Submitted to: Journal of the American Society for Horticultural Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/12/2004
Publication Date: 2/10/2006
Citation: Beaulieu, J.C. 2006. Volatile changes in cantaloupe during growth, maturation, and in stored fresh-cuts prepared from fruits harvested at various maturities. Journal of the American Society for Horticultural Science. 131:127-139. Interpretive Summary: Fresh-cut fruit sales have grown in a linear manner, at roughly $1 billion per year, however, sales have lagged behind their counterpart, vegetables, due to complicated physiological and biochemical events that are not as common in fresh-cut salads. Sale trends for fresh-cut salads indicate clearly that consumers will pay for the convenience of fresh-cut, especially when quality is perceived to be better than or equal to the uncut product. Consumers often buy for the first time based on appearance, but repeat purchases are driven by internal quality factors, such as, flavor and texture. Unfortunately, fresh-cut fruit flavor appears to be inconsistent and often does not seem to retain the typical flavor of the whole, uncut product. Little research has been performed toward understanding mechanisms responsible for generation and/or loss of flavor quality in fresh-cut fruits. Since fruit flavor is highly dependent on the initial ripeness (maturity) of the fruit, we therefore performed an analysis of flavor volatile compounds with cantaloupe that were of known age. Whole fruit was sampled during growth, development, and then distinctly different maturity classes were used to prepare fresh-cut cubes. The volatile patterns were monitored through storage of the fresh-cut product, and this manuscript presents some of the key findings. In summary, there is a maturity-dependent volatile recovery, which is; more mature fruit delivers a higher proportion of volatiles upon cutting, and throughout storage. Also, there appears to be a transient increase in many flavor-related esters after fresh cutting, then a decline, often substantial, that usually occurs 7 days after processing. On the other hand, the proportion of important flavor related acetates continually declines after cutting. This data should illustrate to the industry, that product quality is dependent upon initial product maturity, which is essential for continued sales, and enhancing consumer demand of fresh-cut cantaloupe products.
Technical Abstract: Aside from cost, the most probable reason why consumers are not repeat buyers of many fresh-cut fruits is inconsistent or unsatisfactory flavor and/or textural quality. Research toward understanding mechanisms responsible for generation and/or loss of flavor compounds in fresh-cut fruits is limited. We utilized solid phase microextraction (SPME), and GC-MS to study flavor volatile profiles in anthesis tagged cantaloupe during growth, development, and for fresh-cuts prepared from fruits with five distinctly different harvest maturity. There are 19 compounds that have been considered characteristic impact flavor or aroma compounds (CIFAC), and 18 CIFAC's were routinely recovered and positively identified in 'Sol Real' cantaloupe using polydimethylsiloxane (PDMS) SPME GC-MS. Recovery of total volatiles displayed a significant linear response, and most volatile classes (except aldehydes) generally followed a trend upon processing where full-slip (FS) > ¾-slip > ½-slip > ¼-slip. On day 0, only 80.7, 76.0, and 69.0% total volatiles were recovered in ¾-slip, ½-slip, and¼-slip fruit, compared to FS fruit. During fresh-cut storage, percent total esters followed an increasing linear trend that was maturity dependent. Percent total aromatics and percent aldehydes followed a decreasing linear trend that was maturity-dependent whereby ¼-slip > ½-slip > ¾-slip > FS. During storage, the relative percentage of acetates displayed a maturity dependent decreasing linear trend. The magnitude of the slope decreased with maturity, indicating that the effect of storage time decreased as the maturity increased. In FS, ¾-slip, ½-slip, and ¼-slip cubes, acetates comprised roughly 66.8% of all compounds recovered on day 0 yet, only 35.2 ' 41.8%, and 27.3 ' 32.6% remained on days 9 and 14, respectively. In all maturities, a significant curvilinear increase in relative % of non-acetate esters was observed through storage. There was a uniform change in the ester balance (non acetate ester:acetate ratio) through fresh-cut storage that was independent of initial processing maturity. The overall ester balance changed roughly 2-fold after just 2 days in optimum storage, and after 5 days it increased more than 3-fold. The shift in endogenous ester compounds could be partially responsible for the apparent loss of characteristic flavor in fresh-cut cantaloupe through long-term storage. A correlation between sensory attributes, volatile classes, and individual volatiles is warranted to support this assertion.