杀青条件对酶法提取南瓜果胶影响的研究

探讨了对纤维素酶法提取南瓜果胶效果有影响的两个杀青条件———温度和时间,并研究了优化工艺条件的放大过程。结果表明:杀青温度为85℃,杀青时间为20 min为最佳提取工艺,提取得率为14.3%。在放大15倍的实验中,提取得率为21.4%,这可能是由于放大实验中的测量误差减少所致。实验所得到的最佳果胶提取条件可以为综合利用南瓜提供一定的实验依据。     

柑桔加工下脚料提取类胡萝卜素、橙皮苷、果胶和柠檬苦素

介绍了从柑桔加工下脚料提取类胡萝卜素、橙皮苷、果胶和柠檬苦素类产品的工艺方法 ,并简述了这些产品在医药、食品、日化等方面的应用     

水提薛荔籽果胶对去势雌性大鼠肠道健康的影响

目的:研究水提薛荔籽果胶对去势雌性大鼠肠道健康的影响。方法:将32只雌性SD大鼠按体重随机分为4组:卵巢伪切除组（Sham组）、卵巢切除对照组（OVX-CN组）、15%薛荔籽果胶OVX组（FPLP组）、15%柑橘果胶OVX组（CP组）,分别测定大鼠盲肠组织、游离氨、短链脂肪酸（SCFA）以及微生物数量等反映肠道健康的指标。结果:与OVX空白组比较,FPLP组和CP组能显著增加去势雌性大鼠粪便量、盲肠内容物重、壁湿重（p<0.01）,降低游离氨量（p<0.05）,增加肠道内厌氧菌、乳酸杆菌、双歧杆菌数量,升高有益菌与有害菌比例。SCFA含量都有增加的趋势,除了CP组丁酸与OVX空白组没有差别外,FPLP组和CP组盲肠中SCFA含量与盲肠中OVX空白组相比都显著增加（p<0.05）。结论:水提薛荔籽果胶能改善去势雌性大鼠肠道健康。      

果胶杂质对苎麻纤维及其复合材料性能的影响

研究了苎麻纤维中的果胶杂质对苎麻纤维及其复合材料性能的影响，根据苎麻复合材料综合性能，确定了最佳果胶杂质含量为6．6％。     

OPTIMAL KINETIC PARAMETERS AND BATCH MODELING FOR PECTIN HYDROLYSIS TO GALACTURONIC ACID WITH PECTINEX ULTRA SP-L ENZYME

Galacturonic acid is a monosaccharide obtained by pectin hydrolysis and a suitable substrate to produce bioethanol by fermentation. This article focuses on quantification of citrus pectin hydrolysis to galacturonic acid and provides new, reliable kinetic parameters for the Michaelis-Menten equation when the well-known commercial Pectinex Ultra SP-L is employed as enzyme. They are: r _max  = 1.10 g/(L min), K _m  = 10.42 g/L, and K _IGA  = 10.05 g/L, as obtained with a great accuracy by a nonlinear regression method and confirmed by the three classical linearization procedures (Lineweaver-Burk, Langmuir, and Eadie-Hofstee). The quantification of product inhibition has been achieved, with its inclusion in the rate equation. A batch reactor model yields perfect agreement between predictions and experiments, even under conditions different from those on which the parameters had been determined by regression.     

Modification of Pectin and Hemicellulose Polysaccharides in Relation to Aril Breakdown of Harvested Longan Fruit

To investigate the modification of cell wall polysaccharides in relation to aril breakdown in harvested longan fruit, three pectin fractions (WSP, water soluble pectin; CSP, CDTA-soluble pectin; ASP, alkali soluble pectin) and one hemicellulose fraction (4 M KOH-SHC, 4 M KOH-soluble hemicellulose) were extracted, and their contents, monosaccharide compositions and molecular weights were evaluated. As aril breakdown intensified, CSP content increased while ASP and 4 M KOH-SHC contents decreased, suggesting the solubilization and conversion of cell wall components. Furthermore, the molar percentage of arabinose (Ara), as the main component of the side-chains, decreased largely in CSP and ASP while that of rhamnose (Rha), as branch point for the attachment of neutral sugar side chains, increased during aril breakdown. Analysis of (Ara + Gal)/Rha ratio showed that the depolymerization of CSP and ASP happened predominantly in side-chains formed of Ara residues. For 4 M KOH-SHC, more backbones were depolymerized during aril breakdown. Moreover, it was found that the molecular weights of CSP, ASP and 4 M KOH-SHC polysaccharides tended to decrease as aril breakdown intensified. These results suggest that both enhanced depolymerization and structural modifications of polysaccharides in the CSP, ASP and 4 M KOH-SHC fractions might be responsible for aril breakdown of harvested longan fruit.     

