Fruit Blends Research Articles

Thermal Death of Third Instars of the Caribbean Fruit Fly (Diptera: Tephritidae) Treated in Different Substrates

Eight substrates (air, water, artificial diet, and fruit pulp blends of guava, grapefruit, orange, mango, and orange) were examined for their impact on survival of third-instar Caribbean fruit fly, Anastrepha suspensa (Loew), exposed to 40°C for 67 min. Survival was the greatest for larvae heated in air (92.9 ± 1.1%) and lowest in water (12.1 ± 1.6%). Mortality was intermediate to high and similar among larvae heated in the fruit blends and artificial rearing diet. Percentage water and oxygen of each substrate, pH, and specific gravity did not affect larval mortality, but the type of substrate (air, water, fruit pulp blend) was significant. The upper thermal limits of a quarantine treatment can be screened for all pest life stages by testing time-temperature regimes using air as a substrate.

SENSORY EVALUATION OF JAMS MADE FROM THREE EASTERN THORNLESS AND MARION BLACKBERRIES1

ABSTRACTJams were produced from fruit of eastern thornless blackberries (Black Satin, Chester, Hull Thornless, and Thornfree cultivars) harvested by hand or machine, of a blend of imported fruit from Yugoslavia and Mexico, and of Marion blackberries from Oregon. Jams were evaluated by 12 trained panelists for color, spreadability, consistency, sweetness, blackberry flavor, off‐flavor, and seediness. Jams made from hand‐harvested Marion, and Black Satin were the most red‐purple in color. Machine‐harvested Chester fruit yielded the firmest jam and was among the jams rated with the thickest mouthfeel. Jams of hand‐harvested Thornfree and Black Satin fruit were rated sweetest. No differences were noted among cultivars in seediness or blackberry flavor. Jam of Marion, Black Satin, and Chester fruit had less off‐flavor than the imported fruit blend and Thornfree; however, the intensity of off‐flavor was scored low in all jams. Jams made from hand‐harvested blackberries were less seedy and had more intense blackberry flavor than machine‐harvested fruit.

Pesticide Analysis with the Pulsed-Flame Photometer Detector and a Direct Sample Introduction Device

New methods for fast, sensitive, and informative pesticide analysis in food products are described. These methods are based on sampling with a novel direct sample introduction device (DSI), gas chromatographic analysis, and pesticide detection with the pulsed flame photometric detector (PFPD). Sampling with the DSI is based on introduction of blended fruit or vegetable in a small glass vial that retains the harmful nonvolatile residue and is disposed of after the analysis. The DSI-GC-PFPD combination provides several new features that are demonstrated and discussed: (a) Extract-free analysis is achieved with the DSI, which serves as an effective alternative to sample extraction and cleanup methods. (b) Faster analysis is achieved through the use of the DSI due to the reduction of the upper GC program temperature, since the low-volatility compounds are retained in the sample vial. (c) Relatively efficient and uniform DSI thermal extraction and PFPD detection can be achieved, allowing the use of internal standards for pesticide calibration. (d) Higher sensitivity is provided by the PFPD as well as through the use of the DSI for sampling larger volumes of extract solutions. (e) Sulfur interference is eliminated with the PFPD in its phosphorus-selective detection mode, using software exploiting differences in S and P delayed pulsed flame emission time dependence. (f) Sulfur pesticides are effectively analyzed by the PFPD in its sulfur-selective detection mode at the usual required levels and with less matrix interference than with NPD in the nitrogen mode. (g) Simultaneous sulfur and phosphorus pesticide analysis is demonstrated, including heteroatom identification and the provision of P and S atom ratio information in the analyzed pesticide.

Intravenous infusion of bombesin reduces food intake in humans.

