A Continuous High‐Pressure Carbon Dioxide System for Cloud and Quality Retention in Orange Juice

Abstract

Orange juice (OJ) was treated with a continuous high‐pressure carbon dioxide (HPCD) system, and the quality parameters pH, Brix, titratable acidity (TA), cloud, pectinesterase (PE) activity, color, and sensory attributes were determined. Treatment pressures were 38, 72, and 107 MPa, and CO2/juice (w/w) ratios were from 0.40 to 1.18. Residence time was kept at 10 min. Cloud increased between 446% and 846% after treatments. There were no significant changes in pH and Brix (α= 0.05). TA of the treated juice was found to be significantly different from that of control (α= 0.01). PE was not completely inactivated. There was a small, but significant increase in juice L‐value (α= 0.01) and a decrease in a‐value for color. There was no significant change in b‐values (α= 0.05). Statistical analysis for the sensory data showed no difference between fresh, frozen control juice and treated juice after 2 wk of refrigerated storage at 1.7 °C.

Inactivation of polyphenol oxidase from watermelon juice by high pressure carbon dioxide treatment

“…Hence, there was no change in the pH was observed in muscadine grape juice, after the removal of CO 2 by vacuum during the last stage of dense phase CO 2 processing (Pozo-insfran et al 2007). However, pH did not change in orange juice after HPCD treatment (Kincal et al 2006). It was because that the dissociation constants of carbonic acid and bicarbonate were pKa=6.57 and pKa= 10.62 (Damar and Balaban 2006), the low pH in the original orange juice resulted in the carbonic acid formed by CO 2 dissolving into the juice difficultly being dissociated into H + ions.…”

Effect of high pressure carbon dioxide processing on pectin methylesterase activity and other orange juice properties

“…The change in colour, ∆E (Eq 3) is also presented in Table 6 and visible 385 differences in colour after HPCD treatment have been determined (∆E ≈ 5). Kincal et al (2006) 386 also reported ∆E values as high as 13.83, at 72 MPa and a ratio of 0.64 CO 2 /juice (w/w). Chroma 387 values listed in Table 6 show that HPCD treatment results in a significant lower colour intensity 388 juice after processing but no significance differences have been observed along storage.…”

“…The faster 207 inactivation reached in our work could be due to the way CO 2 was fed into the sample through 208 CO 2 -microbubbles, which helps to maximizes the interface area for the orange juice and the 209 CO 2 . Inactivation percentages slightly higher than 50 % were reached when using a continuous 210 HPCD system (Kincal et al, 2006). Table 1 also presents the inactivation degree of PME in 211 orange juice when using a combined technology of high power ultrasound-assisted supercritical 212 carbon dioxide (HPU-SCCO 2 ).…”

“…During storage cloudvalue decreased, but even after 12 days cloud enhancement remained 18% higher than the 283 original orange juice. Kincal et al (2006) reported a cloud increase higher than 600%, with little 284 influence of operating pressure when orange juice was treated in continuous HPCD equipment. 285 Arreola et al (1991) found that cloud increased from 27% to 400% regardless temperature or 286 treatment time.…”

“…Kincal et al (2006) suggested that HPCD treatment could 294 lead to precipitation of calcium ions present in the orange juice due to the formation of insoluble 295 calcium carbonate. It has been described that dissolved CO 2 could form carbonic acid that 296 dissociates into bicarbonate that could be converted to carbonate when the pressure is released 297 (Kincal et al, 2006) (Yuk et al, 2014). To study the role of formation of insoluble calcium 298 carbonate in cloud stabilization, calcium content was determined before and after HPCD.…”