title: Effect of maturity stages and drying methods on the retention of selected nutrients and phytochemicals in bitter melon (Momordica charantia) leaf.
abstract: The purpose of this study was to investigate the nutrient and phytochemical composition of bitter melon leaves under varying maturity levels and drying techniques. Fresh, oven-dried, and freeze-dried leaves were evaluated over 3 maturity stages. In fresh leaves at various stages, crude fat, crude protein, and soluble dietary fiber contents ranged from 4.2% to 13.6%, 6.4% to 23.1%, and 0.04% to 3.50% on dry-weight basis, respectively. The contents of K, Ca, Mg, Fe, and Zn ranged from 1850.8 to 2811.8, 837.4 to 4978.2, 317.3 to 512.4, 8.4 to 16.7, and 4.1 to 5.9 mg/100 g dry-weight basis, respectively. Vitamin C, beta-carotene, and lutein contents ranged from 397.4 to 1275.1, 154.2 to 422.8, and 737.6 to 1304.6 microg/g dry-weight basis. The major flavonoids and phenolic acids were rutin, gentistic acid, and o-coumaric acid, which ranged from 7.57 to 12.75, 2.53 to 10.11, and 4.24 to 9.75 mg/g dry-weight basis, respectively. In oven-dried samples, 40.2% to 52.3% of vitamin C, 35.4% to 55.4% of beta-carotene, 25.6% to 71.6% of lutein, 26.4% to 84.0% of rutin, trace to 11.4% of gentistic acid, and 7.4% to 46.6% of o-coumaric acid were retained, while the retainment ratios of these components in freeze-dried samples were 84.7% to 99.0%, 76.4% to 99.3%, 90.4% to 96.1%, 39.8% to 99.3%, 24.1% to 68.4%, and 75.8% to 87.0%, respectively. The data showed that freeze-drying better preserves the nutrient and phytochemical quality of bitter melon leaves in comparison to oven-drying. Bitter melon leaf is a rich source of selected nutrients and phytochemicals.
authors.affiliation: College of Food Engineering and Biotechnology, Tianjin Univ. of Science and Technology, TEDA, Tianjin 300457, China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.forename: Navam S
authors.initials: NS
authors.lastname: Hettiarachchy
authors.forename: Ronny
authors.initials: R
authors.lastname: Horax
authors.forename: Pengyin
authors.initials: P
authors.lastname: Chen
authors.forename: Kenneth F
authors.initials: KF
authors.lastname: Over
mesh_terms: D000465:Algorithms; D001205:Ascorbic Acid / Q000032:analysis; D001565:Benzoates / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D002934:Cinnamates / Q000032:analysis; D004041:Dietary Fats / Q000032:analysis; D004043:Dietary Fiber / Q000032:analysis; D005419:Flavonoids / Q000032:analysis; D005511:Food Handling / Q000379:methods*; D005612:Freeze Drying; D014975:Lutein / Q000032:analysis; D008903:Minerals / Q000032:analysis; D029777:Momordica charantia / Q000737:chemistry* / Q000254:growth & development; D010858:Pigmentation; D018515:Plant Leaves / Q000737:chemistry*; D014674:Plant Proteins, Dietary / Q000032:analysis; D013053:Spectrophotometry; D014675:Vegetables / Q000737:chemistry*; D019207:beta Carotene / Q000032:analysis
chemical_list: D001565:Benzoates; D002934:Cinnamates; D004041:Dietary Fats; D004043:Dietary Fiber; D005419:Flavonoids; D008903:Minerals; D014674:Plant Proteins, Dietary; D019207:beta Carotene; D001205:Ascorbic Acid; D014975:Lutein