紫背天葵保健果冻加工工艺研究

以新鲜紫背天葵为主要原料研究紫背天葵保健果冻的生产工艺。对紫背天葵预处理、复合胶凝剂和果冻主要原辅料配比进行了重点研究,结果表明：适宜加工紫背天葵果冻的胶凝剂为卡拉胶、明胶、魔芋胶的复合胶凝剂;紫背天葵保健果冻的最佳配方为20%紫背天葵汁、1.0%复合胶（卡拉胶∶明胶∶魔芋胶/m∶m∶m=4∶3∶3）、20%白砂糖、0.15%柠檬酸。在此工艺条件下所得产品色泽紫红,具有紫背天葵特有清香气,酸甜可口,口感软滑。     

黑豆魔芋果冻的研制

以黑豆和魔芋精粉为主要原料,以白砂糖、柠檬酸、卡拉胶和果冻粉等食用凝胶剂为辅料,对黑豆汁、凝胶剂、白砂糖以及柠檬酸的浓度等工艺条件进行了研究。通过正交试验得出最佳产品配方为:黑豆汁5%、魔芋精粉0.2%、卡拉胶0.6%、白砂糖6%、柠檬酸0.2%。制作出一种香味独特,风味可口,营养丰富且具有较好保健功能的黑豆魔芋果冻。     

双米低脂保健冰淇淋的开发研究

选取新鲜薏米和玉米为原料,以人造奶油代替部分乳脂,依据黏度、膨胀率和感官质量等作为评价指标,通过正交试验获得复合稳定剂的最佳配比为：即瓜尔豆胶:海藻酸钠:卡拉胶:单甘脂:蔗糖酯=6∶3.6∶4∶16∶1,乳化稳定剂添加量为0.4%。双米保健冰淇淋的最佳配方为：脱脂乳粉10%、薏米乳18%、玉米汁17%、人造奶油4.0%,产品质量最好。     

魔芋-卡拉胶复配凝胶质构特性研究

以魔芋-卡拉胶复配胶为原料,使用物性测试仪对复配胶的质构参数断裂强度、弹性、粘性等进行了测定,并研究了相关因素对复配胶质构参数的影响。结果表明：增加魔芋精粉比例可以增强卡拉胶的弹性,而凝胶强度在胶比例为0．9：0．1时达到最大;随复配胶浓度增加,凝胶强度和粘度增加;钾离子的添加使复配胶的凝胶强度和脆度增强;低浓度的蔗糖对复配胶的质构影响不大,高浓度蔗糖可以降低凝胶的断裂强度、粘度和弹性;柠檬酸降低了复配胶的凝胶强度和弹性。     

葛仙米室内规模化培养、群体显微结构及营养成分分析

以葛仙米为材料开展室内规模化培养,在15个月的培养期间,每月可产鲜藻38.3~293.7 kg,每立方米的培养体积葛仙米每月产量波动在9.58~77.45 kg,高温明显降低月产量。在葛仙米的表层和内部的显微结构明显不同,藻丝的长短、排列存在明显的差异。同时以人工培养的葛仙米为材料,测定了其生化组成;结果表明:人工培养的葛仙米含16种氨基酸,蛋白质含量为29.69%;脂肪的含量为0.78%,远低于野生葛仙米中脂肪的含量;维生素的含量较低;砷、铅、汞、镉4种重金属元素含量较低,其含量符合国家食品卫生标准。     

家蝇幼虫营养保健果冻的研制

家蝇Musca domestica L幼虫营养丰富,体内含有多种具有特异生物活性物质,有很好的开发利用价值。以家蝇幼虫为原料,运用正交试验设计对家蝇幼虫营养保健果冻的加工工艺进行研究。结果表明:35%的家蝇幼虫粗提液,15%的白砂糖,0.18%的柠檬酸和1.4%的卡拉胶的工艺参数,可生产具有良好感官和食用品质的家蝇幼虫营养保健果冻;家蝇幼虫粗提液的护色剂使用0.02%抗坏血酸与0.02%柠檬酸,果冻防腐剂使用0.04%山梨酸钾。     

魔芋试管芋营养液栽培生产原原种技术研究

在温室对魔芋试管芋立体多架层营养液栽培生产原原种技术进行了研究。以不同质量分数和比例的N、P、K、Ca、Mg等大量元素和MS培养基的微量元素配制成营养液,对魔芋试管芋进行立体多架层无土栽培试验,结果表明:生长状况和原原种的产量均以N∶P∶K∶Ca:Mg的比例为4∶1∶2.4∶0.2∶0.7的Ⅴ号营养液最高,光照强度以2000~6000 Lux为宜。该试验为魔芋营养液的配方研制及栽培管理技术提供了理论依据。     

