Isolation and structural characterization of rhamnogalacturonan II-borate complex fromPinus densiflora

A boron-containing pectic polysaccharide was isolated from Driselase digests of akamatsu (Pinus densiflora) cell wall. The boron-containing polysaccharide was purified by successive column chromatography of Cosmosil C₁₈ OPN, DEAE Sepharose FF, and Superdex 75. The complex had 0.12% (w/w) boron (B) and¹¹B-NMR spectroscopy showed the complex to be the tetrahedral diester form of boron. The sugar composition and glycosyl linkage analyses showed that the sugar portion of the complex was rhamnogalacturonan-II (RG-11). The boron-attached glycosyl residue was identified to be 2-O-Me-xylose-containing apiosyl side chain in RG-II. These results established that the location of borate in the cell wall is conserved among dicots, gramineous monocots, and coniferous gymnosperm.Part of this study was presented at the 8th Cell Wall Symposium, Norwich, September 3, 1998     

黄秋葵果胶的提取工艺研究

[目的]优化黄秋葵果胶提取工艺。[方法]采用微波辅助酸解法从黄秋葵中提取果胶,以果胶得率为指标,通过考察酸的类型、酸解pH、微波时间、料液比等影响因素,确定黄秋葵果胶最佳提取工艺。[结果]试验得出,微波辅助酸解法提取黄秋葵果胶的最佳工艺条件为:硫酸、酸解pH为3、微波时间5 min、料液比1∶20 g/ml,在此条件下黄秋葵果胶的提取率为13.89%。[结论]以微波辅助酸解法获得的黄秋葵果胶品质符合国家标准,果胶提取率高,具有较好的经济效益和社会效益。     

Ultrastructural study on scab resistance expressed in epidermal pectin layers of pear leaves

Proliferation and collapse of subcuticular hyphae of Venturia nashicola race 1 were studied ultrastructurally, after inoculation of susceptible Japanese pear cv. Kousui, resistant Japanese pear cv. Kinchaku, resistant Asian pear strain Mamenashi 12 and nonhost European pear cv. Flemish Beauty leaves, to understand the nature of the resistance mechanism. After cuticle penetration by the pathogen, the hyphae were observed at lower frequency in epidermal pectin layers and middle lamellae of leaves of the three resistant plants than in those of susceptible ones. This result suggested that fungal growth was suppressed in the incompatible interaction between pear and V. nashicola race 1. In the pectin layers of all inoculated plants, some hyphae had modifications such as breaks in the plasmalemma with plasmolysis, necrotic cytoplasm and degraded cell walls. More hyphae had collapsed in the leaves of the three resistant plants than in those of the susceptible cv. Kousui. In collapsed hyphae, the polymerized cell walls broke into numerous fibrous and amorphous pieces, showing that the scab resistance might be associated with cell wall-degrading enzymes from pear plants.     

Effect of feeding fermentable fiber on synthesis of total and mucosal protein in the intestine of the growing pig

In a previous study, a reduced efficiency of ileal digestible threonine (THR) use for body protein deposition was observed in growing pigs when pectin was included in the diet. This response was not due to increased physical endogenous ileal THR loss. Our aim was to explore the contribution of diet-induced increases in protein synthesis in the colon, especially mucins, to dietary THR requirements. Twelve barrows (21 kg mean BW) were fed either a cornstarch–soybean meal-based diet (Control) or Control with 12% pectin (Pectin). Pigs were given intravenously 1.5 mmol/kg BW of L-1-¹³C valine (40 mol%) to measure fractional and absolute synthesis rates (FSR, ASR, respectively) of mucosal and whole intestinal protein in the jejunum and colon. Dietary pectin inclusion increased plasma levels of glucose, isoleucine and glutamine (P < 0.05) but had no effect on insulin or urea nitrogen (P > 0.10). There were no differences in FSR and ASR of whole intestinal protein in jejunum and colon (P > 0.10). The FSR of mucosal proteins in colon, not in jejunum, was increased with dietary pectin supplementation (P < 0.05). Assuming mucosal protein mass is constant, these results imply that the higher protein synthesis in colon mucosa contributes to the reduced THR efficiency observed in pectin-supplemented diet.     

