Quality Changes of a Fully Ripe Korean Native Pumpkin, Yangsan, during Long-term Storage, and High Temperature and Pressure Treatment

장기저장 및 고온고압 처리에 따른 한국재래종 호박 '양산'의 품질변화

  • Published : 2004.12.31

Abstract

We have studied quality changes of fully ripe fruit of Korean native pumpkin 'Yangsan' regarding the following parameters: pH, sugar content, weight, water content, contents of crude protein and amino acids during 60 days storage at room temperature. As the results, there was no changes in sugar contents according to the storage period, but pH was changing to a little acidic direction with slight decrease in weight and water content. Contents of total crude proteins and comprising amino acids were increased during the storage period. The main contents of amino acids of the Korean native pumpkin, Yangsan, were glutamic acid (15.5%), aspartic acid (10.1%), lysine (8.7%), valine (7.5%), leucine (7.1%) and alanine (6.6%), which were not highly influenced during storage period. Additionally we have investigated the content of free amino acids and color changes during processing of Yangsan under high temperature at $121^{\circ}C$ and high pressure at $1\;kg/cm^2$. In fully ripe fruits, a total of 29 kinds of free amino acids were detected including 8 kinds of essential amino acids (histidine, isoleucine, leucine, lysine, phenylalanine, methionine, threonine and valine). More than 35% of total free amino acids were aspartic acid (20.3%) and asparagine (15.4%); ornithine, citrullin, and arginine, which are related to Ornithine cycle, were also detected in fully ripe fruits. But when treated with high temperature and high pressure, glutamic acid and arginine were decreased rapidly whereas ammnonium chloride was relatively increased. Moreover "b" value as yellow color indicator was decreased from 17.45 to 9.14 while treated for 60 minutes with high temperature and pressure, caused by the degradation of ${\beta}-carotene$ and other yellowish pigments in Yangsan.

상온에서 60일 동안 저장한 ‘양산’ 품종의 국내산 완숙호박 과육의 pH, 당도, 중량, 수분함량, 총단백질 함량 및 단백질을 구성하고 있는 아미노산 함량의 변화에 대하여 조사하였다. 그 결과 당도는 저장기간에 따라 큰 차이가 없었으며, pH는 약간 산성화 되었다. 중량과 과육 내 수분함량은 소폭 감소하는 경향을 보였다. 총단백질 함량과 단백질 내 구성아미노산 함량에서는 저장기간이 길어질수록 증가하는 경향을 보였다. 그러나 아미노산 조성에는 큰 차이가 없었으며 glutamic acid(15.5%), aspartic acid(10.1%), lysine(8.7%), valine(7.5%), leucine(7.1%) 및 alanine(6.6%)의 순서로 존재하였다. 또한 $121^{\circ}C$ 고온 및 $1\;kg/cm^2$의 고압 조건에서 1시간 동안 일정한 간격으로 처리한 완숙호박의 유리아미노산 함량 및 색도 변화를 조사하였다. 유리아미노산 분석결과 모든 처리구에서 필수아미노산 8종(histidine, isoleucine, leucine, lysine, phenylalanine, methionine, threonine, 및 valine)과 이뇨작용과 관련된 아미노산류 3종(ornithine, citrulline, arginine)을 비롯하여 총 29종이 검출되었으며, 이 중에서 aspartic acid와 asparagine이 각각 20.3%와 15.4%를 차지하여 가장 많은 함량을 차지하였다. 이와 같은 유리아미노산 조성은 고온고압 처리시간이 길어질수록 arginine과 glutamic acid는 대폭 감소하였고, ammonium chloride는 오히려 증가하는 경향을 보였다. 처리시간별 과육의 색도는 처리시간에 길어질수록 황색을 나타내는 b값이 줄어, 처리 1시간째에 17.45에서 9.14로 낮아졌다. 이것은 ${\beta}-carotene$을 비롯한 황색계통의 색소들이 상당히 파괴되었기 때문에 생긴 현상으로 보여진다.

Keywords

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