Farnesene and its conjugated triene oxidation products in apple peel are positively correlated with, and thought to be involved in, the storage disorder superficial scald. Levels of these compounds are often estimated by dipping fruit in hexane and measuring the absorbance of the crude extracts at 232 nm (farnesene) and 269 or 281 minus 290 nm (trienes). We have devised a C18 HPLC method with UV detection at 232 and 269 nm that allows the simultaneous quantitation of 80 ng of farnesene and trienes. Using this method we have confirmed the recent report that one conjugated trien-6-ol comprises 90% of the stable oxidation products of farnesene. It was also found that crude hexane extracts of apple peel can give spuriously high values for farnesene and/or trienes when levels of these compounds are low and other UV-absorbing components are present. A group of compounds unrelated to farnesene, with an absorbance maximum at ≈259 nm, were noted in the peel of cv. Gala apples, which produced little farnesene or trienol. This may explain the report that fruit with a high ratio of A258nm/A281nm in peel extracts have a low incidence of scald. The new HPLC method will be applied in subsequent studies of postharvest factors involved in regulation of farnesene synthesis and oxidation.
Bruce D. Whitaker and Theophanes Solomos
Muttalip Gündoğdu, Tuncay Kan, and Mustafa Kenan Gecer
describe the differences in terms of vitamin (A, E, C, carotene, and lycopene), phenolics, and flavonoid contents by HPLC. This study demonstrates once again that apricots are highly healthy food products resulting from their chemical contents. More
Teri Hale*, Richard Hassell, and Tyron Phillips
Taste panel perception and preference of sweetness in three phenotypes (su, se and sh2) of sweet corn harvested at three maturities (early, mature and late) were compared to refractometer measurements and HPLC analysis of fructose, sucrose, and glucose. Panelist rating of sweetness and acceptability significantly correlated with HPLC analysis. These correlations were found for sucrose and total sugars present (for sweetness, r 2 = 0.70 and 0.61; acceptability, r 2 = 0.64 and 0.55). Sucrose significantly correlated with the total sugars present (r 2 = 0.95). The panelists' perception of flavor also correlated significantly with the amount of sucrose present and total sugars (r 2 = 0.66 and 0.59, respectively). Sucrose content was significantly different between se, sh2 and su, with sh2 having the highest level. Taste panels indicated this difference but showed not significant differnece between se and sh2 acceptablity. Su was only acceptable to panelists at early maturity. °Brix did not reflect the taste panels scores and HPLC measurements postively. Soluble solids and taste panel scores were negatively correlated in both the panel's perception of sweetness and acceptability (r 2 = -0.66 and -0.66, respectively) which indicates that as panel scores decreased °Brix increased. Comparison of soluble solids to HPLC analysis, indicate that °Brix was negatively correlated to sucrose and total sugar content, and that as soluble solids increased, the sucrose or total sugar concentration remained constant or decreased. Soluble solids measurements have been positively correlated with sucrose levels in other crops; but this was not the case with sweet corn.
V.M. Russo, J. Williamson, K. Roberts, J.R. Wright, and N. Maness
We thank Julie Collins and Sheila Magby for assistance in the preparation of samples for HPLC analysis. Mention of a trademark, vendor, or proprietary product does not constitute a guarantee or warranty of the product by the USDA and does
Carl M. Jones and James R. Myers
Continued and mounting evidence of the health benefits provided by carotenoid and anthocyanin pigments has increased public interest in dietary sources of these important phytonutrients. Tomatoes (Lycopersicon esculentum) are the primary dietary contributor of lycopene and an important source of beta-carotene. A collection of tomatoes containing the genes hp-1, dg, ogc, Ip, B and Af that are known to affect carotenoid and anthocyanin levels have been analyzed using HPLC. Levels of lycopene, beta-carotene, phytoene, and phytofluene have been determined in these accessions. Accession LA 3005, containing the dg gene, had the highest lycopene levels of the accessions analyzed (14 mg/100 g fresh wt.). A rapid HPLC method for quantitation of carotenoid levels from tomato fruit has been developed. “Heirloom” black and purple tomatoes have also been included in the accessions analyzed and have carotenoid levels comparable to cultivated red tomatoes. Anthocyanin presence has been confirmed only in the accessions LA 1996 (Af) and in some fruit of segregating plants from LA 3668 (Abg). Total monomeric anthocyanin content of LA 1996 as measured by the pH differential method is estimated to be 5.6 mg/100 g in the outer pericarp tissues and 18.6 mg/100 g in the skin tissue.
Rachel A. Itle and Eileen A. Kabelka
estimate carotenoid content and concentration would be beneficial. High-performance liquid chromatography (HPLC) is used to chemically analyze tissues for carotenoid types and concentrations ( Gross, 1991 ). It is labor-intensive and expensive but a
Zi Wei, Peter Jeranyama, Fan Zhang, Carolyn DeMoranville, and Harvey J.M. Hou
syndrome in cranberry leaves, the shade effect on the Chl content and photosynthetic activity in cranberry were investigated by spectrometric, high-performance liquid chromatography (HPLC), and in vivo Chl fluorescence kinetics. Materials and Methods
Peter Boches, Brooke Peterschmidt, and James R. Myers
evaluated for phenolics content using HPLC. ‘Legend’, ‘Gold Nugget’, and LA1996 were used as standards in the second greenhouse evaluation. ‘Legend’ and ‘Siletz’ have very similar size and phenolic profiles and ‘Legend’ served as a substitute standard for
Yiran Li, Asuka Uchida, Akiha Abe, Akihiro Yamamoto, Tomonari Hirano, and Hisato Kunitake
1.5-mL tubes for HPLC analysis as described above. The experiments were repeated three times for statistical analysis via Tukey’s multiple range test. Results PA content changes during germination. We first analyzed the PA content changes during the
Bärbel Röck-Okuyucu, Meltem Bayraktar, Ismail Hakki Akgun, and Aynur Gurel
period of 5 weeks. Completely acclimatized plants were transferred to field conditions at the end of 8 weeks. SGs analysis Chemicals. HPLC grade acetonitrile and methanol were purchased from Merck (Darmstadt, Germany). The ultrapure water, used for the