The 2012 ASHS Annual Conference

Asian pear fruit has been used to treat inflammation, cough, fever, constipation or diabetes mellitus due to its rich dietary fiber and phenolic derivatives. Its practical application mostly is limited to pear juice. However, dietary fibers of pear juice are gradually precipitated and resulted in turbid juice from clear juice over time. Therefore, the aim of study is to develop the easy and economic manufacturing processes to keep clear pear juice over time and to characterize physiochemical properties of produced clear pear juice. There were three steps including the filtration, clarifying, and anti-browning in order to produce clear juice. For the filtration with cheese cloth, filter paper (Whatman # 4), or centrifugation (10 min at 10,000 rpm), pear juice efficiently filtered with centrifugation since pear juice showed the highest L value (lightness) and lowest yellowness (a value). Among various clarifying agents, gelatin, bentonite or pectinase clarified effectively pear juice but tannin or egg albumin did not. The mixture of gelatin(0.2%) and bentonite (0.5%) did clarify well the pear juice with low turbidity. Among anti-browning agents (0.1%) like L-ascorbic acid, NaCl, or citric acid, ascorbic acid prevented the browning of pear juice with the lowest browning index value (2.62), compared to that of NaCl (2.74), or citric acid (2.87). In conclusion, these results suggest that clear pear juice could be manufactured easily and economically by the combination of centrifugation, 0.2% gelatin plus 0.5% bentonite addition and 0.1% L-ascorbic acid addition This study was financially supported by Rural Development Administration (Project No. PJ 907072)