Search

Introduction: Citrus hybrids with Poncirus trifoliata L. Raf. introgression have gained interest due to their tolerance to Huanglongbing (HLB), a devastating disease for Florida citrus agriculture. While these hybrids inherit disease tolerance from P. trifoliata, they sometimes also suffer from undesirable off-flavors. Methods: A selection of thirteen genotypes were harvested over the 2020-2021 and 2021-2022 seasons. Their juices were evaluated by a trained sensory panel and were comprehensively analyzed for their chemical makeup, including soluble solids content (SSC), titratable acidity (TA), volatiles, flavonoids and limonoids. Results & discussion: Overall, along with the commercial orange cultivars 'Valencia' and 'Hamlin', the HLB-tolerant Poncirus hybrid 'US SunDragon,' and the mandarin hybrids Sugar Belle¬, FF-5-51-2, and 'US Superna' had positive citrus flavor quality. Esters, some sesquiterpenes, along with flavonoids, eriocitrin and quercetin-3-(3R-glucosylrutinoside), were positively correlated with orange flavor while b-ionone and eucalyptol were highly abundant in the mandarins. The flavonoid linarin, was more abundant in Poncirus hybrids with off-flavors than in the Poncirus hybrid 'US SunDragon', having high orange flavor. Two mandarin hybrids, FF-5-6-36 and FTP-6-32-67, were not bitter at harvest, but the juice exhibited delayed bitterness after storage at -20°C, which was associated with significant increases of limonin, nomilin, naringenin, and prunin. Interestingly, during freezer storage, a newly identified flavonoid in citrus, tricin-C-hexoside, increased dramatically across all of the genotypes. The identification of diseasetolerant hybrids with satisfactory flavor quality at juicing as well as after storage where delayed bitterness may develop, has great significance for future breeding efforts for fresh fruit or for use in stand-alone juice/juice blends. [ABSTRACT FROM AUTHOR]

There are many reports in the literature, both historical and recent, that indicate that fruit from trees affected by Huanglongbing (HLB) can have off-flavors and result in off-flavored juice.  Several recent studies from Florida where fairly comprehensive sensory and chemical testing has been done, have shown that there are differences in flavor and specific chemical components in juice from healthy and HLB infected trees in some varieties and during some times of the year. However, there are also recent reports from Florida, mainly from production associated research trials and demonstration plots, where juice quality from HLB infected trees is reported to be good and similar to that of juice from healthy trees.  In virtually all of these production-related research trials, the variables measured for juice quality were Brix, acid and ratio and no other organoleptic components were considered.  Although these are standard measures of juice quality, they do not encompass the wide range parameters that are considered by processors and the beverage industry in the evaluation of raw input and final products.  In many cases, sensory evaluation by trained panelists is a routine procedure in the evaluation of input streams and the final product.  Thus sensory components should not be ignored when considering HLB management options, especially as the Florida industry moves towards 100% infection with HLB.  This paper will present some of the progress that has been made to develop methodology to discriminate juice produced from fruit from healthy and infected trees using methods that directly and indirectly measure compounds and characteristics that impact flavor.

Citrus groves receiving nutritional sprays were compared with groves in the same areas managed with conventional fertilization treatments.  Fruit were harvested from healthy and Huanglongbing (HLB)-affected trees. Within HLB-affected trees, fruit were sorted into asymptomatic (HLB-a) and symptomatic (HLB-s) fruit.  Sensory tests were performed using the difference-from-control (DFC) method, where juice from HLB-affected trees was compared with juice from healthy trees.  Results show that panelists could detect differences between juice from HLB-affected and healthy trees in the 2009-2010 and 2010-2011 seasons, regardless of nutritional treatments, for Hamlin and Valencia. Like in previous years, those differences were perceived as more bitter or metallic for early harvests of HLB-affected Hamlin, but those differences were less and inconsistently perceived as more bitter, sweeter or more sour for late harvests or Valencia HLB-affected fruit. In the 2011-2012 season, there were much less differences between juice from healthy and HLB trees, possibly due to a season with high Brix/TA ratio, or due to later harvests.  Results will be discussed in relation to chemical analysis of sugars, acids, and limonoids.  Nutritional treatments that mitigate HLB symptoms on trees did not have a consistent effect on the HLB induced off-flavor of the fruit and juice, necessitating more seasons of study.

Beverage mixtures based on pineapple (Ananas comosus) and turmeric (Curcuma longa) juice as a ready-to-drink product were developed, and their physicochemical, nutritional, and sensory properties were evaluated. Four different concentrations of turmeric juice (5%, 10%, 15%, and 20% (v/v)) were added to pineapple juice to make turmeric-fortified pineapple (TFP) juice samples. Pineapple juice without turmeric was the control. The L*, a*, b*, titratable acidity (TA), total antioxidant capacity, and %DPPH scavenging values, as well as the concentrations of the phenolic compounds curcumin and demethoxycurcumin, were significantly increased with increasing turmeric concentration. Thirty volatile compounds were detected in the mixed juice samples with turmeric. Most of the turmeric-specific compounds, including monoterpenes, sesquiterpenes and turmerones, were detected in the TFP juice samples. While the antioxidant activity of the juice samples increased with increasing turmeric concentration, the pineapple juice fortified with 10% turmeric (10%T) had the best overall quality as determined by panelists. Greater concentrations of turmeric were associated with decreased palatability due to reduced mouthfeel and sweetness and increased aftertaste and sourness. These results suggest that the 10%T juice could be developed into a commercial functional beverage with increased overall flavor and nutritional quality. [ABSTRACT FROM AUTHOR]