苹果渣膳食纤维的改性研究

进行苹果渣膳食纤维的改性试验研究,比较了化学法和物理法对膳食纤维改性的影响,得出物理方法对膳食纤维有较好的改性处理。其中挤压处理后苹果渣SDF的含量由8.45%上升到12.68%;超微粉碎处理后,苹果渣膳食纤维的持水力提高了9.9%,膨胀力提高了9.8%。     

微生物发酵法改性苹果渣膳食纤维理化特性分析

对采用绿色木霉发酵改性的苹果渣膳食纤维的理化特性进行研究。结果表明,改性苹果渣膳食纤维显示较佳的理化性质,膨胀力为6.25mL/g,持水力为4.53g/g。改性苹果渣膳食纤维在pH 2.0条件下对NO_2~-吸附率可达98.8%,可以将NO_2~-浓度降低至3.5μmol/L,有效避免该物质对人体产生危害。吸附胆酸钠的测定结果表明,3g改性苹果渣膳食纤维对胆酸钠的吸附率可以达到72.8%,对降低血清胆固醇具有积极的意义。     

物理改性对燕麦麸皮不溶性膳食纤维理化特性的影响

通过分析物理改性对燕麦麸皮不溶性膳食纤维特性的影响,为进一步研究水不溶性燕麦麸皮膳食纤维的保健功能提供科学依据。采用以500 MPa 20 min 60℃超高压、1500 W 30 min超声波及其联合的方法处理不溶性膳食纤维,分析了物理改性对燕麦麸皮不溶性膳食纤维比面积和粒度、持油性、持水性、膨胀度、悬浮粘度、离子交换能力的影响。结果表明:超高压联合超声波处理比两者单独处理效果显著(p0.05),以1%燕麦麸皮IDF为例,两者联合处理能显著(p0.05)增加燕麦麸皮不溶性膳食纤维比面积13.49倍、持油性2.92倍、膨胀度、粘度值和阳离子交换能力,减少纤维粒度2.8倍,减少持水性2.25倍(持水性以16%燕麦麸皮IDF为例)。因此认为物理改性能加大燕麦麸皮不溶性膳食纤维的综合利用,提高农产品的附加值和食品资源的再利用程度。     

酶解-挤出复合法改性绿豆皮膳食纤维及其结构表征与理化性能

利用酶解-挤出复合法对绿豆皮膳食纤维进行改性,采用单因素和正交实验对影响改性工艺的主要因素进行优化,通过扫描电镜、傅里叶变换红外光谱和X-射线衍射对绿豆皮膳食纤维改性前后的结构进行表征分析,以持油力、持水力、膨胀力、阳离子交换能力和吸附胆固醇能力为绿豆皮膳食纤维理化性能的考察指标。结果表明,当纤维素酶添加量120 U/g、酶解时间4 h、水分添加量70%、挤出温度140 ℃时,可溶性膳食纤维得率为（12.74±0.29）%。改性处理后绿豆皮膳食纤维的表面结构疏松、粗糙,出现多孔性、多层褶皱特征,相对结晶度明显下降,各纤维素组分重新分布,而且有一部分不溶性膳食纤维转化为可溶性膳食纤维。改性处理后绿豆皮膳食纤维的持油力、持水力、膨胀力、阳离子交换能力和吸附胆固醇能力均显著增加。     

乙醇-过氧化氢纤维素酶提取甜菜膳食纤维工艺的研究

以甜菜干粕为原料,用乙醇和过氧化氢提取膳食纤维.分别以甜菜膳食纤维的膨胀力和持水力为评价指标,最佳提取工艺条件:乙醇体积分数65%,过氧化氢体积分数7%,水浴温度35℃,水浴时间75 min.在此条件下可以提高甜菜膳食纤维的膨胀力2.52%,提高持水力3.14%.用纤维素酶改性甜菜膳食纤维,分别以甜菜膳食纤维的膨胀力和持水力为评价指标,得到两种最佳改性条件:一是在酶用量600μL,反应温度60℃,pH 5.5,反应55min条件下处理,可以提高甜菜膳食纤维的膨胀力13.8%;二是在酶用量600μL,反应温度55℃,pH 5.5,反应65min条件下处理,可以提高甜菜膳食纤维的持水力19.7%.     

