Chemical composition, bioactivity, and high-value utilization of asparagus by-products: A comprehensive review

Asparagus ( Asparagus officinalis L.) is widely cultivated for its edible spears, but cultivation and processing generate substantial by-products, including straws, old stems, peels, flowers, fruits, and seeds, many of which remain underutilized despite their nutritional and functional potential. Therefore, asparagus by-products represent an underexploited resource that urgently needs to be re-evaluated. This review provides a concise, PRISMA-guided synthesis of the chemical composition, bioactivities, and high-value utilization pathways of asparagus by-products based on literature retrieved from major databases up to July 2, 2026. Evidence indicates that these by-products are rich in flavonoids, saponins, polysaccharides, dietary fiber, proteins, vitamins, and trace elements, and exhibit antioxidant, anti-inflammatory, antimicrobial, prebiotic, and potential antitumor activities. Current utilization strategies include functional foods, natural bioactive ingredient extraction, health products, feed additives, composting, cultivation substrates, and biotransformation processes. Nevertheless, current research on asparagus by-products is highly fragmented, exhibiting significant disparities across utilization routes, by-product types, extraction methods, bioactivity validation, and safety assessment. This review further systematically sorts the historical evolution of relevant research, comprehensively compares the advantages and inherent limitations of existing extraction technologies and industrialization pathways, and deeply dissects core bottlenecks restricting large-scale industrial transformation, so as to clarify the differentiated development trends of basic research and industrial application in this field, and provide targeted innovative directions for subsequent academic and engineering research. Future work should prioritize standardized characterization, mechanism-based bioactivity studies, green extraction and processing technologies, and application-oriented evaluation to support industrial translation. Overall, asparagus by-products are a promising resource with strong potential to improve resource-use efficiency, reduce environmental burdens, and promote sustainable development of asparagus industry. This study provides novel insights into their development and utilization, offering a strategy for value-added processing and sustainable production.