61B-24 |
Effect of carbon dioxide assisted high pressure processing on the ascorbic acid and headspace volatile retention of Valencia orange juice |
J. M. BOFF1, T. Truong, T. H. Shellhammer, and D. B. Min. (1) Food Science and Technology, The Ohio State University, 110 Parker Food Science and Technology, 2015 Fyffe Road, Columbus, OH 43210-1007 Thermal processing of orange juice is designed to inactivate pectin methylesterase (PME), but can cause flavor and nutrient losses. Recent research has produced an optimized procedure for CO2 assisted high pressure processing (HPP) of orange juice resulting in reduced HPP treatment pressure and processing times while inactivating PME and proving beneficial to volatile and ascorbic acid retention. This research details a direct comparison of CO2 assisted HPP to thermally processed and HPP juice in terms of flavor and ascorbic acid stability over time. Samples of Valencia orange juice were processed by HPP (600 MPa, 25C, 346 sec), HPP+CO2 (600 MPa, 12 psig CO2, 25C, 130 sec) or thermally processed (91C for 30 sec). Volatile compounds were collected and quantified by headspace solid phase microextraction gas chromatography. Ascorbic acid was quantified by HPLC. Measurements were made immediately after processing and periodically over 120 days. Samples were stored in the dark in sealed glass vials. Ascorbic acid content was moderately affected by processing conditions. HPP+CO2 had the highest ascorbic acid content followed by HPP, which was similar to the thermally processed juice. Ascorbic acid content decreased steadily over time for all processes. After 28 days at 4C, HPP+CO2 had the best retention of ascorbic acid (79%) compared to 70% in the thermally processed and 69% in the HPP sample. Total volatile retention was greatly affected by processing with the HPP and HPP+CO2 being significantly higher (p<0.05) than the thermally processed juice, which lost 37%. This trend continued during storage with the HPP, HPP+CO2 and thermally processed juices having retentions of 67%, 65% and 44.7% respectively after 28 days at 4C. These results indicate that both ascorbic acid and volatile retention can be increased by HPP+CO2 treatment and total volatile retention can be increased by HPP when compared to thermally processed juice.
Session 61B, Food Chemistry: Flavor and aroma chemistry
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