玉米麸皮发酵法制备阿魏酰低聚糖及膳食纤维的研究

试验以玉米麸皮为原料,采用平菇液体发酵法制备阿魏酰低聚糖和膳食纤维,同时测定发酵过程中淀粉酶、蛋白酶、纤维素酶和木聚糖酶的活性,并对发酵所得膳食纤维含量及持水性、膨胀力和持油力等性质进行了研究。结果表明玉米麸皮经过平菇发酵8 d后,发酵液中淀粉酶、蛋白酶、纤维素酶和木聚糖酶的酶活均达到最高,分别为978.67 mU/mL、10.15U/mL、256.50、100.76 mU/mL,发酵液中FOs含量为12.515μmol/L。不溶性膳食纤维的提取率为2.83±0.79 g/mL,其持水性、膨胀力和持油性分别为1.37±0.39 g/g、2.17±0.29 mL/g和6.29±0.42 g/g,而可溶性膳食纤维的提取率为0.21±0.01 g/mL,其持水性、膨胀力和持油性分别为4.42±0.01 g/g、1.00±0.07 mL/g和4.75±0.49 g/g。平菇发酵玉米麸皮生产阿魏酰低聚糖和膳食纤维是可行的。     

改性豆渣膳食纤维的理化性质、结构及其益生活性研究

以豆渣膳食纤维为对象,分别采用高速剪切、复合酶解、高速剪切协同酶解改性豆渣膳食纤维,分析其理化性质、结构以及益生活性的变化。结果表明,3种改性方法均能显著改善豆渣膳食纤维的持水性、膨胀力和持油力(P<0.05)。改性后的豆渣膳食纤维可溶性组分增多,粒径减小,微观结构变得疏松多孔;傅里叶变换红外光谱分析结果表明,改性后的豆渣膳食纤维特征吸收峰的分布未发生明显变化,部分峰强度减弱;X射线衍射结果表明,改性处理并未改变豆渣膳食纤维晶体构型。体外发酵实验表明,改性豆渣膳食纤维对嗜酸乳杆菌和乳双歧杆菌均有一定的促进增殖作用,其中对嗜酸乳杆菌的增殖作用更显著;3种改性方式中,高速剪切协同酶解改性制备的豆渣膳食纤维的益生活性最高,主要体现在提高益生菌活菌数和降低培养基pH。因此,高速剪切协同酶解可作为一种改性豆渣膳食纤维的优良方法,提升膳食纤维的理化性质和益生活性,为其在功能食品中应用提供参考。     

改性处理对绿豆皮膳食纤维结构及功能特性的影响

以绿豆皮膳食纤维为试验对象,采用挤出改性、酶解改性、挤出-酶解复合改性3种处理方式对其进行改性处理。以持水力、持油力、膨胀力、阳离子交换能力、吸附葡萄糖能力和吸附胆固醇能力为评价指标,研究改性处理对绿豆皮膳食纤维功能特性的影响。以扫描电子显微镜、X射线衍射和傅里叶变换红外光谱法表征改性处理对绿豆皮膳食纤维结构的影响。结果表明:挤出-酶解复合改性处理的效果最明显,其功能特性得到显著改善,持水力、持油力、膨胀力、阳离子交换能力、吸附葡萄糖能力分别是未改性绿豆皮膳食纤维的1.46,1.15,1.87,6.98,1.66倍;在pH 2和pH 7条件下对胆固醇的吸附能力分别达(2.38±0.05)mg/(mL·g)和(3.45±0.12)mg/(mL·g)。扫描电子显微镜观察结果表明,挤出-酶解复合改性处理后的绿豆皮膳食纤维表面结构粗糙、疏松,出现多层褶皱或多孔性特征。X射线衍射、傅里叶变换红外光谱结果表明,挤出-酶解复合改性处理后的绿豆皮膳食纤维的相对结晶度最低,各纤维素组分重新分布,部分不溶性膳食纤维(IDF)向可溶性膳食纤维(SDF)转化。结论:挤出-酶解复合改性处理是一种改性膳食纤维的较好方法,可为提高绿豆皮膳食纤维的利用率和进一步开发利用其营养价值提供理论依据。     

微波和微粉碎改性对方竹笋膳食纤维性能和结构的影响

以方竹笋膳食纤维为研究对象,进行微波和微粉碎物理改性处理,分析其理化性能和结晶结构变化。以水合性(膨胀力、持水力、结合水力、持油力)和抗氧化性(吸附亚硝酸盐能力、还原力、超氧离子清除率)为方竹笋膳食纤维的理化性能考察指标,通过微波和微粉碎实验分析和讨论,比较膳食纤维改性前后的理化性能。通过扫描电镜、傅里叶红外光谱和X-射线衍射比较分析方竹笋膳食纤维改性前后的结晶结构变化,探讨微波和微粉碎物理改性对膳食纤维结晶结构的影响。结果表明,微波处理后膳食纤维持水力和还原力显著提高(p0.05),比表面积增大;微粉碎处理后膳食纤维持油力显著降低、还原力显著提高(p0.05),部分网状结构消失;2种改性方竹笋膳食纤维的多糖吸收峰无明显变化,结晶结构没有改变、但强度发生了变化。因此,微波改性既能增强方竹笋膳食纤维的水合性,又能提高其抗氧化性能,微粉碎能使方竹笋膳食纤维的抗氧化性增加;微波和微粉碎处理后的方竹笋膳食纤维结晶强度和比表面积增大。     

