Delivery of Catechins from Green Tea Waste in Single- and Double-Layer Liposomes via Their Incorporation into a Functional Green Kiwifruit Juice

Globally, about one million tonnes of tea products, which contain high concentrations of catechins and their derivatives, are wasted annually. Therefore, green tea waste catechins (GTWCs) are worth extracting, processing, protection, and delivery to the human body. In this study, GTWCs were extracted using a green method and then encapsulated in both single- (SLLs) and double-layer liposomes (DLLs). The encapsulated extracts were subsequently incorporated into a fresh green kiwifruit juice. SLLs and DLLs containing GTWCs had a size of about 180 and 430 nm with a zeta potential of −35 and +25 mV, respectively. Electron microscopy illustrated the separation of the SLLs and fibre in kiwifruit juice and attraction of the DLLs to this fibre. Liposomal GTWCs were effectively maintained in the kiwifruit juice during the 28 days of storage (4 °C), demonstrating the effectiveness of this delivery system for high-value bioactives (i.e., catechins) from such a by-product (i.e., green tea waste).