A Combined Approach of Infrared Spectroscopy and Multivariate Analysis for the Simultaneous Determination of Sugars and Fructans in Strawberry Juices During Storage

Abstract

FTIR spectroscopy provided a method potentially transferable to the food industry when associated with the multivariate analysis. The robust 21 PLS models defined in this work provided reliable tools for the rapid monitoring of juices' authenticity and/or deterioration. In this regard, FTIR associated to multivariate analysis enabled the determination of different sugars in a single measurement without the need of pure sugars as standards. This experimental simplicity supports the use of FTIR at the production line, and also contributes to save time in determining carbohydrates' composition and stability, in an environmentally friendly way.

Quantification of free sugars, fructan, pungency and sweetness indices in onion populations by FT‐MIR spectroscopy

“…22 Pairwise linear correlation coefficients (r) between SS, pyruvate, fructan and each of the free sugars were all weak, varying by ±0. 45. The exception was SS and fructan (r = 0.87) where the association was better described by a second-order quadratic (Fructan = 11.3-6 × Brix + 0.7 × Brix 2 ; data not shown), similar to that reported previously.…”

“…For breeding purposes, it has been sufficient to simply characterise carbohydrates as individual free sugars and total fructan. However, recent studies indicate that MIR spectroscopy can be further utilised to fractionate the lowest members of the short‐chain polymers (DP3–DP5) of the fructooligosacharrides . In two of these studies, samples of lyophilised fluids were presented for FTIR analysis in the form of KBr pellets.…”

“…However, recent studies indicate that MIR spectroscopy can be further utilised to fractionate the lowest members of the short‐chain polymers (DP3–DP5) of the fructooligosacharrides . In two of these studies, samples of lyophilised fluids were presented for FTIR analysis in the form of KBr pellets. It remains to be determined whether similarly useful models can be developed for materials such as onion without the need for freeze‐drying.…”

Long-Term Strategy for Assessing Carbonaceous Particulate Matter Concentrations from Multiple Fourier Transform Infrared (FT-IR) Instruments: Influence of Spectral Dissimilarities on Multivariate Calibration Performance

“…To ensure that the number of samples, the distribution of sites, and the sample composition remain the same as in Table 1, only samples whose array index features odd numbers on FTIR1 and even numbers on FTIR2 were included in the calibration. Performance associated with the third scenario, reported in Table II, was evaluated from the same set of test spectra used previously on scenarios (1) and (2). As in Table 1, the significance testing of the RMSEP values do not exceed the critical value F (n ¼ 262, n ¼ 262, 0.95) ¼ 1.275, indicating that the hybrid model predicts OC and EC concentrations equally well on both spectrometers.…”

“…Comparison of OC and EC model performance between FTIR1 and FTIR2 for scenarios(1) and(2), figures of merit are computed from test set FT-IR spectra (n ¼ 263).…”