UV-Vis Spectrophotometry and UPLC-PDA as an Analytical Tool for Standardization of Kappaphycus alvarezii with Chemometrics Approach

SELMA MUTIARAHMA, Dr. Widiastuti Setyaningsih, STP., M.Sc.;Prof. Dr. Ir. Sri Anggrahini, MS.

2021 | Tesis | MAGISTER ILMU DAN TEKNOLOGI PANGAN

Kappaphycus alvarezii dianggap sebagai bahan baku penting untuk berbagai praktik industri yang menghasilkan berbagai produk turunan yang bernilai ekonomi tinggi. Namun, kualitas komoditas ini dapat bervariasi karena beberapa faktor, termasuk area budidaya. Metode Spektrofotometri UV-Vis analitik digabungkan dengan kemometrik diusulkan untuk menstandarisasi alga merah berdasarkan tingkat senyawa fenolik. Korelasi antara spektrum UV-Vis dan hasil UPLC-PDA, dikombinasikan dengan kalibrasi multivariat K. alvarezii ekstrak, dianalisis. Ekstrak disiapkan menggunakan teknik berbasis ultrasound dan selanjutnya dilakukan pengukuran spektral UV-Vis pada 200-800 nm dan UPLC-PDA pada 260 dan 330 nm. Teknik kemometrik, partial least square (PLS), diterapkan pada data yang diperoleh untuk membangun analisis fenolik yang andal dalam K. alvarezii ekstrak. Hasil penelitian menunjukkan bahwa kombinasi panjang gelombang 690-600 dan 450-380 nm serta rentang panjang gelombang 380-200 nm memberikan metode yang valid untuk analisis kuantitatif fenolat yang dipelajari yang termasuk asam hidroksibenzoat, asam hidroksisinamat, dan flavonoid dengan koefisien determinasi (R2) > 0,96 pada model kalibrasi dan validasi, serta nilai RMSEC dan RMSEP < 8%. Metode ini kemudian digunakan untuk menganalisis K. alvarezii sampeldari 13 area budidaya yang berbeda. Prinsip analisis komponen (PCA) distandarisasi K. alvarezii menjadi beberapa kelompok asal geografis berdasarkan komposisi dan kadar senyawa fenolik

Kappaphycus alvarezii is considered an important raw material for industrial practices producing high economic value of various derived products. However, the quality of this commodity may vary due to a number of factors, including the areas of cultivation. An analytical UV-Vis Spectrophotometry method coupled with chemometrics was proposed to standardize the red alga based on the level of phenolic compounds. The correlation between UV-Vis spectra and UPLC-PDA results, combined with multivariate calibration of K. alvarezii extracts, was analyzed. The extracts were prepared using an ultrasound-based technique and subsequently subjected to UV-Vis spectral measurements at 200-800 nm and UPLC-PDA at 260 and 330 nm. Chemometric techniques, partial least square (PLS), were applied to the acquired data to build a reliable analysis of phenolics in K. alvarezii extracts. The result showed that the wavelength combination of 690-600 and 450-380 nm also the wavelength range of 380-200 nm provided a valid method for quantitative analysis of the studied phenolics that belong to hydroxybenzoic acid, hydroxycinnamic acid, and flavonoid with a coefficient of determination (R2) > 0.96 in calibration and validation models, along with RMSEC and RMSEP value < 8%. The method was then employed to analyze the K. alvarezii samples from 13 different cultivation areas. Principle component analysis (PCA) standardized K. alvarezii into some groups of geographic origin based on the composition and the level of phenolic compounds.

Kata Kunci : Eucheuma cottonii, Method Development, Chemometrics, PLS, PCA