桑蚕丝与柞蚕丝混纺产品定量化学分析方法研究

用甲酸/氯化锌法测定桑蚕丝与柞蚕丝混纺产品的纤维含量,考察不同溶解条件对混合物溶解程度的影响,选出最优溶解方案.在此条件下,检测结果与实际含量对应良好,且与FZ/T 40005-2009《桑/柞产品中桑蚕丝含量测定化学法》中氯化钙/乙醇法相比,结果无显著差异,样品溶解时间缩短,溶解温度降低,可操作性增强,检测数据稳定可靠.     

桑蚕丝/羊毛混合物纤维含量定量分析研究

目前桑蚕丝/羊毛混合物的纤维含量定量化学分析法对深色样品中的桑蚕丝溶解不完全,本文通过改变标准FZ/T 01112—2012中甲酸/氯化锌溶解法的试验条件,研究分析溶解桑蚕丝产品的可行性。     

制革行业物化污泥制备再生水处理剂研究

为实现制革行业污泥减量化、无害化、资源化的目标，以水洗-酸溶解为核心工艺，对制革物化污泥制备水处理剂的可行性进行了研究。研究表明，物化污泥的最佳煅烧温度为1 000℃;最佳水洗条件为固液比1∶10,水洗时间1 h,水洗次数2次；最佳酸溶解条件为固液比5 g/L,酸浓度0.5 mol/L,酸溶解温度20℃,酸溶解时间0.5 h;溶液中Cr⁶⁺最佳还原条件为摩尔比(还原剂∶Cr⁶⁺)16∶1,还原温度40℃。在本文的工艺条件下，制革行业的物化污泥可实现最佳的减量化和资源化利用目标。     

甲酸/氯化锌法对羊毛/丝混纺产品进行化学定量分析的研究

利用羊毛和丝在甲酸/氯化锌溶液中溶解性能不同的原理,用甲酸/氯化锌溶液溶解已知混纺织物中的丝纤维,通过试验得出了羊毛与桑蚕丝混纺产品定量分析的甲酸/氯化锌溶液溶解浓度、时间、温度等试验条件,并与现有方法相比较,试验结果表明,甲酸/氯化锌法对羊毛/丝混纺产品进行化学定量分析是可行的。     

大麻纤维在氯化锂/N,N-二甲基乙酰胺溶解体系中的溶解特性

为提高大麻纤维溶解性能,对大麻纤维进行氢氧化钠预处理和氯化锂/N,N-二甲基乙酰胺（LiCl/DMAc）溶解处理。用质量分数为18%的氢氧化钠在60℃处理大麻纤维1～4h,然后将预处理后的大麻纤维在不同温度（70、80、95℃）下溶解于质量分数为10％的LiCl/DMAc溶解体系。用扫描电镜、红外光谱仪 和 X 射线衍射仪对溶解前后的大麻纤维进行表征,测试溶解后溶液黏度值。结果表明：氢氧化钠预处理后纤维素的晶型由纤维素Ⅰ转变为纤维素Ⅱ;溶解温度升高,大麻纤维溶解性增强,95℃条件下,预处理2h和3h的大麻纤维在10%LiCl/DMAc溶解体系中能够完全溶解,溶解质量分别为1.0～1.2g和1.2～1.5g;预处理3h的大麻纤维/LiCl/DMAc溶液黏度值更大,溶液稳定。     

甲酸/氯化锌法对羊毛/丝混纺产品的定量分析

利用羊毛和丝在甲酸/氯化锌溶液中溶解性能不同的原理,用甲酸/氯化锌溶液溶解已知混纺织物中的丝纤维,通过试验得出了羊毛与桑蚕丝混纺产品定量分析的甲酸/氯化锌溶液溶解浓度、时间、温度等试验条件,并与现有方法相比较,试验结果表明,甲酸/氯化锌法对羊毛/丝混纺产品进行化学定量分析是可行的。     

高温酸解辅助酶解猪毛工艺的研究

为了提高猪毛中角蛋白的加工利用,探讨了高温酸解辅助酶解猪毛的工艺条件。以猪毛溶解率和可溶性蛋白质含量为指标,通过单因素试验、正交试验和响应面试验优化猪毛溶解工艺。结果表明:高温酸解处理最优条件为温度125℃、处理时间45 min、盐酸浓度0.25 mol/L,猪毛的溶解率达58.21%;酶解工艺的最优条件为酸解液调整pH值为7.4、复合蛋白酶加酶量为3.4%、酶解时间为10.9 h,猪毛溶解率达86.33%,可溶性蛋白质含量达312.397 mg/g。采用先高温酸解再酶解的方法不仅降低了酸使用量,相比较只采用高温酸解处理猪毛溶解率提高了48.31%。     

