To clarify the changes in the content and bioavailability of 4 kinds of sugars and 4 kinds vitamins in postharvest Cucumis melo L. flesh.

The study examined the flesh of 2 Cucumis melo L.varieties at 7 different post-harvest stages. Using in vitro simulated digestion experiments and high performance liquid chromatography (HPLC), this study analyzed the changes in the content and bioavailability of reducing sugars, fructose, glucose, sucrose, vitamin B₁ (VB₁), vitamin B₂ (VB₂), niacin and nicotinamide in the Cucumis melo L. flesh. One-way analysis of variance and membership function analysis were employed to comprehensively evaluate the post-harvest nutritional components of the Cucumis melo L. flesh.

The bioavailability of the 8 kinds of nutrients in the Cucumis melo L. flesh of both varieties followed the order: Glucose>reducing sugars>fructose>sucrose; VB₂>VB₁>niacin>nicotinamide. Over time, the bioavailability of glucose, reducing sugars, fructose, and nicotinamide in Nasmi Cucumis melo L. flesh showed a fluctuating upward trend, while the bioavailability of VB₁ and niacin in the flesh increased initially and then decreased later, and VB₂ showed a fluctuating decline; the bioavailability of the 4 kinds of sugars and 4 kinds of vitamins in the flesh of Xizhoumi No.25 exhibited fluctuating trends, with significant differences observed among the varieties. Using the membership function analysis method, the bioavailability of sugars and vitamins in the flesh of Nasmi and Xizhoumi No.25 Cucumis melo L. was comprehensively evaluated post-harvest. The results showed that the overall bioavailability of nutritional components in the Cucumis melo L. flesh was highest on the 9th day post-harvest, with values of 0.61 and 0.72, respectively.

The content and bioavailability of the 4 kinds of sugars and 4 kinds of vitamins in the flesh of the 2 Cucumis melo L. varieties exhibit different trends after harvest. It is recommended to develop regulatory technologies based on these characteristics to improve the bioavailability of the nutritional quality of Cucumis melo L. flesh and provide dietary guidance to consumers.