Research on Processing Characteristics of Sedum aizoon L. and Development of Low-GI Meal Replacement Powder

Low Glycemic Index (low-GI) meal replacement powders are increasingly sought for weight management. Sedum aizoon L. is a promising vegetable raw material, yet its processing characteristics remain poorly characterized. This study systematically evaluated the effects of four pretreatments (untreated, freeze-thaw, blanching, blanching plus green protection) and two drying methods (hot-air drying, freeze drying) on S. aizoon L. from the Diqing Plateau, Sedum aizoon L., and optimized a low-GI meal replacement formula. The results revealed that blanching and blanching plus green protection shortened hot-air-drying time by approximately 50% and improved the flowability and compactness of powder (Hausner ratio 1.26, Carr index 20.46%). Qualitative and quantitative analyses revealed that Sedum aizoon L. contained various bioactive substances such as flavonoids and phenolic acids. Freeze drying better retained polyphenols, flavonoids, and vitamin C; the freeze-thaw plus freeze drying exhibited the optimal color protection effect with a chlorophyll content of 1.4843 mg/g. Dried Sedum aizoon L. was evaluated by a trained panel plus electronic nose analysis, while the meal replacement powder was assessed by electronic nose and electronic tongue. A single-factor test, a Plackett-Burman test and a response surface methodology were adopted to optimize the optimal formula of meal replacement powder: Sedum aizoon L. powder 2.3 g, skim milk powder 2.8 g, sugar powder 1.6 g, grain powder 4 g, nut powder 2.6 g, and konjac powder 0.55 g. The meal replacement powder has low estimated GI (eGI) value (eGI < 55) and high dietary fiber content (43.4 g/100 g), with superior aroma and taste versus a commercial reference. These findings support the industrial production of Sedum aizoon L.-based low-GI meal replacement food.