the United States so it can be used in orange juices. The citranges are a group of intergeneric sweet orange x trifoliate orange hybrids. Attributes Sensory factors The taste of oranges is determined mainly by the relative ratios of sugars and acids, whereas orange aroma derives from volatile organic compounds, including alcohols, aldehydes, ketones, terpenes, and esters. Bitter limonoid compounds, such as limonin, decrease gradually during development, whereas volatile aroma compounds tend to peak in mid– to late–season development. Taste quality tends to improve later in harvests when there is a higher sugar/acid ratio with less bitterness. As a citrus fruit, the orange is acidic, with pH levels ranging from 2.9 to 4.0. Sensory qualities vary according to genetic background, environmental conditions during development, ripeness at harvest, postharvest conditions, and storage duration. Nutritional value and phytochemicals Orange flesh is 87% water, 12% carbohydrates, 1% protein, and contains negligible fat (see table). As a 100 gram reference amount, orange flesh provides 47 calories, and is a rich source of vitamin C, providing 64% of the Daily Value. No other micronutrients are present in significant amounts (see table). Oranges contain diverse phytochemicals, including carotenoids (beta-carotene, lutein and beta-cryptoxanthin), flavonoids (e.g. naringenin) and numerous volatile organic compounds producing orange aroma, including aldehydes, esters, terpenes, alcohols, and ketones. Orange juice contains only about one-fifth the citric acid of lime or lemon juice (which contain about 47 g/L). Grading The United States Department of Agriculture (USDA) has established the following grades for Florida oranges, which primarily apply to oranges sold as fresh fruit: US Fancy, US No. 1 Bright, US No. 1, US No. 1 Golden, US No. 1 Bronze, US No. 1 Russet, US No. 2 Bright, US No. 2, US No. 2 Russet, and US No. 3. The general characteristics graded are color (both hue and uniformity), firmness, maturity, varietal characteristics, texture, and shape. Fancy, the highest grade, requires the highest grade of color and an absence of blemishes, while the terms Bright, Golden, Bronze, and Russet concern solely discoloration. Grade numbers are determined by the amount of unsightly blemishes on the skin and firmness of the fruit that do not affect consumer safety. The USDA separates blemishes into three categories: General blemishes: ammoniation, buckskin, caked melanose, creasing, decay, scab, split navels, sprayburn, undeveloped segments, unhealed segments, and wormy fruit Injuries to fruit: bruises, green spots, oil spots, rough, wide, or protruding navels,