双叉犀金龟成虫最佳食料筛选

在人工气候室条件下(26℃±1℃,RH 70%±5%,L∶D=14 h∶10 h),研究了6种水果对双叉犀金龟Allomyrina dichotoma成虫寿命以及子代数量的影响。结果显示,各处理雌虫寿命均显著长于雄虫,雌虫寿命46.67～55.08 d,雄虫寿命23.78～33.33 d,各处理间无显著差异;饲喂西瓜Citrullus lanatus(Thunb.) Matsum.etNakai子代数量最多,达39.44头/雌,与香蕉Musa nanaLour.、苹果Malus pumilaMill.和商品果冻处理无显著差异,饲喂葡萄Vitis viniferaL.和香瓜Cucumis meloL.处理均显著低于这4个处理;选择子代数量最多的西瓜、苹果、香蕉分别制作人工饲料果冻,用商品果冻作为对照,在15 d和35 d分别2次调查每对成虫的子代数,结果显示混合果冻、商品果冻、苹果果冻和西瓜果冻显著高于香蕉果冻,且各果冻处理在0～15 d和16～35 d的子代数量差异不同;综合比较两年水果饲喂和人工饲料果冻饲喂结果,饲喂混合果冻、商品果冻、西瓜果冻和苹果果冻4个处理的子代数量最高,平均达...     

不同种类魔芋的色素观察

为探索魔芋中色素的含量与分布,采用目测和显微镜对4个种类的魔芋进行观察研究。结果显示,红魔芋、黄魔芋中的色素最多,花魔芋次之,白魔芋最少。色素体呈环状,大小为10~25μm,主要分布在叶片的栅栏组织、海绵组织和薄壁细胞中。     

盐胁迫对地木耳和葛仙米生理生化特性的影响

地木耳为一种耐干旱的陆生念珠藻 ,葛仙米则是水生念珠藻 ,由于对各自生境的适应 ,二者在对盐胁迫的反应上可能会有差异。为了阐明这种差异 ,研究了不同盐度胁迫下它们的光合活性、可溶性糖、脯氨酸含量及质膜透性的变化。结果表明 ,高盐胁迫下地木耳和葛仙米的光合活性均降低 ;在 0 .8mol·L- 1 的盐浓度下胁迫 48和 96h后 ,地木耳仍可检测到微弱的光合活性 ,而在葛仙米中已检测不到。地木耳中脯氨酸升高 ;可溶性糖含量升高 ,增幅为87%— 2 0 0 % ;质膜透性比对照略有增加 ,但不同盐度之间差别不大。葛仙米中脯氨酸含量降低 ;可溶性糖含量在NaCl小于 0 .4mol·L- 1 时随盐度的升高而升高 ,增幅为 1 0 0 %— 1 0 0 0 % ,当高于 0 .4mol·L- 1 时随盐度的升高而降低 ;质膜透性随盐度增加而增加 ,在盐浓度为 0 .6和 0 .8mol·L- 1 时 ,均达 90 %以上。结果表明 ,地木耳比葛仙米更能耐受盐度胁迫 ;可溶性糖在地木耳和葛仙米抵抗盐胁迫中有重要作用 ,而脯氨酸在葛仙米抗盐胁迫中可能不作为相容溶质起作用     

Regulation of expression of glutamine synthetase in a symbiotic Nostoc strain associated with Anthoceros punctatus.

A characteristic of N2-fixing cyanobacteria in symbiotic associations appears to be release of N2-derived NH4+. The specific activity of the primary ammonium-assimilating enzyme, glutamine synthetase (GS), was found to be three- to fourfold lower in Nostoc sp. strain 7801 grown in symbiotic association with the bryophyte Anthoceros punctatus than in free-living Nostoc sp. strain 7801. Quantitative immunological assays with antisera against GS purified from Nostoc sp. strain 7801 and from Escherichia coli indicated that similar amounts of the GS protein were present in symbiotic (50 micrograms mg-1) and free-living (68 micrograms mg-1) cultures. The conclusion from these experiments is that GS is regulated by a posttranslational mechanism in Anthoceros-associated Nostoc sp. strain 7801. However, the results of comparative catalytic and immunological experiments between N2- and NH4+-grown free-living Nostoc sp. strain 7801 implied control of GS synthesis. A correlation was not observed between the level of GS expression and the extent of symbiotic heterocyst differentiation in Nostoc sp. strain 7801 associated with A. punctatus.     