不同厂商氯化锌试剂对莱赛尔/棉混合物定量分析的影响

用甲酸/氯化锌溶液分析莱赛尔与棉混合物时,影响因素主要是试剂温度和溶解时间。在溶解温度70℃条件下,通过对氯化锌试剂、前处理和样品量多少等影响因素研究发现,不同厂商的氯化锌试剂配制的甲酸/氯化锌溶液溶解莱赛尔纤维能力有差异,相对应的棉纤维的d值也不同,需要分别测定溶解时间和对应的棉纤维的d值。     

溶解温度及NMMO溶剂浓度对纤维素溶解的影响

针对Lyocell纤维制备过程中存在溶解状态不易量化、溶解能耗大的问题,研究了不同温度下,纤维素在不同浓度N-甲基吗啉-N氧化物(NMMO)溶剂中的溶解方式与效率,利用溶解过程中的搅拌功率-时间曲线及显微镜照片等表征不同溶解工艺的区别,并计算不同工艺的能耗。结果表明:在较高温度或较高的NMMO质量分数条件下(110℃/76%或105℃/79%),浆粕直接溶解,纤维素呈现"崩裂溶解";而在较低的温度或者较低NMMO质量分数条件下,浆粕先溶胀再溶解,纤维素呈现"溶胀溶解"。纤维素非晶区溶解时搅拌功率迅速上升,纤维素微小难溶粒子溶解时搅拌功率维持稳定。此外,较高的NMMO质量分数可以缩短37%的溶解时间,降低33%的机械能;较高温度可以缩短25%的溶解时间,降低18%的机械能。浆粕在高浓度高温下溶解,具有低能耗,溶解速度快的优点。     

还原法与金属盐法结合溶解废旧羊毛

为实现废旧羊毛再生利用,提高大分子角蛋白回收率,采用NaHSO3/LiBr/SDS溶解体系处理废旧羊毛制取无毒稳定、高溶解率、高分子量的角蛋白溶液.通过试剂用量、pH值、反应温度、反应时间各单因素对比试验,以羊毛溶解率、大分子量角蛋白提取率为测试指标,确定反应最佳条件.结果表明:在NaHSO3浓度为0.5 mol/L、...     

Use of digital images to estimate CIE color coordinates of beef

The objective of this study was to evaluate the use of digital images (DI) to estimate CIE L^*a^*b^*, hue angle and chroma of beef, as compared to a colorimeter (CM). Loin samples from 21 steers finished with high-grain diets were displayed under retail-simulated conditions. Color readings were obtained from 63 cores covering the full spectrum of discoloration in beef. CIE L^*, a^*, and b^* were measured with a surface-reflectance CM. Red, green and blue (RGB) values were obtained from DI and sequentially transformed to XYZ and CIE L^*a^*b^* color space. Hue angle and chroma were calculated from a^* and b^* values. Regressions of CM on DI for a^*, hue angle and chroma had R² values of 0.93 and above. Average color difference () between the predicted and the actual CM L^*, a^*, and b^* values for 13 samples that were not included in the regressions was 1.57, below reported thresholds of detection for 50% of observers. Color readings from DI could be used to accurately predict color coordinates measured by CM, especially a^*, hue angle and chroma. Use of digital imaging could become a practical tool to detect changes in beef color and other muscle foods.     

聚类法分析不同品种树莓的加工特性

以15 个不同品种的树莓鲜果为实验材料,对果实的组成分、理化指标、VC、粗蛋白、总酚和花色苷含量进行测定分析。通过聚类分析,筛选出适合不同树莓产品加工的品种。结果表明：不同品种树莓的硬度值、果实出汁率、可溶性固形物含量、可滴定酸含量、糖酸比差异较大,硬度值在18.20～49.50 g之间,‘Cuthbert’硬度值最小（18.20 g）,硬度值最大的为‘米克2号’（49.50 g）,出汁率分布变幅为58.27%～79.80%,其中‘Cuthbert’出汁率最低（58.27%）,出汁率最高的为‘Creston’（79.80%）。可溶性固形物含量在6.86%～10.60%之间,可溶性固形物含量最高的为‘Cuthbert’（10.60%）,最低的为‘菲尔杜德’（6.86%）。糖酸比最大的为‘Sunrise’（7.42）,‘Willamette’糖酸比值最小（1.75）。15 个树莓品种的多酚氧化酶、过氧化物酶的活性和色泽稳定性差异较大。VC含量在6.86～10.60 mg/100 g之间;粗蛋白含量分布变幅为0.70～1.49 g/100 g;总酚含量在1.41～3.44 g/100 g之间。花色苷含量介于72.35～393.88 mg/100 g之间。初步评价：第1类的‘Rideau’、‘米克1号’和‘米克2号’,适合于果汁、果酒类产品的加工;‘Zeva Remontant’、‘Nova’适合树莓罐头类产品加工;适合加工果脯类产品的‘Willamette’、‘Omet’、‘Festival’和‘Sunrise’为第2类。‘Rideau’、‘米克1号’、‘米克2号’、‘Willamette’、‘Sunrise’和‘Nova’这6 个品种果实综合品质比较好,是适合于进一步树莓栽培品种选育和深加工的良好品种。     

