부산대학교 도서관

This study evaluated the impact of blanching pak choi stems and leaves in various solutions (distilled water, 2% NaCl, and 2% citric acid) at 100°C on their quality characteristics. The highest stem heating loss was observed in the sodium chloride solution (S-NB) at 15.10% (p<0.001), and the highest leaf heating loss was in L-NB at 11.44% (p<0.001). No significant variation was found in the moisture content of both stems and leaves. Relative to the control, the L value (lightness) of the stem decreased while the b value (yellowness) increased (p<0.05). In the leaves, the a value (redness/greenness) and b value increased in L-CB, whereas they decreased in other groups (p<0.05). S-NB exhibited the highest true retention (TR) of total polyphenol content (TPC) in stems (p<0.01) and the highest TR of total flavonoid content (TFC) as well (p<0.001). For leaves, the highest TR of TPC and TFC was in L-WB (p<0.001). In terms of antioxidant activity, S-NB in stems and L-WB in leaves showed the highest scavenging activity measured by DPPH and ABTS+ assays (p<0.001). Microorganisms were absent in all pretreatment groups but present in the control. The results suggest that blanching pak choi stems in 2% NaCl solution and leaves in water optimally preserves biologically active compounds and nutrients.