| The tibetan turnip is rich in nutrition.It has many functions.Vegetable pickling is not only a method of preservation,but also can present different flavor from fresh vegetables.Tibetans have a history of pickling tibetan turnip,but there is no relevant report this.Tibetan turnip is a Cruciferae Brassica plant.At present,some popular pickled vegetables belong to Brassica of Cruciferae,such as mustard,cabbage,kohlrabi and so on.Therefore,the pickle of Tibetan turnip is a direction that can be explored.Low salt is the development direction of the pickled vegetable products.The pickled vegetable products with high salt content are difficult to eat directly.Most of them need to be eaten with other foods.Moreover,excessive salt intake every day will cause many diseases.Now many low salt pickled products are obtained after desalination,which will make the pickled products lose a lot of nutrients.The aim of this experiment is to reduce the salt content of pickled products of turnips and make them edible directly.In this paper,fresh turnip were used as raw materials,referring to the semi-dry fermentation of salted vegetables such as mustard tuber was used to dehydrate the turnip by wind-dehydrated or salt-dehydrated,and then natural fermentation was used to make the low-salt turnip.After that,making the comparison of the difference of quality change between the two kinds of pickled products during curing and fermentation period,the difference of quality of pickled products after ripening period and the difference of quality change during preservation period.The conclusion is as follows:1.During the curing period,the water content,total sugar,total flavone,total phenol and Vc content,pH value and L* value of the two kinds of salted vegetables showed a downward trend,while the salt content,total acid,amino acid nitrogen content,a* and b* values showed an upward trend.After 7 days' curing,The salt content of the salt vegetable of wind-dehydrated was always significantly higher than that of salt-dehydrated,while the total acid content and pH value were significantly higher than that of the salt-dehydrated ones(P<0.05).After curing for 14 days,there was no significant difference in water content between the two kinds of pickles(P>0.05).Thepeak content of nitrite of wind-dehydrated ones was 11.16 mg/kg,and the peak content of nitrate of salt-dehydrated ones was 16.21 mg/kg,the difference was significant(P<0.05).After 12 days of curing,the content of nitrite of of wind-dehydrated ones was always significantly lower than that of salt-dehydrated ones.There was no significant difference(P>0.05)in the total sugar content between the two kinds of pickles.After 60 days of curing,the amino acid nitrogen content of the wind-dehydrated salt vegetable was significantly lower than that of the salt-dehydrated salt vegetables(P<0.05).The a*and b* values of the of wind-dehydrated salt vegetables were significantly higher than those of the of salt-dehydrated salt vegetables(P<0.05).After 60 days of salting,the total flavonoids and phenols of the wind-dehydrated salt vegetables were significantly higher than those of the salt-dehydrated salt vegetables(P<0.05),while the Vc content was lower than that of the salt-dehydrated salt vegetables,but the difference was not significant(P>0.05).2.After two months of ripening,the salt content of the salt vegetable of wind-dehydrated turnip was only 6.10%,which was significantly lower than that of the salt-dehydrated turnip 8.83%(P<0.05);the other physical and chemical components of the salt vegetable of wind-dehydrated turnip were significantly higher than that of the salt-dehydrated turnip except VC(P<0.05);the essential amino acid content and total amino acid content of the salt vegetable of wind-dehydrated turnip were significantly higher than that of the salt-dehydrated turnip.The a* and B* values of the salt vegetable of wind-dehydrated turnip were also significantly higher than those of the salt-dehydrated turnip(P<0.05),indicating that the browning degree of the salt vegetable of wind-dehydrated turnip was greater.Phenyl isothiocyanate was the highest content of flavor substances in the two kinds of pickle products,27.07% of which were cured with wind-dehydrated turnip,17.33% of which were cured with salt-dehydrated turnip.The antioxidant activity of wind-dehydrated turnip is better than that of salted-dehydrated turnip.According to the fuzzy comprehensive evaluation,71.5% of the people prefer the c wind-dehydrated turnip,while only 47.5% salt-dehydrated turnip.DPPH free radical scavenging ability and ABTS +ˇfree radical scavenging ability of the salt-dehydrated turnip root salt vegetable block were significantly higher than that of the salt-dehydrated turnip(P<0.05);the total reducing power of the salt-dehydrated turnip was 1.79 mg anti cyclic acid/G,and the salt-dehydrated turnip was 1.76 mg anti cyclic acid/g,the difference was not significant(P>0.05).According to the fuzzy comprehensive evaluation,71.5% of the people like the wind-dehydrated turnip,andonly 47.5% like the salt-dehydrated turnip.3.After desalination,the salt content of the finished product of salt-dehydrated turnip was 6.06%,which was significantly lower than that of 8.83% before desalination(P<0.05).After 180 days storage,there was no significant difference in water content and total acid content of the same kind of salt vegetable in different storage temperature(P>0.05).There was no significant difference(P>0.05)between 5? and normal temperature storage of wind-dehydrated turnip,but it was significantly higher than that under 35?(P<0.05),and under 35? and normal temperature storage of salt-dehydrated turnip was significantly lower than that under 5 ?(P<0.05).There was no significant difference in the content of amino acid nitrogen between the wind-dehydrated turnip(P>0.05).However,the amino acid nitrogen content of the salt-dehydrated turnip stored at 5? was significantly higher than which stored at 35?.The(35)E value of the wind-dehydrated turnip which preserved at 5? was lower than that of salt-dehydrated turnip,but there was no significant difference(P>0.05),while the(35)E value of the wind-dehydrated turnip which preserved at room temperature and 35? was significantly lower than that of the salt-dehydrated turnip(P<0.05).The total number of total plate count of both of the two kinds of turnip was less than 200 CFU/g,and the coliform group was less than 0.3 MPN/g.There was no significant difference between the total flavone content of the wind-dehydrated turnip at 5? for 180 days and that at the other two storage conditions(P>0.05),while the contents of total flavonoids,total phenols and ascorbic acid in the salt-dehydrated turnip preserved at 5? for 180 days were significantly higher than those in the other two storage conditions(P<0.05). |
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