5 种淡水鱼肌肉热特性比较研究

为研究不同品种名优淡水鱼冷藏保鲜及热加工的特性,采用差示扫描量热法研究武昌鱼、草鱼、黄颡鱼、鲈鱼和鳜鱼5 种新鲜淡水鱼鱼肉的水分含量、冰点、变性温度、变性热焓和比热容并进行品种间的比较。结果发现：5 种淡水鱼冰点分布在－0.57～－0.1 ℃之间;50 ℃附近热吸收峰起始温度分布在37～41.57 ℃之间,终止温度分布在60.47～62.33 ℃之间;变性热焓在1.680 0～2.499 7 J/g之间;70 ℃附近热吸收峰的起始温度分布在66.33～71.13 ℃之间,终止温度分布在73.60～82.20 ℃之间,变性热焓在0.418 0～0.512 2 J/g之间;鱼肉的比热容在1.658 0～3.862 3 J/（g·K）之间。结果表明：在5 种新鲜淡水鱼中,武昌鱼水分含量和冰点相对较低;草鱼肌球蛋白和鳜鱼肌动蛋白变性温度和变性热焓相对较高,蛋白质稳定性更高;新鲜鱼肉的比热容高于冻结鱼肉,加工后鱼肉的比热容高于未加工鱼肉。     

五味子乙素逆转人结肠癌细胞多药耐药性

目的:研究五味子乙素(SchisandrinB,SchB)抑制逆转耐奥沙利铂人结肠癌细胞(THC-8307/OXA)多药耐药性(MDR)。方法:采用噻唑蓝(MTT)比色法检测奥沙利铂(OXA)和五味子乙素的细胞毒性;Western Blot检测SchB对耐奥沙利铂人结肠癌细胞THC-8307/OXA细胞BCRP蛋白水平的影响。结果:SchB(12.5、25、50μg/mL)对人结肠癌细胞(THC-8307)和THC-8307/OXA无显著毒性作用(P>0.05,)OXA对THC-8307的IC50为3.50μg/mL,而对THC-8307/OXA的IC50为12.21μg/mL,THC-8307/OXA较THC-8307对OXA耐药3.49倍,SchB(12.5、25、50μg/mL)能使OXA对THC-8307/OXA细胞的IC50从12.21μg/mL依次下降至5.94、4.47、3.15μg/mL,逆转倍数分别为2.06、2.73、3.88倍。Western Blot检测SchB(25μg/mL)和OXA(20μg/mL)处理48h后,THC-8307/OXA细胞BCRP蛋白表达明显降低。结论:SchB具有逆转耐奥沙利铂人结肠癌细胞的MDR作用,其作用机理与下调BCRP表达有关。     

Image Analysis of Representative Food Structures: Application of the Bootstrap Method

ABSTRACT:  Images (for example, photomicrographs) are routinely used as qualitative evidence of the microstructure of foods. In quantitative image analysis it is important to estimate the area (or volume) to be sampled, the field of view, and the resolution. The bootstrap method is proposed to estimate the size of the sampling area as a function of the coefficient of variation (CV _Bn ) and standard error (SE _Bn ) of the bootstrap taking sub-areas of different sizes. The bootstrap method was applied to simulated and real structures (apple tissue). For simulated structures, 10 computer-generated images were constructed containing 225 black circles (elements) and different coefficient of variation (CV _image ). For apple tissue, 8 images of apple tissue containing cellular cavities with different CV _image  were analyzed. Results confirmed that for simulated and real structures, increasing the size of the sampling area decreased the CV _Bn  and SE _Bn . Furthermore, there was a linear relationship between the CV _image  and CV _{Bn .} For example, to obtain a CV _Bn  = 0.10 in an image with CV _image  = 0.60, a sampling area of 400 × 400 pixels (11% of whole image) was required, whereas if CV _image  = 1.46, a sampling area of 1000 × 100 pixels (69% of whole image) became necessary. This suggests that a large-size dispersion of element sizes in an image requires increasingly larger sampling areas or a larger number of images.     

