Abstract
In the context of sustainable development and resource diversification, research on environmentally friendly chitosan (CS) new resource has garnered increasing attention. Traditionally regarded as low-value byproducts, insect pupae have emerged as an ideal raw material for CS production due to their high chitin content. In this study, CS was first extracted from silkworm pupae and then combined with tea tree essential oil (TTO) to form an edible coating, which was used for preserving germ-retained rice (GRR). Through single-factor and orthogonal experiments, the optimal formulation was determined as 1.5 % (w/v) CS, 2.5 % (v/v) TTO, and 0.3 % (v/v) Tween-80. This formulation exhibited strong antioxidant activity, with DPPH and hydroxyl radical scavenging rates exceeding 75 %. GRR coated with the preservative formulation was stored at 25 °C and 65 % RH for 30 days. Results demonstrated that the preservative formulation significantly mitigated quality deterioration in GRR by reducing increases in fatty acid value (27.59 vs. 37.06 mg/100 g in the control group) and malondialdehyde content (0.74 vs. 0.88 μmol/g), suppressing amylose accumulation (14.37 % vs. 15.47 %), and minimizing protein loss (6.26 % remaining vs. 6.14 % in the control group). Additionally, it preserved the texture of cooked GRR by maintaining lower hardness (1.99 vs. 2.11 N) and higher elasticity, cohesiveness, and chewiness. The silkworm pupae CS-TTO preservative formulation is a natural and effective solution that extends the shelf life of GRR while maintaining its nutritional and textural properties, making it a promising option for applying insect-derived CS in grain storage.
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•A silkworm pupae CS-TTO preservative formulation for GRR preservation was developed.•The optimized CS-TTO formulation exhibited strong antioxidant activity.•The CS-TTO formulation delayed GRR quality deterioration and maintained texture.•The insect-derived CS shows promise for grain preservation.