As a traditional and popular dietary supplement, lotus rhizome starch (LRS) has health benefits for its many nutritional components and is especially suitable for teenagers and seniors. In this paper, the approximate composition, apparent amylose content (AAC), and structural characteristics of five LRS samples from different regions were investigated, and their correlations with the physicochemical properties of granular and gelatinized LRS were revealed. LRS exhibited rod-shaped and ellipsoidal starch granules, with AAC ranging from 26.6% to 31.7%. LRS-3, from Fuzhou, Jiangxi Province, exhibited a deeper hydrogel color and contained more ash, with 302.6 mg/kg iron, and it could reach the pasting temperature of 62.6 °C. In comparison, LRS-5, from Baoshan, Yunnan Province, exhibited smoother granule surface, less fragmentation, and higher AAC, resulting in better swelling power and freeze-thaw stability. The resistant starch contents of LRS-3 and LRS-5 were the lowest (15.3%) and highest (69.7%), respectively. The enzymatic digestion performance of LRS was positively correlated with ash content and short- and long-term ordered structures but negatively correlated with AAC. Furthermore, the color and network firmness of gelatinized LRS was negatively correlated with its ash content, and the retrograde trend and freeze-thaw stability were more closely correlated with AAC and structural characteristics. These results revealed the physicochemical properties of LRS from different regions and suggested their advantages in appropriate applications as a hydrogel matrix.

The gelation process and hydrogel properties of calcium salt-induced alginate hydrogels are influenced by anion-specific effects. In this study, we investigated the effects of CaSO₄, CaI₂, and Ca(C₅H₉O₃)₂ [calcium β-hydroxy-β-methylbutyrate, CaHMB] on the gelation behavior of alginate hydrogels, using various mannuronic/guluronic acid (M/G) ratios to elucidate the underlying mechanisms of anion-specific effects. Here, at a high M/G ratio (2:1), the gelation time of CaSO₄, as a low-solubility calcium source, delayed the formation of the calcium alginate hydrogel. The gelation time was 1.8 times that of the high-solubility calcium source CaHMB. Strongly hydrated ions (such as SO₄²⁻ and C₅H₉O₃⁻) caused the removal of water molecules from polysaccharide chains, resulting in the formation of small pores on the pore wall. Moreover, weakly hydrated chaotropic anions (I⁻) promoted the binding of alginate polysaccharide chains and water molecules, resulting in the slower thermal decomposition of water inside the gel. However, when the M/G ratio was reduced to 1:1 or 1:2, the influence of the three calcium salts on the water and thermodynamic properties of the hydrogels decreased, indicating that the anion-specific effect weakened. This study highlights the importance of anion-specific effects on the properties of alginate hydrogels and provides insights into the utilization of these effects to fabricate functional hydrogels with variable properties.

To exploit high-value-added clam ( Meretrix meretrix ) products, the effects of pretreatment methods and microbial transglutaminase (MTGase) on the gelation process of clam surimi were studied.

This study investigated the gel performance of Spanish mackerel surimi gels (SMSGs) modified by three anionic polysaccharides: κ-carrageenan (KC), ι-carrageenan (IC), and gellan gum (GG). By incorporating polysaccharides, SMSGs showed a 24.9–103.4% improvement in gel and textural properties, in which KC and IC had more improvement effects than GG. Moreover, polysaccharides led to a 10.7–13.1% increment in WHC, a shortened water migration from 61.34 to 52.43–55.93 ms in T₂₂, and enhanced thermal stability of SMSGs. The content of α-helix in SMSGs reduced markedly accompanied by a concurrent enhancement of β-sheet and β-turn by adding polysaccharides, where β-sheet and β-turn are positively correlated with hardness being favorable for gelling. The microstructure of SMSGs/polysaccharides showed a homogeneous network mainly due to hydrophobic interactions and disulfide bonds in SMSG-based gels. This study will demonstrate the effectiveness of KC, IC, and GG in improving the texture and functionality as well as expanding the application of surimi products.

To improve the gel quality of low-salt shrimp surimi gel (SSG) from Pacific white shrimp (Litopenaeus vannamei), L-arginine (L-Arg), L-lysine (L-Lys), and L-proline (L-Pro) were used as partial substitutes for NaCl. The effect of the three amino acids on gel properties, protein conformation, microstructure, and in vitro digestion of low-salt SSG were systematically analyzed. Macro-/microstructural analyses revealed that L-Arg, L-Lys, and L-Pro promoted denser three-dimensional networks in low-salt SSG with smaller pore sizes. Compared with the low-salt control (LC) group, the addition of L-Arg, L-Lys, and L-Pro significantly increased the gel strength of low-salt SSG. Cooking loss was significantly decreased from 10.80% (LC group) to 1.89–4.31%. Protein solubility and turbidity results demonstrated that all amino acids markedly enhanced protein solubilization and inhibited protein aggregation. L-Arg and L-Lys mainly promoted hydrogen and disulfide bonds, but reduced hydrophobic interactions and ionic bonds. L-Arg impaired digestibility only in the gastric phase, whereas L-Lys suppressed digestibility across both gastric and intestinal phases. Through molecular docking technology, ASN-238 and LYS-187 of myosin (the dominant gel-forming protein) are the key shared binding residues with three amino acids. These findings suggest that amino acids provide a feasible approach to specifically modulate the gel characteristics of low-salt surimi products.