Partial characterization of extracellular polysaccharides from cyanobacteria

Four cyanobacterial strains, Cyanothece sp., Oscillatoria sp., Nostoc sp. and Nostoc carneum were studied for physico-chemical characterization of extracellular polysaccharide (EPS) secreted during the controlled growth condition. Hydrolyzed EPSs showed the compositional involvement of four sugar moieties viz. mannose, glucose, xylose and ribose in varying combinations. Infrared spectra of EPSs showed a specific absorbance of O-H stretching at 3448-3400 cm(-1), asymmetrical-symmetrical C-H stretching at 2924 and 2854 cm(-1) and a bending vibration of C-H at 1400-1380 cm(-1). Absorbance at 1259 and 1140 cm(-1) with Cyanothece sp. EPS, indicated the presence of sulfur containing functional group. Thermal gravimetric analysis and differential scanning calorimetric analysis confirmed the polysaccharides thermal stability as high as around 250 degrees C. In the presence of 0.1 M NaCl aqueous solution, the intrinsic viscosity of polysaccharides from Oscillatoria sp. and Nostoc sp. decreased 1.6 fold, whereas, 3-5 fold reduction in intrinsic viscosity was observed with commercially available guar and xanthan gum.     

球形念珠藻的生化组成分析

测定了葛仙米的生化组成,结果表明,葛仙米的蛋白、氨基酸和总糖含量分别为28．33％、23．35％和24．19％;灰分和粗脂肪原含量分别为14．63％和5．34％;还含有较为丰富的粗脂肪和无机元素,特别是钙、镁元素的含量较高。     

Tensile and Tear Strength of Carrageenan Film from Philippine <Emphasis Type="Italic">Eucheuma</Emphasis> Species

The tensile and tear strength of carrageenan film from Philippines Eucheuma species were investigated using NEC tensilon universal-testing machine according to American Society for Testing Materials methods. These properties are important for assessing carrageenan film as packaging material. The and types were used in the study. The effect of glycerine on the tensile and tear strength including elongation was also evaluated. Addition of glycerine tended to lower the tensile strength of the film and increase its elongation properties including the tear strength. Carrageenan film without glycerine was much stronger. Glycerine made the film more flexible and easy to deform. The composite film of carrageenan and konjac gum did not exhibit elongation. It also showed higher tensile strength than did the composite film of carrageenan and xanthan gum. Compared with -type carrageenan film, -type carrageenan film without glycerine was more comparable to low-density polyethylene (LDPE) film in terms of tensile strength as was the composite film of carrageenan–konjac gum. The -type carrageenan film with glycerine was more comparable to LDPE film in terms of tear strength. The elongation reading for carrageenan film was lower than that for LDPE film. Morphologic studies showed that the carrageenan film had sets of pores distributed randomly at different places as compared to LDPE film. It also showed that the carrageenan film was more fibrous than LDPE film.     

Growth kinetics of 1–2 mm and 3–4 mm colonies of Nostoc sphaeroides (Cyanophyta) in outdoor culture

Nostoc sphaeroides Kützing was cultivated in paddlewheel-driven raceway ponds and the growth kinetics of 1-2 mm and 3-4 mm colonies of N. sphaeroides was studied. The biomass productivities in 2.5 m(2) raceway ponds inoculated with 1-2 mm and 3-4 mm colonies were 5.2 and 0.25 g dry wt m(-2) d(-1), respectively. Furthermore, differently sized colonies showed different relative water content, total soluble carbohydrates, chlorophyll a content and density of filaments. This is the first report on mass culture of N. sphaeroides under outdoor conditions.     

Dietary intake of artificial food color additives containing food products by school-going children

Nutritional risk in children is associated with food safety. This is the first study to identify the food type consumed by 6–17-year-old school-going children in Saudi Arabia. Eight permitted artificial food color additives, including Tartrazine (E102), Sunset Yellow (E110), Carmoisine (E122), Allura Red (E129), Indigo Carmine (E132), Brilliant Blue (E133), Fast Green (E143), and Black PN (E151), and two non-permitted ones, Erythrosine (E127) and Red 2G (E128), were determined using 24-h dietary recall questionnaires. Artificial color additives in 839 food products were divided into nine categories, including biscuits, cakes, chocolates, chips, ice cream, juices and drinks, candy, jelly, and chewing gum, are determined using high performance liquid chromatography and diode array detector. The results indicated a high intake of juices and drinks, ice cream, and cakes, but low consumption of chewing gum among school-going children. Among the permitted artificial food color additives, Brilliant Blue (E133) (54.1%) and Tartrazine (E102) (42.3%) were the most commonly used. Sunset Yellow (E110) in one chocolate sample, Tartrazine (E102) and Sunset Yellow (E110) in one and two juice and drink samples, respectively, and Brilliant Blue (E133) in two candy samples exceeded the permitted level. Therefore, further investigations are needed to provide insights into the possible adverse health effects of high intake of these additives in artificial food coloring on the test population are warranted.     

