A two-dimensional capillary gas chromatographic method was developed to separate and quantify aromatic volatiles of celery in one analysis. The isolation, identification, and quantification of the volatile compounds of four cultivars of blanching celery (Apium graveolens L. var. dulce) and six cultivars of celeriac (Apium graveolens L. var. rapaceum) are described. The qualitative composition of Likens-Nickerson extracts of both cultivars is similar. The concentration of terpenes and phthalides, the key volatile components, found in various cultivars of both celery and celeriac varied over a wide range.
Fredy Van Wassenhove, Patrick Dirinck, Georges Vulsteke and Niceas Schamp
Meny Benady, Amots Hetzroni, James E. Simon and Bruce Bordelon
We have developed an electronic sensor (“sniffer”) that measures fruit ripeness rapidly and nondestructively by measuring the aromatic volatiles that are naturally emitted by ripening fruit. In this study, we evaluated the potential of using the fruit ripeness sniffer in the quality sorting of blueberries. Blueberries were first visually classified into four distinct ripeness classes: unripe; half-ripe; ripe; and over-ripe and quantitatively measured for color, firmness, TSS, and sugar acid ratio. Ripeness classification accuracy with the sniffer matched or exceeded that of all other ripeness indices. The sniffer differentiated unripe, ripe and over-ripe berries within one second, but could not distinguish between the unripe and half-ripe class. Detection of l-2 damaged or 1-2 soft fruit spiked within a large container of 24-37 high quality ripe fruit was also achieved, but required a response time of 10 seconds. Electronic sensing of aromatic volatiles may be a useful new technique in the grading and sorting of blueberries.
Solveig J. Hanson and Irwin L. Goldman
Earthy aroma and sweet flavor, conferred by the volatile terpenoid geosmin (trans-1,10-dimethyl-trans-9-decalol) and sucrose, respectively, are two essential flavor components of table beet (Beta vulgaris ssp. vulgaris). To elucidate the influence of genotype, growing environment, and fertilizer treatment on geosmin concentration and sucrose [as total dissolved solids (TDS)] in table beet, a field-based genotype × environment study was conducted using a split-split plot design. Four site × year combinations served as whole plots; MgSO4·H2O and CaSO4 comprised split plot fertilizer treatments; open-pollinated cultivars Bull’s Blood and Touchstone Gold, F1 hybrid Merlin, and inbred line W357B constituted split-split plot genotype treatments. Geosmin concentration was measured via gas chromatography–mass spectrometry using headspace solid-phase microextraction, and TDS was measured via refractometry. Variation in geosmin concentration was attributable to a strong genotype effect and significant genotype × year and year × site interactions. Genotypes were observed to have characteristic geosmin concentration and variance, despite being grown in soils with widely divergent physical and chemical properties. While a significant genotype main effect was also present for TDS, it occurred in the context of significant four-way and three-way genotype × environment interactions, plus significant effects of year and year × site interaction. Neither geosmin concentration nor TDS was significantly influenced by fertilizer treatment or fertilizer × environment interactions, averaged across genotypes. Genetics determined a larger proportion of variance for geosmin concentration than TDS in the four table beet genotypes assessed, as reflected in repeatability measurements of 0.90 and 0.43, respectively. This experiment provides support for the primacy of genotype in determining table beet geosmin concentration and a comparatively moderate role of genotype in determining table beet TDS. Thus, genetic manipulation of table beet geosmin could yield cultivars with signature flavor characteristics to serve both niche and mainstream consumer groups, expanding market opportunities for breeders and growers.
James J. Polashock, Robert A. Saftner and Matthew Kramer
., 2005 ) and the mechanism of disease resistance among cultivars is not known. Aromatic volatiles contribute to the aroma and flavor of fruit and vegetables, including highbush blueberry ( Forney, 2001 ). Emitted volatiles from highbush blueberry fruit
Robert Saftner, Gene Lester and Judith A. Abbott
A new hybrid orange-fleshed netted melon has been bred specifically for use by the fresh-cut industry in winter. Quality characteristics of fresh-cut chunks from the hybrid were compared to those of its parental lines and to commercial cantaloupe and honeydew fruits available in winter. Female parent and hybrid chunks had higher soluble solids content (SSC) and firmness, and lower aromatic volatile concentrations versus that of the male parent. Hybrid chunks also had higher SSC (>3%) and were firmer (>5 N) than commercial fruit, and showed no appreciable differences in aromatic volatile concentrations to commercial honeydew or in surface color to commercial cantaloupe. Consumers liked the flavor, texture, sweetness, and overall eating quality of the hybrid chunks better than those of its inbred parents and winter honeydew and as well as or better than that of winter cantaloupe. Hybrid fruit stored 5 weeks at 1 °C under modified atmospheric conditions, then fresh-cut and stored 14 d in air at 5 °C maintained good quality (firmness = 51 N, SSC = 12.2%, surface pH = 6.0, beta-carotene and ascorbic acid concentrations = 14 and 182 mg·kg-1, respectively), and showed no signs of tissue translucency or surface pitting despite microbial populations approaching 8 log cfu·g-1. The results indicate that the orange-fleshed hybrid melon is a promising new melon type for fresh-cut processing, especially during the winter.
W.B. Phippen, N. Ozer, A. Hetzroni, J.E. Simon, B. Bordelon, D.J. Charles, P. Angers, G.E. Miles, L.M. Malischke and D. Trinka
An electronic sniffer that nondestructively detects aromatic volatiles was used to grade commercially packaged blueberries. A total of 1,358 containers of commercial blueberries entering MBG grading facilities were first “sniffed” using the electronic sniffer, graded by USDA or MGB inspectors, and then subjected to discrimination analyses. The electronic sniffer separated the fresh top grade (grade 1) of fruit from the rest of the grades of blueberries with ≤ 82.79% accuracy when grading into five classes, and ≤89.3% when grading into three quality classes. The sniffer was also able to distinguish hand-harvested fruit from machine-harvested fruit from all cultivars tested (Bluecrop, Jersey, and Elliot). Highest classification accuracy was achieved with four gas sensors operating simultaneously within the sniffer. A stable signal response was achieved in 10 seconds, with each berry pack sampled at 10, 20, 40 and 80 seconds.
