不同因素对马铃薯淀粉-黄原胶复配体系粘度的影响

以粘度为评价指标,由试验确定复配体系配比为马铃薯淀粉5%、黄原胶0.3%的基础上,通过单因素试验和响应面试验研究不同因素对马铃薯淀粉-黄原胶复配体系粘度的影响.结果表明:当pH 6、温度69℃、搅拌时间28min、盐离子浓度0.03mol/L时,复配体系的粘度为27 606mPa·s,与预测值27 787mPa·s的相对误差为0.65%,差异不显著,回归模型拟合良好,这一粘度均较相同浓度的马铃薯淀粉或黄原胶粘度高很多.     

魔芋胶与瓜胶未来产业竞争态势分析

比较魔芋和瓜尔豆生物学特性、现有资源区位优势及魔芋胶和瓜胶产品性状等,魔芋胶在理化指标方面明显优于瓜胶,尤其是粘度及凝胶特性显著好于瓜胶。弥勒魔芋规模种植必将伴随魔芋产量的大幅增加,可提升我国魔芋产业在全球的市场份额及产业集中度,显著增强魔芋胶的竞争力,逐渐动摇瓜胶在传统产业中的现有竞争优势。     

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.     

新疆果树原胶的出胶调查

以新疆果树为试材,研究了山桃、蟠桃、桃杏、杏、巴旦杏、李子、李子幼林、水蜜桃、黄果山楂、新疆梨、石榴共11个果树原胶的出胶率和出胶量.结果表明:山桃、蟠桃、巴旦杏、桃杏和杏的出胶率和出胶量较大,高达90％的树木都出胶,且单株出胶量多在40～50 g;李子和水蜜桃的出胶率则较小,一般在25％,单株出胶量1～3 g;黄果山楂、新疆梨和石榴未发现出胶.     

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。