The Composition of Strawberry Aroma Is Influenced by Cultivar, Maturity, and Storage

Abstract

Strawberry (Fragaria ×ananassa Duch.) fruit have a unique, highly desirable flavor and are one of the most popular summer fruits. Sugars, acids, and aroma volatiles contribute to the characteristic strawberry flavor, which is dependent on the proper balance of these chemical constituents. While sugars and acids are responsible for the sweetness and tartness of the fruit, aroma volatiles provide the unique, fruity flavors that characterize a fresh strawberry. The aroma of fresh strawberries is dependent on many factors. The large genetic variability in the nature of strawberry aroma results in differences in flavor among cultivars. In addition, the aroma changes dramatically during fruit ripening after harvest; therefore, it is important to preserve and enhance the ripe fruit aroma during postharvest handling. The loss of this desirable aroma or the development of objectionable aromas reduces the quality and marketability of fresh strawberries. In this review we will discuss the chemical nature of strawberry aroma and how it is affected by various factors, including cultivar, maturity, and postharvest environment. CHEMICAL COMPOSITION OF AROMA Volatile chemicals are responsible for the aroma and contribute to the flavor of fresh strawberries. These compounds comprise only 0.01% to 0.001% of the fruit fresh weight but have a major effect on its quality (Buttery, 1981). Fresh strawberries produce numerous volatile compounds; as many as 360 have been isolated (Latrasse, 1991) including esters, aldehydes, ketones, alcohols, terpenes, furanones, and sulfur compounds (McFadden et al., 1965). Esters are quantitatively and qualitatively the most abundant class of these compounds; 131 different ones have been identified in strawberry aroma (Latrasse, 1991). Esters provide the fruity and floral notes and they comprise from 25% to 90% of the total volatiles in fresh ripe fruit (Douillard and Guichard, 1990; Ito et al., 1990; Pyysalo et al., 1979; Schreier, 1980). Other classes of compounds, which may comprise up to 50% of strawberry volatiles, include aldehydes (Schreier, 1980) and furanones (Larsen and Poll, 1992). Alcohols account for as much as 35% of the volatiles, but normally contribute little to strawberry aroma (Larsen and Watkins, 1995b). While terpenes normally comprise <10% of strawberry volatiles and sulfur compounds <2%,

Analysis of strawberry volatiles using comprehensive two-dimensional gas chromatography with headspace solid-phase microextraction

“…Thus, the more-volatile analytes might be more easily extracted, and appear at comparatively higher concentrations. This reflects the compound's contribution to the fruit aroma, but does not give its true concentration in the tissue [7]. Ultimately this method of extraction could not be used to accurately quantify the level of compounds in the sample, a problem other authors have encountered with this sampling approach [32,15].…”

“…Strawberries have a complex aroma with more than 360 identified constituents composed of alcohols, esters, aldehydes, ketones and furanones [5]. This complexity is compounded by the fact that aroma is known to vary with berry variety [6,7], season, and agronomic and climatic growing conditions [8]. Furthermore, Watson et al [9], have shown that volatiles examined in the variety Elsanta, showed highly significant differences with harvest date (pick-to-pick variation; P < 0.01) and even between fruit on a single harvest date.…”

Composition of phenolics and volatiles in strawberry cultivars and influence of preharvest hexanal treatment on their profiles

“…Even though these volatiles comprise about 0.01 to 0.001% of the fresh fruit weight, they have a significant impact on the overall flavor of strawberry (Buttery 1981). Strawberry aroma is dependent on many factors, and studies report that genotypes or cultivar exhibit considerable variations in the profiles of the volatiles they produce (Forney et al 2000). In this study, cultivars exhibited distinct differences in the chemical composition of volatiles.…”

“…Recently, caryophyllene oxide has shown cytoxicity against several cancer cell lines (Jun et al 2011). Previous studies reported that esters comprised 25Á90% of the total number of volatiles in ripe strawberry fruit (Perez et al 1992;Forney et al 2000). Among the esters, butanoates comprised the predominant proportion of esters.…”

“…The volatile profiles of strawberry are complex and vary depending on cultivars. There has been considerable debate as to which volatiles are the most important in producing the characteristic aroma of strawberries, but this is highly variable and their content depends mainly on stage of ripeness, varietal differences, climate and location (Larsen et al 1992;Forney et al 2000).…”