UV spectral fingerprinting and analysis of variance-principal component analysis: a useful tool for characterizing sources of variance in plant materials.
UV spectral fingerprints, in combination with analysis of variance-principal components analysis (ANOVA-PCA), can differentiate between cultivars and growing conditions (or treatments) and can be used to identify sources of variance. Broccoli samples, composed of two cultivars, were grown under seven different conditions or treatments (four levels of Se-enriched irrigation waters, organic farming, and conventional farming with 100 and 80% irrigation based on crop evaporation and transpiration rate). Freeze-dried powdered samples were extracted with methanol-water (60:40, v/v) and analyzed with no prior separation. Spectral fingerprints were acquired for the UV region (220-380 nm) using a 50-fold dilution of the extract. ANOVA-PCA was used to construct subset matrices that permitted easy verification of the hypothesis that cultivar and treatment contributed to a difference in the chemical expression of the broccoli. The sums of the squares of the same matrices were used to show that cultivar, treatment, and analytical repeatability contributed 30.5, 68.3, and 1.2% of the variance, respectively.
Food Composition and Methods Development Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, USA. d.luthria@ars.usda.gov
Devanand L
DL
Luthria
Sudarsan
S
Mukhopadhyay
Rebecca J
RJ
Robbins
John W
JW
Finley
Gary S
GS
Banuelos
James M
JM
Harnly
D000383:Agriculture / Q000379:methods*; D001937:Brassica / Q000737:chemistry* / Q000145:classification* / Q000254:growth & development; D058870:Food, Organic; D005612:Freeze Drying; D010936:Plant Extracts / Q000737:chemistry; D015203:Reproducibility of Results; D012643:Selenium / Q000008:administration & dosage; D013056:Spectrophotometry, Ultraviolet; D014867:Water
D010936:Plant Extracts; D014867:Water; D012643:Selenium