豆天蛾氨基酸及脂肪酸分析与评价

对豆天蛾幼虫氨基酸及脂肪酸组成进行了分析测定,结果表明:豆天蛾幼虫含有18种AA和8种EAA,EAA/TAA为53.34%,属于优质完全蛋白质昆虫。豆天蛾幼虫不饱和脂肪酸含量61.74%,其中亚麻酸和油酸的含量较高,亚麻酸含量高达34.11%;饱和脂肪酸含量36.43%,其中棕榈酸的含量较高。     

保加利亚乳杆菌生长性能与后酸化的关系初探

以5株德氏乳杆菌保加利亚亚种为出发菌株,详细研究了5株菌的生长代谢、酸敏感性及蛋白水解力,并分析了这些特性与后酸化之间的关系。结果表明:5株菌的生长性能与后酸化之间存在紧密联系。其中,菌株的生长速度和糖分解代谢能力与后酸化成正比;对酸较敏感菌株的后酸化也较弱;菌株的蛋白水解能力与生长速度和后酸化之间没有明显的相关性。     

锦纶面料迷彩伪装印花初探

以锦纶面料为主要研究对象,采用弱酸性染料二种配方对其进行印花,并测试其不同配方印花后的耐皂洗色牢度、耐摩擦色牢度、耐汗渍色牢度、耐日晒色牢度以及反射率等,结果表明弱酸性染料用于锦纶织物印花后,不仅有较佳的色牢度,并且防红外效果能达到军用产品要求,因此有较好的实用性。     

离子液体[Bmim]Cl预处理对两种高结晶多糖酸水解的影响

以酵母β-葡聚糖和凝结多糖这两种高结晶多糖为研究对象,采用偏光显微镜、X射线衍射(XRD)和DNS法研究了离子液体[Bmim]Cl预处理对多糖结晶结构和酸水解效率的影响。XRD图谱分析发现,[Bmim]Cl预处理后酵母β-葡聚糖和凝结多糖的结晶度明显下降。离子液体[Bmim]Cl预处理酵母β-葡聚糖和凝结多糖显著提高其酸水解效率。在4mol/LTFA及100℃条件下,酵母β-葡聚糖(水解时间2h)和凝结多糖(水解时间3h)酸水解产物中还原糖的含量分别为84.36g/100g和96.07g/100g,明显高于未经离子液体处理的53.44g/100g和46.80g/100g。     

酸性条件下高压均质对大豆蛋白结构与功能特性的影响

通过还原电泳、粒度分布以及内源荧光扫描光谱等手段研究了酸性条件(pH3.0)下高压均质处理对大豆蛋白结构的影响,并测定了改性样品功能特性的变化。结果表明,酸性条件下高压均质对大豆蛋白亚基组成影响较小。随着均质压力的上升,改性样品的粒径呈现先增大后下降的趋势,在40MPa时达到最大值,为94.33nm;而内源扫描最大吸收波长λmax也呈现先增大后下降的过程,表明大豆蛋白结构先展开后聚集,在20MPa时,其λmax为336.0nm,展开程度达到最大。功能特性方面,均值压力为20MPa时能有效改善大豆蛋白的溶解性;其乳浊液的粒径随着均质压力的增大而不断下降。     

金红石型高品质二氧化钛的制备

钛白粉具有良好的光学特性、易分散性、耐老化性和化学稳定性,在造纸行业有着广泛的应用。本文介绍了纳米金红石型二氧化钛的性质、生产方法,并主要探索采用硫酸法制备纳米金红石型二氧化钛,采用马尔文激光粒度分析仪、扫描电镜、透射电镜和X-射线衍射仪对实验产物进行表征。实验结果表明,该方法制得的二氧化钛具有较小的粒径以及较好的白度。     

The effects of physical refining on the formation of 3-monochloropropane-1,2-diol esters in relation to palm oil minor components

The formation of 3-monochloropropane-1,2-diol (3-MCPD) esters in refined palm oil during deodorisation is attributed to the intrinsic composition of crude palm oil. Utilising D-optimal design, the effects of the degumming and bleaching processes on the reduction in 3-MCPD ester formation in refined palm oil from poor-quality crude palm oil were studied relative to the palm oil minor components that are likely to be their precursors. Water degumming remarkably reduced 3-MCPD ester formation by up to 84%, from 9.79 mg/kg to 1.55 mg/kg. Bleaching with synthetic magnesium silicate caused a further 10% reduction, to 0.487 mg/kg. The reduction in 3-MCPD ester formation could be due to the removal of related precursors prior to the deodorisation step. The phosphorus content of bleached palm oil showed a significant correlation with 3-MCPD ester formation.     

