Colorimetric Furfural Measurement as an Index of Deterioration in Stored Citrus Juices

Abstract

Furfural arising in citrus juice as a result of deterioration during storage may be recovered and concentrated by rapid distillation and then calorimetrically determined by reaction with 10% aniline in acetic acid‐ethanol. As little as 25 μg per liter of furfural can be measured. The development of noticeable furfural parallels the development of off‐flavor and provides a useful numerical index for the extent of degradation. Results of a brief storage study on orange juice are reported.

Hunter color dimensions, sugar content and volatile compounds in pasteurized yellow passion fruit juice (Passiflora edulis var. flavicarpa) during storage

“…4). This behavior was observed in orange juice by several authors (Nagy and Dinsmore, 1974;Dinsmore and Nagy, 1972;Mijares et al 1986). In our studies, the lowest variation was noted in the juice treated at 85 º C/27s (R) at (3.7% -from 0.27ppm to 0.28ppm).…”

Non-enzymatic browning in citrus juice: chemical markers, their detection and ways to improve product quality

“…Acid catalysis is functional even under oxidative conditions and that ascorbic acid is partially responsible for orange juice discoloration. Since it was observed that ascorbic acid breakdown in orange juice results in furfural production and furfural buildup closely parallels quality loss in citrus products, furfural indexing has been proposed as a basis for quality control (Dinsmore and Nagy 1972;Nagy and Dinsmore 1974;Nagy and Randall 1973). In addition to ascorbic acid, pentoses and uronic acids are also known to produce furfural on breakdown.…”

“…The method consisted of distilling 200 ml of single-strength orange juice from which 2 mL was taken and to this was added 2 ml of 95 % ethyl alcohol and 1 ml of aniline reagent (5 ml of freshly distilled aniline made up to 50 ml with glacial acetic acid). The color which developed after 15 min was measured at 515 nm (Dinsmore and Nagy 1972;Nagy and Randall 1973). Examination of canned juice showed that for every 5°C temperature rise in storage there was an approximate doubling of the furfural content.…”

Colorimetric methodology for monitoring the cellulose insulating paper degradation in electrical equipments filled with mineral oil

“…The intensity for the resulting color is measured at 520 nm with an UV-VIS spectrophotometer. This method has been proposed in a previous work published by Dinsmore and Nagy (1972), who developed a methodology to detect 2-FAL in commercial citrus juices down to a level of 5 ppb. In citrus juice, for example, both 2-FAL and 5-HMF are useful indicators of temperature abuse (Dinsmore and Nagy 1972).…”

“…This method has been proposed in a previous work published by Dinsmore and Nagy (1972), who developed a methodology to detect 2-FAL in commercial citrus juices down to a level of 5 ppb. In citrus juice, for example, both 2-FAL and 5-HMF are useful indicators of temperature abuse (Dinsmore and Nagy 1972). Some other methods to determine 2-FAL in food industry have been evaluated (Friedemann et al 1964;Meydav and Berk 1978) and the most commonly employed is the spectrophotometric method proposed by Winkler (Winkler 1955).…”