Studies on chemical compositions and antioxidative activity of Caulerpa lentillifera and C. racemosa

• Main Authors: Ting-Ju Chang, 張婷如
• Other Authors: Chyuan-Yuan Shiau
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/26695584309567490357

碩士 === 國立臺灣海洋大學 === 食品科學系 === 99 === Seaweed Caulerpa is commonly known as sea grape, which is the emerging algae aquaculture in recent years. Little information on chemical composition and properties of Caulerpa was available. Therefore, this study is carried out to analysis the chemical composition. Besides, the different extraction conditions were used to evaluate the antioxidant activities of Caulerpa lentillifera and C. racemosa. The moisture content of C. lentillifera was 95%, ash 1.7%. Protein and lipid were in a little amount. Ash increased after vacuum freeze-drying. The ash content of C. racemosa was less than C. lentillifera, whereas protein, ammonia and urea were higher. The dominant nucleotide-related compounds of C. lentillifera and C. racemosa were Guanine, IMP and CMP. The major free amino acids of C. lentillifera and C. racemosa were Glutamic acid, Phosphoserine, Glycine, Aspartic acid and Alanine. The major saturated fatty acids of C. lentillifera and C. racemosa were C14:0, C16:0 and C18:0; and the unsaturated fatty acids were C16:1, C18:1, C18:2, C20:3, C20:4 and EPA (C20:5), respectively. Two kinds of Caulerpa were treated by vacuum freeze-drying and hot air drying. Four different solvents (water, methanol, ethanol and 50% ethanol) were used for extraction at 25oC and 50oC, respectively. The antioxidant activities of extracts were measured by DPPH scavenging activity, ABTS+ scavenging activity and reducing power. For DPPH scavenging activity, all of ethanol extracts had the best scavenging ability, followed by methanol. The extracts of ethanol and methanol had better ABTS+ scavenging activities. The ethanol extract showed the highest reducing power among four solvent extracts. The sample of C. lentillifera and C. racemosa by vacuum freeze-drying had a higher antioxidant activity than that of hot air drying. The effect of extraction temperature on antioxidant activity was not significant. Ethanol and methanol extracts of C. lentillifera and C. racemosa had more total phenol compounds and reducing sugar contents. Reducing sugar contents correlated well with antioxidant activities.