黄蒿籽胶提取工艺及流变学特性的研究

以黄蒿籽为原料采用盐析方法提取植物胶,研究了多种因素对提取率的影响,用正交试验L9(3)4得到最佳提取工艺条件:Al2(SO4)3用量为滤液的1/10mL,盐析pH值6.0,脱盐pH值2.5,脱盐时间60min。同时还分析测定了浓度、温度以及常见金属离子对黄蒿籽胶黏度的影响,并且与8种增稠剂黏度进行比较,试验结果表明,黄蒿籽胶具有良好的开发应用价值。     

胡麻胶在冰淇淋中应用的研究

对胡麻胶与羧甲基纤维素钠(CMC-Na)、海藻酸钠及单甘酯在冰淇淋中的协同作用进行了研究。通过正交试验得出胡麻胶与其他稳定剂、乳化剂的最佳应用比例。冰淇淋混合料中各种稳定剂履乳化剂的用量为：胡麻胶0．25％，海藻酸钠0．1％，CMC-Na0．1％，单甘酯0．05％，由此制得的冰淇淋组织状态均匀细腻。口感柔滑，抗融性好，膨胀率理想。     

In vitro ruminal fermentation characteristics of gum arabic under concentrate and forage substrate conditions

Gum arabic (GA) has potential rumen modifier functions. This is the first study to investigate the in vitro ruminal fermentation characteristics of GA. Rumen fluid was collected from ruminal fistulated wethers; rolled barley and ryegrass straw were used as substrates for concentrate and forage conditions, respectively. Besides incubating with the substrates alone (control), GA or potato starch (PS) was added at 0.2%, 1.0%, and 2.0% along with substrates. Under the concentrate substrate condition, GA treatments showed higher total gas production in 24-h incubation, but lower methane production in 24- and 48-h incubation compared with PS treatments (p < 0.05). The 1.0% and 2.0% GA and 0.2% and 1.0% PS treatments showed higher dry matter and neutral detergent fiber digestibility and lower NH₃-N, and higher short chain fatty acid concentrations compared with the control at 24-h incubation (p < 0.05). The GA treatments also showed a lower acetate/propionate ratio than PS treatments at 48-h incubation (p < 0.01). Under the forage substrate condition, the treatment effects were not significant, except for a higher proportion of propionate with GA than with PS at 24 and 48 h of incubations. We thus concluded that GA supplement may exert potential rumen modifier effects particularly under concentrate feeding condition.     

脱色仙草叶胶对树薯淀粉可食膜机械性质及水气阻隔性的影响

仙草为中国传统的药用植物。探讨了以淀粉和仙草叶胶制备可食膜的可行性。未来将进一步探讨脱色仙草叶胶添加树薯淀粉可食膜微结构的变化。     

玉米淀粉与黄原胶复配体系流变和凝胶特性分析

为考察胶体对淀粉流变及凝胶特性的影响,该文以玉米淀粉为原料,加入不同比例黄原胶,研究两者复配后流变及凝胶特性的变化,对其相互作用机理进行了初步探讨。结果表明,玉米淀粉及两者复配体系属于屈服-假塑性流体,随着黄原胶比例的提高,复配体系的稠度系数显著增加,流体指数降低,假塑性增强,但黄原胶比例大于10%时,增加不再显著。动态流变学试验显示,复配体系具有更为优越的黏弹性,黄原胶可与淀粉分子间相互作用形成氢键,使得分子链段间的缠结点增加,同时,可延缓及阻止部分直链淀粉分子间的重新排列,从而抑制淀粉凝胶体系的回生,复配体系形成了质地更为柔软的凝胶。综合考虑,在实际应用中选择玉米淀粉与黄原胶质量比为9.0∶1.0 g/g较为适宜。研究结果可为更好的在食品工业中应用玉米淀粉/黄原胶复配体系及品质控制提供参考。     

