Optimization of material concentration and extraction time on yield and α-tocopherol content of sea lettuce (Ulva lactuca L.)

Abstract

Ulva lactuca L. is a group of green algae (Chlorophyta). Ulva lactuca L. grows and spreads on rocky beaches in Indonesia and contains various bioactive compounds that are beneficial to health such as α-tocopherol. The purpose of this study was to determine the surface response methodology (RSM) equation, optimization, and overlaid point in obtaining the maximum yield and α-tocopherol extract of Ulva lactuca L. Treatment of the study was the concentration of the material (X1) and the extraction time (X2). Data analysis was performed using a surface response methodology (RSM) with a central composite design (CCD). The results of the research on yield and α-tocopherol show the maximum shape. The concentration of the ingredients and the extraction time in producing the yield (Y1) of sea lettuce extract are following the equation Y1 = -20.12 + 3.018 X1 + 3.232 X2 - 0.1228 X12 - 0.1728 X22 - 0.1459 X1X2 with a value of R2 = 0.85. While the content of α-tocopherol (Y2) follow the equation Y2 = -205,242 + 43,849 X1 + 6,031 X2 - 2,530 X12 - 1,076 X22 + 661 X1X2 with a value of R2 = 0.78. The optimization results showed that the yield value was 2.42% and the content of αtocopherol compound of 18.16% was obtained from 9.27% material concentration and extraction time of 5.53 hours. The overlaid point produces maximum yield and α-tocopherol at two points. The first point is the material concentration of 9.3% and the extraction time of 5.7 hours, and the second point is the material concentration of 9.4% and the extraction time of 5.4 hours. The optimum yield and content of α-tocopherol of Lettuce (Ulva lactuca L.) can be determined by using Response Surface Methodology.