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Journal : Indonesian Journal of Chemistry

Validation of Mineral (Fe, Zn, and Cu) Analysis Methods in Carbohydrate, Protein and Fat-Rich Samples Using Microwave Digestion Method Faridah, Didah Nur; Solihat, Imas; Yuliana, Nancy Dewi
Indonesian Journal of Chemistry ARTICLE IN PRESS
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (424.675 KB) | DOI: 10.22146/ijc.42297

Abstract

Destruction process using both dry and wet conditions serves as a significant step in mineral quantification. Wet destruction using microwave-assisted digestion refers to the standard method of AOAC (2012); in this work, we modified the destruction procedures provided in microwave digestion manual book, including temperature, reagent volume (HNO3 and H2O2), and length of destruction. The experiment works aimed (1) to validate the procedures in destruction process using microwave digestion; (2) to quantify Fe, Zn and Cu in various food matrices (canned peas, canned fish, full cream powdered milk) using a validated method. The method was evaluated according to linearity, accuracy, precision, absolute and relative LOD, LOQ, and intra-reproducibility. Measurement of Fe, Zn and Cu were considered to have a satisfying accuracy at a range of 80–115%, with a good precision value (% RSD < 2/3 CV Horwitz), while regression curves R2 > 0.995. The results showed that data collected from the modified method was not significantly different compared to those from the AOAC method. The currently developed method also fulfilled the acceptability requirements for laboratory analysis.
FTIR and HPLC-Based Metabolomics of Yacon Leaves Extracts (Smallanthus sonchifolius [Poepp & Endl.] H. Robinson) from Two Locations in Indonesia Aziz, Zulhelmi; Yuliana, Nancy Dewi; Simanjuntak, Partomuan; Rafi, Mohamad; Abdillah, Syamsudin
Indonesian Journal of Chemistry ARTICLE IN PRESS
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (17.372 KB) | DOI: 10.22146/ijc.43453

Abstract

Smallanthus sonchifolius [Poepp. & Endl.] H. Robinson (Asteraceae) also known as Yacon or insulin plant, is traditionally used for treating diabetes. Varying geographical origins and postharvest handling, however, seem to affect quantitative and qualitative metabolites in the leaves of Smallanthus sonchifolius [Poepp. & Endl.] H. Robinson (Yacon). The study was conducted to compare and differentiate metabolites profile/fingerprint of Yacon leaves which were grown and obtained from different locations in Pulau Jawa i.e. Lembang (Jawa Barat) and Wonosobo (Jawa Tengah). Three different solvents (95% ethanol, 50% ethanol and water) were used to synthesize Yacon leaves extracts, in order to determine the suitable solvent to produce discernable differentiation through FTIR and HPLC-based metabolomics. Principal Component Analysis (PCA) of FTIR data (4000–400 cm1 wavenumber) indicated that Yacon leaves extracted with ethanol at 95%, had a distinctive FTIR fingerprint profile when compared to others. However, the FTIR-based PCA could not differentiate the extracts based on their geographical origins, although PCA analysis of HPLC-data successfully differentiated the extracts based on their geographical origins. Furthermore, the prominent peak for the leaves extract from Lembang and Wonosobo as regards retention time, was observed at 21.59–25.10 min and 20.69–21.695 min respectively. Notably, R2Y and Q2 value obtained by cross-validation and permutation tests showed all multivariate models were statistically reliable. Overall, there is the need to conduct further research using a more sophisticated tool such as LC-MS, to identify which metabolites represented by the aforementioned FTIR and HPLC data.