The extent and pattern of Eucalyptus regeneration in an agricultural landscape

The process of natural regeneration is critical for sustaining remnant native vegetation and the ecosystem services it supports. We quantified the extent and pattern of Eucalyptus regeneration within remnant vegetation in a fragmented agricultural landscape in south-eastern Australia. Eucalyptus regeneration was absent at 42% of sites. Using an information-theoretic approach, we explored 13 possible models of Eucalyptus regeneration across multiple scales. The explanatory variables in the four models with empirical support (and their summed Akaike weights) were: grazing intensity (1.0), native ground cover (0.99), remnant area (0.83), tenure (0.67), canopy cover (0.21) and vegetation type (0.11). Averaging across these four models we predicted that the probability of Eucalyptus regeneration was highest (0.95) in relatively unmodified remnant native vegetation, that is, remnant vegetation on public land where grazing was light and the understorey was dominated by native plants. In contrast, the predicted probability of Eucalyptus regeneration was lowest (0.12) in small remnants on private land where grazing was heavy. Our results suggest that a large proportion of all remnant native vegetation in this landscape will disappear under existing land management and farming practices. Reducing grazing pressure within intensively grazed remnants appears to be the single most effective management intervention that will mitigate this threat. This will require a shift in conservation priorities away from large, intact remnants where regeneration does not appear to be affected, to poorer quality remnants—often small remnants or scattered trees—where regeneration is typically absent.     

桃胶和竹醋涂膜对猕猴桃果实采后软化机理研究

为探究桃胶和竹醋涂膜处理对猕猴桃采后果实软化的作用机理。以‘翠玉’猕猴桃为试材,采用2%桃胶、0.5%竹醋及桃胶+竹醋复合涂膜处理浸泡3 min,置于（5±1）℃、湿度为90%~95%的冷库中贮藏,研究果实硬度、细胞壁组分、软化相关酶活性及其基因表达量的变化规律。结果表明,复合涂膜处理显著抑制多聚半乳糖醛酸酶（PG）、β-半乳糖苷酶（β-Gal）、纤维素酶（Cx）和果胶酯酶（PE）的活性,降低PG、β-Gal、Cx和PE基因的表达,有效抑制细胞壁骨架物质、原果胶和纤维素的降解,延缓可溶性总糖和可溶性蛋白含量的上升,从而维持果实的硬度,延迟果实后熟软化。综上,桃胶和竹醋复合涂膜保鲜效果优于单一处理,是延缓猕猴桃果实细胞壁代谢和保持果实品质的有效措施。     

福建省脂松香质量调查与提高质量的建议

对连续15 a福建省脂松香生产企业的质量抽检调查及统计分析结果表明,各个级别脂松香质量的各项主要技术指标均优于目前的国家标准(GB/T 8145—2003)要求,但仍存在影响脂松香质量的问题。要通过实施松香全过程质量控制,并加快品牌创建,不断满足市场对产品质量的多样化要求,以提高松香产品质量与效益。     

生物脱胶苎麻纤维性能研究

应用一种简便、廉价的细菌脱胶方法对苎麻进行脱胶，研究脱胶后的苎麻纤维性能。结果表明，苎麻细菌脱胶后残胶率1．82％，达到了脱胶要求。且松散了苎麻纤维横截面组织结构，对苎麻中纤维素无破坏，提高了上染色率12％左右，单纤维强力比碱液脱胶的大0．15N／tex，对白度影响不大。说明该脱胶法是一种绿色生产工艺。     

Infestation Density of Eucalyptus Gall Wasp,Leptocybe invasa Fisher and La Salle (Hymenoptera: Eulophidae) on Five Commercially Grown Eucalyptus Species in Tanzania

This study explores infestation density of Leptocybe invasa on five commercially grown Eucalyptus species in Coastal, Plateaux, and Southern Highlands agroecological zones of Tanzania. Infestation density between agroecological zones, Eucalyptus species, age classes and tree crown parts, relationship between stand altitudes and the magnitude of infestation, damage index, species age, and abundance of L. invasa on different Eucalyptus species were examined. There were significant differences in infestation between zones and Eucalyptus species. Eucalyptus tereticornis was more affected, followed by E. camaldulensis, and E. saligna was the least while E. grandis and E. citriodora were not affected. No significant differences in damage between different crown parts were observed. Trees with age of 1–3 yr were damaged more than those of age 4–6 yr. Pest infestation increased with an increase of L. invasa abundance but decreased with an increase of altitudes. Control efforts needs to focus on controlling the spread of the pest, using silvicultural methods and planting resistant Eucalyptus species.