| Summary: | 碩士 === 國立宜蘭大學 === 食品科學系碩士班 === 97 === Abstract
After soaking with different pH solutions for 9 hours, sesame ( Sesamum indicum ) was placed in growth incubator at 26 ℃ for 6 days’ germination. Sesame seedlings were sampled each date in the period of germination, then freeze dried for the following studies. Methanol extracts of sesame seedlings and sesame oil were then used for antioxidants analysis and antioxidation activity evaluation in this study.
In order to trace the changes of proximate composition in sesame during germination, the ingredients of sesame seedling was analyzed. There was no significant difference on the content of crude protein ( 24 — 25 % DM ) and ash (4—6% DM ), nevertheless the amount of crude fat decreased ( 53—31 % DM ) while carbohydrate ( 40 — 18 % DM ) increased proportionally in the period of germination. Regard to the fatty acid composition in sesame oil, there was no significant difference in percentage of fatty acid constituents during germination of sesame.
The changes of antioxidants in sesame seedlings and sesame oils showed that the content of total polyphenols and phytosterols increased significantly during germination, and distributed within 7 — 35.2 mg / g and 1.9 — 17.84 mg / g MeOH extract respectly. The content of phytosterols in germming sesame pretreated with phosphate buffered saline were higher than that of DIW pretreatment, and the amount of total polyphenols raised fastest in all of the soaking pretreatments when pretreated with pH 9-PBS. On the contrary, the quanty of sesamin, sesamolin and γ - tocopherol contained in sesame were decreased in the period of germination, their levels were within 194 — 62 mg / 100 g oil, 209 — 103 mg / 100 g oil and 51 — 37 mg / 100 g oil respectly.
For evaluating the antioxidation capacity of sesame during germination, the reducing power, DPPH free radical scavenging ability and ORAC capacity were estimated. In the period of germination, the reducing power, scavenging DPPH free radical and ORAC activity of sesame seedlings and sesame oil were accelerated. However, The - carotene antioxidation and chelating ability of ferrous raised at the early period of germination, and then declined at a later period. In generally, regardless the methods used for estimating the antioxidative activity, the antioxidative activity of sesame seedlings and oils in pH 9-PBS and pH 7-PBS soaking pretreatment systems were higher than that of others, and the result for pH 3-PBS system was the worst of all.
The correlation between antioxidation capacity and the content of total polyphenols in methanol extracts of sesame seedling and oil was studied. The results showed that there were significant correlations between total polyphenols content and DPPH free radical scavenging activity ( r = 0.95 ) and reduing power ( r = 0.96 ), and followed by ORAC ( r = 0.74 ). With regard to the correlation between that in sesame oil, similar results were observed as in sesame seedling. Significant correlation between total polyphenols content and antioxidation capacities of DPPH free radical scavenge ( r = 0.97), reduing power ( r = 0.96 ) and ORAC ( r = 0.93 ), next for the chelating ability of ferrous ( r = 0.60 ).
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