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Eugene K. Blythe and Jeff L. Sibley

basal quick-dip ( Blythe et al., 2004 ). Preparation of liquid auxin solutions with the thickening agent sodium cellulose glycolate (SCG) enhances adhesion of the auxin solutions to the bases of stem cuttings, thus increasing the duration of exposure

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E.A. Baldwin and Bruce W. Woods

Pecans (Carya illinoinensis) are full of unsaturated fatty acids, which are subject to oxidative cleavage. This results in the development of rancid off-flavors, which render the nuts unmarketable. For this reason, pecans must be stored under costly refrigerated conditions. Furthermore, pecans usually undergo retail distribution and marketing at ambient conditions, which promote development of off-flavors. Application of cellulose-based edible coatings reduced off-flavor, and improved overall flavor scores while adding shine to the nuts during 14 months of storage under ambient conditions. Development of rancidity involves hydrolysis of glycerides into free fatty acids, oxidation of double bonds of unsaturated fatty acids to form peroxides and then autooxidation of the free fatty acids once the peroxides reach a sufficient level to perpetuate this reaction. One of the products of autooxidation is hexanal which is, thus, a good indicator of rancidity. Analysis of pecans by gas chromatography revealed that hexanal levels were reduced in coated nuts by 5- to over 200-fold compared to uncoated controls, depending on the coating treatment. Some of the coating treatments affected nut color, but overall flavor and appearance were improved by certain formulations.

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Robert H. Stamps and Heidi M. Savage

slow-release water product that could be applied postproduction when extended watering intervals are desired. CW is a soft gel formed by combining a cellulosic substrate (e.g., carboxylmethylcellulose) with a hydrated metallic salt (e.g., zinc sulfate

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Shugang Zhao, Jiamin Niu, Linying Yun, Kai Liu, Shuang Wang, Jing Wen, Hongxia Wang, and ZhiHua Zhang

were used in each replicate. Measurement of cellulose content. The lyophilized shell samples were used in the determination of cellulose content. After being ground, the shell powder was sieved through a 120-mesh sieve and subjected to acetic acid

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Yong-Soo Hwang, D.J. Huber, and L.G. Albrigo

Cell wall composition and structure were examined in visually normal (N), granulated (G), and collapsed (VC) juice vesicles of `Marsh Seedless' grapefruit (Citrus paradisi) Macf.). According to gel-filtration data, VC appeared to be associated with a modification of water-soluble (WSP) and chelate-soluble (CSP) pectin molecular weight (Mr); small-Mr pectins increased, whereas large-J4. pectins decreased. The difference in M = of pectins did not appear to be mediated by polygalacturonases. Molecular weight of hemicelluloses did not differ. Granulated vesicles contained about two times more structural polysaccharides (pectins, hemicelhdose, and cellulose) than N vesicles, although hemicellulose and pectin M = modification were absent. Ion-exchange profiles of WSP, CSP, and hemicelhrlose fractions of VC and G vesicles were not different from those of N vesicles. Individual cells in vesicles with G and these vesicles themselves were much larger than those of N vesicles, whereas cells in VC were partially or completely collapsed.

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A.W. Stretch, M.K. Ehlenfeldt, and V. Brewster

In vitro conidia production by Monilinia vaccinii-corymbosi (Reade) Honey, the cause of mummy berry disease in blueberry, was significantly enhanced by cellulose acetate membranes placed on the surface of V-8 juice agar for most of the pathogen isolates tested, compared to V-8 juice agar alone. Temperature and light affected conidia production, but the effects were not consistent. Higher temperature (22 vs. 15 °C) yielded better sporulation, but the effects of light environment were variable. When 55 isolates from various sources were rated visually for sporulation on cellulose acetate membranes at 22 °C under ambient light/dark cycles, a wide range of conidium production was observed, and three of 55 isolates (6%) were identified as having very high conidia production.

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Raymond G. McGuire and Guy J. Hallman

Harvested, mature-green guava (Psidium guajava L.) fruit were coated with cellulose- or carnauba-based emulsions to compare the effect on fruit ripening and quality of ripened fruit. Coatings containing 2% or 4% hydroxypropylcellulose significantly slowed softening an average of 35% or 45%, respectively, compared to uncoated fruit (a delay of 1 to 2 days in September and 4 to 5 days by January). A 5% carnauba formulation slowed softening by 10% to 30% and was most effective at reducing weight loss. Neither of the cellulose- nor the carnauba-based coatings affected the decay susceptibility of softened fruit, but coated fruit did not develop as much color, had a lower soluble solids concentration, and were more prone to surface blackening in storage than uncoated fruit.

