The effects due to Candidatus Liberibacter infection, commonly called citrus greening or Huanglongbing (HLB), on volatile and nonvolatile components of orange juices, OJ, were examined using GC-MS and high-performance liquid chromatography (HPLC). HLB symptomatic, asymptomatic, and control "Hamlin" and "Valencia" oranges were harvested from December to May during the 2007 to 2008 harvest season. Brix/acid levels in control and asymptomatic juices were similar but symptomatic juices were as much as 62% lower than control juices. No bitter flavanone neohesperidosides were detected and polymethoxyflavone concentrations were well below bitter taste thresholds. Limonin concentrations were significantly higher (91% to 425%) in symptomatic juice compared to control but still below juice bitterness taste thresholds. Juice terpenes, such as gamma-terpinene and alpha-terpinolene, were as much as 1320% and 62% higher in symptomatic juice than control. Average ethyl butanoate concentrations were 45% lower and average linalool was 356% higher in symptomatic Valencia OJ compared to control. Symptomatic Valencia OJ had on average only 40% the total esters, 48% the total aldehydes, and 33% as much total sesquiterpenes as control juice. Total volatiles between control and symptomatic juices were similar due to elevated levels of alcohols and terpenes in symptomatic juice. There were no consistent differences between asymptomatic and control juices. The chemical composition of juice from HLB/greening symptomatic fruit appears to mimic that of juice from less mature fruit. The reported off-flavor associated with symptomatic juices probably stem from lower concentrations of sugars, higher concentrations of acid as all known citrus bitter compounds were either below taste thresholds or absent.

Pulsed ultraviolet light (PUV), a non-thermal food processing technology, is reported to be able to inactivate enzymes and reduce allergen levels from peanut extracts. The objective of this study was to determine if PUV would reduce the allergen levels and allergenic potency of soy extracts. Soy extracts were treated with PUV at various times (2, 4 and 6 min), centrifuged, and analyzed by SDS-PAGE and an indirect ELISA for IgE binding or allergenic potency. Results showed that PUV treatment led to an increase in sample temperature/weight loss but a decrease in the levels of soy allergens (i.e., glycinin and ?-conglycinin) as shown in SDS-PAGE. Allergens were reduced probably through aggregation which increased with treatment time. IgE binding was reduced as well in the following order: 20%, 44% and 50% reductions in absorbance values at 2, 4, 6 min, respectively (the latter two were not significantly different (p < 0.05%) from each other). It was concluded that PUV was capable of reducing the allergenic potency of soy extracts, and that the optimal PUV treatment time was 4 min. Clinical data is still needed before PUV can find an application in the development of less allergenic soybean beverages and products.

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Alcohols, aldehydes, ketones, amines, and sulfur compounds are essential aroma compounds related to fish flavor and spoilage. Gas chromatography‐mass spectrometry (GC‐MS) is an instrument that is widely used to identify and quantify volatile and semi‐volatile compounds in fish products. In this research, a simple and accurate GC‐MS method was developed to determine the aroma profile of mahi‐mahi and tuna for chemical indicators of spoilage. In the developed GC‐MS method, trichloroacetic acid (TCA) solution was used to extract analytes from homogenized fish samples. The purge and trap system was used for sample introduction, and the GC‐MS with an RTX‐Volatile Amine column was able to separate compounds without a derivatization procedure. The created purge and trap gas chromatography‐mass spectrometry (PT‐GC‐MS) method could identify and quantify twenty aroma compounds in mahi‐mahi (Coryphaena hippurus) and 16 volatile compounds in yellowfin tuna (Thunnus albacares) associated with fish spoilage. The amines (dimethylamine, trimethylamine, isobutylamine, 3‐methylbutylamine, and 2‐methylbutanamine), alcohols (2‐ethylhexanol, 1‐penten‐3‐ol and isoamyl alcohol, ethanol), aldehydes (2‐methylbutanal, 3‐methylbutanal, benzaldehyde), ketones (acetone, 2,3‐butanedione, 2‐butanone, acetoin), and dimethyl disulfide strongly statistically correlated with poorer quality tuna and mahi‐mahi and were considered as the key spoilage indicators. Practical Application A simplified and rapid purge and trap gas chromatography‐mass spectrometry (PT‐GC‐MS) method developed in this research was able to identify and quantify important spoilage compounds in mahi‐mahi and yellowfin tuna. This method is an efficient analytical method for determining volatile profiles of fish samples for industry analytical labs or the government. The identified analytical quality markers can be used to monitor the spoilage level of tuna and mahi‐mahi.