甘薯膳食纤维酶法改性及其特性研究

采用纤维素酶和木聚糖酶相结合,对甘薯膳食纤维进行改性研究。通过单因素试验和正交试验优化甘薯膳食纤维酶法改性工艺条件,并对改性前后膳食纤维的理化特性和抗氧化活性进行分析研究。结果表明:甘薯膳食纤维酶法改性中,纤维素酶最适添加量1.2%,木聚糖酶最适添加量1.6%,最佳酶解时间30 min,最适料液比1∶11,获得的可溶性膳食纤维得率为8.84%。与天然膳食纤维相比,改性后的甘薯膳食纤维持油力上升,膨胀力和持水力下降(P0.05)。同时,酶法改性显著提高了甘薯膳食纤维对DPPH的清除能力,增强了甘薯膳食纤维的功能特性。     

哈蟆油非水溶性成分酶解前后耐缺氧活性研究

比较研究哈蟆油非水溶性成分酶解前后的耐缺氧作用。设立哈蟆油非水溶性成分及其酶解物的低、中、高剂量组和空白对照组,连续灌胃30 d。测定小鼠的常压耐缺氧时间、亚硝酸钠中毒存活时间、急性脑缺血性缺氧存活时间。结果表明:与对照组比较,酶解前各剂量组的常压耐缺氧时间、亚硝酸钠中毒存活时间、急性脑缺血性缺氧存活时间均无显著性差异;酶解后各剂量组常压耐缺氧时间具有显著性差异,中、高剂量组亚硝酸钠中毒存活时间具有显著性差异,中剂量组急性脑缺血性缺氧存活时间具有显著性差异。哈蟆油非水溶性成分无耐缺氧作用,酶解后产物具有显著的耐缺氧作用。     

大米通电加热特性的研究

研究了大米的通电加热工艺,并研究了大米通电加热后微观结构的变化,并与传统的加热方式进行了比较。结果表明大米经浸泡12h后,通电加热蒸煮20min口感最佳,通电加热蒸煮的米粒口感明显好于电炉加热。通电加热后的米粒微观结构与电炉加热的米粒微观结构有明显差异,通电加热的米粒糊化程度高于电炉加热。     

辣椒酱防腐剂的研制

针对辣椒酱开盖后在食用期间容易起霉、变坏的问题进行了研究,并从中分离出了三株细菌、三株霉菌,针对这些微生物进行了有效的抑菌实验,并开发出了相应的防腐剂,添加了0.05%防腐剂的辣椒酱在开盖后室温下放置了25d才开始发霉。     

饮酒口干程度检测方法的探索性研究

研究饮酒后口干程度的检测方法并开展探索性应用。采用适应性喂养良好的小鼠,先后采用水、酒精灌胃,均检测禁水后不同时间点的血清渗透压,初步确定饮后口干程度与血清渗透压的关系。将血清渗透压指标的检测与动物醉酒试验结合,通过检测灌胃饮酒小鼠翻正反射恢复后血清渗透压,探索性应用于白酒、保健酒等酒类饮后口干程度的对比分析。本文为酒类产品在研发过程中涉及到的饮后口干程度的研究提供了定量检测方法,为开发高品质的白酒、保健酒等提供参考与指导。     

面团发酵过程中小麦淀粉理化性质的变化

以小麦粉为原料,结合水洗和离心提取小麦淀粉,研究面团发酵过程中一次发酵、二次发酵和醒发工序对直链淀粉含量、溶解度、溶胀度、糊化特性和凝胶特性等理化性质的影响。试验结果表明:发酵后直链淀粉质量分数提高3.7%～8.18%;采用黏度速测仪(RVA,Rapid visco analyzer)分析醒发后小麦淀粉的峰值黏度、谷值黏度和最终黏度分别上升52 RVU、58.67 RVU和73.33 RVU;采用质构仪(TPA,Texture profile anal-ysis)对发酵过程小麦淀粉凝胶特性进行研究,发现醒发后凝胶特性有所改善,硬度提高48.60 g,弹性提高0.03,内聚性、回复性分别提高0.05、0.15。     

