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United States Department of Agriculture

Agricultural Research Service

Research Project: IMPROVING THE SENSORY QUALITY AND SHELF LIFE OF FRESH-CUT FRUIT PRODUCTS

Location: Food Processing and Sensory Quality Research

Title: Characterization and semi-quantitative analysis of volatiles in seedless watermelon varieties using solid phase micro-extraction.

Authors
item Beaulieu, John
item Lea, Jeanne

Submitted to: Journal of Agriculture and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 14, 2007
Publication Date: April 18, 2007
Citation: Beaulieu, J.C., Lea, J.M. 2007. Volatile characterization in seedless watermelon varieties using spme. Journal of Agriculture and Food Chemistry. 54:7789-7793.

Interpretive Summary: Fresh-cut fruits are rapidly gaining popularity in the American marketplace, and the relative market share for seedless watermelon is increasing. Seed companies are breeding new varieties for size, firmness, and yield; attempting to capture more of the fresh-cut market. However, numerous flavor, texture, and postharvest quality-related issues are limiting the success of fresh-cut watermelons. Sweetness and sugars are crucial breeding focus for fruit quality, yet, volatile compounds also play an important role regarding consumer acceptance. However, we found no literature for volatile appraisal in seedless watermelon varieties, and no reports using a rapid solid phase microextraction (SPME) method in watermelons. Therefore, the objective of this experiment was to identify volatile and semi-volatile compounds in seedless watermelon varieties using a rapid, non-destructive SPME method with gas chromatography-mass spectrometry (GC-MS). Aldehydes, alcohols, ketones, and 1 furan compound were recovered. The most abundant compounds in 5 varieties were 3-nonen-1-ol/(E,Z)-2,6-nonadienal, (E)-2-nonenal and (Z)-6-nonenal. Hexanal was most abundant (37.7%) in one variety (Pure Heart). The most abundant ketone compound was 6-methyl-5-hepten-2-one (2.8 – 7.7%). Some sensory attributes reported for these compounds are melon, citrus, cucumber, orange, rose, floral, guava, violet, vegetable, green, grassy, herbaceous, pungent, fatty, sweet, and waxy. Identifying and relating these compounds to sensory attributes will allow for future monitoring of the critical flavor compounds in seedless watermelon after processing and throughout fresh-cut storage.

Technical Abstract: Seedless triploid watermelons have increased in popularity since the early 1990’s, and the demand for seedless fruit is on the rise. Sweetness and sugars are crucial breeding focus for fruit quality. Volatiles also play an important role, yet, we found no literature for seedless varieties, and no reports using solid phase microextraction (SPME) in watermelon. The objective of this experiment was to identify volatile and semi-volatile compounds in 5 seedless watermelon varieties using Carboxen/DVB/PDMS SPME with GC-MS. Fully ripe, 2-day old fresh watermelons, were sanitized, rinsed, and the rind removed with a sharp knife. Thick slices (5 cm) were cut and placed on a Silver King Kutlett to cut 2.5 x 2.5 x 5.0 cm bars. Three bars were combined and squeezed through miracloth to produce rapid juice extracts for immediate headspace SPME GC-MS. Aldehydes, alcohols, ketones, and 1 furan (2-pentyl furan, a lipid oxidation product) were recovered. Based on total ion count peak area, the most abundant compounds in 5 varieties were 3-nonen-1-ol/(E,Z)-2,6-nonadienal (16.5 – 28.2%), (E)-2-nonenal (10.6 – 22.5%), and (Z)-6-nonenal (2.0 – 11.3%). Hexanal was most abundant (37.7%) in one variety (Pure Heart). The most abundant ketone was 6-methyl-5-hepten-2-one (2.8 – 7.7%). Some sensory attributes reported for these compounds are melon, citrus, cucumber, orange, rose, floral, guava, violet, vegetable, green, grassy, herbaceous, pungent, fatty, sweet, and waxy. Identifying and relating these compounds to sensory attributes will allow for future monitoring of the critical flavor compounds in seedless watermelon after processing and throughout fresh-cut storage.

Last Modified: 9/22/2014
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