Abstract
The structure of fresh orange tissue, juices, comminuted bases and products has been studied by microscopy. The techniques employed were light microscopy, thin sectioning, negative staining, freeze etching and scanning electron microscopy. Physical and chemical parameters of the particles in the juices, bases and products were also measured and these included cloud level, estimation of hesperidin content and refractive index of hesperidin. The appearance of the cells found in the flavedo, albedo, segment membrane and juice sac were sufficiently characteristic to enable the origin of the various cellular fragments found in the processed juice to be ascribed to a particular tissue origin. The structures observed in the oil ring formed in the neck of bottles of certain beverages was found to be mainly lipid materials. The form of the lipid was different on beverages with contrasting processing history. Numerous aggregates of oil droplets and hesperidin crystals were observed in the cloudy portion of the beverages, and a substantial number of these particles were less than 0.5?m diameter. A method was evolved for estimating the crystalline hesperidin content of the sample based on the difference in the ultraviolet absorption of a methanol and aqueous extract of the beverage. It was concluded that the quantity of hesperidin present in orange beverages is an important, although not the sole factor in determining its cloud level. Samples with a high cloud level contained high levels of hesperidin. A limited study of lemon beverages indicated that hesperidin content may not play such an important role in their cloud level.