Screening for acetylcholinesterase inhibitory activity in cyanobacteria of the genus Nostoc

Fifty-four cyanobacterial strains of the genus Nostoc from different habitats were screened for acetylcholinesterase inhibitory activity. Water-methanolic extracts from freeze-dried biomasses were tested for inhibitory activity using Ellman's spectrophotometric method. Acetylcholinesterase inhibitory activity higher than 90% was found in the crude extracts of Nostoc sp. str. Lukesova 27/97 and Nostoc ellipsosporum Rabenh. str. Lukesova 51/91. Extracts from Nostoc ellipsosporum str. Lukesova 52/91 and Nostoc linckia f. muscorum (Ag.) Elenk. str. Gromov, 1988, CALU-980 inhibited AChE activity by 84.9% and 65.3% respectively. Moderate AChE inhibitory activity (29.1-37.5%) was found in extracts of Nostoc linckia Roth. str. Gromov, 1962/10, CALU-129, Nostoc muscorum Ag. str. Lukesova 127/97, Nostoc sp. str. Lhotsky, CALU-327 and Nostoc sp. str. Gromov, CALU-998. Extracts from another seven strains showed weak anti-AChE activities. The active component responsible for acetylcholinesterase inhibition was identified in a crude extract of Nostoc sp. str. Lukesova 27/97 using HPLC and found to occur in one single peak.     

The influence of locust bean gum and dextran on the gelation of κ-carrageenan

The interaction of κ-carrageenan with locust bean gum and dextran has been studied by rheology, differential scanning calorimetry (DSC), and electron spin resonance spectroscopy (ESR). Rheological measurements show that the carrageenan gel characteristics are greatly enhanced in the presence of locust bean gum but not in the presence of dextran. Carrageenan/locust bean gum mixtures show two peaks in the dsc cooling curves. The higher temperature peak corresponds to the temperature of gelation and its intensity increases at the expense of the lower temperature peak as the proportion of locust bean gum in the mixture increases. Furthermore, the DSC heating curves show enhanced broadening when locust bean gum is present, indicating increased aggregation. These results are taken as evidence of carrageenan/locust bean gum association. The gelation process has also been followed by ESR using spin-labeled carrageenan. On cooling carrageenan solutions, an immobile component appears in the ESR spectra signifying a loss of segmental mobility consistent with chain stiffening due to the coil → helix conformational transition and helix aggregation. For carrageenan/locust bean gum mixtures, carrageenan ordering occurs at temperatures corresponding to the higher temperature DSC setting peak and the temperature of gelation. Similar studies using spin-labeled locust bean gum show that its mobility remains virtually unaffected during the gelation process. It is evident, therefore, that carrageenan and locust bean gum interact only weakly. It is proposed that at low carrageenan concentrations the gel network consists of carrageenan helices cross-linked by locust bean gum chains. At high carrageenan concentrations the network is enhanced by the additional self-aggregation of the “excess” carrageenan molecules. For carrageenan/dextran mixtures, only one peak is observed in the dsc cooling curves. The onset of gelation shifts to higher temperatures only at very high (20%) dextran concentrations and this is attributed to volume exclusion effects. Furthermore, there is no enhanced broadening of the peaks in the DSC heating curves as for the carrageenan/locust bean gum systems. It is therefore concluded that carrageenan/dextran association does not occur. The difference in behavior between locust bean gum and dextran is attributed to the greater flexibility of the dextran chains. © 1996 John Wiley & Sons, Inc.     

魔芋葡甘露低聚糖的酶法制备工艺的初步研究

利用β-甘露聚糖酶产品水解魔芋胶制备魔芋葡甘露低聚糖的工艺条件。在加样顺序、pH、酶添加量、时间、温度等单因素试验的基础上,进一步通过正交试验确定的最佳工艺条件为:魔芋胶浓度10g/L,酶添加量为100U/g,pH5.5,45℃条件下,酶解时间1.5h。再利用酵母发酵去除可发酵性糖的方法,以获得最终产物为100%的魔芋葡甘露低聚糖。