For quality improvement and standardization of traditional kochujang, the kochujang with eight-types meju (Brick shape, Grain shape) prepared with different microorganisms such as Aspergillus oryzae, Aspergillus sojae, and Bacillus subtilis were made. The changes of physicochemical characteristics a...
For quality improvement and standardization of traditional kochujang, the kochujang with eight-types meju (Brick shape, Grain shape) prepared with different microorganisms such as Aspergillus oryzae, Aspergillus sojae, and Bacillus subtilis were made. The changes of physicochemical characteristics and enzyme activities of various kochujang were compared with market products during fermentation at 25℃ for 100 days. The results from the experiments were as follows:
1. The moisture content and titratable acidity of kochujang were increased from the initial 40.94±0.99% and 15.62±0.98 mL (0.1 N NaOH) to 41.69±1.12% and 20.47±2.05 mL at 100-days of fermentation, respectively. The difference of moisture content was little in various strain types and meju shapes. pH and saltness of kochujang were 4.89±0.05 and 9.44±0.17% at initial stage, respectively, and decreased to 4.70±0.04 and 8.9±016% at 100-days of fermentation.
2. Amino-type nitrogen content of kochujang gradually increased to 60-days of fermentation and showed the highest value (159.8 mg%) at 100-days of fermentation in kochujang made by using Grain shape meju prepared with A. sojae. The color during fermentation not showed significant difference in all kochujang and ΔE value generally increased in all samples.
3. Aerobic cell count during fermentation maintained 7-8 log CFU/g by 80-days of fermentation, and anaerobic cell count gradually decreased to 6-7 log CFU/g at 100-days of fermentation. Yeast count maintained 5-6 log CFU/g until 80-days of fermentation, and fungi count drastically decreased to 40-days of fermentation and thereafter, maintained 2 log CFU/g during fermentation.
4. α-Amylase activity was 0.760 unit/g in Brick shape meju kochujang prepared with A. sojae and B subtilis, and β-amylase activity was 2.790 unit/g in Grain shape meju kochujang prepared with A. sojae and B subtilis at 100-days of fermentation. Acidic protease activity and neutral protease activity in Grain shape meju kochujang prepared with A. sojae were 4.760 and 0.886 unit/g at 100-days of fermentation, respectively.
5. Free sugar content of kochujang decreased with fermentation period. The difference between initial stage and 100-days of fermentation was 0.42% in Brick shape meju kochujang prepared with A. sojae. Alcohol content showed the highest value 1.17% in Brick shape meju kochujang prepared with A. sojae and B. subtilis at 60-days of fermentation, and thereafter, gradually decreased.
6. CMP, AMP, hypoxanthin, guanine, and xanthosine were major nucleotides at initial stage of fermentation and their contents except CMP and AMP gradually increased during fermentation. At 100-days of fermentation, the contents of hypoxanthin, guanine, and xanthosine were 16.05-20.49, 10.06-11.07, and 7.06-12.44 mg%, respectively. However, there were no significant differences with treatments and fermentation time.
From these results, no significant difference in quality between the kochujang prepared with various mejus and the market products was confirmed. Especially, Grain shape meju kochujang prepared with A. sojae was better than the market products in the aspects of sensory evaluation, content of organic acids, nucleotides, and neutral protease activity.
For quality improvement and standardization of traditional kochujang, the kochujang with eight-types meju (Brick shape, Grain shape) prepared with different microorganisms such as Aspergillus oryzae, Aspergillus sojae, and Bacillus subtilis were made. The changes of physicochemical characteristics and enzyme activities of various kochujang were compared with market products during fermentation at 25℃ for 100 days. The results from the experiments were as follows:
1. The moisture content and titratable acidity of kochujang were increased from the initial 40.94±0.99% and 15.62±0.98 mL (0.1 N NaOH) to 41.69±1.12% and 20.47±2.05 mL at 100-days of fermentation, respectively. The difference of moisture content was little in various strain types and meju shapes. pH and saltness of kochujang were 4.89±0.05 and 9.44±0.17% at initial stage, respectively, and decreased to 4.70±0.04 and 8.9±016% at 100-days of fermentation.
2. Amino-type nitrogen content of kochujang gradually increased to 60-days of fermentation and showed the highest value (159.8 mg%) at 100-days of fermentation in kochujang made by using Grain shape meju prepared with A. sojae. The color during fermentation not showed significant difference in all kochujang and ΔE value generally increased in all samples.
3. Aerobic cell count during fermentation maintained 7-8 log CFU/g by 80-days of fermentation, and anaerobic cell count gradually decreased to 6-7 log CFU/g at 100-days of fermentation. Yeast count maintained 5-6 log CFU/g until 80-days of fermentation, and fungi count drastically decreased to 40-days of fermentation and thereafter, maintained 2 log CFU/g during fermentation.
4. α-Amylase activity was 0.760 unit/g in Brick shape meju kochujang prepared with A. sojae and B subtilis, and β-amylase activity was 2.790 unit/g in Grain shape meju kochujang prepared with A. sojae and B subtilis at 100-days of fermentation. Acidic protease activity and neutral protease activity in Grain shape meju kochujang prepared with A. sojae were 4.760 and 0.886 unit/g at 100-days of fermentation, respectively.
5. Free sugar content of kochujang decreased with fermentation period. The difference between initial stage and 100-days of fermentation was 0.42% in Brick shape meju kochujang prepared with A. sojae. Alcohol content showed the highest value 1.17% in Brick shape meju kochujang prepared with A. sojae and B. subtilis at 60-days of fermentation, and thereafter, gradually decreased.
6. CMP, AMP, hypoxanthin, guanine, and xanthosine were major nucleotides at initial stage of fermentation and their contents except CMP and AMP gradually increased during fermentation. At 100-days of fermentation, the contents of hypoxanthin, guanine, and xanthosine were 16.05-20.49, 10.06-11.07, and 7.06-12.44 mg%, respectively. However, there were no significant differences with treatments and fermentation time.
From these results, no significant difference in quality between the kochujang prepared with various mejus and the market products was confirmed. Especially, Grain shape meju kochujang prepared with A. sojae was better than the market products in the aspects of sensory evaluation, content of organic acids, nucleotides, and neutral protease activity.
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