Sediment in tea beverages: Formation mechanisms and reduction strategies

Background

Tea beverages with a market cap exceeding 44 billion dollars characterize unique flavor and health benefits. “Tea cream” denotes the turbidity that occurs when tea infusions cool down. Further formation of tea sediment during the shelf-life affects appearance, leading to flavor deterioration. Currently, tea beverage enterprises mainly rely on physical removal or chemical dissolution to decrease sediment. As the sediment formation mechanisms remain unclear, effective controlling methods are scarce, which limits the development of high-quality tea beverage and increases production costs.

Scope and approach

This review comprehensively concludes studies on tea beverage sediment in the recent 10 years. We first elucidate the chemical composition and formation mechanisms of tea sediment, then conclude the factors influencing its formation. Among the methods for controlling tea sediment, we selectively focus on the regulation of tea compounds in extraction with further enzyme treatment. Final suggestions for future research on tea sediment utilization are provided.

Key findings and conclusion

Tea polyphenols, proteins and caffeine, constitute the key components of tea beverage sediment. The leaching, binding and conversion of these contributors are related to raw tea materials and extraction conditions. Covalent and non-covalent interactions drive to the generation of polyphenol-CAF and polyphenol-protein complexes, resulting in tea sediment. Physical, chemical, and biological solutions have been employed to reduce sediment. But challenges remain in mass production and practical application of tea beverages. Future tea beverage research should focus on the effective, feasible, and safe tea sediment controlling strategies to merit the long-term maintenance of tea infusion quality and the applicability in large-scale industrial production.