枫香叶分离物抗氧化活性及对枇杷的贮藏保鲜效果

以枫香叶分离物（枫香叶依次经乙醇提取、乙酸乙酯萃取、大孔树脂层析、50%乙醇洗脱后所得产物）为实验材料，分别研究其还原力及对1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl，DPPH）自由基、O2－·、·OH的清除能力和对枇杷的贮藏保鲜效果。用10、30、50 mg/100 mL的枫香叶分离物溶液对枇杷果实进行浸泡处理，6 ℃贮藏，每5 d测定一次枇杷果实的腐烂指数、硬度、可溶性固形物含量、可滴定酸含量、相对电导率、过氧化物酶（POD）活性、苯丙氨酸解氨酶（PAL）活性、木质素含量等果实的品质和生理指标。结果表明：枫香叶分离物具有较高的还原力和DPPH自由基、O2－·、·OH清除率；且枫香叶分离物处理可以有效控制枇杷果实腐烂指数、硬度、细胞膜渗透性及PAL活性和POD活性的升高，延缓可溶性固形物、可滴定酸含量的下降和木质素的积累，对于长期贮藏的枇杷果实具有较好的保鲜作用，其中以10 mg/100 mL枫香叶分离物的实用性较好。

Antioxidant Activity of Extract from Liquidambar formosana Hance Leaves and Its Effect on Preserving the Quality of Loquat Fruits during Refrigerated Storage

In this study, the antioxidant activity of extract from Liquidambar formosana Hance leaves (LE) obtained
by sequential steps including ethanol extraction, ethyl acetate extraction, macroporous resin chromatography
with aqueous ethanol elution was evaluated by reducing power, and 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide
anion and hydroxyl radical scavenging assays. Meanwhile, the effect of the extract on preserving the quality of loquat
fruits was investigated by storing the fruits at 6 ℃ after steeping in 10, 30 or 50 mg/100 mL LE solution. Decay index,
hardness, total soluble solid (TSS) content, titratable acid (TA) content, membrane permeability, peroxydase (POD) activity,
phenylalanine ammonia lyase (PAL) activity and lignin content were determined every 5 days to evaluate the quality and
physiological characteristics of loquat fruits during storage. The results showed that LE had strong radical scavenging
activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide anion, hydroxyl free radicals and significant reducing
power, and could inhibit the increases in decay index, hardness, membrane permeability, PAL activities and POD activities,
and slow down the decreases in TSS and TA contents and the accumulation of lignin. In conclusion, LE has bright prospects
in quality preservation of loquat fruits and treatment 1 (10 mg/100 mL) has better practicability.