五节芒栽培糙皮侧耳的子实体质构分析

利用质构分析仪,比较分析分别以五节芒(Miscanthus floridulus)和棉籽壳为主料栽培获得的糙皮侧耳(Pleurotus ostreatus)子实体的质构指标,同时测算二者干制率和杀青率差异。结果表明,相对于常规棉籽壳培养料栽培,菌草配方栽培糙皮侧耳的菌盖咀嚼性、硬度和回复性较差,菌柄回复性、硬度、内聚性和咀嚼性较差,而且子实体的干制率和杀青率也较低。     

C and N turnover in structurally intact soils of different texture

The turnover of native and applied C and N in undisturbed soil samples of different texture but similar mineralogical composition, origin and cropping history was evaluated at −10 kPa water potential. Cores of structurally intact soil with 108, 224 and 337 g clay kg⁻¹ were horizontially sliced and ¹⁵N-labelled sheep faeces was placed between the two halves of the intact core. The cores together with unamended treatments were incubated in the dark at 20 °C and the evolution of CO₂-C determined continuously for 177 d. Inorganic and microbial biomass N and ¹⁵N were determined periodically. Net nitrification was less in soil amended with faeces compared with unamended soil. When adjusted for the NO₃-N present in soil before faeces was applied, net nitrification became negative indicating that NO₃-N had been immobilized or denitrified. The soil most rich in clay nitrified least N and ¹⁵N. The amounts of N retained in the microbial biomass in unamended soils increased with clay content. A maximum of 13% of the faeces ¹⁵N was recovered in the microbial biomass in the amended soils. CO₂-C evolution increased with clay content in amended and unamended soils. CO₂-C evolution from the most sandy soil was reduced due to a low content of potentially mineralizable native soil C whereas the rate constant of C mineralization rate peaked in this soil. When the pool of potentially mineralizable native soil C was assumed proportional to volumetric water content, the three soils contained similar proportions of potentially mineralizable native soil C but the rate constant of C mineralization remained highest in the soil with least clay. Thus although a similar availability of water in the three soils was ensured by their identical matric potential, the actual volume of water seemed to determine the proportion of total C that was potentially mineralizable. The proportion of mineralizable C in the faeces was similar in the three soils (70% of total C), again with a higher rate constant of C mineralization in the soil with least clay. It is hypothesized that the pool of potentially mineralizable C and C rate constants fluctuate with the soil water content.     

云南4种典型材用丛生竹宏观解剖结构与主要物理力学性质的关系

对云南４种典型的材用丛生竹（龙竹Ｄｅｎｄｒｏｃａｌａｍｕｓｇｉｇａｎｔｅｕｓ,甜龙竹Ｄｅｎｄｒｏｃａｌａｍｕｓｂｒａｎｄｉｓｉ,黄竹Ｄｅｎｄｒｏｃａｌａｍｕｓｍｅｍｂｒａｎａｃｅｕｓ,油勒竹Ｂａｍｂｕｓａｌａｐｉｄｅａ）的维管束密度、纤维比量、密度、含水率、干缩率、顺纹抗压强度和弦向抗弯强度的检测结果认为：４种竹材之间和同一竹种内径向、弦向和纵向上的结构和物理力学性质的分布存在着较大的差异。对结构指标与主要物理力学性质之间关系的分析结果认为：纤维比量比维管束密度与竹材物理力学性质的关系更为密切;４种竹材的纤维比量与密度、弦向抗弯强度和顺纹抗压强度呈正比关系,与饱湿含水率呈反比关系。     

Dough rheological properties and noodle-making performance of non-waxy and waxy whole-wheat flour blends

Dough rheological properties and noodle-making performance of non-waxy whole-wheat flour (WWF) with partial- or full-waxy (PW- or FW-) WWF substitution were studied. The substitution levels were 0, 250, 500, 750, and 1000 g/kg, respectively. FW-WWF reduced the peak viscosity and pasting temperature of WWF blends as its substitution level was increased due to its higher proportions of B-type starch granules and short amylopectin chains, while PW-WWF increased peak viscosity with the increasing substitution level because of its higher amylopectin content. As demonstrated by farinograph and rheometer measurements, FW-WWF interfered with gluten development because of the increased competition for water by arabinoxylans and amylopectin; however, PW-WWF enhanced dough strength due primarily to its increased protein content. Consequently, FW-WWF showed a detrimental effect on cooked noodle texture as the cooked noodle hardness was reduced by 50% at the 1000 g/kg substitution level. In contrast, PW-WWF enhanced noodle integrity and elasticity by increasing cooked noodle cohesiveness and resilience by 10.1% and 14.8%, respectively, at the 1000 g/kg substitution level. The results suggest that with waxy WWF substitution, the changes in starch composition, arabinoxylans, and protein content could modify the interactions among flour components and influence the quality characteristics of noodle products.     