Influence of Oxygen, Carbon Dioxide, and Degree of Cutting on the Respiration Rate of Rutabaga

ABSTRACT: Both the O₂-consumption and CO₂-production rates of uncut and cut rutabaga were measured in a closed system. Compared to enzymatic and 1st-order linear models, a 2nd-order expression was found to best predict respiration rates under the conditions typically found in modified atmosphere packages. The concept of degree of cutting was introduced to quantitatively analyze the effect of wounding on respiration rates. A linear relationship was observed between the respiration rates at a fixed pO₂ and pCO₂ and the quantified degree of cutting injury. Mathematical expressions were developed that accurately describe the relationship between respiration rates, O₂ and CO₂ partial pressures, and the degree of cutting.     

Reaction of melanoidins with sulphur dioxide: stoichiometry of the reaction

Sulphur dioxide, in the form of sulphur(IV) oxoanions(S(IV)), e.g. HSO^-₃, SO^2-₃, reacts irreversibly with non-enzymic browning model melanoidins (M_r > 12000, prepared by combination of 1.25 mol glucose with 1 mol glycine (pH 5.5, 90°C, 22 hr)). When the reaction with S(IV) is carried out for > 39 days at 40°C and pH 5.5 with initial concentrations of melanoidin of 5.71 g/l and S(IV) of 0.0371 M (equivalent to c . 2400 ppm SO₂), up to one sulphur atom is incorporated for every two molecules of glucose used to form the polymer. This stoichiometry is discussed in relation to the degree of unsaturation of the melanoidin.     

响应面试验优化黑脉羊肚菌多酚纯化工艺及其抗氧化活性

以吸附率和解吸率为评价指标,研究9 种大孔吸附树脂对黑脉羊肚菌多酚吸附及解吸性能,采用响应面法建立NKA-Ⅱ树脂纯化黑脉羊肚菌多酚的二次多项回归模型,对多酚的纯化工艺进行优化,并比较纯化前后多酚的抗氧化活性。结果表明：最佳纯化树脂为NKA-Ⅱ。吸附的最佳工艺条件为上样液质量浓度295.86 μg/mL、上样流速1.90 mL/min、上样液pH 2.84,解吸的最佳工艺条件为乙醇体积分数78.56%、洗脱速率0.80 mL/min、洗脱剂pH 3.08;在此条件下吸附率可达98.69%,解吸率可达92.75%,纯化前后羊肚菌多酚纯度提高了2.94 倍。黑脉羊肚菌多酚纯化前1,1-二苯基-2-三硝基苯肼自由基清除率、2,2’-联氮基-双-（3-乙基苯并噻唑啉-6-磺酸）二氨盐自由基清除率和还原力EC50值分别为1.48、0.015、2.35 mg/mL,纯化后分别为0.52、0.004、0.69 mg/mL,纯化后抗氧化活性明显增强。     

Water desorption isotherms of two varieties of sweet potato

Water desorption isotherms were determined for New Zealand sweet potato at 25, 40 and 55°C, and for Philippines sweet potato at 28°C. The isotherms were sigmoid in shape and of type II according to the BET classification. The data were fitted to eight two-parameter equations reported in the literature. The effect of water activity, a_w, and temperature, T °C, on the equilibrium moisture content, M _e g water/100g dry solids, was best described for New Zealand sweet potato by: Me = 20.51 T-^0.204 (a_w/(1-a_w)0.39 for a_w= 0.06–0.81     

Effects of available soil volume on growth, bud fertility and water relations of young Shiraz grapevines

Effects of available soil volume (ASV) on growth, water relations and bud fertility of drip-irrigated Shiraz grapevines ( Vitis vinifera ) were examined during their establishment in the 2000/01 growing season under field conditions in the Goulburn Valley, Australia. Vines were planted into different size subterranean containers to create a range of confined ASV treatments (viz. 0.15, 0.4, 0.8 and 1.2 m³/vine referred to as ASV₁₅, ASV₄₀, ASV₈₀ and ASV₁₂₀, respectively) and compared with a deep ripped treatment where the ASV was unconfined (ASV_UC). Pruning weight, trunk cross-sectional area, and daily average fractional photosynthetically active radiation interception ( f_daily ) increased with increasing ASV but were lowest in the ASV_UC treatment. f_daily attained a maximum by mid-February 2001 in ASV₁₅ but continued to increase in all other treatments. Water relations data showed high leaf water potential (φ_leaf) in ASV₁₅ compared to the other treatments. Our results suggest that reduced growth in smaller soil volumes was not a consequence of water stress. Leaf conductance ( g _L) tended to be low in the ASV₁₅ treatment in comparison with the ASV_UC treatment. Increasing ASV from 0.15 to 1.2 m³/vine increased the number of bunches per vine in the following season by 32%. This increase was not due to improvement in the number of bunches per shoot, but resulted from an increased number of shoots bursting per node. By contrast, ASV_UC significantly reduced bud fertility. The implications of these results for vine establishment in shallow soils are discussed.