Volatile compounds in dried grapes

Abstract

Volatile compounds were isolated from fresh Sultana grapes, from pale golden-brown sultanas prepared by drying on racks after treatment with a commercial dipping solution, and from dark brown sultanas dried in sunlight without dipping. The fresh grape volatiles were found in the dipped sultanas but not in the undipped sultanas. Undipped sultanas contained considerable amounts of furfural and related compounds which were present in relatively small amounts in the dipped sultanas. It is suggested that these compounds, commonIy associated with non-enzymic browning, may account for the malty, caramellike aroma of the undipped sultanas and that their production is inhibited by the drying conditions given to the dipped sultanas. The dipped sultanas contained several carbonyl compounds which were not observed in the undipped sultanas.

Characterization of Free Flavor Compounds in Traminette Grape and Their Relationship to Vineyard Training System and Location

“…The concentrations of nerol and linalool in all cultivars were lower than their perception thresholds of 400 and 100 μg/L, respectively (Table 2) (Ribereau‐Gayon and others 1975). The C 6 ‐aldehydes were predominant in all cultivars, which agree with previous reports indicating high concentrations of C 6 ‐aldehydes in various grape cultivars (Stevens and others 1967; Ramshaw and Hardy 1969; Belancic and others 1997; Oliveira and others 2000). These compounds were highest in Chardonnay, lowest in Riesling, and intermediate in Traminette (Table 2 and Figure 2).…”

Browning reactions during storage of low-moisture Australian sultanas: Evidence for arginine-mediated Maillard reactions

“…Although there is published evidence for the occurrence of Mailllard reactions in grape products, sweet-wine products (Cutzach et al 1999) and sultanas (Karadeniz et al 2000, Simal 1996, Cañellis et al 1993, Aguilera et al 1987, Bolin 1980, McBride et al 1984, Ramshaw and Hardy 1969 Similarly, there are only limited studies examining the role of oxygen in long-term storage browning. In addition, the widely practised step of 'sunfinishing' sultanas is known to produce higher quality, more colour-stable fruit, but it is unknown whether this improved stability is due to the reduction of a w alone or through a reduction in active PPO enzyme.…”

“…Drying sultana grapes Most dried Sultana grapes (sultanas) produced in Australia are subjected to an alkaline 'cold-dip' following harvest to accelerate drying and thus produce light-golden coloured sultanas as dried fruit (Fogerty and Burton 1981, Grncarevic and Lewis 1976, Grncarevic and Hawker 1971, Ramshaw and Hardy 1969, Radler 1964, Grncarevic 1963). The 'cold dip' process is critical to this outcome.…”

“…However, it is not known whether the browning that occurs during sultana storage is due to PPO oxidation reactions, slower Maillard-type reactions (Cañellis et al 1993, Aguiliera et al 1987, or a complex interaction of oxidised phenolic species with Maillard reaction products (Es- Safi et al 2000). Maillard reactions have long been suspected as a factor in sultana browning during storage (Ramshaw and Hardy 1969) and are discussed below.…”

Levaduras no-Saccharomyces para modular el aroma secundario de los vinos: incremento del acetato de 2-feniletilo mediante cultivos iniciadores mixtos

“…Dentro de este grupo también se incluyen compuestos que se generan en el transcurso de la manipulación, preparación, extracción y acondicionamiento del mosto en la bodega y entre ellos cabe destacar aldehídos, cetonas y diferentes tipos de alcoholes (Stevens et al, 1967;Ramshaw y Hardy, 1969;Schreier, 1979).…”