Evaluation of Antioxidant Properties of Dry Soup Mix Extracts Containing Dill (Anethum sowa L.) Leaf

Soups are consumed for nutritive benefits and
also by patients whose intake of solids is considerably
reduced due to several pathological reasons. Dehydrated
soup mix is a convenient product due to its less volume and
long storage life at ambient temperatures. Soup mix
formulated with functional ingredients, modified potato
flour (thickening agent), and dill leaf powder (DLP) was
evaluated for its antioxidant properties. Aqueous and
methanolic extracts of soup mix were prepared, and their
total phenolic content, reducing power ability, and free
radical-scavenging activity were determined. Significant
improvement in total phenolics was observed as a result of
addition of DLP that led to enhancement of its antioxidant
properties. The phenolic acid profile of the soup mix base
contained mainly tannic acid, while protocatechuic, gentisic,
vanillic acid, and syringic acids were contributed by
DLP. The reducing power ability of soup mix was increased
by about 2.5 times in aqueous and about seven times in
methanolic extracts, as a result of DLP addition. Concentration-
dependent scavenging activity was observed, and
IC50 (scavenging of 50% 1,1-diphenyl-2-picrylhydrazyl
radical) values were reduced from 16.5 to 3.8 μg/mL in
aqueous and from 9.1 to 3.9 μg/mL in methanolic extracts
as a result of addition of DLP. The moisture–humidity
relationship studies of soup mix conducted to determine its sorption behavior showed that the product exhibited caking
tendency above 8.9% moisture corresponding to a critical
relative humidity of 56%.