低温等离子体处理对精练后棉织物性能的影响

通过改变低温等离子体处理的气体类型，功率、时间工艺参数，对精练后的棉织物进行改性处理，测试了处理后棉织物的性能。结果表明，经等离子改性处理后，棉织物的拉抻断裂强力和毛细管效应有明显提高，撕裂强力和折皱回复角变化不大，在扫描电子显微镜下可观测到棉纤维表面有明显刻蚀现象。     

The effect of the previous crop on the growth,nitrogen uptake and yield of winter barley intended for malting

Winter barley which received a range of nitrogen rates, was grown at Rothamsted as a test crop after winter oats, winter barley, winter beans, oilseed rape or potatoes, to compare the effects of previous crop on growth and N uptake. In the autumn following the first year crops, the largest amount of residual inorganic N found in the soil was after potatoes, the smallest after oats. Throughout the second season the heaviest crops of barley, which also contained the most N, were after potatoes, and the lightest were after barley. To produce grain with a N concentration of less than 1.8% N (w/w, dry wt), acceptable for malting, it was found that not more than 75 kg N ha⁻¹ after barley and 125 kg N ha⁻¹ after oats, 100 kg N ha⁻¹ after beans and 50 kg N ha⁻¹ after rape or potatoes could be applied. The results demonstrated that barley of acceptable quality for malting can be grown after a break crop, providing that the rate of N fertiliser is suitably adjusted to take account of the residual fertility, but the results do not suggest that residual soil N affects the grain N concentration differently to N applied as fertiliser early in the season.     

Technological Studies on the Dehydration of the Nile Bolti Fish (Tilapia nilotica)

Chemical and microbiological analysis of bolti fish: moisture, chloride, fat, total volatile bases (T.V.B.), thiobarbituric acid value (T.B.A.), total bacterial count and coliforms were estimated in fresh bolti fish, after brining, drying and during storage at room temperature for 3 months. The moisture content decreased after drying but become stable during the storage period. Chloride increased after brining but no noticeable changes were observed after drying and during 3 months storage. The fat content was not affected by previously processes. T.V.B. and T.B.A. increased after brining, drying and throughout storage period. The rate of increase was higher for dehydrated samples than for sun-dried ones. The reduction of total bacterial count is due to the high salt content and the lack of free water in fish tissues after drying. Coliforms were not present after brining, drying and throughout the storage periods.     

Influence of the tear film on optical quality of the eye

The optical quality of the tear film of the eye was tested by measuring the retinal image before and after the break-up time (BUT). An objective method was used based on the evaluation of the retinal image of a point test projected onto the fovea. The loss of an entire tear film would result in a decrease in the optical quality because of corneal irregularities and the formation of an irregular tear lens after the BUT. Our results confirm the expected loss both of non-contact lens wearers and contact lens wearers. Also, the fact that the optical deterioration found after the BUT is greater for contact lens wearers confirms that soft contact lens wear produces a disruption of the tears.     

Study on the microflora and biochemistry of cocoa fermentation in the Dominican Republic

Cocoa fermentation was monitored at the IDIAF (Instituto Dominicano de Investigaciones Agropecuarias y Forestales) "Mata Larga" experimental station, in San Francisco de Macoris, Dominican Republic. The maximum average fermentation temperature reached 51 degrees C after 48 h and the pH reached 4.5 after 144 h of fermentation. A significant decrease in glucose, fructose and citric acid was seen in the pulp over the first 48 h. There was a delay of 24 h between maximum microbial growth and maximum concentrations of the respective metabolites, which occurred after 48 h for ethanol and after 72 h for acetic acid. A maximum concentration in lactic acid was found after around 120 h of fermentation. The aerobic mesophilic flora increased from 6.1x10(6) to a maximum of 4.2x10(7) CFU g(-1) of dry matter after 48 h of fermentation. Yeasts displayed maximum development after 24 h (6.1x10(7) CFU g(-1) of dry matter), whilst for lactic and acetic acid bacteria it occurred after 48 h (7.3x10(7) and 1.5x10(8) CFU g(-1) of dry matter respectively). The yeasts isolated belonged to the genera Hanseniaspora and Candida, the lactic acid bacteria to the genus Lactobacillus, and the acetic acid bacteria to the genus Acetobacter. The differences compared to other fermentation trials concerned the micropopulation from a qualitative point of view.