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R.C. Ebel, W.A. Dozier, B. Hockema, F.M. Woods, R. Thomas, B.S. Wilkins, M. Nesbitt, and R. McDaniel

This study was conducted to determine fruit quality of Satsuma mandarin Citrus unshiu, Marc. `Owari' grown on the northern coast of the Gulf of Mexico. Soluble solids increased linearly and titratable acidity decreased quadratically during October and November for the four sampling years. There was no significant interaction between sampling date and year. There was a significant year effect for titratable acidity, but not soluble solids or their ratio. A 10:1 soluble solids to titratable acidity ratio was observed on 10 Nov. Variation in fruit weight corresponded with cropload. Fruit weight increased during the sampling period due to an increase in fruit length since there was no change in width. Peel color was yellow-orange by 10 Nov., with many fruit still exhibiting patches of green color. Because of some green color present in the peel, the fruit would have to be degreened for successful marketing in U.S. retail chain stores.

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Catherine Belisle, Uyen T.X. Phan, Koushik Adhikari, and Dario J. Chavez

in 2016. Table 2. Mean values for soluble solids concentration (SSC), total titratable acidity (TTA), and SSC/TTA ratio of 30 commercial peach cultivars included in this study over two seasons grown in Georgia. For TTA, values ranged from 0.26% for

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T.M.M. Malundo, R.L. Shewfelt, G.O. Ware, and E.A. Baldwin

Information on important flavor components for fruit and vegetables is lacking and would be useful for breeders and molecular biologists. Effects of sugar and acid levels on mango (Mangifera indica L.) flavor perception were analyzed. Twelve treatments, identified using a constrained simplex lattice mixture design, were formulated by adding sugar (60%), citric acid (40%), and water to an equal volume of mango homogenate. Using 150-mm nonstructured line scales, a trained panel evaluated the treatments according to 11 flavor descriptors. Titratable acidity (TA), pH, and total soluble solids (TSS) were also determined. Acid concentration affected ratings for sweet, sour, peachy, pine/terpentine, astringent, and biting. Except for sour taste, all descriptors were affected by sugar content while increasing water increased intensities of all flavor notes. TA, pH, and TSS/TA correlated (P < 0.01) with and were useful predictors (r > 0.80) of sour taste and chemical feeling descriptors astringent and biting. TSS, however, was not a particularly good indicator of sweetness (r = 0.72) or any other descriptor except possibly peachy (r = 0.79). It is evident from this study that sugars and acids enhance human perception of specific flavor notes in mango, including aromatics.

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Victorine Alleyne and John R. Clark

An investigation was conducted over 2 years to evaluate the effect of N rate and time of application on fruit composition of `Arapaho' thornless erect blackberry (Rubus L., subgenus Eubatus). N from ammonium nitrate was applied at 56 or 112 kg·ha-1 in single applications, or at 112 kg·ha-1 as a split application with 0 kg·ha-1 as the control. Increasing N rates increased fruit N and pH but did not affect soluble solids concentration, titratable acidity, sugar-acid ratio, and total solids. Timing of N application had no effect on the fruit characteristics measured.

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Craig Kallsen

Previous research has shown that nitrogen fertilization rates may influence fruit quality characteristics of navel oranges [(Citrus sinensis) (L.) Osbeck]. The objective of this study was to determine, for equal seasonal N applications, if the timing of the last seasonal nitrogen fertigation promotes early fruit maturity or affects fruit size. The study consisted of four treatments with the total seasonal allocation of nitrogen fertilizer applied by ≈1 May, 1 June, 1 July, and 1 Aug. in an experimental site in a commercial orange grove in the southern San Joaquin Valley of California. The source of nitrogen was a liquid calcium ammonium nitrate injected through the irrigation system. No significant treatment differences in soluble solids concentration, titratable acidity, the ratio of soluble solids concentration to titratable acidity, percent juice, fruit color and fruit diameter were detected in fruit sampled in October. Similarly, in September, no significant differences in leaf nitrogen were found among treatments. These results do not support the hypothesis that applying the total seasonal application of nitrogen early in the season results in earlier orange maturity or larger fruit size, at least not for trees that have leaf N in the optimum range.

