more closely the impact of fruit waxing on sensory quality as influenced by HTFA treatment; and 3) examine the effect of HTFA treatment on flavor volatiles to better understand the impact of this treatment on flavor. Materials and Methods Fruit Navel
David Obenland, Sue Collin, James Sievert and Mary Lu Arpaia
Elizabeth A. Baldwin, Myrna O. Nisperos-Carriedo and Manuel G. Moshonas
Whole tomato fruit (Lycopersicon esculentum Mill.), cvs. Sunny and Solarset, were analyzed at 5 different ripening stages for ethylene and CO2 production. Homogenates from the same fruit were prepared for determination of color, flavor volatiles, sugars and organic acids. Of the flavor volatiles measured, only eugenol decreased during ripening in both varieties and 1-penten-3-one in `Sunny' tomatoes. Ethanol, and trans-2-trans-4-decadienal levels showed no change or fluctuated as the fruit matured while all other volatiles measured (cis-3-hexenol, 2-methyl-3-butanol, vinyl guiacol, acetaldehyde, cis-3-hexenal, trans-2-hexenal, hexanal, acetone, 6-methyl-5-hepten-2-one, geranylacetone and 2-isobutylthiazole) increased in concentration, peaking in the later stages of maturity. Synthesis of some volatile compounds occurred simultaneously with that of climacteric ethylene and color. `Solarset' fruit exhibited higher levels of sugars and all flavor components except ethanol, vinyl guiacol, hexanal and 2-methyl-3-butanol in the red stage. There were no differences between these varieties for acids
R.E. McDonald, T.G. McCollum and E.A. Baldwin
The objective of this study was to determine the effects of prestorage heat treatments on chilling tolerance of tomatoes. Mature-green `Agriset' tomato fruit (Lycopersicon esculentum Mill.), either C2H4-treated or not, were immersed in 42C water for 60 min, held in 38C air for 48 hours, or not treated, and then stored at either 2C (chilled) or 13C (nonchilled) for 14 days before ripening at 20C. Heat-treated fruit stored at 2C and transferred to 20C ripened normally while nonheated fruit decayed before reaching red ripe. Color (a*/b* ratio), lycopene content, and internal quality characteristics of fruit were similar at the red-ripe stage irrespective of method of heat treatment. In red-ripe heat-treated fruit, free sterol levels were significantly higher in chilled fruit than in nonchilled fruit. Heating fruit in 38C air resulted in significantly higher levels of some free sterols compared with heating fruit in 42C water. Of the 15 flavor volatiles analyzed, six showed significantly decreased concentrations as a result of C2H4-treatment and seven showed decreased concentrations when stored at 2C before ripening. Some volatiles were decreased by the heat treatments. Prestorage short- and long-term heat treatments could allow for storage of mature-green tomatoes at lower temperatures with little loss of their ability to ripen normally.
Elizabeth A. Baldwin, Myrna O. Nisperos-Carriedo and Jacqueline K. Burns
`Valencia' oranges were-treated with an experimental polysaccharide-based coating, a commercial shellac-based water wax, or were left uncoated. The fruit were stored at 16 or 21C with 95% RH. Samples were periodically analyzed for internal gases, flavor volatiles, water loss, and `Brix. Coated fruit had lower internal O2 and higher CO2 and ethylene levels as well as higher levels of many flavor volatiles (including ethanol) compared to uncoated. The differences were greatest for shellac-coated fruit at the higher storage temperature. No differences were found for °Brix. The shellac-coating gave the best weight-loss control and the most restricted gas exchange. The low gas permeability characteristic of this type of shellac coating may result in altered flavor for fruit held at 21C.
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.
Fernando Maul, Steven A. Sargent, Elizabeth A. Baldwin and Charles Sims
`Agriset-761' and `CPT-5' tomato fruits were harvested at green stage and subsequently exposed to a postharvest exogenous ethylene-air mixture (100 ppm C2H4 at 20°C). Tomatoes with visual symptoms of ripening (breaker stage = <10% red coloration) were removed from ethylene treatment after 1, 3, and 5 days and were transferred to 20°C and 85% RH. At “table-ripe” stage (full red coloration and 4-mm fruit deformation after 5 email@example.comN), whole fruit samples were analyzed for difference/discrimination sensory evaluations, aroma volatile profiles, and chemical composition. Flavor of fruits gassed for 1 day was rated significantly different than that of fruits gassed for 3 or 5 days (n = 25 panelists) for both cultivars. Several panelists noted the perception of “rancid” and “metallic” tastes, and “lingering” aftertaste in fruits gassed for 5 days. Chemical composition assays showed that flavor differences could be partially due to a significant increase in pH values between fruits gassed for 1 and 5 days (4.23 and 4.34, respectively for `Agriset-761') and a significant decrease in titratable acidity (0.91% and 0.73%, respectively, for `Agriset-761'; 1.04% and 0.86%, respectively, for `CPT-5'). No significant differences in soluble solids content or total sugars were found in any treatments for either cultivar. `Agriset-761' showed significant increases in the concentrations of acetone, hexanal, 2+3 methylbutanol, and a decrease in 2-isobutylthiazole, whereas, `CPT-5' fruits showed significant increases in hexanal, 2+3 methylbutanol, trans-2-heptenal, 6-methyl-5-hepten-2-one, 2-isobutylthiazole, β-ionone, geranylacetone, and a decrease is ethanol concentration. In both cultivars, these significant differences in important aroma volatile compounds could be of enormous relevance in the perception of off-flavor/off-odors.
