Fermentation-Derived Polysaccharide Rewrites How Potato and Corn Starch Cook and Age

Starchy foods live or die by two invisible processes that unfold in every kitchen and every supermarket cold case: gelatinization, the moment starch granules absorb heat and water and collapse into a viscous paste, and retrogradation, the slow molecular rewinding that turns yesterday’s soft bread or fresh rice pudding into something hard, stale and weeping water. Food scientists have long battled both with chemical modification, but consumer demand for clean-label ingredients has pushed researchers toward natural additives that can do the same job without a synthetic credential in sight. A new study published in Food Chemistry: X offers one of the most detailed pictures yet of how a single fermentation-derived polysaccharide called Salecan reshapes these processes, and how dramatically its effects depend on the botanical origin of the starch it meets.

Salecan is not an ordinary hydrocolloid. Produced by microbial fermentation, it was approved as a novel food additive by the U.S. FDA in 2020 and by China’s National Health Commission in 2021. Structurally, it is a linear, unbranched glucan built from a repeating unit of seven beta-1,3-linked and two alpha-1,3-linked glucose residues, with purity exceeding 90 percent. That linearity matters enormously. Most familiar anionic polysaccharides, from xanthan gum to carrageenan and pectin, carry highly branched backbones and heterogeneous branch distributions, features that create steric hindrance and thermodynamic incompatibility with starch chains. Salecan’s naked backbone can align and entangle directly with starch molecules, while its uniformly distributed carboxyl groups from succinyl and pyruvyl substituents provide consistent negative charge across the entire chain. As a fermentation product, it is also immune to the seasonal and geographic constraints that complicate plant- and seaweed-derived gums.

To test whether Salecan’s behavior depends on starch structure, the research team led by Wanping Xiong and Xianggui Chen at Sichuan University paired two starches that sit at opposite ends of the botanical spectrum. Potato starch, a tuber starch, features large oval granules of 15 to 100 micrometers, negatively charged monophosphate ester groups on its molecular chains, a B-type crystalline pattern and a highly cross-linked granular architecture. Corn starch, the cereal archetype, presents small polygonal granules of 5 to 20 micrometers, a nearly neutral surface, an A-type crystalline pattern and a substantially higher amylose content of 25 to 28 percent with a lower degree of polymerization. Every major structural determinant of polysaccharide-starch interaction therefore differs between the pair, making it an ideal contrast model.

The divergent results began immediately. When Salecan was added at concentrations from 0.5 to 2 percent by starch dry weight, both starches showed delayed gelatinization, with pasting curves shifted to the right and peak times significantly prolonged, findings confirmed by differential scanning calorimetry. But the viscosity story split cleanly along charge lines. In potato starch, Salecan dramatically reduced peak, trough and final viscosity, and at 2 percent addition the consistency coefficient fell by 81.56 percent. The authors attribute this to electrostatic repulsion between the negatively charged potato starch and the anionic polysaccharide, which confines Salecan to the granule surface as a barrier that blocks water ingress and amylopectin leaching. Corn starch behaved in the opposite way: Salecan increased its peak viscosity, breakdown strength and final viscosity, with the consistency coefficient surging by 332.9 percent at 2 percent addition, because the neutral granules allowed Salecan to disperse through the paste and leached amylose supplied abundant hydroxyl groups for hydrogen bonding and chain entanglement.

Rheological measurements reinforced the split. All composite pastes displayed shear-thinning pseudoplastic behavior, but Salecan reduced the apparent viscosity and shear stress of potato starch systems while raising those of corn starch. Frequency sweep tests showed that Salecan depressed the storage and loss moduli of potato gels yet elevated the moduli of corn gels in a concentration-dependent fashion. For food engineers, this duality is a gift. High-viscosity tuber pastes used in sauces, custards and dessert gels become easier to pump and process without sacrificing final gel integrity, while cereal-based soups, gravies and bakery fillings gain viscosity and thermal stability exactly where hot filling and cooling demand them.