新型生物质果胶吸附材料的制备及水溶液中铜离子(Ⅱ)吸附性能研究

为了评价生物质果胶碱化改性在重金属离子废水处理方面的吸附性能,利用水提-醇沉法提取纯化豆腐柴叶中天然果胶,并通过碱化作用,制备新型生物质果胶吸附材料,同时对水溶液中重金属铜离子进行吸附试验,考察其吸附率和单位吸附量。然后,通过分析新型生物质果胶吸附材料组分半乳糖醛酸含量及酯化度,探讨其吸附机制。实验结果表明,天然果胶在pH 9的环境中碱化作用30 min时,可获得具有高效吸附水体中铜离子的新型生物质果胶吸附材料,其吸附率和单位吸附量分别达到89.6%(0.10 g)和105 mg/g(0.02 g)。另外,在果胶组分半乳糖醛酸含量和酯化度分析方面,果胶碱化作用未造成半乳糖醛酸分子的丢失,但可促使果胶中羧酸酯的水解,形成对应的羧酸钠盐,提升对水体铜离子的吸附性能。     

微波辅助提取胡萝卜中果胶的工艺研究

采用微波辐射的方法提取胡萝卜中的果胶.实验考察了微波辐射时间、微波火力、草酸铵浓度、料液比及醇析中乙醇浓度对提取率的影响.实验确定微波条件下提取果胶的最佳工艺条件是:微波辐射时间2min,微波火力为中火,草酸铵浓度4g·L-1,料液比1:15 (g:mL),醇析中乙醇的浓度是70％,提取率可达6.907％.     

Accelerated weathering of pectin/poly(vinyl alcohol) blends studied by spectroscopic methods

The blends of pectin (PEC) and poly(vinyl alcohol) (PVA) at different components ratios were prepared by mixing in water. Thin polymeric films of PEC/PVA blends and pure polymers were obtained by casting method. All samples were then artificially aged using Suntest apparatus (Atlas) up to 780 h. The changes in chemical structure during sample ageing have been monitored by infrared and ultraviolet‐visible absorption spectroscopies. The first stage of weathering (up to ～ 300 h) was very slow and alteration of chemical structure was negligible in all samples. Prolonged ageing (>300 h) caused more significant degradation processes. FTIR spectra exhibited the highest changes in hydroxyl and carbonyl band ranges indicating the efficient photooxidation of macromolecules. The mechanisms of the observed processes have been discussed. It was found that PVA undergoes faster photoxidative degradation than pectin aged at the same conditions. The PEC/PVA blends exhibited the improved resistance to weathering comparing with both polymers aged individually. Mutual stabilization effect can be explained by intermolecular interactions between PEC and PVA confirmed by spectroscopic methods. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Pectinesterase and polygalacturonase in changes of pectic matter in olives (cv. Hojiblanca) intended for milling

Virgin olive oil is a highly valued product, and it is important to optimize extraction yield. The pectic composition and the related enzymatic activities, present in the raw material, are variables that may affect that process. The pectinolytic activities producing modifications in the pectic matter of olive fruits (variety Hojiblanca) during ripening and the associated changes in texture were studied. Pectinesterase (PE) activity increased with ripeness until reaching a peak when anthocyanin synthesis in the fruit became marked (turning color stage). From then on, it decreased. In contrast, polygalacturonase (PG) activity in the ripe-green fruit decreased sharply when anthocyanin formation began (small reddish spots stage) and then increased, reaching a maximum in the ripe-black fruit. Parallel changes were noted in the texture and pectic content of the olives, related to endo- and exo-PG enzymatic activities, together with a decrease in the degree of esterification of the pectic matter, which could be associated with PE action. The distribution of the pectic fractions in the raw material and the changes in them during the olive oil extraction process showed the role of PE and PG in the fruits that was related to the yield of extracted oil.