Journal article
Determination of total phenolic content and antioxidant capacity of onion (Allium cepa) and shallot (Allium oschaninii) using infrared spectroscopy
Food chemistry, Vol.129(2), pp.637-644
11/15/2011
Handle:
https://hdl.handle.net/2376/104523
PMID: 30634280
Abstract
► We propose a novel rapid method using infrared spectroscopy to quantify total antioxidant capacity in plants in the substitution of traditional wet chemistry methodology. ► Several spectroscopic-based chemometric models were established and validated. Those models could be used in future for prediction of onion antioxidant profile. ► DPPH, TEAC and FRAP values of different types of onions and shallots were measured and those data are partially supplemented to previous relevant studies.
Total phenolic content (TPC) and total antioxidant capacity (TAC) of four onion varieties (red, white, yellow and sweet) and shallot from selected locations (Washington, Idaho, Oregon, Texas and Georgia) were determined using Fourier transform infrared (FT-IR) spectroscopy (4000–400cm−1). The Folin–Ciocalteu (F–C) assay was used to quantify TPC and three assays were used to determine TAC, including 2,2-diphenyl-picrylhydrazyl (DPPH) assay, Trolox equivalent antioxidant capacity (TEAC) assay and ferric reducing antioxidant power (FRAP) assay. Partial least squares regression (PLSR) with cross-validation (leave-one-out) was conducted on onion and shallot extracts (n=200) and their corresponding F–C, DPPH, TEAC and FRAP values were employed to obtain four independent calibration models for predicting TPC and TAC for the extracts. Spectra from an extra 19 independent extracts were used as an external validation set for prediction. A correlation of r>0.95 was obtained between FT-IR predicted and reference values (by F–C, DPPH, TEAC and FRAP assay) with standard errors of calibration (SEC) and standard errors of cross-validation (SECV) less than 2.85, 0.35 and 0.45μmolTrolox/g FW of extracts for TEAC, FRAP and DPPH assay, respectively; and 0.36mggallic acid/g FW of extracts for the F–C assay. In addition, cluster analysis (principal component analysis (PCA)) and discriminant function analysis (DFA) could differentiate varieties of onions and shallot based upon infrared spectral features. Loading plots for the various chemometrics models indicated that hydroxyl and phenolic functional groups were most closely correlated with antioxidant capacity. The use of mid-infrared spectroscopy to predict the total antioxidant capacity of vegetables provides a rapid and precise alternative to traditional wet chemistry analysis.
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Details
- Title
- Determination of total phenolic content and antioxidant capacity of onion (Allium cepa) and shallot (Allium oschaninii) using infrared spectroscopy
- Creators
- Xiaonan Lu - School of Food Science, Washington State University, P.O. Box 646376, Pullman, WA 99163, USAJun Wang - College of Food Science and Engineering, Northwest A&F University, Yangling 712100, PR ChinaHamzah M Al-Qadiri - Department of Nutrition and Food Technology, The University of Jordan, Amman 11942, JordanCarolyn F Ross - School of Food Science, Washington State University, P.O. Box 646376, Pullman, WA 99163, USAJoseph R Powers - School of Food Science, Washington State University, P.O. Box 646376, Pullman, WA 99163, USAJuming Tang - Department of Biological System Engineering, Washington State University, Pullman, WA 99163, USABarbara A Rasco - School of Food Science, Washington State University, P.O. Box 646376, Pullman, WA 99163, USA
- Publication Details
- Food chemistry, Vol.129(2), pp.637-644
- Academic Unit
- Biological Systems Engineering, Department of; Food Science, School of
- Publisher
- Elsevier Ltd
- Identifiers
- 99900546842301842
- Language
- English
- Resource Type
- Journal article