Texas red grapefruit was designated the official state fruit of Texas in 1993. A fairly new citrus, grapefruit is believed to be a cross between a pummelo and an orange.The grapefruit family includes white, red (sweeter than white), pummelo (father of the grapefruit and the largest citrus), minneola (cross between tangerine and grapefruit), and sweeties (cross between the pummelo and the grapefruit).

Texans have grown grapefruit in the Rio Grande Valley for about 100 years. Around 1929 a mutation on a single tree became the famed Texas Ruby Red, which received the first-ever patent awarded to a grapefruit.

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Links:

Texas Rubies - Winter's Treasure: Texas Cooking
Grapefruit Sunriser Recipe: Chef2Chef
Romaine Salad with Texas Ruby Reds: Culinary Cafe
American Food and Agricultural Symbols
American Food Holidays
Nutrition Facts and Fun: ABC Kids - N. Dakota U
Food Safety and Nutrition: USDA Kids, Teens, Educators
Nutrition Explorations for Kids: Ariana's Nutrition Expe
US Food Industry Facts & History by Spike and Jamie