The inner, middle and outer layers make up the double-layered Black sesame glutinous rice ball

Traditional black sesame glutinous rice balls mostly adopt single-component homogeneous filling, where sesame paste serves as the only inner core. Although this classic formula delivers stable nutty flavour, its taste dimension remains relatively monotonous, lacking layered sensory changes when biting. The innovative double-layered glutinous rice ball breaks through conventional filling design, and builds a three-phase composite filling system including inner core layer, intermediate transition layer and outer wrapping layer. Peanut and sesame raw materials are reasonably distributed among different layers, constructing a distinct layered peanut-sesame filling structure, which brings progressive taste and flavour experience while keeping the product's basic processing adaptability for frozen production.

Each layer undertakes differentiated functional and sensory missions. The innermost core layer usually selects fine-ground roasted peanut paste as the main body. After low-temperature baking and fine grinding, peanuts release rich roasted nutty aroma. This inner core maintains moderate oil content and particle fineness, forming a concentrated peanut-flavour centre. When consumers bite through the outer structure, the dense peanut taste is released first. The inner core controls appropriate viscosity to avoid excessive flow-out during boiling; meanwhile, particle size is strictly managed to prevent piercing the intermediate layer under thermal expansion in hot-water cooking.

The middle transition layer plays the role of flavour buffering and structural isolation, which is the key to stabilising the whole three-layer filling. This layer mostly takes compound blending of partial black‑sesame powder and small-proportion peanut components. It neither purely copies the strong sesame flavour of the outer layer nor duplicates the single peanut taste of the inner core. The transition material forms a continuous dense film between inner peanut core and outer sesame wrapping layer, preventing direct material mixing and inter-diffusion of oil phases between two main flavour systems. Without this intermediate barrier, peanut and sesame oil‑soluble flavour substances will mutually infiltrate during frozen storage, and the layered feature will gradually disappear, turning into a mixed homogeneous filling. Rheological matching of the middle layer is critical. Its melting point and oil separation property need to sit between the inner and outer layers, so that each layer can keep independent morphology after heating.

The outermost wrapping layer is dominated by classic black-sesame filling components. Roasted black-sesame powder, plant grease and a small amount of sweet substances are mixed evenly, forming the outer shell of composite filling. When the glutinous-rice wrapper is bitten open, consumers first taste the mellow black-sesame aroma brought by this outer layer. As chewing proceeds, the middle transition flavour unfolds, and finally the rich peanut-based inner core comes into play. Such sequential sensory presentation realises the progressive shift from sesame flavour to mixed transition taste and then to prominent peanut nutty notes.

Raw-material matching directly determines whether layered structure can survive industrial freezing-thaw cycles and boiling procedures. Oil-phase compatibility of three layers needs careful adjustment. Too large difference in oil polarity among layers will cause interfacial instability, leading to inter-layer permeation and blurred boundaries during long-term frozen shelf life. Grinding fineness of peanut and sesame powder also exerts influence. Excessively fine powder raises oil exudation risk, while over-coarse particles may generate structural gaps inside filling layers. Sweetness distribution is another design point. Sweet substances can be proportionally distributed in each layer rather than concentrated in single position, avoiding sudden sweetness fluctuation in the mouth.

In actual industrial production, special filling injection equipment is required to complete one‑shot moulding of inner-middle-outer three-layer structure. Compared with ordinary single‑material filling, process parameters such as material-feeding pressure, flow rate and temperature of three-way filling device must be precisely synchronised. Improper parameter setting may cause deformation of inner peanut core, partial fracture of middle transition layer or uneven thickness of outer sesame wrapping layer. After filling compounding, rapid low-temperature shaping locks each independent layer morphology before wrapping with glutinous-rice dough, reducing material inter‑diffusion caused by residual heat.

For terminal eating experience, the three‑layer peanut-sesame filling brings richer sensory depth than traditional single-flavour glutinous rice balls. Each bite contains successive flavour changes of sesame, transitional compound taste and peanut nutty notes. Even so, product developers need to balance structural complexity and shelf-life stability. Although layered design enhances novelty, it puts forward stricter requirements for raw-material quality control and production precision. This multi‑layer filling structure provides a feasible innovative idea for the product iteration of traditional frozen glutinous-rice-ball food, combining two popular nut flavours of black sesame and peanut into one individual glutinous rice ball through spatial layering design.