Oranges juice, ascorbic acid content

Figure 3. Changes in ascorbic acid content of freshly squeezed orange juice and reconstituted orange juice concentrate during storage in refrigerator (62)...

Atkins et al. (14) reported that most of the ascorbic acid that occurs in the orange is present as a constituent of the peel. Based on the weight of whole fruit, the juice contains about 25% of the total ascorbic acid content. The juice of the grapefruit contains only about 17% of the total ascorbic acid content on the same basis. 

Squires and Hanna (79) examined 17 brands of reconstitued orange juice in plastic-coated cardboard containers that were purchased at the retail level then stored at 4°C. Their data indicated that the ascorbic acid contents of these chilled orange juice samples decreased at a rate of about 2% per day. 

In a series of five studies of 14 days each, the effects of ascorbic acid on manganese utilization were investigated. The usual basal diet was modified to lower the ascorbic acid content by substituting apple juice for the usually-fed orange and tomato juices. 

Esteve et al (2005) studied nutritional characteristics of orange juices that can be found on the market and their evolution with time (1-6 weeks), and storage temperature in refrigeration (4 and 10°Q. The ascorbic acid content of the juices decreased during storage, faster at 10 than at 4°C. The shelf life of the juices, based on 50% of the initial ascorbic acid concentration, was 42 days at 4°C and 35 days at 10°C. 

The content of ascorbic acid, in milligrams per 100 mL, in orange juice is determined by a redox titration using either 2,6-dichlorophenolindephenol or N-bromosuccinimide as the titrant. 

Composition. Scientific data concerning liquids washed with water from orange juice finisher pulp was first published by Olsen et al. (30). They studied Brix/acid ratios, sucrose, reducing sugars, pH, pectic constituents, turbidity, pulp content, ascorbic acid, viscosity, and flavonoid content of experimental and commercial samples. Characterization of pulp-wash continued with publication of quality data (31), examination of pectic substances (32), microbiology (33), and comparison of pulp-wash with orange concentrate (34). 

Strips of LDPE, from the inner liner of the "bag in the box" at a surface to volume ratio double the actual ratio in a 6 gallon bag, were inserted into glass jars, which were hot filled with orange juice and stored at 35°C. In contrast to the degradative effect of the PE contact layer of the cartons, no detrimental effect on browning, ascorbic acid, and taste, as compared to juice in glass, was found in this case. However, also in this case d-limonene content was reduced to about half the initial content in a short time. 

Orange juice appears not to interact, despite its calcium content, because at the relevant pH values in the gut, the calcium is bound to components within the orange juice (citric, tartaric and ascorbic acids) and is not free to combine with the tetracycline. ... 

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