| Summary: | 碩士 === 國立屏東科技大學 === 食品科學系所 === 96 === Areca fruits (Areca catechu Linn.) are rich in polyphenols, alkaloids, natural fiber, lipid, and polysaccharides. Polyphenols are crude antioxidant which exhibit antioxidant activity, antimutagenicity, etc. Areca fruits are one of the abundant produces in Taiwan and a large quantity wastes are generated annually. We can make good use of areca fruits to improve economical value of areca fruits. In this study, optimum extraction method for extracting polyphenols from areca fruits were investigated. The aim of this study is to elucidate the effect of different varieties (white, red and white sharp), harvest seasons (summer and winter) and size (size I, II and III) on the polyphenols and proanthocyanidin contents of areca fruits, and try to understand the contribution of these components on antioxidant activity. Analyses include antioxidant component (total polyphenols and proanthocyanidins concentration), antioxidant capacity (FRAP and DPPH scavenging ability), gel filtration, HPLC analysis and ESI-MS analysis. In addition, we added polyphenols to troche film to increase application of areca fruits, and studied the effect of storge on physical characteristics, polyphenolic contents and antioxidant capacities. Analyses include mechanical characteristics (tensile strength and elongation), water vapor permeability (WVP), water activity, moisture content and total viable counts.
Results showed that 70 percentage of alcohol and the ratio of areca fruit to solvent 1:10 is the optimum extraction for areca fruits. In different varieties, red varieties exhibited the highest total polyphenols, proanthocyanidins concentration, FRAP and DPPH scavenging ability, followed by white sharp varieties, and white varieties. In different harvest seasons, summer harvested was better than winter harvested. In different sizes, size III was the highest followed sequentially by size II, and size I. Statistic analysis revealed that total polyphenols is significantly correlated with proanthocyanidins concentration. Total polyphenols and proanthocyanidins concentration are highly correlated with FRAP and DPPH scavenging ability. FRAP is highly correlated with DPPH scavenging ability. Fractionation of crude polyphenols extract with LC showed that two peaks after elution with 95% alcohol and 50% acetone were obtained, respectively. The second fraction from 50%acetone (FII) exhibited the greatest antioxidant capacity followed by 95%alcohol (FII). The fractions were analyzed by high-performance liquid chromatography and electrospray-ionization mass spectroscopy. Catechin and epicatechin were identified in 95% alcohol FII; proanthocyanidins comprised of dimers and trimers were identified in 50% acetone FII. A hypothesis is made that the antioxidant capacity is related with proanthocyanidins. As to the appilication product, heating process can decrease alkaloids in areca fruits. After heating for 3 hours, the decrease in alkaloids were 76.18 percentage. We added polyphenols from areca fruits to troche film and conducted the storage test. The results showed that the elongation of troche film was reduced along storage time, yet tensile strength, water vapor permeability, water activity and moisture content were not significantly changed. Total viable counts were conformed in standard. In conclusion, areca fruits are rich in polyphenols and have great antioxidant capacity, but polyphenolic contents were influenced by varieties, harvest seasons and size. Proanthocynidins is an important contributor for the antioxdant capacity of areca fruit which could play a important role for application of areca fruit in the future.
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