Exopolysaccharides (EPS) produced by Arthrospira platensis (A. platensis) has been widely applied in industry and commerce for its various activities but the accumulation of EPS in culture medium may influence the growth of A. platensis reversely. This work aims to explore the impacts of initial pH, nitrogen source and concentration, phosphate concentration and recycle times of the culture medium on the growth of A. platensis and the secretion of its EPS. The results showed that EPS accumulated with the increase in recycle times of culture medium. The optimal initial pH for the growth of A. platensis was 8.50, and high pH of 11.5 inhibited the growth of biomass while resulting in highest EPS content of 92.87 mg/g DW. Excessive and limited nitrogen (NaNO₃ of 25.00 g/L and NaNO₃ < 2.50 g/L) and phosphate (K₂HPO₄ of 5.00 g/L and K₂HPO₄ < 0.50 g/L) inhibited the biomass production of A. platensis by 1.28–30.77% and 14.29–45.05%, respectively. EPS yield of 97.57 mg/g DW and 40.90 mg/g DW were obtained under NaNO₃ of 25.00 g/L and K₂HPO₄ of 5.00 g/L due to salt stress. These findings are beneficial in providing a theoretical basis for high yield EPS from A. platensis without affecting biomass yield.

Starchy foods are an essential part of people’s daily diet. Starch is the primary substance used by plants to store carbohydrates, and it is the primary source of energy for humans and animals. In China, a variety of plants, including edible medicinal plants, such as Pueraria root, yam tuber and coix seed, are rich in starch. However, limited by their inherent properties, kudzu starch and other starches are not suitable for the modern food industry. Natural starch is frequently altered by physical, chemical, or biological means to give it superior qualities to natural starch as it frequently cannot satisfy the demands of industrial manufacturing. Therefore, the deep processing market of modified starch and its products has a great potential. This paper reviews the modification methods which can provide excellent functional, rheological, and processing characteristics for these starches that can be used to improve the physical and chemical properties, texture properties, and edible qualities. This will provide a comprehensive reference for the modification and application of starch from medicinal and edible plants.

This study investigated the physicochemical properties of Camellia oleifera husks collected from three regions of Jiangxi Province (Ganzhou—GZ, Yichun—YC, and Jiujiang—JJ) and extracted tea saponins via microwave-assisted solvent extraction (MASE), aiming to provide a theoretical basis for the high-value utilization of this agricultural by-product. The husks from YC were rich in bioactive compounds such as tea saponins (16.29 ± 0.02%), with lower cellulose (21.05 ± 1.05%) and lignin (12.48 ± 1.14%) contents and higher hemicellulose (27.40 ± 0.80%) content. The husks from JJ exhibited abundant porosity and a larger specific surface area (40–60 mesh, 4.15 ± 0.04 m²/g). Single-factor extraction experiments indicated that the microstructure and chemical composition of Camellia oleifera husks significantly affected the extraction efficiency of saponins, tannins, and flavonoids. The optimal extraction conditions for tea saponins were established using Box–Behnken response surface methodology, with the liquid-to-solid ratio identified as the most critical factor. Optimal conditions for GZ husks were a liquid-to-solid ratio of 46.75 mL/g, ethanol concentration of 35.5%, extraction time of 6 min, and microwave power of 350 W, with the extraction yield of 7.49 ± 0.01%. Optimal conditions for YC husks were a liquid-to-solid ratio of 50.55 mL/g, ethanol concentration of 40.13%, extraction time of 6 min, and microwave power of 350 W, with the extraction yield of 16.29 ± 0.02%. Optimal conditions for JJ husks were a liquid-to-solid ratio of 47.44 mL/g, ethanol concentration of 37.28%, extraction time of 6 min, and microwave power of 350 W, with the extraction yield of 9.39 ± 0.02%. The study provides important scientific evidence for understanding the structure–function relationship of Camellia oleifera husks and offers practical guidance for developing sustainable industrial processes to convert agricultural by-products into high-value bioactive compounds, thereby promoting resource recycling and economic benefits in the Camellia oleifera industry.

Limnospira platensis is a promising sustainable biomass for functional food production. During cultivation, it secretes extracellular polysaccharides (EPS) with underutilized potential as food ingredients. This study aimed to strategically fractionate Spirulina EPS (SEPS) by molecular weight (MW: 100 kDa) to elucidate their structure-function relationships for targeted food applications. We found distinct functional diversification: The mid-MW fraction (SEPS-2, 30–100 kDa) was an amphiphilic glycoprotein complex with potential interfacial activity. The high-MW fraction (SEPS-3, >100 kDa) formed a dense, glucose-rich glucan network, suggesting utility as a natural thickener or texturizer. In contrast, the low-MW fraction (SEPS-1, <30 kDa), rich in deoxy-sugars, exhibited superior antioxidant capacity, indicating potential as a bioactive preservative or nutraceutical. Spectroscopic and morphological analyses linked these structural differences to their physicochemical properties. Notably, the 30–100 kDa fraction transitions from a cultivation byproduct to a functional food architect, where its interfacial properties can be leveraged to engineer stable, clean-label emulsion-based food products. This work provides a foundation for the valorization of L. platensis EPS, demonstrating how MW-directed fractionation can unlock tailored functionalities-from bioactive agents to structural polymers-for the development of next-generation foods from circular bioeconomy streams.