Quality Characteristics of wheat Nuruk and Optimum Condition of Liquid Starters for Aspergillus sp.

Aspergillus 속 곰팡이를 이용한 액체종국 제조 및 밀누룩의 품질특성

  • Choi, Jeong-Sil (Fermentation & Food Processing Division, Department of Agro-food Resource, NAAS, RDA) ;
  • Jung, Seok-Tae (Fermentation & Food Processing Division, Department of Agro-food Resource, NAAS, RDA) ;
  • Kim, Joo-Yeon (Fermentation & Food Processing Division, Department of Agro-food Resource, NAAS, RDA) ;
  • Choi, Ji-Ho (Fermentation & Food Processing Division, Department of Agro-food Resource, NAAS, RDA) ;
  • Choi, Han-Seok (Fermentation & Food Processing Division, Department of Agro-food Resource, NAAS, RDA) ;
  • Yeo, Soo-Hwan (Fermentation & Food Processing Division, Department of Agro-food Resource, NAAS, RDA)
  • 최정실 (농촌진흥청 국립농업과학원 농식품자원부 발효이용과) ;
  • 정석태 (농촌진흥청 국립농업과학원 농식품자원부 발효이용과) ;
  • 김주연 (농촌진흥청 국립농업과학원 농식품자원부 발효이용과) ;
  • 최지호 (농촌진흥청 국립농업과학원 농식품자원부 발효이용과) ;
  • 최한석 (농촌진흥청 국립농업과학원 농식품자원부 발효이용과) ;
  • 여수환 (농촌진흥청 국립농업과학원 농식품자원부 발효이용과)
  • Received : 2011.10.07
  • Accepted : 2011.12.03
  • Published : 2011.12.28

Abstract

This study focus was primarily the development of liquid starters for Aspergillus oryzae and Aspergillus niger prepared with wheat bran as a low cost culture medium. For the preparation of the liquid media wheat bran was added at rates of 0, 5, 10, 15 and 20% and the Aspergillus sp. strains were then inoculated to these prepared broths. The results indicated that the more that wheat bran was contained in the medium, the more mycelia was produced for A. oryzae and A. niger. The highest enzyme activities were obtained with a 10~15% adding rate of wheat bran for both strains. Changes in the enzyme activities of the liquid starters during various incubation times (0, 24, 48, 72 and 96 hrs), indicated that the highest enzyme activities were seen between 48 and 72 hrs of culture. In addition, a comparative study was carried out on the production of enzymes using wheat as a substrate in nuruk, with liquid starter made from fermented agents according to the same concentrations used with the wheat bran. The pH, acidity, amino acidity, reducing sugar content and enzyme activity (${\alpha}$-amylase, glucoamylase, acidic protease) of wheat nuruk made with liquid starter were compared with those of wheat nuruk made with solid starter. The results suggest that the liquid starter is superior in both cases.

고역가 액체종국 제조 및 배양기술을 개발하기 위해, Aspergillus 속의 곰팡이(A. oryzae, A. niger)를 이용한 밀기울 첨가율 별(0, 5, 10, 15 및 20%) 배지를 이용한 액체종국을 제조하여 이들의 품질 특성을 조사하였다. 액체종국의 일반성분 및 효소활성(glucoamylase, acidic protease)을 조사한 결과, 배지에 밀기울 첨가량이 많을수록 균사체량이 많아졌을 뿐만 아니라 산도, 아미노산도도 증가하는 것을 알 수 있었고 액체종국에 첨가하는 밀기울 농도가 달라짐에 따라 각 균주의 효소활성이 바뀌는 것을 알 수 있었다. 또한, 효소활성에 따른 최적 배양시간은 곰팡이 종류에 따라 차이가 있었고 A. oryzae와 A. niger 곰팡이의 액체종국 배양은 10~15% 밀기울을 첨가하여 48~72시간 배양하는 최적조건을 규명하였다. 기존에 사용되었던 고체종국과 비교하여 밀입국제조에 종국으로써 적합한지를 구명하고자 A. oryzae와 A. niger를 사용한 고체종국을 접종한 밀누룩을 대조구로 하여 밀기울 10% 액체배지로 만든 액체종국의 접종량 별(1, 3, 5, 10%) 밀누룩의 배양시간 별(0, 15, 20, 36, 38, 40 hrs) 및 이화학적 특성과 효소활성(${\alpha}$-amylase, glucoamylase, acidic protease)변화를 비교하였다. 결론적으로 시간과 인력등의 경제적 가치가 많이 투입되는 고체종국 보다는 누룩 제조시 액체종국을 사용하는 것이 여러 가지 측면에서도 유리 하다고 여겨진다.

Keywords

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