Influence of Infusion Conditions on the Chemical and Nutritional Properties of Tea ( Camellia sinensis ): A Review

Tea (Camellia sinensis) is widely consumed worldwide and represents an important dietary source of bioactive compounds, including catechins, polyphenols, caffeine, free amino acids, and flavonoids. The extraction efficiency and stability of these compounds during tea preparation are strongly influenced by infusion conditions and processing variables. This review critically evaluates the effects of environmental factors, pre- and post-harvest practices, and infusion parameters on the nutritional and chemical composition of tea infusions. Emphasis is placed on steeping temperature, infusion time, water quality, leaf-to-water ratio, particle size, repeated infusions, and teapot material, all of which significantly affect the release and retention of bioactive constituents and antioxidant activity. Current evidence indicates that increasing infusion temperature generally enhances the extraction of phenolic compounds and antioxidant capacity; however, excessive temperatures or prolonged brewing may accelerate degradation of heat-sensitive compounds and adversely affect sensory quality. The review further identifies existing knowledge gaps regarding low-temperature infusion approaches and their potential to optimize the recovery and preservation of health-promoting compounds while maintaining desirable sensory attributes.