Simultaneous Determination of the Saponification Value, Acid Value, Ester Value, and Iodine Value in Commercially Available Red Fruit Oil (Pandanus conoideus, Lam.) Using 1H qNMR Spectroscopy

Abstract

Red fruit oil (RFO) can be extracted from fruits of Pandanus conoideus, Lam., an endogenous plant of Papua, Indonesia. It is a commonly used essential original traditional medicine. By applying a newly developed quantitative 1H NMR (qNMR) spectroscopy method for quality assessment, a simultaneous determination of the saponification value (SV), acid value (AV), ester value (EV), and iodine value (IV) in RFO was possible. Dimethyl sulfone (DMSO2) was used as an internal standard. Optimization of NMR parameters, such as NMR pulse sequence, relaxation delay time, and receiver gain, finally established the 1H NMR-based quantification approach. Diagnostic signals of the internal standard at δ = 2.98 ppm, SV at δ = 2.37–2.20 ppm, AV at δ = 2.27–2.20 ppm, EV at δ = 2.37–2.27 ppm, and IV at δ = 5.37–5.27 ppm, respectively, were used for quantitative analysis. The method was validated concerning linearity (R2 = 0.999), precision (less than 0.83%), and repeatability in the range 99.17–101.17%. Furthermore, this method was successfully applied to crude RFO, crude RFO with palmitic and oleic acid addition, and nine commercial products. The qNMR results for the respective fat values are in accordance with the results of standard methods, as can be seen from the F- and t-test (< 1.65 and < 1.66, respectively). The fundamental advantages of qNMR, such as its rapidity and simplicity, make it a feasible and existing alternative to titration for the quality control of RFO.

Chemometric analysis applied to 1H NMR and FTIR data for a quality parameter distinction of red fruit (Pandanus conoideus, lam.) oil products

“…In contrast, an RFO product with a higher degree of unsaturation will approach the BSO position because it has more unsaturated fatty acids than OVO. Furthermore, a visualisation grouping PCA model can be obtained based on the value of the degree of unsaturation for the entire RFO product, 27 as previously reported by Triyasmono et al 18 Figure 7 shows that both spectral data sets can be delineated classes into six categories (IV: < 10; 40–60; 60–70; 70–80; 80–90; and > 90).…”

“…Meanwhile, the presence of BSO, OVO, and VCO independently and OR modifiers can be used to compare the distribution pattern classification due to changes in the variable matrix (see Section 2). Figure 8 depicts the PCA visualisation grouping of all total samples into seven categories according to acid values based on Triyasmono et al 18 reported (AV: < 10; 20–40; 40–60; 60–70; 70–80, 80–90, and > 90) for the spectrum of both methods.…”

“…In contrast, an RFO product with a higher degree of unsaturation will approach the BSO position because it has more unsaturated fatty acids than OVO. Furthermore, a visualisation grouping PCA model can be obtained based on the value of the degree of unsaturation for the entire RFO product, 27 as previously reported by Triyasmono et al 18 In comparison, three products (SBM, PR, and FR) and ORSO are close to BSO, so it is suspected that BSO was added to the product component, causing an increased degree of unsaturation. Therefore, it is grouped as higher than OR (80-90).…”

“…The receiver gain was set to 4, and a line broadening factor of 0.3 Hz was applied for processing 18 . Previously, measurements of the full spin–lattice relaxation (T1) of the protons in the sample were carried out according to Holzgrabe 19 and Triyasmono et al 18 The total acquisition time was 15 min.…”

“…The experiments were carried out at 300 K; spectral width: 30.0 ppm (time domain size: 160 k), relaxation delay: 9 s, number of scans: 32, acquisition time: 6.81 s, pulse width: 30°, pulse sequence: zg30, no rotation. The receiver gain was set to 4, and a line broadening factor of 0.3 Hz was applied for processing 18 . Previously, measurements of the full spin–lattice relaxation (T1) of the protons in the sample were carried out according to Holzgrabe 19 and Triyasmono et al 18 The total acquisition time was 15 min.…”