1,498 research outputs found
Disposable pyruvate biosensors for routine assessment of onion flavour
No full textThe UK-grown onion sector shows strong potential for growth through new
product development as consumers become increasingly aware of the health and dietary
benefits of fresh onion consumption. Prospects for the production of new, more palatable
sweet onions will be boosted by the development of improved grower diagnostics for
flavour standardisation. Growers require simple-to-use on-farm diagnostics to assure
flavour quality. The introduction of pungency tests has led to increased mild onion sales,
however currently tests are out-sourced and as a result costly. Through this Defra-
(Department for Agriculture Food and Rural Affairs) sponsored research project
(HL0164), hand-held biosensor technology, adapted from the medical sector, has been
developed for improved and lower cost pungency and sweetness analysis in onions. Cont/d
Understanding the mechanisms behind onion bulb dormancy in relation to the potential for improved onion storage
No full textOnion (Allium cepa L.) is the most economically important Allium crop. Onion
cultivars adapted for growth in temperate regions require long days for bulb initiation, so the summer crop is stored over-winter. Deterioration in store is largely due to resumption of growth. Extended storage of onions is currently dependent on the synthetic sprout
suppressant maleic hydrazide, whose future use is uncertain due to pressure to reduce
residues in foods.
Abscisic acid (ABA) has previously been linked with dormancy in a relative of
onion (A. wakegi). Bulb ABA concentration in three onion cultivars (viz. Renate, Ailsa
Craig and SS1) with contrasting storage lives declined exponentially during controlled atmosphere (CA – 3% CO2, 5% O2; 2°C) storage at the same rate in each cultivar.
Sprouting occurred at a minimal ABA concentration (ca. 50-120 ng g-1 DW). It was
proposed that extended periods of high concentrations of ABA may delay sprouting.
An ABA analogue (PBI-365) and exogenous ABA, were applied as preharvest foliar sprays (cvs. Renate, Carlos, Dinaro, Hysam, Red Baron and SS1), or as postharvest bulb soaks (cv. Hysam) with the aim of increasing endogenous ABA concentration and, thereby, extending the storage period. Endogenous bulb ABA concentration was not affected. Bulb ABA concentration again decreased during storage at a range of temperatures (4, 12 and 20°C) and sprouting occurred at minimal ABA concentration (ca. 75-150 ng g-1 DW). After the onset of sprouting, ABA concentration increased again, probably due to synthesis by the sprout. The concentration of certain carbohydrates has
been linked with storage potential. No straightforward relationship between ABA and
non-structural carbohydrate (NSC; fructose, glucose, sucrose and fructans) metabolism
could be determined. It was therefore postulated that ABA is more likely to play a role in mediating cell elongation rather than cell division, or that minimal ABA concentration could be a trigger for remobilisation of carbohydrates.
Controlled atmosphere (CA) is used to extend storage life of onions; however, shelf-life can be compromised. The effects of the transition between CA (3 % CO2, 5 %
O2; 2°C) and air storage on ABA concentration, quality characteristics, respiration rate(RR) and NSCs in three onion cultivars (viz. Renate, Carlos and SS1) were investigated. The RR of the short storing cultivar, SS1, was greatest by ca. 0.5-fold. The RR increased on removal from CA storage, with no accompanying decrease in carbohydrate
concentration, indicating that the increased RR may have been a transient stress response.
Storage of onions cv. SS1 for three weeks in air, followed by three weeks CA was as
effective in suppressing sprout growth as six weeks continuous CA storage. Bulb ABA
concentration decreased significantly between the time of harvest and after curing.
Therefore the current practice of curing onions for extended periods at high temperatures could be reducing bulb ABA concentration, and therefore storage life.
The literature concerning the role of ethylene in onion storage is limited and
conflicting. The effect of 1-methylcyclopropene (1-MCP; an ethylene perception inhibitor) on sprout growth in onions cv. SS1 stored at a range of temperatures (4, 12 and 20°C) was investigated, along with quality characteristics, NSCs and ABA. Sprout
growth was reduced in onions treated with 1-MCP and stored at 4 or 12°C, but not at
20°C. Approximately 2-fold greater concentrations of sucrose, glucose and fructose were maintained in 1-MCP-treated bulbs stored at 12°C as compared with untreated bulbs. It appeared that 1-MCP reduced carbohydrate metabolism.
Both ethylene and ABA are highly likely to impact significantly on onion storage
life. The results are discussed in relation to the potential to influence storage life by
changes in horticultural practices, including the recommendation to re-evaluate the curing and drying protocol, and to investigate the possibility of delaying the start of CA storage
The production and marketing of onions
No full textTitle from PDF caption (viewed on December 13, 2017)."(Supersedes Cir. No. 8)."This archived document is maintained by the State Library of Oregon as part of the Oregon Documents Depository Program. It is for informational purposes and may not be suitable for legal purposes.Mode of access: Internet from the Oregon Government Publications Collection.Text in English
Forgiving Onions
No full textThis thesis consists of a work of fiction by the author in five parts, entitled: "Onions," "Peeling Potatoes," "No Vegetables in LaLa Land," "The Produce Section," and "The Apple Tree.
Forgiving onions
No full textThis thesis consists of a work of fiction by the author in five parts, entitled: "Onions," "Peeling Potatoes," "No Vegetables in LaLa Land," "The Produce Section," and "The Apple Tree.
Organic functionalization and optical properties of carbon onions
No full textHere we report, for the first time, a method for chemically
functionalizing onions from arc discharge soots. The new methodology not only allows the isolation of giant fullerenes, but especially renders them soluble in organic solvents, such that their solution properties can be studied for the first time
Ultrahigh vacuum scanning probe microscopy studies of carbon onions
No full textCarbon onions were prepared by DC are charge method. The behavior and electronic propel ties of carbon onions on highly oriented pyrolytic graphite (HOPG) substrate were studied by ultrahigh vacuum atomic force microscopy and scanning tunneling microscopy (UHV AFM/STM). UHV AFM/STM images showed that these ellipsoidal carbon onions tended to aggregate into clusters on the surface of HOPG. The scanning tunneling spectroscopy indicated that the electrical properties of carbon onions were between graphite and single-shell fullerenes. (C) 2001 Elsevier Science B.V. All rights reserved.Nanoscience & NanotechnologyPhysics, Condensed MatterSCI(E)EI5ARTICLE2300-304
PRODUCT DIFFERENTIATION PROTECTION: DEVELOPING A STRATEGY FOR MULTIPLE PRODUCERS OF REGIONAL SPECIALTY CROPS
No full textSpecialty crops grown by multiple producers are often viewed by consumers as differentiated products that command a price premium. Since price premiums are dependent upon differentiation of an item from generic counterparts, specialty crops must have distinctive identities that cannot be copied or mimicked by others. Trademarks are normally employed to differentiate and protect products, but the limitation of trademarks to products from a single source means that differentiation of specialty crops grown by multiple producers may involve difficulties in precluding free riders from adopting the same name. Through a case study of Georgia's Vidalia Onions and an examination of producer price data, this article explores the problem of the protection of product differentiation of regional specialty crops grown by multiple producers.Agribusiness,
United States, farmer harvesting onions in Palmer
No full textWoman picking green onions in garden.GrayscaleSorensen Safety Negatives, Binder: North & Central America
Pakistan, men planting onions in field in Lahore
No full textForward view of man planting onions in field.GrayscaleSorensen Safety Negatives, Binder: Asia
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