution can be utilized to help find more genetic resources and cultivate variety to meet the needs for starch applications.