Encapsulation of polyphenols from fermented wastewater of Miang processing by freeze drying using a maltodextrin/gum Arabic mixture as coating material

Abstract

Freeze drying using a maltodextrin/gum Arabic mixture (50 : 50%w/w) as coating material could be used to encapsulate phenolic compounds of wastewater from Miang (fermented tea leaf) production. The effect of concentrated fermented Miang water: coating material ratios of 10:1, 30:1, and 50:1 on the encapsulation efficiency was investigated. The result revealed that as the weight ratio of concentrated fermented Miang water to maltodextrin/gum Arabic mixture increased, the encapsulation efficiency decreased while the antioxidant capacity of Miang powder increased due to a higher phenolic concentration in the encapsulation process. The weight ratio of concentrated fermented Miang water to maltodextrin/gum Arabic mixture of 10 : 1 was the suitable ratio to encapsulate phenolic compounds with the efficiency as high as 99.40%. The IC50 values of DPPH and ABTS assays for the obtained Miang powder were 24.19 and 332.75 µg/ml, respectively. Additionally, the Miang powder contained gallocatechin, epigallocatechin, catechin, epicatechin, gallocatechin gallate, gallic acid, and caffeine. Practical applications Fermented Miang water (fermented tea leaf; Camellia sinensis var. assamica) as wastewater from Miang production is an attractive source of natural bioactive compounds, particularly phenolic compounds with antioxidant activity. These phenolic compounds were efficiently encapsulated by freeze drying using a maltodextrin/gum Arabic mixture as coating material. The phenolic compounds identified in Miang powder were gallocatechin, epigallocatechin, catechin, epicatechin, gallocatechin gallate, gallic acid, and caffeine. Therefore, the fermented Miang water that is thrown away and not used for other processes could be produced as Miang powder that is applied as an alternative source of natural antioxidants for food supplements, pharmaceuticals, cosmetics and other health products.