南瓜薄饼的配方研究

[目的]探讨制作南瓜薄饼的最佳配方.[方法]通过单因素试验研究了南瓜、白砂糖、人造奶油、小苏打和食盐的含量对南瓜薄饼饼干品质的影响并进行了感官品质鉴定;通过正交试验得出了制作南瓜薄饼的最佳配方并进行了质构分析.[结果]在南瓜75％,白砂糖10％,人造奶油20％,小苏打0.40％,食盐1.25％,其他成分适量的条件下,制作而成的南瓜薄饼风味显著且品质最优.[结论]研究制得的南瓜薄饼满足人们对于饼干品质的要求,并且营养丰富.     

基于TPA模式对3个葡萄品种果实质构性能的比较

为了探讨不同葡萄品种果实质地的多面分析方法并筛选适宜的评价指标,以我国3个主栽葡萄品种巨峰、玫瑰香、红地球的成熟果实为试材,采用质地多面分析(TPA)法,利用物性测试仪测定了果肉的硬度、弹性、凝聚性和咀嚼性;并利用SPSS数据分析软件,对葡萄果肉4个质地参数之间的相关性进行了分析。结果表明:红地球的果肉硬度、弹性、凝聚性和咀嚼性均显著高于其他2个品种,而玫瑰香与巨峰的果肉质地参数除弹性外其他指标差异均不显著;质地参数两两之间均呈正相关,其中,咀嚼性与硬度的相关性达到了显著水平(P0.05)。在对葡萄果肉质地进行简单评价时,可以将去皮硬度作为反映葡萄咀嚼性的重要指标。     

枇杷果实采后质地的变化与调控

 以枇杷果实为材料, 通过1 - 甲基环丙烯(1-MCP) 和温度处理, 探索其对采后枇杷果实衰老过程质地的影响。结果表明, 枇杷果实采后在20℃贮藏过程中, 脂氧合酶(LOX) 活性、超氧自由基(O·2 ) 积累和苯丙氨酸解氨酶( PAL) 活性均呈峰型变化, 果肉组织相对电导率持续增加, 果实硬度趋于增大, 果肉渐趋粗糙少汁, 具有组织木质化的特征。12MCP可以显著抑制PAL和LOX活性, 减缓O·2 生成, 延缓组织衰老进程和硬度的增加。1℃低温贮藏可以有效延缓果实的衰老进程, 但会导致果实出现冷害, 其典型症状也表现出了组织木质化。采后枇杷果实衰老过程中的硬度增加与冷害胁迫下的果实组织木质化具有相似的基本特征, 但其内在机制可能不同。     

油松球果小卷蛾化蛹行为

为了有效防治油松球果小卷蛾(Gravitarmata margarotana)对红松(Pinus koraiensis)的危害,在实验室内对其化蛹行为进行了研究。结果表明:油松球果小卷蛾幼虫无自发的聚集化蛹行为;在土壤及松针中幼虫均能结丝茧并在其中化蛹,但在光滑的容器里不能启动结茧行为,从而化蛹失败。光照对幼虫在土中化蛹场所的选择有影响,在暗区化蛹的数量明显高于光照区;土壤结构对幼虫化蛹场所的选择无影响,在壤土和沙土中化蛹的数量无明显差别。     

体细胞数对发酵乳品质的影响研究

为确定用于生产发酵乳的原料乳质量标准,以提高发酵乳产品品质,选用蒙牛自有牧场30头不同健康状况、不同泌乳期的荷斯坦牛原料乳,按体细胞数分为低于20万个/mL组、20万-80万个/mL组及大于80万个/mL组,在发酵乳制备的当天及样品冷藏后的第1、7、14、21天分别测定发酵的产酸曲线、发酵乳的质构特性。结果表明,随着原料乳中体细胞数的增加,产品黏度下降,弹性降低,硬度增加,pH值降低,品质下降。     

预处理对香蕉片质构特性的影响

[目的]优选能够有效改善香蕉果肉质构性质的预处理方法.[方法]选用香蕉为原料,探讨了热烫处理、外源钙离子、果胶甲酯酶及复合处理对鲜切香蕉片质构特性的影响.[结果]试验表明,果胶甲酯酶复合热处理对香蕉片硬化效果较理想,在添加0.005％果胶甲酯酶（以浸泡液质量计）时,香蕉片硬化效果最优.相较于其他处理方式,香蕉片硬度、弹性和咀嚼性得到了明显的改善.[结论]该试验可为香蕉深加工工艺的研究提供理论基础.