The second half of the study tackled retrogradation, the costlier enemy of shelf life, and here Salecan proved a unifying remedy. Storing gels at 4 degrees Celsius for up to 21 days, the researchers tracked gel hardness with texture analysis, water mobility with low-field nuclear magnetic resonance, crystallinity with X-ray diffraction, molecular order with Fourier transform infrared spectroscopy and microstructure with scanning electron microscopy. Every technique converged on the same conclusion: at 1 percent addition, Salecan significantly slowed the aging of both starches, cutting gel hardness by 33.63 percent for potato starch and 31.19 percent for corn starch relative to controls.

The water-migration data are particularly striking. During storage, bound water progressively escapes the starch matrix and becomes free water, a process that culminates in syneresis, the unappetizing pooling of liquid that ruins chilled desserts and fillings. Free water appeared in plain corn starch gel after only three days and in potato starch gel after fourteen days. At 1 percent Salecan, the free water fraction after 21 days fell from 3.75 percent to 0.54 percent in potato gels and from 15.81 percent to 6.31 percent in corn gels. X-ray diffraction showed that Salecan did not change the crystal type formed during aging but significantly lowered relative crystallinity, while infrared ratios revealed suppressed short-range molecular order and reduced double-helix formation at the same optimal dosage. Interestingly, both hardness and structural indices followed a U-shaped dose curve, first falling and then rebounding at high concentrations, because Salecan’s intense water-holding capacity ultimately concentrates amylose in the remaining solvent and promotes renewed association.

The proposed mechanism weaves these observations together. During short-term retrogradation, Salecan’s linear backbone entangles with amylose and sterically blocks chain re-association, delaying initial network formation. During long-term storage, it disrupts the hydrogen-bond reformation needed for double-helix nucleation, impedes the ordered alignment of amylopectin side chains, and physically retains water within the gel network. Scanning electron microscopy captured the microstructural fingerprints of these effects: Salecan produced smaller, more orderly pores and tighter matrix interconnection in potato gels, while in corn gels it preserved a smoother, looser honeycomb structure by resisting the dehydration shrinkage that normally crumples high-amylose networks. No new covalent bonds were detected, confirming that the interactions are dominated by hydrogen bonding and physical entanglement.

Perhaps the most surprising results came from simulated digestion. Freshly gelatinized starch with Salecan was hydrolyzed more slowly by alpha-amylase and amyloglucosidase, because the additive suppresses complete gelatinization and its dense composite network shields enzyme binding sites on starch molecules, a finding that points toward low-glycemic-index versions of instant porridges, steamed rice alternatives and gluten-free breads. Yet after seven days of retrogradation, the pattern inverted: Salecan-containing gels were digested faster than highly crystallized plain retrograded gels, precisely because Salecan had prevented the formation of enzyme-resistant crystalline domains. That inversion doubles as independent mechanistic evidence, confirming from a nutritional angle that Salecan suppresses resistant crystal formation during aging. The authors caution that their structural-dependence conclusions rest on just two contrasting starches, and that broader starch panels will be needed to validate generality. Still, the prospect of a single clean-label, fermentation-produced ingredient that simultaneously tames viscosity where it runs too high, boosts it where it falls short, prevents staling, stops syneresis and reshapes glycemic response is exactly the kind of multifunctional tool the clean-label food industry has been searching for.

Subject of Research: Modulation of potato and corn starch gelatinization, retrogradation and digestibility by the anionic polysaccharide Salecan

Article Title: Structure-dependent modulation of potato and corn starch gelatinization and retrogradation by Salecan

Article References: Xiong, W., Hu, L., Ni, C., Zhao, J., Huang, Y., Yang, X., Chen, P., & Chen, X. (2026). Structure-dependent modulation of potato and corn starch gelatinization and retrogradation by Salecan. Food Chemistry: X, 39, Article 104470. https://doi.org/10.1016/j.fochx.2026.104470

Image Credits: AI Generated

DOI: 10.1016/j.fochx.2026.104470

Keywords: Salecan, starch gelatinization, starch retrogradation, potato starch, corn starch, food hydrocolloids, rheology, X-ray diffraction, water migration, in vitro digestion, low glycemic index, clean label