Carotenoid Content of Butternut Squash Cultivars Following Harvest and Storage

Butternut squash is a high value niche crop usually grown in cooler climates. New cultivars offer adaptation to the humid and warm North Carolina climate. Butternut is high in alpha and beta carotenoids and contributes over 20% of the required daily value of provitamin A in a serving. Twenty five cultivars grown at three locations from eastern to western NC (USDA climate zones 8 to 5) were harvested at 60, 80 and 120 days after planting, respectively. Twenty five cultivars were evaluated for soluble solids content and carotenoid composition after harvest, and thirteen of these were stored for 0, 5 and 9 weeks at 13°C, 70% RH. Samples were cut from the center of the squash neck, steam microwaved until tender (about 7 min at 900 W), frozen at -20 °C, thawed, and homogenized. Soluble solids content was measured using a digital refractometer. Carotenoids were extracted with hexane and determined using high performance liquid chromatography. Cultivars consistently highest in total carotenoids at harvest were the personal size ‘Honeynut’ and ‘Butterscotch’ (6-9 mg/100 g fresh weight) and the fresh market cultivars ‘Metro’, ‘Betternut900’, ‘Avalon’, ‘Waltham’, ‘Butterfly’ and ‘RB4757A’ (6-8 mg/100 g fwt). Soluble solids content ranged from 7 to 11% at week 0 and increased to 7 to 18% at week 9 of storage among cultivars. Total carotenoid and beta carotene content increased on average 50-70% between weeks 0 and 9 of storage. These results show that provitamin A content can increase substantially in stored butternut squash and that there is a range of cultivars suited for North Carolina production that are high in provitamin A content at harvest.