Extraction optimization and microencapsulation of phenolic antioxidant compounds from lemon balm (Melissa officinalis L.): Instant soluble tea production

The purpose of this study was to extract phenolics from lemon balm followed by microencapsulation with spray drying. The optimum extraction conditions were 100 degrees C for the temperature and 120 min for the time with TPC of 6,365 mg GAE/100 g and ABTS radical scavenging activity of 9,196 mg TEAC/100 g. Lemon balm extracts were spray dried using three different air inlet temperatures (130 degrees C, 165 degrees C, and 200 degrees C) of which 165 degrees C was provided better scores than the other points in terms of microencapsulation yield (65.9%), microencapsulation efficiency (99.4%), dry matter (98.3%), and water activity (0.160). The inlet air temperatures had an insignificant (p > .05) effect on the antioxidant capacity of the microcapsules. Phenolic acids in lemon balm were slightly affected by the extraction and spray drying conditions. However, extraction followed by spray drying resulted in significant loss in the amount of volatiles such as geranial, neral, citronellal, and caryophyllene. Practical applications Hot water extracts of the medicinal and aromatic plants are consumed as herbal tea across the world and their biological activity varies depending on the extraction conditions. Furthermore, bioactive compounds are sensitive to environmental conditions when the compounds dissolved in water. The conditions necessary for the effective extraction of bioactive compounds are specific to the target plant and it is a problem for the consumer. Optimization of extraction conditions of lemon balm phenolics could provide useful information for the consumer and food industry. The production of phenolic microcapsules (instant soluble tea) from lemon balm could facilitate herbal tea preparation and reduce the preparation time.

Automated summary

This study aimed to extract phenolics from lemon balm and microencapsulate them through spray drying, leading to improved bioactivity. Optimization of extraction conditions for lemon balm phenolics could provide useful information for consumers and the food industry.