外源碳源对葡萄酵素微生物生长代谢 及生物活性的调节作用

本文以红糖、白糖与蜂蜜为外源碳源添加物,探讨葡萄酵素发酵过程中酵母菌和乳酸菌生长代谢及超氧化物歧化酶(Superoxide dismutase,SOD)和抗氧化活性的差异。采用平板菌落计数法测定微生物菌数;高效液相色谱法(High Performance Liquid Chromatography,HPLC)分析有机酸含量;邻苯三酚法检测SOD酶活;1,1-二苯基-2-三硝基苯肼(1,1-Diphenyl-2-picrylhydrazyl,DPPH)自由基、2,2'-联氮双(3-乙基苯并噻唑啉-6-磺酸)(2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid),ABTS+)自由基和羟基(Hydroxyl radical,OH)自由基清除实验比较抗氧化能力。结果表明,添加碳源减缓酵母生长及乙醇代谢,促进乳酸菌生长及进行产酸活动。其中,红糖、白糖对酵母菌生长及乙醇代谢抑制能力较强,发酵后乙醇浓度各为2.07%vol、1.62%vol,显著低于蜂蜜组(P<0.05);红糖促进乳酸菌生长并提高总酸含量及SOD酶活,发酵后pH由4.16降至3.83,SOD酶活由71.68 U/mL增至91.05 U/mL。与白糖、蜂蜜及对照组相比,添加红糖发酵显著提高葡萄酵素的DPPH、ABTS+、OH自由基清除率(P<0.05)。原葡萄液含有大量酒石酸、苹果酸,添加所有碳源发酵显著增加葡萄酵素中苹果酸、及乳酸、乙酸、柠檬酸等含量(P<0.05),但酒石酸含量在添加红糖条件下显著减少(P<0.05),而添加白糖、蜂蜜对酒石酸含量影响不大。因此,添加红糖有利于改善葡萄酵素微生物的生长代谢及提高产品的营养价值。

Regulating Effect of Exogenous Carbon Source on Microbial Growth and Metabolism in Grape Fermentation and Its Bioactivity

In this paper,the difference of growth and metabolism of yeast and lactic acid bacteria,as well as superoxide dismutase(SOD)activity and antioxidant capacity was investigated by adding extra carbon sources,including brown sugar,white sugar or honey in the grape-fermentation. The microbial count was measured by plate colony-counting method. Organic acid contents were determined by high performance liquid chromatography(HPLC). SOD activity was determined by pyrogallol autooxidation method. Antioxidant capacities were studied by(1,1-Diphenyl-2-picrylhydrazyl)DPPH free radical,(3-Ethylbenzothiazoline-6-sulfonic acid)ABTS+ free radical and(Hydroxyl radical)OH free radical scavenging experiments.The results showed that the addition of carbon source retarded yeast growth and ethanol metabolism,and simultaneously facilitated the growth of lactic acid bacteria and acid production. Among them,brown sugar and white sugar had strong inhibition ability on yeast growth and ethanol metabolism,the ethanol concentration reached 2.07%vol and 1.62%vol after fermentation respectively,which was significantly lower than honey group(P<0.05). Brown sugar could promote the growth of lactic acid bacteria and increase the total acid content and SOD activity. The pH value decreased from 4.16 to 3.83,and the SOD activity increased from 71.68 U/mL to 91.05 U/mL after fermentation. In comparison with white sugar,honey and control group,adding brown sugar significantly increased the DPPH,ABTS+,OH free radicals scavenging rate(P<0.05)in grape fermentation. The raw grape juice contained a lot of tartaric acid and malic acid,but the addition of all carbon source significantly increased the content of malic acid and lactic acid,acetic acid and citric acid. Whereas,the content of tartaric acid decreased significantly(P<0.05)by adding brown sugar,and it did not change much by adding white sugar and honey. In conclusion,the addition of brown sugar in grape-fermentation was beneficial to improve the growth and metabolism of microorganisms and enhance the nutritional value of products.