Kimchi Kimchi Fermentation Strain Screening And Processing Of Lotus Root

Lotus root is an important aquatic vegetable which is in high water content and tissue crisp. It is easy for lotus root to brown and lose nutritional value after picked.So people process and utilize lotus root in many ways to prevent its deterioration. Currently in lotus industry of China, the main processing method is initial process, and it shows a low ratio. If lotus or substandard lotus in export processing can be used to make pickles, it will be very meaningful to the diversification and circulation of lotus products, since it can improve product’s nutrition and prolong storage time. In this study, lotus of "mei ren hong" from Baoying county was used to make pickles, and good bacteria were selected from the lotus pickles. And then, the fermentation performance of those strains was studied. After that, natural fermentation and inoculating fermentation were analyzed comparatively on the quality of lotus pickle. And the storage quality of inoculating fermented lotus pickle was also researched. The major achievements and results were concluded as follows:63strains of lactic acid bacteria and35strains of yeast were isolated from natural fermented lotus pickle. After a series of screen,3strains with good fermenting property were obtained, they were lactic acid bacteria L17and L33, and yeast Y27.According to their morphology, physiological and biochemical characters, L17was identified as L.brevis,L33was identified as L.fermentum, Y27was identified as Hansenula anomala. The optimum growth temperature of L17,L33andY27were30℃,35℃and25℃,respectively. The optimum salinity extend of these three strains were all0-6%.L17, L33and Y27were single and compound inoculated in lotus to ferment. The results showed that fermenting with mixture of strains was much better than fermenting with single strain in content of total acid, nitrite and sensory quality. Comprehensively analyzed various targets, the best proportion of3strains were confirmed to be L17:L33:Y27=2:1:1.Normal design of three factors three levels was adopted.In this design, temperature, salinity and inoculation were chosen to be factors, and total acid, nitrite and sensory evaluation were chosen as targets. Experimental results showed that the optimum condition of fermentation was:temperature30℃. salinity5%, inoculation1%. Results of three targets from verification experiment were:total acid0.6089%, nitrite0.4412mg/kg, sensory evaluation87.1. To study the effect of different ingredients on lotus pickle, a normal design of three factors three levels was conducted. The amount of sugar, garlic and ginger were chosen to be factors, total acid, nitrite and sensory evaluation were chosen to be targets. The optimum ratio was: sugar2%, garlic3%, and ginger1%. Under the optimal condition, the content of total acid was0.6217%, the content of nitrite was0.3722mg/kg, and sensory evaluation was95.1.Changes in different fermentation process were measured. Results showed that inoculating fermentation was better than natural fermentation. Inoculating fermentation achieved ripe in four days which was shorter than natural fermentation. It also had a lower content of the peak "nitrite", and after the stable condition, its content of nitrite was under0.4mg/kg. It had a high content of reducing sugar on the fourth day, and then quickly decreased to harmonious. The amino nitrogen kept a high content after its equilibrium which was0.0833%. The main volatile compounds of natural and inoculating fermented lotus were determined by GC-MS method, and results showed that inoculating fermented lotus contains more esters, hydro carbons and less alcohol, ethers, acids and ketones than natural fermented lotus. And it was found that inoculating fermented lotus put up higher quality after all the targets were analyzed between different fermentations.Inoculating fermented lotus was differently handled in package and sterilization to study its storage quality. Vacuum-packed pickles showed better quality than common-packed ones, and it would be much better if it was stored in temperature of4℃.Pasteurization had some bad influence on lotus pickle, so it was not work for the store of fermented lotus. And it could keep a good quality for lotus pickle by store in4℃with vacuum-pack in60days.