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Donald T. Krizek and Roman M. Mirecki

Cellulose diacetate has been widely used in UV-B enhancement studies under field and controlled-environment conditions since the early 1970s to remove wavelengths below ≈290 nm, without any evidence of toxicity effects. However, while conducting UV-B exclusion studies in window boxes covered with cellulose diacetate (CA) or in Plexiglas chambers lined with CA, there was marginal chlorosis and cotyledon epinasty in `Ashley' cucumber, which is normally resistant to elevated UV-B, while seedlings exposed to open sunlight and those grown under polyester (PE) film to exclude UV-B were free of visible injury. These findings suggested that the CA filter itself may be causing toxicity. To test this hypothesis, a UV exclusion study was conducted in which CA or Teflon (T), both UV-B and UV-A transmitting films, were used to cover window boxes in the following four combinations (top/bottom): CA/CA, CA/T,T/CA, and T/T. When CA was used as the bottom filter (CA/CA and T/CA), the plants showed significantly greater leaf injury and a 2- to 3-fold reduction in growth than when T was used as the bottom filter (CA/T and T/T). These findings suggest that toxicity is caused by CA itself rather than by solar UV-B radiation, possibly as a result of outgassing of phthalates known to be used as plasticizers in the manufacture of CA. Further evidence that CA was responsible for leaf injury was provided by a companion study in which T was replaced by PE and damage was still observed, although no significant growth effects of CA position were observed.

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Alvan Gaus and Matthew Rogoyski

A set of 3 experiments was conducted to determine if cellulose fibers (CF) could reduce the incidence of sunburn injury in `Paulared' apples. Sunburn injury was artificially increased in these experiments by fruit manipulation and removal of shading vegetative growth to expose apples to at least 4 hours of direct sunlight. The 4 treatments applied included an unsprayed control, a commercial binding agent (CBA), a 1% corn starch (CS) colloidal suspension, and a 3% CF suspension that contains CBA and CS. No differences between treatments were found in the first experiment. The CF suspension concentration was increased to 9% for the second experiment. This resulted in uneven CF distribution on the fruit surface and no significant differences between treatments. The third experiment was designed to more precisely determine sunburn symptom expression by delineating the manipulated fruit surface area directly exposed to sunlight prior to treatment. The resulting percent of area that showed a white (bleached) sunburn symptom was significantly less for the apple fruit treated with CF than CBA alone.

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R. Potjewijd, M.O. Nisperos, J.K. Burns, M. Parish, and E.A. Baldwin

Varying the cellulose component of coating formulations affected the survival of two yeast biocontrol agents, Candida guillermondii (Castelani) Langeron and Guerra strain US7 and Debaryomyces sp. strain 230, when these yeasts were incorporated into the coating. Using methylcellulose as the main film-former gave the most recovery of the yeasts after an incubation period for both strains. Significant control of decay on naturally infected `Pineapple' and `Valencia' oranges [Citrus sinensis (L.) Osb.] was demonstrated for US7 in a methylcellulose-based coating for the first 2 to 4 weeks of storage at 16C and 90% relative humidity. During this time, US7 in methylcellulose formulations was similar in decay control to a commercial shellac coating with imazalil at 2000 mg·liter–1. A US7 concentration of at least 105 colony-forming units/cm was maintained on the coated fruit surface of `Valencia' oranges for 3 weeks of storage. Suppression of decay by US7 was improved by the addition of glucose and calcium chloride to the coating formulation. Although nearly equal in concentration recovered, Debaryomyces strain 230 was not as effective as US7 in disease suppression of `Pineapple' oranges. The addition of US7 to Nature Seal, a coating material made with methylcellulose, had neither a quantitative nor a qualitative effect on the pathogen population compared to the same formulation without the antagonist. Chemical name used: 1-[2-(2,4-dichlorophenyl)-2-(2-propenyloxy)ethyl]-1H-imidazole (imazalil).