R.E. McDonald, T.G. McCollum and E.A. Baldwin
Mature-green `Sunbeam' tomatoes (Lycopersicon esculentum Mill.) were treated in varying order with C2H4, 42 °C water for 1 hour, 38 °C air for 2days, held 2 days at 20 °C (partial ripening), or not treated and then stored at 2 °C (chilled) for 14 days before ripening at 20 °C. Heat-treated fruit stored at 2 °C and transferred to 20 °C ripened normally, while 63% of nonheated fruit decayed before reaching the red-ripe stage. Partially ripened fruit developed more chilling injury, were firmer, were lighter, and were less red in color than fruit not partially ripened. Lycopene content and internal quality characteristics of fruit were similar at the red-ripe stage irrespective of sequence of C2H4 exposure, heat treatment, or a partial ripening period. Of the 15 flavor volatiles analyzed, 10 were reduced by storage at 2 °C, Exposure to C2H4 before the air heat treatment reduced the levels of four volatiles, while C2H4 application either before or after the water heat treatment had no effect on flavor volatiles. Two volatiles were decreased and two were increased by partial vipening, Storage at 2 °C decreased the level of cholesterol and increased levels of campesterol and isofucosterol in the free sterol pool. Exposure to C2H4 before or following heat treatments, the method of heat treatment, and partial ripening had little effect on free sterols, steryl esters, steryl glycosides, or acylated steryl glycosides in the pericarp of red-ripe fruit. A shortor long-term heat treatment of mature-green tomatoes could permit storage at low temperatures with little loss in their ability to ripen normally, whereas partial ripening did not reduce chilling injury.
Gregory M. Peck, Preston K. Andrews, John P. Reganold and John K. Fellman
Located on a 20-ha commercial apple (Malus domestica Borkh.) orchard in the Yakima Valley, Washington, a 1.7-ha study area was planted with apple trees in 1994 in a randomized complete block design with four replications of three treatments: organic (ORG), conventional (CON), and integrated (INT). Soil classification, rootstock, cultivar, plant age, and all other conditions except management were the same on all plots. In years 9 (2002) and 10 (2003) of this study, we compared the orchard productivity and fruit quality of `Galaxy Gala' apples. Measurements of crop yield, yield efficiency, crop load, average fruit weight, tree growth, color grades, and weight distributions of marketable fruit, percentages of unmarketable fruit, classifications of unmarketable fruit, as well as leaf, fruit, and soil mineral concentrations, were used to evaluate orchard productivity. Apple fruit quality was assessed at harvest and after refrigerated (0 to 1 °C) storage for three months in regular atmosphere (ambient oxygen levels) and for three and six months in controlled atmosphere (1.5% to 2% oxygen). Fruit internal ethylene concentrations and evolution, fruit respiration, flesh firmness, soluble solids concentration (SSC), titratable acidity (TA), purgeable volatile production, sensory panels, and total antioxidant activity (TAA) were used to evaluate fruit quality. ORG crop yields were two-thirds of the CON and about half of the INT yields in 2002, but about one-third greater than either system in 2003. High ORG yields in 2003 resulted in smaller ORG fruit. Inconsistent ORG yields were probably the result of several factors, including unsatisfactory crop load management, higher pest and weed pressures, lower leaf and fruit tissue nitrogen, and deficient leaf tissue zinc concentrations. Despite production difficulties, ORG apples had 6 to 10 N higher flesh firmness than CON, and 4 to 7 N higher than INT apples, for similar-sized fruit. Consumer panels tended to rate ORG and INT apples to have equal or better overall acceptability, firmness, and texture than CON apples. Neither laboratory measurements nor sensory evaluations detected differences in SSC, TA, or the SSC to TA ratio. Consumers were unable to discern the higher concentrations of flavor volatiles found in CON apples. For a 200 g fruit, ORG apples contained 10% to 15% more TAA than CON apples and 8% to 25% more TAA than INT apples. Across most parameters measured in this study, the CON and INT farm management systems were more similar to each other than either was to the ORG system. The production challenges associated with low-input organic apple farming systems are discussed. Despite limited technologies and products for organic apple production, the ORG apples in our study showed improvements in some fruit quality attributes that could aid their marketability.
John C. Beaulieu, Maureen A. Tully, Rebecca E. Stein-Chisholm and Javier M. Obando-Ulloa
://www.ipmcenters.org/cropprofiles/docs/LAcitrus.pdf > Steffen, A. Pawliszyn, J. 1996 Analysis of flavor volatiles using headspace solid-phase microextraction J. Agr. Food Chem. 44 2187 2193 Swingle, W.T. Reece, P.C. 1967 The botany of citrus and its wild relatives, p. 190–340. In: Reuther, W., H.J. Webber
Stanley J. Kays and Yan Wang
Using the sweetpotato as a model, we identified precursors of critical flavor volatiles by fractionating, based upon solubility, raw roots into major groups of constituents. Volatile thermophyllic products from the individual fractions were analyized and compared to those from non-extracted root material. Volatile components were seperated and identified using GC-MS and quantified using internal standard methodology. Mechanisms of synthesis of flavor volatiles via thermophyllic reactions will be discussed, as will postharvest treatments that can modulate eventual aromatic properties of cooked plant products.