堆沤温度对后熟过程中榧籽主要营养物质变化的影响

Effect of Retting Temperature on Transformation of Main Nutrients in Seeds of Different Torreya grandis Cultivars during After-Ripening Period

【目的】比较不同堆沤温度处理下野生种和栽培种榧籽后熟过程中主要营养物质的变化,探讨不同品种榧树营养物质转化及其后熟品质形成的调控机制,为提高榧籽后熟品质和香榧产业链的健康发展提供理论和实践指导。【方法】以4种榧籽(栽培种:朱岩榧、丁香榧和东榧3号;野生种:木榧)为试验材料,观察不同堆沤温度[(20±2)℃,记为T 20;(30±2)℃,记为T 30 ]处理下4种榧籽的种衣颜色并测定淀粉含量、可溶性蛋白含量、含油率及各脂肪酸组分等指标。【结果】1) T 20 处理20天时,4种榧籽的种衣均呈深黑褐色;T 30 处理10天时,除木榧外,其余3种榧籽的种衣均呈深黑褐色。2)堆沤前,木榧和丁香榧的淀粉含量明显高于其余2种榧籽。与堆沤前相比,T 20 处理20天和T 30 处理10天时,除木榧的淀粉含量无明显变化外,其余3种榧籽的淀粉含量均显著下降。3)堆沤前,朱岩榧和东榧3号的可溶性蛋白含量明显高于丁香榧和木榧。与堆沤前相比,T 20 处理20天时,除木榧外,其第3种榧籽的可溶性蛋白含量均显著增加;T 30 处理10天时,除朱岩榧外,其余3种榧籽的可溶性蛋白含量均显著增加。4)堆沤前,4种榧籽的含油率和不饱和脂肪酸含量高低次序均为丁香榧>东榧3号>朱岩榧>木榧。与堆沤前相比,T 20 处理20天时,4种榧籽的含油率和不饱和脂肪酸含量均显著增加;T 30 处理10天时,丁香榧和东榧3号的含油率和不饱和脂肪酸含量最高,朱岩榧次之,木榧最低。【结论】堆沤前,朱岩榧、丁香榧和东榧3号3种栽培种榧籽的品质明显优于野生种木榧。堆沤后熟处理后,4种榧籽的营养物质均存在淀粉下降和油脂增加,其中栽培种东榧3号的含油率增加最为显著,其次是丁香榧,野生种木榧最差。可见,尽管不同堆沤温度处理下不同品种榧树后熟过程存在明显差异,但后熟温度上升可明显加快榧籽的后熟进程,主要表现在淀粉分解加快,蛋白质和油脂的合成加快。

【Objective】 This study aimed to investigate the transformation of nutrients in seeds of different Torreya grandis cultivar sand the change characteristics of its after-ripening qualityby comparing the changes in main nutrients of the wild, half cultivated and cultivated T. grandis seeds during after-ripening period under different retting temperatures. 【Method】Two retting temperature [(20 ± 2)℃, named as T20;(30 ± 2)℃, named as T30] were applied in this study. The seeds of four T. grandis cultivars(cultivated seeds: T. grandis ‘Zhuyan’ and T. grandis ‘Dingxiang’,T. grandis ‘Dong No.3’;wild seeds: T. grandis Fort. Ex. Lind)were used as experimental materials to determine the changes in the inter seed coat color, starch content, soluble sugar content,soluble protein content, oil content and fatty acid compositions during after-ripening period under the two different retting temperature conditions.【Result】1) The inter seed coat color of the four T. grandis cultivars changed from red to dark brown after 20 days of treatment with T20. Except for T. grandis Fort. Ex. Lind, the inter seed coat color of the other three T. grandis cultivars was turned to dark brown after 10 days of treatment with T30. 2) Before the retting treatments, the starch content in seeds of T. grandis Fort. Ex. Lind and T. grandis ‘Dingxiang’ was significantly higher than that in the other two cultivars. Compared with before retting treatment, the starch content of three T. grandis cultivars dramatically decreased after 20 days of treatment with T20 and 10 days of treatment with T30 except that the starch content of T. grandis Fort. Ex. Lind seeds did not chang significantly. 3) The soluble protein content in seeds of T. grandis ‘Zhuyan’ and T. grandis ‘Dong No.3’ was significantly higher than that in T. grandis ‘Dingxiang’ and T. grandis Fort. Ex. Lind. In comparison with before retting treatment, the soluble protein of the seeds of three T. grandis cultivars except for T. grandis Fort. Ex. Lind dramatically decreased after treatment with T20 for 20 days, and the soluble protein of three T. grandis cultivars except for T. grandis ‘Zhuyan’ significantly increased after treatment with T30 for 10 days. 4) The oil content and unsaturated fatty acid content in seeds of the four T. grandis cultivars were in the order of T. grandis ‘Dingxiang’ > T. grandis ‘Dong No.3’> T. grandis ‘Zhuyan’ > T. grandis Fort. Ex. Lind.In comparison with before retting treatment, the oil content and unsaturated fatty acid content in the seeds of four T. grandis cultivars significantly increased after treatment with T30 for 20 days. The oil content and unsaturated fatty acid content were significantly higher in T. grandis ‘Dingxiang’ and T. grandis ‘Dong No.3’ than those in the other two T. grandis cultivars, with T. grandis Fort. Ex. Lind the lowest, after treatment with T30 for 10 days.【Conclusion】It was indicated that the seed quality ofthree cultivated T. grandis was better than that of the wild T. grandis before retting treatment. After retting treatment,the starch content in seeds of the four T. grandis cultivars significantly decreased, while the oil content significantly increased. The increase of the oil content in T. grandis ‘Dong No.3’ was significantly higher than that in the other three T. grandis cultivars after retting treatment, and the increase of the oil content in T. grandis Fort. Ex. Lind was lowest among the four T. grandis cultivars. Although, the response of the four T. grandis cultivars to different retting temperature were different, the higher retting temperature significantly accelerated the after-ripening process of seeds of the four T. grandis cultivars by increasing decomposition of starch and synthesis of proteins and lipid.