Formol index

Adjustment of the formol values in commercial orange juice with inexpensive amino acids such as glycine has been detected by Benk and Cutka (67) by means of thin-layer and paper chromatography. Aranda et aT. (68) studied the TLC amino acid patterns as a means of detecting adulteration by amino acids and concluded that amino acids added in sufficient quantities to balance the formol index value could be detected. 

The formol index (total free amino acids) was the best predictor of browning rate of concentrates during storage for a given commodity. While haze and sediment formation were quality factors of major interest in this study, none of the juices or concentrates produced were particularly troublesome in this regard. The phenolic and protein profiles should still provide a reference with which unstable experimental or commercial samples can be compared in the future, however. In addition to color and appearance, quality factors of flavor, astringency, bitterness, viscosity and mouthfeel warrant investigation. 

Protein hydrolysis, evaluating degree of fluorescamine reaction, 146-147 formol titration, 147-148 ninhydrin reaction, 142-144, 153 pH-stat, 149-151, 153 TCA solubility index, 152 TNBS reaction, 144-146... 

Sample Initial Browning Index Rate Constant Formol Value... 

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