SENSORY & OBJECTIVE QUALITY ATTRIBUTES OF BETA-CAROTENE AND LYCOPENE-RICH TOMATO FRUIT

Authors: Stommel, John; Abbott, Judith; Saftner, Robert; Camp, Mary

Submitted to: Journal of the American Society for Horticultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/9/2004
Publication Date: 3/1/2005
Citation: Stommel, J.R., Abbott, J., Saftner, R.A., M. Camp. 2005. Sensory and objective quality attributes of beta-carotene- and lycopene-rich tomato fruit. J. Amer. Soc. Hort. Sci. 130:244-251.

Interpretive Summary: Consumers judge tomato quality by the flavor and texture when they eat them, but it is the appearance that usually determines whether they will taste them in the first place. We conducted a taste comparison of two varieties of cherry tomato that produce red fruit and two that produce orange fruit to determine whether consumers had a color bias. First we camouflaged the tomato color by using dim red lighting in the tasting room and asked tasters about aroma, flavor, and texture of each of the four kinds of cherry tomatoes. Then we asked the same people to taste the tomatoes under natural lighting conditions where they could distinguish orange fruit from red fruit. Fruit were also measured in the laboratory for sugar and acid content, aroma chemicals, and the pigments that cause the orange or red color (beta-carotene and lycopene, respectively). When consumers could distinguish fruit color, they preferred the appearance of red-colored fruit and they scored all fruit as having better overall eating quality than when color was camouflaged. But they scored many of the flavor and texture attributes of each variety similarly under both natural and camouflage lighting. The taste comparison studies, together with laboratory measurements of fruit components, demonstrated that color has an influence on perceptions of fruit appearance, flavor, aroma, textural attributes, and overall eating quality and indicated that a color bias for red-colored fruit existed among the consumers tested. Although competition with red-colored cherry tomatoes limits use of orange fruit, there are specialty market opportunities for premium priced value-added products such as these where color variation is prized. These results will be useful for plant breeders in developing new specialty cultivars and for retail marketing of these products.

Technical Abstract: Consumer acceptance of fresh and processed tomato products is influenced by product appearance, flavor, aroma, and textural properties. Color is a key component that influences a consumer's initial perception of quality. -carotene and lycopene are the principal carotenoids in tomato fruit that impart color. In addition to imparting color, these compounds are valued for their retinoid and/or antioxidant properties. Analytical and sensory analyses of fruit quality constituents were conducted to assess real and perceived differences in fruit quality between orange-pigmented, high -carotene cherry tomato genotypes and conventional lycopene-rich, red-pigmented cherry tomato cultivars. Thirteen sensory attributes were evaluated by untrained consumers under red masking light conditions where differences in fruit color could not be discerned and then under white light. Panelists preferred the appearance of the red-pigmented cultivars when viewed under white light, but scored many of the other fruit quality attributes of red and orange-pigmented genotypes similarly whether they could discern the color or not. Irrespective of light conditions, significant genotype effects were noted for fruit appearance, sweetness, acidity/sourness, bitterness, tomato-like flavor, unpleasant aftertaste, firmness in fingers, juiciness, skin toughness, chewiness, bursting energy, and overall eating quality. Attributes whose scores differed between white and red masking lights were intensities of tomato aroma, tomato-like flavor, sweetness, bursting energy, and juiciness, plus overall eating quality. Masked lighting conditions lowered sensory attribute scores of all genotypes for a number of these quality attributes. Fruit juiciness and tomato-like flavor intensity of red cultivars were scored higher under white, but not red, light. Irrespective of light conditions, high -carotene lines were scored firmer and crunchier than named red cultivars. High -carotene genotypes contained higher levels of sugars and soluble solids than the red-pigmented cultivars. Titratable acidity in high -carotene genotypes was greater than or equal to that of red-fruited cultivars. Total volatile levels did not differ among genotypes; however, several individual volatiles were significantly higher in high -carotene genotypes. The results demonstrate a color bias for red-pigmented fruit and highlight the influence that color has on perception of tomato fruit quality.