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E.A. Baldwin, J.W. Scott, M.A. Einstein, T.M.M. Malundo, B.T. Carr, R.L. Shewfelt, and K.S. Tandon

The major components of flavor in tomato (Lycopersicon esculentum Mill.) and other fruit are thought to be sugars, acids, and flavor volatiles. Tomato overall acceptability, tomato-like flavor, sweetness, and sourness for six to nine tomato cultivars were analyzed by experienced panels using a nine-point scale and by trained descriptive analysis panels using a 15-cm line scale for sweetness, sourness, three to five aroma and three to seven taste descriptors in three seasons. Relationships between sensory data and instrumental analyses, including flavor volatiles, soluble solids (SS), individual sugars converted to sucrose equivalents (SE), titratable acidity (TA), pH, SS/TA, and SE/TA, were established using correlation and multiple linear regression. For instrumental data, SS/TA, SE/TA, TA, and cis-3-hexenol correlated with overall acceptability (P = 0.05); SE, SE/TA (P≤0.03), geranylacetone, 2+3-methylbutanol and 6-methyl-5-hepten-2-one (P = 0.11) with tomato-like flavor; SE, pH, cis-3-hexenal, trans-2-hexenal, hexanal, cis-3-hexenol, geranylacetone, 2+3-methylbutanol, trans-2 heptenal, 6-methyl-5-hepten-2-one, and 1-nitro-2-phenylethane (P≤0.11) with sweetness; and SS, pH, acetaldehyde, aceton, 2-isobutylthiazole, geranlyacetone, β-ionone, ethanol, hexanal and cis-3-hexenal with sourness (P≤0.15) for experienced or trained panel data. Measurements for SS/TA correlated with overall taste (P=0.09) and SS with astringency, bitter aftertaste, and saltiness (P≤0.07) for trained panel data. In addition to the above mentioned flavor volatiles, methanol and 1-penten-3-one significantly affected sensory responses (P = 0.13) for certain aroma descriptors. Levels of aroma compounds affected perception of sweetness and sourness and measurements of SS showed a closer relationship to sourness, astringency, and bitterness than to sweetness.

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Eric T. Stafne, Amir Rezazadeh, Melinda Miller-Butler, and Barbara J. Smith

, titratable acidity (TA), pH, and firmness were measured. Soluble solids concentration of blackberry juice obtained by crushing a sample of harvested whole berries with hand was determined with a digital hand-held refractometer (Atago, Osaka, Japan) for both

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Graham H. Barry, William S. Castle, Frederick S. Davies, and Ramon C. Littell

Sources of variation in juice quality of `Valencia'sweet orange [Citrus sinensis(L.) Osb.] were quantified and their relative contributions to variability in juice quality were determined, from which sample sizes were estimated. Commercial orchards of `Valencia' sweet orange trees on Carrizo citrange [C. sinensis × Poncirus trifoliata (L.) Raf.] rootstock were selected at four geographic locations representing the major citrus-producing regions in Florida. Within- and between-tree variation in soluble solids concentration (SSC) and titratable acidity (TA) were estimated in two experiments over two or three seasons, respectively. Variance components for all treatment effects were estimated to partition total variation into all possible component sources of variation. Seasonal variation in SSC and TA was relatively small, but larger for TA than SSC. Variation in SSC among blocks within a location was intermediate to low, and was less than variation among locations. In contrast, tree-to-tree variation in SSC and TA was large, in spite of sampling from trees of similar vigor and crop load, and variation in SSC and TA among fruit was relatively large. Based on results of this study, samples consisting of 35 fruit are required to detect differences (P ≤ 0.05) of 0.3% SSC and 0.06% TA, whereas 20-fruit samples can be used to detect differences of 0.4% SSC and 0.08% TA. Seven replications are required to detect differences of 0.5% SSC and 0.1% TA, with small gains in precision when tree numbers exceed 10.

