线辣椒果实中几种营养物质和CAT、POD活性的变化规律

Changes in nutritional quality and anti-oxidant exzyme activity in line pepper fruit

为确定不同加工目标线辣椒果实的最佳采收时期,探明果实品质变化的生理机制,以线辣椒品种（系）陕椒2006、L6、L3-2和2005-2共4个品种为材料,测定了果实发育期间相关物质的变化规律。结果表明,4个品种的各指标变化趋势大致相同：1）果实中的VC和干物质含量（质量分数）随着成熟度的增加而增加,红熟期达到最高;蛋白质和可溶性总糖含量则在果实发育初期（花后16～23 d）有一下降过程,以后又上升,最终也在接近红熟时达到最高。红熟期4品种的VC含量分别为170.340、175.898、200.996和173.944 mg/100g（FW）,干物质含量分别为12.853%、12.647%、12.873%和15.455%,蛋白质含量分别为35.069、39.379、34.291和37.849 mg/g（FW）,可溶性总糖含量分别为27.111、28.125、25.508、26.974 mg/g（FW）。2）辣椒素总的变化趋势是,幼果期（花后16～23 d）含量很低（4品种分别为3.69、15.15、7.86和13.65 mg/g（DW））,并且增长缓慢,开花23 d后迅速增长,花后23～37 d的平均日增长量达2.082（陕椒2006）～5.706 mg/g（DW）（L3-2）,绿熟期（花后37～44 d）达到高峰（4品种分别为45.408、55.072、87.994和83.734mg/g（DW））,随后平缓下降。因此,制做干辣椒或辣椒酱的线辣椒,其最佳采收期为红熟期,在此期间红色素及其他营养指标都到最高值;以提取辣椒素为目的的线辣椒,其最佳采收期则为绿熟期。3）过氧化物酶（POD）活性是果实发育前期较高,中期较低,后期又升高（花后16、37和58 d,4个品种的POD活性分别为32～64、16～23和16～29μg/（g·h））;过氧化氢酶（CAT）活性是开花后16、30和37 d较低,23、30和37 d之后较高。POD和CAT活性总体上均与辣椒素含量呈负相关。

The best harvest time for line pepper fruit for different processing target and the physiological mechanism of changes in fruit quality, such as vitamin C, protein, total soluble sugars, dry matter and capsaicin content during fruit development were determined in four line pepper varieties. Also studied were changes in catalase （CAT） and peroixidase （POD） activities. The content of vitamin C and dry matter （percentage mass content） increased with fruit ripening and peaked in the red-mature period; the content of protein and total soluble sugars decreased in the early stage of fruit development （16th-23th day after flowering）, and then gradually increased to a peak in the red-mature period. The capsaicin content was very low and increased slowly in unripe fruits （ 16th - 23th day after flowering）, but rapidly from 23 d after flowering, with a peak in the green-mature period （37th- 44th day after flowering） and then slowly declined. Therefore, the best harvest time is the red-mature period if dry pepper or sauce is the processing targeh the green-mature period should be preferred if extracting capsaicin is the processing target. The POD activity was higher in the early stage of fruit development, lower in the middle-stage, and then increased. The CAT activity was lower at 16, 30 and 37 d after flowering and higher at 23, 30 and 37 d after flowering. The was no definite relationship between changes in vitamin C, protein, total soluble sugar, dry matter and capsaicin content and those of POD and CAT activity; the activity of POD and CAT was inversely proportional to capsaicin content during ripening of line pepper fruits. The result indicated that POD and CAT are probably involved in the metabolism of capsaicin.