Marination of deep-water pink shrimp with rosemary extract and the determination of its shelf-life

The effect of the antioxidant activity of rosemary extract on marinated deep-water pink shrimp (Parapenaeus longirostris Lucas, 1846) stored at 1 °C was investigated. Chemical, physical, instrumental, microbiological and sensory analyses were performed to investigate the quality changes and to determine the shelf-life of marinated shrimps. Chemical composition of the shrimp was determined and no significant difference (P > 0.05) was found between the control group (without rosemary extract) and the experimental group (with rosemary extract). Both groups contained 2% citric acid. There was no significant difference (P > 0.05) between the sensory analysis of control and experimental groups on storage days 0, 15, 30, 45 and 60 while rancidity was noted by the panelists in the control group on day 75. The TBA value of the control group reached the consumption limit on day 75 but it was still ‘very good’ for the experimental group. Although the bacterial load of both groups were lower than the consumption limits on storage day 75, TBA value limited the shelf-life of the control group but the experimental group was still of good quality for consumption after 75 days.     

Antioxidant and nitric oxide production inhibitory activities of galacturonyl hydroxamic acid

The self-prepared pectin hydroxamic acid has been reported to have antioxidant activities [Yang, S. S., Cheng, K. D., Lin, Y. S., Liu, Y. W., & Hou, W. C. (2004). Pectin hydroxamic acids exhibit antioxidant activities in vitro. Journal of Agricultural and Food Chemistry, 52, 4270–4273]. In this study, the galacturonic acid (GalA), the monomer unit of the pectin polymer, was esterified with acidic methanol (1 N HCl) at 4 °C with gentle stirring for 5 days to get galacturonic acid methyl ester which was further reacted with alkaline hydroxylamine to get galacturonyl hydroxamic acid (GalA–NHOH). The GalA–NHOH was used to test the antioxidant and antiradical activities in the comparison with GalA. The scavenging activities of GalA–NHOH against DPPH radicals (half-inhibition concentration, IC₅₀, was 82 μM), hydroxyl radicals detected by electron spin resonance (IC₅₀ was 0.227 nM in the comparison with Trolox of 0.433 μM), superoxide radicals (IC₅₀ was 830 μM) were determined. The protection activities of GalA–NHOH against hydroxyl radicals-mediated calf thymus DNA damages, linoleic acid peroxidation and peroxynitrite-mediated dihydrorhodamine 123 oxidations were also investigated. It was found that the GalA–NHOH exhibited dose-dependently antioxidant activity and few or none was found in GalA. The GalA–NHOH was used to evaluate the suppressed activity of nitric oxide (NO) productions of RAW264.7 cells in the presence of lipopolysaccharide (LPS, 100 ng/ml) as inducers. It was found that GalA–NHOH (0.02–0.1 mg/ml) could dose-dependently suppress the NO productions (expressed as nitrite concentrations) in RAW264.7 cells without significant cytotoxicity.     

BTH诱导采后桃果实抗病性反应对其贮藏品质的影响

以"大久保"水蜜桃果实(Prunus persica(L.)Batsch cv.‘OkuBa’)为试材,研究了0.2 g/L BTH处理诱导的桃果实抗病性反应对其贮藏品质影响。实验结果表明:0.2 g/L BTH处理可有效诱导桃果实在20℃贮藏期间的SAR反应,促进抗病相关酶几丁质酶和β-1,3-葡聚糖酶活性以及总酚含量的上升,从而有效控制了果实贮藏期间P.expansum导致的青霉病的发展;但BTH处理诱导的SAR反应同时显著降低了桃果实在贮藏期间的乙烯峰值以及葡萄糖和蔗糖含量,并可抑制总黄酮、总花色苷和类胡萝卜素的积累,从而导致果实出现后熟及次生代谢产物合成速度减慢等不良症状。由此推测,BTH诱导的SAR抗病性反应对采后桃果实来说是一个不可逆的物质和能量消耗过程,可能会影响果实后熟品质的形成。