EFFECT OF DRYING TEMPERATURE ON BIOACTIVE COMPONENTS OF MORINGA LEAVES AND EVALUATION OF STORAGE STABILITY

Abstract

The study was aimed to determine the effect of drying temperatures on the phytochemicals of moringa leaf and the effect of packaging materials on the storage stability of moringa leaf powder. The fresh moringa leaves were collected from Dharan-14, Vijayapur, Nepal. The leaves were passed through the destalking and cleaning procedures. It was dried at 45℃, 55℃ and 65℃ in cabinet drier and then powdered to a fine consistency. Both fresh and dry moringa leaves were analyzed for the bioactive components such as total phenolic content, total flavonoid content, tannin content, chlorophyll and antioxidant activity. The leaf powder dried at optimum temperature were then stored in three packaging materials i.e., HDPE pouches, LDPE pouches, PET bottle at room temperature. During storage, moisture content and Total Plate Count of leaf was analyzed at the interval of 1 week and 5 weeks respectively. The proximate composition of fresh moringa leaf was found to be 86.896 ± 0.25997%, 7.043 ± 0.47%, 19.923 ± 0.32%, 9.173 ± 0.345%, 8.51 ± 1.304% and 55.574 ± 1.159% for moisture, crude fat, crude protein, crude fiber, Ash and carbohydrate respectively on the dry basis except for moisture content. Result showed that drying decreased the levels of phytochemicals content and antioxidant activity significantly (p<0.05) as compared to the fresh leaves. However, drying at 55℃ showed a lesser loss of bioactive components with the value of TPC, TFC, chlorophyll, tannin and antioxidant activity to be 23.42 mg GAE/g, 25.53 mg QE/g, 3.72 mg/g, 8.12 mg/g and 60.33 % RSA respectively. The sensory analysis showed that the sample dried at 55℃ has higher acceptability as compare to other sample. The sample packaged in HDPE pouches was found superior in term of moisture content, total plate count and sensory evaluation followed by PET bottle with PP cap. The highest moisture content and total plate count was found in sample packaged in LDPE pouches. Leaves dried at 55℃ was found superior in term of bioactive component and sensory analysis.