The Effect Of Ultra-high Pressure (UHP) Processing On The Flavor In Sichuan Pickled

This article focuses on exploring the effect of ultra-high pressure (UHP) processing on organic acids and volatile compounds in Sichuan pickled. The organic acids and volatile compounds in pickled radish,pickled cowpea, sichuan sauerkraut, and pickled radish treated by UHP and thermal processing are analysed systematically, and combined with sensory evaluation to explore the main flavor components and the effect of UHP processing on Sichuan pickled. Through the above contents, the main conclusion of this paper are as follows:1. The organic acids were analyzed by HPLC in pickled radish, pickled cowpea, sichuan sauerkraut. The results show that the eight organic acids, Oxalic acid, tartaric acid, malic acid, ascorbic acid, lactic acid, acetic acid, citric acid and succinic acid, have significant differences. Taste evaluation shows that pickled radish, pickled cowpea have no significant difference, they have significant difference with sichuan sauerkraut,and their value are higher than sichuan sauerkraut.2. The volatile compounds of pickled radish, pickled cowpea and Sichuan sauerkraut were analyzed by GC-MS, and 32、59、35 compounds were identified respectively. The key volatile compounds of the pickled radish which were determined by relative odor activity value(ROAV) were ethyl butyrate、dimethyl disulfide and dimethyl trisulfide. Linaloo、ethyl-2-Methylbutyrate、ethyl hexanoate、 ethyl phenylalanine、ethyl palmitate、4-ethyl phenol and decanal play an important role in the odor. Linaloo、ethyl butyrate、ethyl hexanoate、ethyl caprylate、dimethyl disulfide、dimethyl trisulfide、4-ethyl phenol、decanal and nonanal is the key volatile compounds of the pickled cowpea. Ethyl phenylalanine and ethyl palmitate play an important role in the odor. Linalool、ethyl butyrate、dimethyl disulfide、dimethyl trisulfide、4-ethyl phenol and decanal is the key volatile compounds of the Sichuan sauerkraut. Ethyl hexanoate、ethyl phenylalanine、ethyl palmitate and nonanal play an important role in the odor. Taste evaluation showed that pickled cowpea is best with value of 5.47, followed by pickled radish with 5.03, Sichuan sauerkraut with 4.50. While olfactory evaluation showed that pickled cowpea is best with value of 5.30, followed by Sichuan sauerkraut with 4.87, pickled radish with 4.50.3. The studies on different pressure processing on oxalic acid, malic acid, lactic acid, acetic acid, citric acid and succinic acid in pickled radish showed that the impact of ultra high pressure was not significant, while the impact on ascorbic acid degradation was significant. The higher, the lower. The processing time only had significant impact on ascorbic acid. The longer, the less ascorbic acid left. But the loss rate of ascorbic acid was decrease with the processing time increasing.4. The pressure had significant impact on volatile compounds. After the Sichuan Pickled were treated by 200Mpa, the number of volatile compounds increased by 19, and the relative content increased by 17.88%; While treated by 300Mpa, the number of volatile compounds was no more or less, but the relative content decreased by 4.7%; Further more, treated by 400Mpa, the number of volatile compounds decreased by 4, and the relative content decreased by 1.64%. Of all the volatile compounds, alcohols^ esters、sulphide、phenols and aldoketones were greatly influenced by ultra-high pressure.5. The number of volatile compounds and its relative content were influenced by the processing time. The number of volatile compounds and its relative content decreased with the increasing of processing time at the same pressure. The volatile compounds was the most different after ultra high pressure processing(200Mpa,20min) with treatment(200Mpa,10min). Dimethyl disulfide was eliminated after ultra high pressure processing for a long time, and the nausea excitant odour in Sichuan Pickled was reduced.6. The content of oxalic acid, lactic acid, acetic acid and succinic acid increased after the thermal processing. While the loss rate of ascorbic acid amounted to 77.08%, which is far more than that of ultra high pressure processing. The number of volatile compounds and total relative content in pickled radish after the thermal processing fallen sharply, only 18 kinds、50.27% left. Meanwhile the relative content of dimethyl disulfide and dimethyl trisulfide increased, with total content amounted to 32.91%, which amount 65.47% of the pickles’ volatiles. Compared with thermal processing, ultra high pressure processing was more effectively to maintain or even improve pickled flavor.7. The taste of pickled radish had no significant differences, compared with those pickled radish treated by thermal processing and different ultra pressure and time, while the sense of smell had significant differences. The value of olfactory evaluation showed that 200X20>300X20>400X20>400X10>the raw materials>300X10> 200X10>thermal processing, of which the pickled treated with 200X20 was 6.33, the pickled after thermal processing was only 4.01.