Robert A. Saftner*, Judith A. Abbott and Gene E. Lester
New fresh-cut melon products prepared from orange-fleshed honeydews have recently become available in retail markets. We compared fresh-cut chunks of orange-fleshed honeydew (`Temptation' and four breeding lines), green-fleshed honeydew (`Honey Brew'), and cantaloupe (`Cruiser'). All genotypes had similar respiration and ethylene production rates and soluble solids contents: genotype means for soluble solids contents were between 9.4% and 10.1 %. Five hundred untrained consumers preferred the flavor, texture, and overall eating quality of the orange honeydews to the green cultivar, with `Temptation' scoring highest. `Temptation' chunks were less firm at the time of processing and after 12 days storage than chunks prepared from all other genotypes. The color of orange-fleshed honeydew chunks was intermediate between that of cantaloupe and green-fleshed honeydew and the color was maintained during 12 days storage. Total aromatic volatiles from juice extracts of orange-fleshed honeydew chunks was 1.2 to 4.7 times higher than that of green-fleshed honeydew extracts and volatiles from cantaloupe was >4.8 fold greater than extracts from `Temptation' and >9.3 fold higher than that of other honeydew extracts. Many individual volatiles were identical in cantaloupe and honeydews; however, honeydew genotypes, particularly the orange-pigmented types, were distinctive from cantaloupe in having relatively high levels of various nonenyl and nonadienyl acetates of uncharacterized aromas. The results indicate that `Temptation' and other orange-fleshed honeydews are a promising new melon type for fresh-cut processing.
Amots Hetzroni, Denys J. Charles and James E. Simon
A nondestructive electronic sensory system (electronic sniffer) that responds to volatile gases emitted by fruit during ripening was developed. It is based upon a single semi-conductor gas sensor placed within a rigid plastic cup equipped with a gas inlet to flush the head between samples. This gas sensor reacts with the range of reductive gases such as the aromatic volatiles that are naturally emitted by the ripening melon fruit. The sensor cup is placed on the exterior of the fruit and the change in electrical conductivity is recorded. In 1994, we examined the electronic sniffer as a tool to nondestructively determine ripeness in `Superstar', `Mission', and `Makdimon' melons. Fruits were manually classified into five ripeness stages based on external appearance and slip stage. Melons were first sampled nondestructively for color, weight, size, and slip stage, and then subjected to the electronic sniffer. Then, fruit volatiles, flesh firmness, and total soluble solids were measured. The electronic sniffer was able to accurately classify melons into three ripeness classes: unripe, half-ripe, and ripe for `Superstar' and `Mission'. The sniffer was only able to separate ripe from over-ripe in `Makdimon', which is known to become over-ripe and deteriorate rapidly. Using the sniffer as a tool to nondestructively measure ripeness and its potential application in fruit quality will be discussed.
L.G. Albrigo, R. Russ, R. Rouseff and R.A. Bazemore
Except for `Orlando' and `Minneola' tangelos, most citrus hybrids grown in Florida are small-flowered and produced less than half the nectar of large-flowered cultivars. Sugar contents in large- and small-flowered cultivars were not different in 1997, but the concentration of sugars doubled in 1998 over 1997 for small-flowered hybrids, while nectar volume was about one-half of that in the previous year. Nectar volume of large-flowered cultivars increased slightly in 1998 compared to 1997. Of four aromatic volatiles measured from headspace over flowers, `Robinson' and `Ambersweet' were lowest in total while other cultivars had only some specific differences. Grapefruit flowers produced high limonene levels, while `Sunburst', `Fallglo', and `Valencia' gave off the most myrcene. Bees were tested for flower preference in a round, white screenhouse using a mini-hive and duplicated fresh-cut flower bouquets each day. Bees preferred large-flowered cultivars with more nectar. Some other preferences also were observed. In the field, hedge-rows limited cross movement of bees in mature blocks of hybrids, which limits the number of contiguous rows of the preferred cultivar for good pollinization. Timing of bee hive placement was also critical to get bee movement into the intended block because flowering times differ for some cultivars and bees develop inital preferences.
Denys J. Charles, Amots Hetzroni and James E. Simon
Recent developments in electronic odor-sensing technology has opened the opportunity for non-destructive, rapid, and objective assessment of food quality. We have developed an electronic sensor (electronic sniffer) that measures aromatic volatiles that are naturally emitted by fruits and fruit products. The ability of our sniffer to detect contamination in fruit juice was tested using tomato juice as a model system. Tomato juice was extracted from cultivar Rutgers and divided into eight glass jars of 300 g juice each. The jars were divided into two treatments: the control jars contained tomato juice mixed with 0.15% sorbic acid to suppress microbial growth, and the experimental jars contained only tomato juice. All the jars were placed open, on a counter top in the laboratory for 8 days. The juice was tested daily with the electronic sniffer and for pH. The total volatiles in the headspace of the juice was extracted on alternating days via dynamic headspace method using charcoal traps, analyzed by gas chromatography, and confirmed by GC/mass spectometry. The results indicate that the sniffer is able to detect differences between the two treatments 4 days after the tomato juice was exposed to ambient atmosphere. The electronic sniffer output for the control juice showed a monotonous decline, while the output for the experimental juice exhibited a sharp incline after day four. This sensor output correlated well with the total volatiles.