大枣加工中氧化型维生素C和还原型维生素C的变化

以大枣为原料,在浸提、澄清工序中,通过抗氧化剂和果胶酶处理试验,旨在探索大枣在加工过程中氧化型维生素C和还原型维生素C的变化规律,达到最大限度保存大枣中总维生素C的目的。结果表明,(1)采用植酸处理对还原型维生素C的保存效果最好;(2)0.04%的六偏磷酸钠和0.06%的EDTA-2Na对氧化型维生素C和还原型维生素C都具有较好地保存作用;(3)茶多酚和EDTA-2Na对氧化型维生素C的降解起抑制作用;(4)六偏磷酸钠可使氧化型维生素C和总维生素C的含量增高;⑤采用果胶酶处理对氧化型维生素C具有较好地保存作用。     

以甜菜粕取代小麦的全混合颗粒饲料对羔羊瘤胃pH值的影响

本试验选用24只3-3.5月龄的波德代(♂)×蒙古羊(♀)和陶赛特(♂6)×蒙古羊(♀)杂交一代羔羊,按2×2×2因子设计,研究了两个营养水平下以高果胶的甜菜粕取代小麦的全混合颗粒饲料对两种羔羊瘤胃pH值的影响。结果表明,低营养水平组的pH值显著高于高营养水平组(P=0.015);食后4 h(P-0.019)、6 h(P=0.009)的pH值在营养水平和饲料间存在互作,高营养水平组,小麦组羔羊的瘤胃液pH高于甜菜粕组,而低营养水平组、甜菜粕组的pH高于小麦组;羊品种对pH值无影响。     

用酸水解法从南瓜中提取果胶的研究

研究了用酸水解法从南瓜中提取果胶的工艺,并就影响果胶得率的几个主要因素进行了实验,确定了提取果胶的最佳工艺条件为:提取液pH值2.0,提取温度100℃,提取时间90min,沉淀剂乙醇的浓度70%。     

不同南瓜品种果实生长发育过程中果胶物质的动态变化

 选用 4个南瓜品种 (12 4、12 5属印度南瓜品种 ;黄狼、大粒裸仁属中国南瓜品种 ) ,研究其果实发育过程中果胶物质的组成及其动态变化规律。结果表明 ,在南瓜果实生长发育过程中 ,南瓜果胶的主要组成成分为酸溶性果胶 (ASP) ,其含量在果实发育过程中占总果胶 (TP)含量的 72 .8%～ 91.3%,水溶性果胶 (WSP)与草酸溶性果胶 (OSP)含量较少。在果实发育过程中 ,就WSP与OSP的变化规律而言 ,品种 12 4与 12 5表现基本一致 ,而黄狼与大粒裸仁表现基本一致 ;4个品种的ASP与TP的变化规律基本一致 ,在第 30天含量达到最高 ,随后随着果实的成熟逐渐下降。不同南瓜品种在同一生长期果胶含量有差异 ,12 4与 12 5的果胶含量均高于黄狼与大粒裸仁。 4个品种中 ,12 5的果胶含量最高 ,大粒裸仁南瓜含量最少 ,12 5在第 30天TP含量占果实鲜重的 2 .43%。     

果胶型柠檬果粕关键技术的研究

[目的]探讨微波干燥柠檬皮渣的最佳工艺条件,并研究果胶型柠檬皮渣干燥前的预处理关键技术.[方法]以柠檬皮渣为原料制备柠檬干渣,采用正交试验法对柠檬皮渣进行干燥预处理,探讨不同的灭酶时间、粒度大小的选择、复合磷酸盐处理时间、微波功率的选择对果胶的提取、干渣得率、产品色泽、能量消耗以及干燥时间的影响.[结果]试验表明,对柠檬皮渣进行沸水灭酶3 min,粒度选择3 ～5 mm,复合磷酸盐处理5 min,微波干燥用480W,此最佳工艺条件下干燥30 g新鲜柠檬渣得到产品6.556 1 g,鲜渣所消耗的能量0.19 kW·h,所用的总时间15 min,干渣中果胶质为16.556 1％,感官得分是88分.[结论]试验优化的工艺可提高柠檬皮渣干燥的得率,降低能耗,提高果胶的提取率,保持干渣颜色基本不变,运用于工业生产可降低生产成本,提高工业生产利润.     

响应面法优化微波辅助提取山楂果胶工艺

[目的]用微波辅助提取山楂叶片果胶,并对提取工艺进行优化.[方法]以山楂叶片为材料,采用微波辅助提取工艺进行果胶提取.在单因素试验的基础上,得到各因素的最佳水平,再采取3因素3水平进行组合设计.[结果]单因素试验得到的3个因素的最佳水平为：pH l.5,微波处理时间2 min,料液比1∶130 g/ml.通过分析得到了山楂叶片果胶提取率与3个影响因素pH、微波处理时间、料液比的回归模型.方差分析结果显示,相关极显著,模型拟合较好.最终得到最佳提取工艺：pH为1.87,微波处理时间为2.11 min,料液比为1：124.34 g/ml,果胶提取率的预测值为6.59％.[结论]研究可为工业生产山楂果胶提供一定的参考依据.