76C-37 |
Phytochemical composition of different varieties of watermelons (Citrullus lanatus) grown at three different locations |
A. PUERTA-GOMEZ and L. A. Cisneros-Zevallos. Horticultural Sciences Dept., Texas A&M University, Horticulture & Forest Sci., Texas A&M University, College Station, TX 77843 Watermelons have a good content of different types of phytochemicals with carotenoids being the main secondary metabolites with known health benefits properties. The accumulation and stability of those phytochemicals may be affected by pre-harvest factors and environmental conditions associated with location. It is stated that harvest maturity, soil fertility, irrigation, light intensity, and temperature may affect lycopene content in watermelons. Our objective was to determine the effects of growing location in the accumulation of phytochemicals of yellow-fleshed and red-fleshed watermelons varieties (Willhite-Summergold-Hybrid, Hillhite-Gem Dandy-Triploid, and Peto Seed-Royal Sweet-Hybrid) adapted to three different Texas climates (Weslaco, Overton, and Lubbock). Watermelon varieties were evaluated for quality attributes such a color (L*, a*, b* values) and texture. HPLC and spectrophotometric methods were used to identify and quantify carotenoids, phenolics, vitamin C and sugars. A free radical method was used for the evaluation of antioxidant activity. Additionally, total acidity, soluble solid content, pH, density, fruit size, and dry matter were evaluated on all samples. Our results show that watermelons have a low content of phenolics in the range of 15 to 25 mg/100g, being slightly higher for the melons grown in Lubbock. Differences were observed more among locations than between varieties, as it was seen for size, pH, density and soluble solid content. The antioxidant activity in watermelons was given mainly by the lipophilic content (e.g., lycopene, b-carotene and xanthophylls), which was at least 3 times higher than the antioxidant activity given by the hydrophilic fraction (phenolics, and vitamin C). In general, vitamin C content was also low for the three varieties analyzed in all locations. The results suggest that there is some effect of growing location on the accumulation of phytochemical in watermelons. The selection of appropriate pre-harvest factors could influence the synthesis of secondary metabolites that have shown health benefit properties.
Session 76C, Fruit & Vegetable Product: Fresh Fruits and Vegetables
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