对位芳纶纤维成纸性能研究

本研究针对芳纶纤维的抄造特性,初步探讨了芳纶纤维的预处理、打浆性能与纤维微观形态对芳纶纸性能的影响。研究表明,芳纶短切纤维用十二烷基苯磺酸钠(LAS)预处理后,可以明显改善其分散性能;芳纶浆粕纤维在槽式打浆机中进行打浆处理,在一定范围内,随着打浆度的提升,可以有效提升芳纶纸成纸性能。     

投喂次数对杂交鲟幼鱼摄食率及生长的影响

在(18±1)℃的水温条件下,研究4种不同投喂次数对俄罗斯鲟(♀)与欧洲鳇(♂)杂交幼鱼摄食率及生长的影响.结果表明:杂交鲟生长受投喂次数的影响较大,投喂次数从4次/d增加到7次/d时,6次/d组的摄食率显著高于其他各组(P＜0.05);体重增加率、特定生长率均有不同程度提高,6次/d时达到最大(P＜0.05);饵料系数6次/d组显著低于其他各组(P＜0.05),其他各组间差异均不显著(P＞0.05).杂交鲟幼鱼培育过程中适宜的投喂次数为6次/d.     

避雨栽培对酿酒葡萄果实氨基酸含量的影响

本研究利用高效液相色谱技术,分析避雨栽培和露地栽培条件下赤霞珠和霞多丽果实发育过程中21种氨基酸含量的变化.结果表明:避雨栽培除了显著降低这两个品种的果实中赖氨酸和脯氨酸含量外,对其它氨基酸含量的影响不尽相同.在霞多丽果实中,避雨栽培促进了大多数氨基酸含量的增加,而在赤霞珠果实中这些氨基酸的积累受到抑制.该研究对避雨栽培技术在酿酒葡萄生产中的应用具有重要的参考价值.     

几种冷冻新技术对食品冻结过程中冰晶形成的影响

冷冻技术在现代食品加工工业中起着十分重要的作用,水结晶是冷冻过程的关键步骤。文章介绍几种冷冻新技术对食品冻结过程中水结晶的影响的研究进展,包括高压冷冻、超声波冷冻、渗透脱水冷冻、抗冻蛋白、冰核活性蛋白以及其它冷冻新技术。并阐述这些新技术对冰晶的影响机制,旨在能够更好地了解、预测及控制水结晶的过程,并进一步改进冷冻过程和提高冷冻食品的品质。     

Correlation between instrumental texture and colour quality attributes with sensory analysis of selected cheeses as affected by fat contents

This study evaluated several physical and sensory parameters of different types of cheese available in the Polish market. The measurements of textural properties were conducted in an Instron universal testing machine, while the colour properties of cheeses were measured using a Minolta chromameter. The chemical composition was determined by means of the near‐infrared spectroscopy (NIRs). Moreover, a trained sensory panel was invited to assess the cheese texture‐related properties. Generally, cheeses with reduced fat content were characterised by higher hardness, adhesiveness, cohesiveness and elasticity. Texture‐related parameters of cheese with canola oil were comparable to that of most of full‐fat cheeses. The correlation analysis between physical and sensory attributes related to cheese textural properties indicated the potential applications of TPA, shear and penetration tests (r = 0.766, r = 0.75 and r = 0.765, respectively) for the evaluation of sensory properties related to the hardness. Meanwhile, the elasticity of cheese obtained from sensory evaluation was strongly correlated with the elasticity determined from the shear test (r = 0.722) and moderately correlated with the elasticity from penetration test (r = 0.588), indicating a need to refine the method of penetration test. In addition, cheeses exhibited higher meltability during convection heating at 230 °C than microwave heating. The values of meltability for cheese with reduced fat content were lower than those of full‐fat cheese.     

Degradation of curdlan using hydrogen peroxide

Curdlan, a linear glucan interconnected by β-(1 → 3) linkages, is soluble in alkaline solutions but not in water, which limits its wide application, particularly in the food industry. In this study, curdlan was subjected to oxidative degradation using hydrogen peroxide (H₂O₂). The optimal hydrolysis conditions were determined, and the results were as follows: reaction time, 40 min; temperature, 60 °C; H₂O₂ concentration, 1.5% (v/v); and NaOH concentration, 2.5 M. Under these optimised conditions, the maximum dextrose equivalent value (13.49%) was obtained. The composition and the structure of the hydrolysates were characterised by high-performance liquid chromatography and Fourier-transform infra-red spectroscopy, respectively. The hydrolysates were filtered, neutralised with HCl, concentrated to ∼12% (w/v), desalted, and freeze dried to yield a water-soluble, white powder. The (1 → 3)-β-d-glucan oligosaccharide content of the product was 98.6% and the yield was 91.4% (w/w).     

脂肪酶催化多烯酸乙酯合成工艺的研究

探讨了利用Candida sp.99-125脂肪酶产品转酯化合成多烯酸乙酯的过程。深入研究了底物摩尔比、酶用量、反应温度、水含量对鱼油乙酯合成的影响,以及反应中固定化酶的重复利用性等问题。试验结果表明,采用最佳转酯化反应的工艺条件,最高单批转化率可以达到90%以上,固定化酶的反应批次能达到10次以上。     

棕榈油对人体血脂影响的研究进展

棕榈油是从棕榈果实中提取出来的食用植物油,是目前世界上产量最大的植物油,饱和脂肪酸和不饱和脂肪酸比例接近。作为一种饱和度较高的油脂,棕榈油一直被认为是一种升高人体血清胆固醇水平、引起血脂紊乱的植物油,但是这一结论受到越来越多的争议。本文就现有关棕榈油膳食干预资料进行整理总结,从而全面了解棕榈油对人体血脂影响。     

斗式提升机传动机构的研究

简要介绍了斗式提升机的几种主要传动形式及其优缺点,着重阐述了传动机构要件中减速机、锥套联轴器、液力耦合器和逆止器等的选型、安装和使用,并提出斗式提升机传动机构的设计趋势和新技术应用。     

水分对常压射流等离子体处理羊毛针织物毡缩性的影响

通过扫描电镜(SEM)、原子力扫描探针显微镜(AFM)与纤维摩擦因数测定仪(FFT)描述了水分对常压射流等离子体(JPAP)处理亲水性羊毛的表面微观形态、表面粗糙度、纤维定向摩擦效应以及针织物毡缩性的作用。结果表明,湿态、干态及水浸处理,不同程度地有利于JPAP对羊毛的表面改性。尤其是湿态处理,对鳞片的刻蚀效果显著,对静态与动态定向摩擦效应(DFE)作用明显,但对纤维表面平均粗糙度的贡献略小,能够基本达到毡缩率小于8.0%的机可洗标准。