Tea (Camellia sinensis L.) anthocyanins and their compounded stability through conjugation: A promising instrument to synthesize green, halochromic, active and intelligent packaging

Abstract

In packaging, an increasing swing toward green innovations enhancing food quality and consumer satisfaction is persisting. Halochromic, active and intelligent packaging (HAIP) protects food and monitors quality via efficient indicators. Natural anthocyanins have become popular for HAIP due to their prompt color-changing ability in response to varying pH, antimicrobial, and antioxidant activity. Tea, especially purple varieties, is a rich source of anthocyanins and contains cyanidin, delphinidin, pelargonidin, petunidin in significant quantities, and peonidin, malvidin in comparatively minor quantities along with their acylated and non-acylated derivative, as predominant anthocyanins, such as cyanidin-3-O-galactoside, cyanidin-3-O-arabinoside, cyanidin-3-O-β-D-(6-(E)-p-coumaroyl)-glucopyranoside, delphinidin-3-O-galactoside, pelargonidin-3-O-rutinoside, petunidin-(E)-p-coumaroyl-galactopyranoside and pelargonidin-3-O-galactoside, which could be used in the synthesis of HAIP having unique hues. Several of these tea anthocyanins are destroyed by different factors, such as temperature, light, enzymes, and others, leading to their diminished activity. Different conjugation procedures could be used to stabilize the integrity of tea anthocyanins. These procedures, including co-pigmentation, self-association, metal-complexation, acylation, and encapsulation, use hydrogen bonding, π-π stacking, van der Waals forces, hydrophobic and electrostatic interaction with other molecules such as metals, organic acids, fatty acids and their esters, phenolic acids, biopolymers and other molecules to increase the stability of tea anthocyanins. Tea anthocyanins have potent antioxidant, antimicrobial, and pH-responsive qualities that can be used in producing efficient HAIP. Thus, advancing tea anthocyanin-based HAIP requires a multi-faceted approach, including researching purple tea for exploring the type and concentration of different important anthocyanins, enhancing their stability using tea's native and other bioactive compounds, using them in robust HAIP and shifting the trend from research to real-time applications.