Gas Chromatography–Olfactometry Analyses of Volatiles Produced by ‘Fallglo’ and ‘US Early Pride’ Tangerines

‘Fallglo’ is a popular tangerine (Citrus reticulata Blanco) cultivar with high eating quality. However, ‘Fallglo’ may contain as many as 30–40 seeds per fruit. ‘US Early Pride’ is a seedless mutation of ‘Fallglo’ with similar quality attributes. The objective of the current study was to determine if ‘Fallglo’ and ‘US Early Pride’ fruit differed in the composition or quantity of aroma-active volatiles produced over time. Fruit were harvested bi-weekly from October to December. Juice was carefully extracted from 50 fruit, and volatiles were analyzed using gas chromatography (GC). Two subjects evaluated the GC effluents by olfactometry in triplicate runs for each sample. Volatile identification was done by GC-mass spectrometry and confirmed by sniffing of authentic standards. The same 32 aroma-active compounds were perceived in ‘Fallglo’ and ‘US Early Pride’, of which 25 were identified. Compounds were classified in odor descriptor groups: fatty (10 compounds), plastic or rubber (seven compounds), fruity or citrus (four compounds), floral (four compounds), mushroom (two compounds), green (two compounds) and other (one compound). ‘Fallglo’ and ‘US Early Pride’ had similar aroma intensities for the three first harvests (26 Oct., 3 Nov., 17 Nov.), but ‘Fallglo’ had higher levels of two fruity odorous peaks (E-2-pentenal and the coeluting compounds E-2-hexenal and ethyl 2 methyl butanoate) than did ‘US Early Pride’ at the December harvest. The last harvest showed significantly higher aroma intensity for six peaks in each cultivar, with only two peaks in common in both cultivars

Development of an Araucaria araucana Beer-like Beverage: Process and Product

The seed from the Araucaria araucana (in Spanish, piñon) tree, native to Chile and Argentina, is sold mainly as raw seed. Engineering a process to add value to piñon has the potential to positively impact local indigenous communities with very little ecological impact because it is routinely harvested in the wild. This study evaluated the feasibility of using 100% piñon, or as a blend with barley malt, to produce a beer-like beverage, while also evaluating consumer acceptance of the beverage’s piñon characteristics. Prototypes generated based on 93% piñon and 7% oat (enzymatic treatment of α-amylase, glucoamylase, protease and β-glucanase), as well as 50% piñon and 50% barley (no external enzymatic treatment), were evaluated. Overall acceptability by a consumer acceptance panel (21 consumers) rated the 100% piñon and the piñon–barley malt blend 5/9 and 7/9, respectively. The piñon–barley malt blend prototype stood out for its low level of carbohydrates, high potassium content and banana and clove aromas

An HPLC-MS characterization of the changes in sweet orange leaf metabolite profile following infection by the bacterial pathogen Candidatus Liberibacter asiaticus.

Huanglongbing (HLB) presumably caused by Candidatus Liberibacter asiaticus (CLas) threatens the commercial U.S. citrus crop of an annual value of $3 billion. The earliest shift in metabolite profiles of leaves from greenhouse-grown sweet orange trees infected with Clas, and of healthy leaves, was characterized by HPLC-MS concurrently with PCR testing for the presence of Clas bacteria and observation of disease symptoms. Twenty, 8-month-old 'Valencia' and 'Hamlin' trees were grafted with budwood from PCR-positive HLB source trees. Five graft-inoculated trees of each variety and three control trees were sampled biweekly and analyzed by HPLC-MS and PCR. Thirteen weeks after inoculation, Clas was detected in newly growing flushes in 33% and 55% of the inoculated 'Hamlin' and 'Valencia' trees, respectively. Inoculated trees remained asymptomatic in the first 20 weeks, but developed symptoms 30 weeks after grafting. No significant differences in the leaf metabolite profiles were detected in Clas-infected trees 23 weeks after inoculation. However, 27 weeks after inoculation, differences in metabolite profiles between control leaves and those of Clas-infected trees were evident. Affected compounds were identified with authentic standards or structurally classified by their UV and mass spectra. Included among these compounds are flavonoid glycosides, polymethoxylated flavones, and hydroxycinnamates. Four structurally related hydroxycinnamate compounds increased more than 10-fold in leaves from 'Hamlin' and 'Valencia' sweet orange trees in response to Clas infection. Possible roles of these hydroxycinnamates as plant defense compounds against the Clas infection are discussed

Principal component analysis of HPLC-MS leaf metabolites from ‘Valencia’ and ‘Hamlin’ trees.

<p><b>A</b>) score plot of leaf metabolites from ‘Valencia’ trees 3 weeks after inoculation; <b>B</b>) score plot of leaf metabolites from ‘Hamlin’ trees 3 weeks after inoculation; <b>C</b>) score plot of leaf metabolites from ‘Valencia’ trees 38 weeks after inoculation; <b>D</b>) score plot of leaf metabolites from ‘Hamlin’ trees 38 weeks after inoculation.</p

Progression of huanglongbing (HLB)-related symptoms in ‘<i>Candidatus</i> Liberibacter asiaticus’-inoculated ‘Valencia’ sweet orange seedlings.

<p><b>A</b>) leaves from control plants 19 weeks after inoculation; <b>B</b>) leaves from HLB-grafted plants 19 weeks after inoculation; <b>C</b>) leaves from control plants 29 weeks after inoculation; <b>D</b>) leaves from HLB-grafted plants 29 weeks after inoculation; <b>E</b>) leaves from control plants 35 weeks after inoculation; <b>F</b>) leaves from HLB-grafted trees 35 weeks after inoculation.</p

Typical APCI-HPLC-MS chromatograms of ‘Hamlin’ and ‘Valencia’ leaf extracts and mass-spectra and UV spectra of unknown 5, 6, 7, and 9.

<p>A) selective ion recording chromatograms of “<i>m/z</i>” specie of 177 in the positive ion mode; <b>B</b>) negative electrospray ionization mass spectra ; <b>C</b>) UV spectra of unknown <b>5</b>, <b>6</b>, <b>7</b>, and <b>9</b>. </p

Progression of huanglongbing (HLB)-related symptoms in ‘<i>Candidatus</i> Liberibacter asiaticus’-inoculated ‘Hamlin’ sweet orange seedlings.

<p><b>A</b>) leaves from control plants 19 weeks after inoculation; <b>B</b>) leaves from <i>C</i>Las-grafted plants 19 weeks after inoculation; <b>C</b>) leaves from control plants 29 weeks after inoculation; <b>D</b>) leaves from <i>C</i>Las-grafted plants 29 weeks after inoculation; <b>E</b>) leaves from control plants 35 weeks after inoculation; <b>F</b>) leaves from <i>C</i>Las-grafted trees 35 weeks after inoculation.</p