# Valorization of Bayberry (Morella rubra) Leaf By-Products: Impact of Growth Stage and Drying Method on Phytochemical Profile and Potential as Functional Food Ingredients

## TL;DR

This paper explores how to best harvest and process bayberry leaves to maximize their health benefits and use as functional food ingredients.

## Contribution

The study identifies optimal growth stages and drying methods for preserving or enhancing bioactive compounds in bayberry leaves.

## Key findings

- Freeze-drying preserved color, structure, and heat-sensitive nutrients like ascorbic acid and monoterpenes.
- Thermal drying methods increased extraction of polyphenols and antioxidant activity in hot water extracts.
- Shade drying significantly degraded leaf quality due to enzymatic oxidation.

## Abstract

Bayberry (Morella rubra Lour.; syn. Myrica rubra (Lour.) Siebold & Zucc.) leaves are rich in bioactive compounds but remain underutilized. This study investigated the optimal harvest stage and processing methods to develop high-quality functional powder. We first compared three growth stages: red buds (RB), new leaves (NL), and old leaves (OL). RB exhibited the highest antioxidant capacity and unique volatile profile; however, NL was selected for processing optimization due to the balance between quality and biomass availability. Subsequently, NL was subjected to freeze-drying (FD), mechanical drying (MD), steaming followed by MD (S-MD), and shade drying (SD). Results showed that FD preserved the vibrant green color, glandular trichome structure, ascorbic acid, and fresh volatiles (monoterpenes). Conversely, thermal drying (MD and S-MD) disrupted cellular barriers, which facilitated the extraction of minerals and robust polyphenols like myricitrin, yielding the highest extraction of flavonoids and corresponding antioxidant activity, measured by hydrophilic oxygen radical absorbance capacity (H-ORAC), in hot water extracts than FD. SD significantly degraded quality due to prolonged enzymatic oxidation. While FD is ideal for preserving aesthetics and heat-sensitive nutrients, low-cost MD and S-MD are recommended for producing antioxidant-rich powders for functional food applications where extraction efficiency is prioritized.