山药酸奶的研制

将新鲜牛奶与经处理的山药再加乳酸菌,通过恒温发酵后冷藏制得一种集山药和酸奶于一体的新型保健饮品.通过L9(34)正交试验得出最佳配料组合.牛奶中加入10%山药浆,8.4%蔗糖,0.7%稳定剂,3%混合发酵剂在43℃条件下进行乳酸发酵可制得品质优良、风味良好的山药酸奶.     

山药漆腐叶斑病病原菌的鉴定及其生物学特性研究

在河南山药(Dioscorea opposita)主产品种‘铁棍山药’生产中出现了一种新的叶部病害,田间发病株率为6.6%。该病害主要发生在植株下部叶片,病斑圆形褐色,具同心轮纹,后期病斑上产生大量黑色孢子堆。对该病害的病原菌进行了组织分离培养和柯赫氏法则验证。其分生孢子座碗状或浅盘状,分生孢子梗呈笤帚状分枝,分生孢子梗顶端着生棒状产孢细胞;分生孢子长椭圆形、棒形、长卵形或梨形,透明无色,不分隔,两端钝圆,大小为1.7~2.5μm×4.9~6.8μm。病原菌菌落白色绒毛状,产生大量墨绿色胶质状分生孢子团,呈环状排列。用ITS通用引物对病原菌的基因组DNA进行扩增并测序(序列在GenBank的登录号为KY369166),同源性比对结果显示其与露湿漆斑菌(Myrothecium roridum)的一致性达到99%,结合形态学鉴定结果,确定该病害的病原菌为露湿漆斑菌。病原菌的最适生长温度为30℃,分生孢子致死温度为52℃,pH 5~10之间该菌生长良好,光暗(12 h/12 h)交替最有利于病原菌产孢,菌丝生长的最适碳氮源为乳糖和丙氨酸,产孢的最适碳氮源为果糖和酵母。     

优质块状紫山药新品种苏蓣1号的选育

苏蓣1号是从浙江紫莳药中通过系统选育方法筛选出的块状山药新品种。该品种属于粗短块状紫山药,生育期中等偏迟,155d(天)左右。单株结薯2个左右,块茎表皮紫褐色,肉紫色,长25cm左右,周长20cm左右,质量1.0kg左右,花青素和淀粉含量分别高达9.28‰和23.9%,不结零余子,每667m~2产量可达2000kg。适宜于江苏全省范围露地种植,优先推荐在沿江地区推广应用,适宜于机械化操作。     

山药主要病害研究进展和生产中存在的问题

综述了近几年来山药主要病害的病原、症状和防治方法,提出了生产中存在的问题和今后的研究方向。     

发酵山药酸奶的工艺探讨

用山药发酵法生产营养奶口感好,而且营养丰富,具有药食同源的功效.本文介绍了山药营养奶的生产工艺、操作要点、配方和产品的特点.     

微波膨化山药脆片的加工工艺研究

以新鲜蕲春山药(Dioscorea opposita)为材料,采用微波膨化工艺,开发一种新型的山药脆片.通过分析比较,考察了山药片厚度、氯化钠溶液浓度、干燥时间、微波功率及膨化时间对山药脆片脆度和色度(b*值)的影响.结果表明,当山药片厚度为1.5 mm、氯化钠溶液的浓度为3％、70℃条件下干燥80 min、微波功率420 W、微波膨化时间60 s时,山药片的脆度值为6.917,色度(b*值)为13.62,介于最佳范围内.在此工艺条件下制得的山药脆片含水量为0.44％,总糖含量为14.11％,氨基酸含量为9.89％.所得到的山药脆片产品组织饱满、口感松脆、咸淡适中、颜色金黄、无焦化现象,具有山药的清香气味.     

微波真空冷冻干燥时怀山药的微CT孔道分布

局部温度过高的问题限制了微波真空冷冻干燥（microwave freeze drying,MFD）技术在果蔬干燥中的广泛应用。发展传热传质理论是解决MFD局部温度过高问题的根本途径。数值模拟是研究传热传质机理的重要方法,并有望解决MFD中局部温度过高的问题。利用详细的孔径和孔隙分布建立结构模型对数值模拟至关重要。该研究以怀山药为样品,利用微CT（X-ray micro-computed tomography）技术分析不同干燥仓压力（100、200、300 Pa）和微波加载量（0.5、1.0、1.5、2.0 W/g）时孔隙和孔隙分布的变化。结果表明,干燥仓内的低压环境更倾向于形成小孔隙,干燥仓内压力的变化对外层的孔隙大小和分布无明显影响,但对内层的孔隙大小和分布有明显影响。微波加载量对内、外层的孔隙大小和分布均有显著影响。研究结果将为解决MFD中局部温度过高问题的数值计算研究提供试验支持。     

DIAGNOSIS AND RECOMMENDATION INTEGRATED SYSTEM: A TOOL FOR DETECTING NUTRIENT DEFICIENCIES IN YAM

The objective of the study carried out in the Upper Oueme Catchment in Benin (West Africa) was to assess the nutrient status in yam (Dioscorea rotundata) through the Diagnostic and Recommendation Integrated System (DRIS), to compare yield, foliar nutrient concentrations and the variance of nutrients of low-and high-yielding groups. Field experiments were carried out in 2001 and 2002 using a randomized complete block design with four treatments, 2001: n = 80, 2002: n = 109) at three sites: Beterou, Dogue, and Wewe. Nitrogen (N), followed by potassium (K), phosphorus (P), and magnesium (Mg) were identified as the most limiting nutrients in 2001 whereas sulfur (S) followed by N was identified as most limiting ones in 2002. Imbalanced nutrition was observed in both the years but was higher in 2001 compared in 2002. They may be utilized as a basis for calibrating the fertilization program of yam.     

Problems and Perspectives of Yam-Based Cropping Systems in Africa

SUMMARY

Yams (Dioscorea spp.) constitute an important starchy staple in sub-Saharan Africa (SSA) where food security for a growing population is a critical issue. Mixed cropping in yam based systems is the norm in the region and productivity of yams in these systems is below potential. It is concluded that there is much scope for improvement of yam based cropping systems in SSA in order to meet the needs of the region. The strategy of crop breeding to select yam varieties suitable for various cropping systems must consider a truly multidisciplinary systems approach. Further manipulation must be made to tuber dormancy to expand flexibility in field propagation in different cropping systems and improve storage and marketing. The sustainability of yam based cropping systems in SSA could improve if agronomic research was focused on strategies for improving soil fertility, weed and pest management including design of cropping systems and suitable rotations.     

浙江黄岩紫莳药在苏南地区的生长发育动态特征分析

在南京地区观察浙江黄岩紫莳药的生长发育动态,结果表明:浙江黄岩紫莳药营养器官快速增长期为出苗后45～86 d,营养器官衰退期为出苗后86 d以后。块茎加速膨大期在出苗后86 d前后,块茎膨大表现为:出苗后86～110 d快速增粗,出苗后86～167 d快速伸长,同期也为块茎快速膨大期和块茎鲜重快速增长期,而块茎干物积累快速增长期在出苗后110～167 d,出苗后165 d左右块茎占整株重量80%以上,为紫莳药块茎采收始期。