Orange juice, acid concentrations

Applications of cation and anion resins are varied and include purification of sugar, identification of drugs and biomacromolecules, concentration of uranium, calcium therapy to help increase the amount of calcium in our bones (i.e., increase the bone density), and use as therapeutic agents for the control of bile acid and gastric acidity. In the latter use, a solid polyamide (Colestid) is diluted and taken with orange juice, which facilitates removal of bile acids from the body. This removal helps the body to produce more bile acid from cholesterol, thus effectively reducing the cholesterol level. 

Figure 5-5 shows data for an experiment in which ascorbic acid (vitamin C) was measured in orange juice by an electrochemical method. The current between a pair of electrodes immersed in the juice is proportional to the concentration of ascorbic acid. Eight standard additions increased the current from 1.78 to 5.82 p,A (column C), which is at the upper end of the desired range of 1.5- to 3-fold increase in analytical signal. 

B 5. A 10-mL sample of pure orange juice was diluted with 40 mL of metaphosphoric acid solution. Then 10 mL of the diluted juice was titrated to an end point with 9.27 mL of DCIP. A blank required 0.25 mL of DCIP. A 1-mg sample of pure ascorbic acid required 6.52 mL (after blank correction) of DCIP. What is the concentration of ascorbic acid in the orange juice in mg/100 mL ... 

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

The loss of ascorbic acid during extraction, finishing, and blending is minimal. Based on the data of Sale (70) and Hayes et al. (71), the loss should be no greater than 2%. Hayes et al. (71) prepared orange juice concentrates having 50-60% solids and reported a mean retention of 96.6% of ascorbic acid. 

Figure 5. Ascorbic acid retention in 54° Brix concentrated orange juice as a function of storage temperature ((O) —17.8°C (O 7.2°C (A) 23.9°C)...

Reduced-Acid Frozen Concentrated Orange Juice... 

A reduced-acid frozen concentrated orange juice is presently being test marketed by The Coca-Cola Company Foods Division. 

Based on a review of all the data gathered for reduced-acid FCOJ, it is apparent that any changes that do occur are of an insignificant nature and do not alter the nutritional quality of the processed orange juice. The product of commerce is of equivalent quality to the more popular product, frozen concentrated orange juice. 

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). 

Table III. Concentrations of y-Aminobutyric Acid and Arginine (mg/100 ml + std. dev.) Orange Juices (Reconstituted to Single...

Other investigators have used maximum and minimum concentration values of specific amino acids as a criteria of authenticity. Brenoe (55) reported means and confidence intervals for all of the amino acids in Greek orange juice. Special emphasis was placed on glycine since it is present in very low levels in citrus juices but is relatively abundant in protein hydrolysates. 

Sawyer (53J included the concentrations of ascorbic and nicotinic acids along with other analytical parameters to detect orange juice adulteration by dilution or addition of peel extracts. He observed that the relation between the total invert sugar to total soluble solids ratio and nicotinic acid became significantly correlated by the dilution of juices with sucrose or partially inverted sucrose. 

A subgroup of the German Chemical Society (173,174) recently published a system which proposed a means of evaluating the juice content of low-juice beverages. It is based on the concentrations of potassium, phosphorus, proline, formol number, isocitric acid and malic acid. Equations for the juice content of lemonades and orange juices (with possible mixture of tangerine or mandarin juice) based drinks are ... 

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