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Jinhe Bai, Elizabeth A. Baldwin, Kevin L. Goodner, James P. Mattheis, and Jeffrey K. Brecht

Apples [Malus sylvestris (L.) Mill var. domestica (Borkh.) Mansf. (`Gala', `Delicious', `Granny Smith' and `Fuji')], pretreated or nontreated with 1-methylcyclopropene (1-MCP, 0.6 to 1.0 μL·L–1 for 18 hours at 20 °C), were stored in controlled atmosphere (CA, 1 to 1.5 kPa O2; 1 to 2 kPa CO2) or in regular atmosphere (RA) for up to 8 months at 1 °C. Firmness, titratable acidity (TA), soluble solids content (SSC), and volatile abundance were analyzed every month directly or after transfer to air at 20 °C for 1 week to determine effect of 1-MCP, storage atmosphere and storage time on apple quality immediately after cold storage and after simulated marketing conditions at 20 °C. The 1-MCP ± CA treatments delayed ripening and prolonged storage life as indicated by delayed loss of firmness and TA in all four cultivars during storage. The 1-MCP ± CA also slightly delayed loss of SSC for `Gala' but had no effect on SSC levels for the other cultivars. There were differences among treatments for firmness and TA content [(1-MCP + RA) > CA] for `Gala', `Delicious', and `Granny Smith' apples, but not for `Fuji'. These differences were generally exacerbated after transfer of fruit to 20 °C for 1 week. A combination of 1-MCP + CA was generally best [(1-MCP + CA) > (1-MCP + RA) or CA] for maintaining `Delicious' firmness and TA. However, the treatments that were most effective at retaining TA and firmness also retained the least volatiles. The results indicate that the efficacy of 1-MCP and CA in maintaining apple quality factors is cultivar dependent and that 1-MCP + RA may be a viable alternative to CA for optimal eating quality for some cultivars.

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Xiuren Zhang, Guoguang Luo, Ronghui Wang, Jing Wang, and David G. Himelrick

The relationship of assimilate supply to grape (Vitis vinifera L.) berry growth and development was studied with a seeded (`Kyoho') and a seedless (`Seedless Wuhehong') cultivar. A single shoot girdling between the second and third nodes below the basal cluster at the end of Stage I of berry growth shortened Stage II (the lag phase) of `Kyoho' grape berries by 10 days, and eliminated Stage II in `Seedless Wuhehong' grape berries. Double shoot girdling between the second and third nodes below the basal cluster and above the upper cluster, respectively, at the same time at the end of Stage I, advanced Stage II by 3 days in both cultivars. Normal accumulation of dry weight in the `Kyoho' grape berry is in a double sigmoidal pattern, but it became a single sigmoidal pattern in response to a single basal girdling. The highest percent moisture in berries was at 20 days after full bloom. Rapid changes in berry pectin substances lagged behind those of soluble solids and titratable acidity, and behind the onset of berry softening at veraison in `Kyoho', but not in `Seedless Wuhehong', for which the three processes were concurrent. It is suggested that the slow growth of the berries during Stage II is a result of a decrease in the rate of water accumulation on a whole berry basis and a decrease in accumulation of dry matter in the skin and flesh (pericarp) due to assimilate competition within grapevines and within berries. The relationships between levels of endogenous hormones (IAA, GA3, zeatin, zeatin riboside, and ABA) and berry growth were also studied with `Kyoho' grapes. The results showed that the slow growth of grape berries during Stage II was associated with assimilate competition between the skin-flesh (pericarp) and seeds, and with peak shifts of concentrations of IAA, GA3, zeatin and zeatin riboside. Changes in ABA levels were closely associated with ripening and senescence during late Stage III.