Study on Fabrication and Stability of Starch-Lycium barbarum Complex

In this investigation, the starch-Lycium barbarum complex (CS-LB) was fabricated using corn starch (CS) and Lycium barbarum (LB) through a high-speed shear method. The stability of the guest molecules was also explored. The influence of shear time, rotational speed, and LB to CS mass ratio on Lycium barbarum pigment (LP) content and its stability were investigated. The CS-LB was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA). It was found that the content of LP in the product was 0.99±0.03 mg per gram when the shear time was 1.5 hours, the rotational speed was 12000 r/min, and the mass ratio of LB to CS was 3:1. The SEM results illustrated that the products had an agglomerated morphology. The XRD results showed that the crystal domain of starch particles was destroyed and transformed into amorphous structures due to the high-speed shear treatment, but the CS-LP crystalline structure changed into a V-type, which was promoted by the interaction between CS and active components of LB. The FT-IR results showed that the absorption peak at 3421 cm−1 shifted, indicating that CS and LB were bound through hydrogen bonds. The TGA results showed that the thermal stability of the product was also enhanced, with a mass retention rate of 36% at 600 ℃ for the composite. Thus, the CS-LB could be effectively fabricated by high-speed shear treatment. Additionally, it was found that the composite could effectively reduce the effects of temperature, oxygen, and light on the stability of guest molecules in stability experiments. The shelf-life of guest molecules was also extended, enabling them to perform their related functions better.