Influence of Dehydration Techniques on Physicochemical, Antioxidant and Microbial Qualities of Ipomoea aquatica Forsk.: An Underutilized Green Leafy Vegetable

Investigations were carried out to determine changes in physicochemical and microbial qualities of oven‐dried, sun‐dried and freeze‐dried Ipomoea aquatica Forsk., a popular leafy vegetable (known as kangkung). Sun drying showed low retention of fat and fiber with insignificant changes in protein content, whereas, freeze‐dried samples showed high retention of ascorbic acid. Results of 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging assay showed higher inhibition in oven‐dried samples, followed by freeze‐dried and sun‐dried samples. In addition, freeze‐dried samples retained chlorophyll better among the three dried samples. Total bacteria, yeast and mold counts and Escherichia coli count in kangkung showed significant decrease on drying. PRACTICAL APPLICATION: Drying is an age‐old technique used to preserve food. Results of this work can be beneficial to consumers who might be interested in being acquainted with the retention of the overall qualities of dried leafy vegetables. Results obtained are expected to promote the commercial application of dried kangkung as a raw ingredient and develop value‐added healthy food products such as crackers and refreshing healthy drink mixes.