The raw material pre-treatment composition of the filling that locks in the flavor of the Black sesame glutinous rice balls

Black sesame filling defines the core flavor of black sesame glutinous rice ball, and the release and retention of sesame-roasted aroma largely depend on raw-material pre-treatment before filling blending. Conventional high-temperature quick-roasting can produce strong instant roasted notes, yet it easily triggers excessive lipid oxidation, volatile-aroma loss and local scorched bitter substances. Low-temperature baking emerges as a mild pre-treatment method, optimizing the component balance inside black sesame, locking characteristic nutty fragrance and restraining off-flavor generation, so as to deliver stable, rich aroma for glutinous rice ball fillings during industrial production and frozen shelf-life storage.

During low-temperature baking, a series of mild thermal reactions reshape the chemical composition of black sesame. A moderate Maillard reaction takes place between intrinsic amino acids and reducing sugars, generating desirable roasted-sesame-related volatile compounds without over-pyrolysis. Meanwhile, partial bound aromatic substances embedded in oil-protein matrix are slowly released. Unlike high-temperature treatment that volatilizes most small-molecule aroma components in a short time, low-temperature condition retains more key flavor substances including pyrazines, furans and short-chain aldehydes, which constitute the authentic mellow sesame note for fillings.

Lipid‑phase transformation is another critical change in this pre-treatment process. Raw black sesame contains native lipoxygenase and peroxidase. If these enzyme systems remain active in finished filling, they will continuously catalyze fat oxidation during frozen storage, producing rancid off-odors and destroying filling flavor. Controlled low-temperature baking effectively inactivates oxidative-related endogenous enzymes, improving the oxidative stability of sesame oil inside raw material. Proper thermal treatment also promotes protein denaturation in sesame particles, and the denatured protein network can physically encapsulate oil droplets and aromatic small-molecules, building a natural barrier to slow down aroma escape and fat deterioration in long-term frozen circulation.

Nevertheless, baking temperature and holding time must be strictly controlled. Insufficient low‑temperature processing fails to fully deactivate enzymes and unlock bound fragrance precursors, resulting in flat, faint sesame taste. Over-extended heating even under low-temperature conditions will still cause gradual dissipation of delicate volatile aromas and partial lipid degradation. After baking, rapid cooling is an indispensable link in pre-treatment composition. Hot sesame directly entering filling mixing procedure will accelerate thermal-induced aroma loss and premature oil separation. Quick cooling stabilizes the newly-formed flavor-locked microstructure and prevents secondary thermal damage to fragrance components.

When producing glutinous rice ball fillings, low-temperature-baked black sesame is further matched with oil-phase and solid-phase auxiliary components. The roasted sesame powder with locked fragrance cooperates with vegetable oil or sesame oil system, where oil phase dissolves and preserves hydrophobic aromatic molecules. The particle size of milled baked sesame also influences fragrance-locking performance. Moderate grinding fineness balances aroma release and retention; over-fine grinding breaks protein encapsulation structure, accelerating oil exudation and aroma volatilization of filling in later-stage storage.

Compared with untreated raw black sesame or high-temperature-roasted material, low-temperature baked raw-material endows black sesame glutinous rice ball with more consistent flavor performance. After long-term frozen storage, fillings still maintain prominent roasted-sesame notes, without obvious rancidity or bitter burnt taste. During consumer cooking, the locked-in fragrance components are re-released under boiling-water heating, forming full-bodied aromatic perception when glutinous rice balls are eaten. For clean-label frozen dessert manufacturers, low-temperature baking pre-treatment provides a physical fragrance-locking solution relying on raw-material component regulation, reducing dependence on exogenous flavor additives and realizing flavor upgrading of traditional glutinous-rice-ball products.