The genus Citrus belongs to the family Rutaceae and comprises about 40 species. Due to its nutritional value and flavor, Citrus is one of the fruits 308being consumed fresh or as juice. Citrus fruits have been shown to possess anti-inflammatory, antioxidant, antitumor, and antifungal activities (Ghafar et al., 2010). These fruits contain a variety of sugars, citric acid, ascorbic acid, carotenoids, minerals, essential oils, etc., and play an important role in human nutrition as an excellent source of antioxidants (ascorbic acid, carotenoids, and phenolic compounds) (Rekha et al., 2012). Citrus grandis is a crisp citrus fruit native to south and southeast Asia. Due to favorable climatic condition, the fruit is one of the major fruit crops in Sikkim. The fruit is usually pale green to yellow when ripe, with sweet white (or, more rarely, pink or red) flesh and very thick albedo (rind pith). It is the largest citrus fruit, 15–25 cm (5.9–9.8 in) in diameter, and usually weighing 1–2 kg (2.2–4.4 lb) (Growing the Granddaddy of Grapefruit, 2014). Ascorbic acid is the most important vitamin and natural antioxidant in fruit juices, especially in Citrus sp., and it protects the organism from oxidative stress (Ebrahimzadeh et al., 2004; Fernandez-Lopez et al., 2005).