Infusion of bombesin into healthy young men at two dosages (1.33 and 4.0 ng.kg-1.min-1) resulted in a significant 135-g reduction in intake of a yogurt and fruit blend, compared with saline infusions, at the higher dose, but only a 20-g (nonsignificant) reduction at the lower dose. There were no overt side effects, although half of the subjects reported a slightly elevated (mean elevation = 0.5 on a 1-5 category scale) sick sensation when receiving bombesin at the higher dose, but not when receiving saline. At the higher dose, the mean palatability of the test meal was reduced by 0.5 units on a nine-point scale of liking. This study demonstrates for the first time in humans that a slow intravenous infusion of bombesin can decrease spontaneous food intake when infused at the rate of 4 ng.kg-1.min-1 beginning at the onset of a meal. These results confirm that the short-term satiety effect of peripherally administered bombesin previously reported in animals can be obtained in humans.

Volatile constituents of Asian pear (Pyrus serotina)

The volatiles of Asian pear (Seuri cultivar) were studied by high-resolution gas chromatography and combined gas chromatography/mass spectrometry (GUMS) using vacuum simultaneous distillationextraction of blended fruit and dynamic headspace sampling of intact and enzymatically inhibited blended fruit. Esters were the dominant constituents in all of the samples. A total of 72 components were identified in the headspace of intact fruit, including 39 constituents reported for the first time in pear. Odor unit values calculated from concentration and odor threshold data indicate that the following compounds are important contributors to pear aroma: ethyl 2-methylbutanoate, ethyl hexanoate, ethyl butanoate, ethyl 2-methylpropanoate, hexyl acetate, ethyl heptanoate, hexanal, ethyl pentanoate, and ethyl propanoate. Asian pears (Pyrus serotina) are a completely distinct species from the more common European-type pears (Pyrus communis L.) such as Bartlett and La France and are not a cross between apples and pears. Though the volatile constituents of Bartlett pears have been extensively investigated (Maarse and Visscher, 1984), there has been, to our knowledge, only one publication on the flavor compounds of Asian pears (Shiota et al., 1981). These researchers studied four Asian pear cultivars [Nijisseiki (20th Century), Kosui, Hosui, and Kikusuil and found distinct compositional differences between the peel and pulp. The peel contained major amounts of nonanal, cy-farnesene, phenylacetaldehyde, and straight-chain hydrocarbons with 19-23 carbon atoms, while the pulp had ethyl butanoate, hexanol, hexyl acetate, butylbenzene, and

Stability of vitamin C in fruits and fruit blends

AbstractThe levels of the two biologically active forms of vitamin C, ascorbic acid (AA) and dehydroascorbic acid (DHAA), were determined in individual fruits, in fruit blends and in model systems over a 3‐h incubation period at room temperature. There was essentially no reduction in the AA content in the orange juice sample and in the model solution of analytical l‐ascorbic acid. A rapid decrease in the AA content was observed in the banana, apple and guava samples and in blends consisting of orange juice‐banana‐apple or L‐ascorbic acid‐banana‐apple blends. However, the reduction in AA was concomitant with a quantitative increase in DHAA content.

Comparative Development and Fecundity of Corn Earworm1 Reared on Selected Wild and Cultivated Early-Season Hosts Common to the Southeastern U.S.2,3

The corn earworm, Heliothis zea (Boddie), was reared on corn soy blend (CSB) artificial diet, flowers and fruit of toadflax, Linaria canadensis L.; frosty blue lupine, Lupimis augttstifolins L., cranesbill, Geranium carolinianum L; crimson clover, Trifolium incarnatum L; narrow leaf vetch, Vicia angustifolia Reichard; cudweed, Gnaphalium spathulatum Lam.; or on the leaf roll of whorl-stage Ioana sweet corn. There were significant differences in time to pupation and adult emergence, weights of pupae and adults, preoviposition periods, numbers of spermatophores transferred, and numbers of eggs oviposited. Mean time to pupation ranged from 21.8 days on CSB diet to 30.6 days on corn leaf roll. Mean preoviposition period ranged from 2.0-2.9 days on CSB diet and crimson clover, respectively, and total number of eggs oviposited ranged from 2069 to 417, respectively.