Korean Journal of Food Science and Technology (한국식품과학회지)

Korean Society of Food Science and Technology (한국식품과학회)
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Effects of Malt Modification on ${\beta}$-Glucan Solubility and Beer Viscosity

보리의 발아정도가 맥아의 ${\beta}$-glucan 용해성 및 맥주의 점도에 미치는 영향

  • Lee, Young-Tack (Department of Food Science and Biotechnology, Kyungwon University)
  • 이영택 (경원대학교 식품생물공학과)
  • Published : 2008.06.30
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Abstract

Two barley malt samples were selected at two different stages of germination, a well-modified malt germinated for 96 hr and a poorly-modified malt for 60 hr, and were analyzed for total, insoluble, and soluble ${\beta}$-glucan contents. The total ${\beta}$-glucan content in raw barley was 3.96%, and the content was reduced during malting. The total ${\beta}$-glucan contents of the poorly- and well-modified malts were 1.02% and 0.18%, respectively. After 4 days of germination, approximately 95% of the ${\beta}$-glucan present in the barley was degraded. A significantly higher proportion of water-soluble ${\beta}$-glucan was found in the well-modified malt, suggesting that ${\beta}$-glucan solubility was dependent on cell wall modifications in the malt (${\beta}$-glucan breakdown). The proportion of water-soluble ${\beta}$-glucan was also affected by the extraction temperature. The two differently modified malts were mashed isothermally at 45, 55, 65, and 75oC for 2 hr. An increasing mashing temperature resulted in increased viscosity for the wort and the resulting beer. The viscosity of the wort from the well-modified malt was significantly low, due to its low initial malt ${\beta}$-glucan with increased solubility as well as a presumably sufficient ${\beta}$-glucanase activity during mashing.

발아시간에 따라 덜 변형된 맥아(60시간 발아)와 적절히 변형된 맥아(96시간 발아)의 총, 불용성 및 수용성 ${\beta}-glucan$ 함량을 측정하였다. 보리의 총 ${\beta}-glucan$ 함량은 3.96%였으며 발아 중에 감소하였는데 덜 변형된 맥아에서는 1.02%인 반면에 적절히 변형된 맥아에서는 0.18%로 급격히 감소하였다. 적절히 변형된 맥아는 $21^{\circ}C$와 $45^{\circ}C$ 추출온도에서 ${\beta}-glucan$ 용해성이 덜 변형된 맥아에 비해 현저하게 증가하였다. 변형정도가 다른 두가지 맥아에 대하여 당화온도별로 당화 후 맥즙과 맥주의 점도를 분석하였다. 당화온도가 $45-75^{\circ}C$로 증가함에 따라 맥즙과 맥주의 점도가 증가하였으며 적절히 변형된 맥아가 덜 변형된 맥아에 비해 점도의 상승이 크지 않았다. 이는 적절히 변형된 맥아는 덜 변형된 맥아에 비해서 당화과정중에 ${\beta}-glucan$ 용해성이 상대적으로 높지만 초기 ${\beta}-glucan$의 함량이 낮을 뿐 만 아니라 맥아에 충분히 합성되어 발달된 ${\beta}-glucanse$의 활성에 의해 당화과정 중에 용출되어지는 ${\beta}-glucan$의 분해가 이루어지기 때문인 것으로 판단되었다.

Keywords

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