黄原胶对消失模铸造涂料性能的影响

为提高消失模铸造水基涂料的质量,探讨了黄原胶作为微量添加剂对涂料性能的影响.试验研究表明,铸造涂料中加入适量的黄原胶可提高悬浮性、显著增大涂料粘度和涂挂性、改善涂料的流变行为.黄原胶还可显著提高涂层的强度,但使涂层透气性略有降低.鉴于黄原胶的优异性能,可望在消失模铸造水基涂料中获得应用.     

植物胶压裂液用有机硼交联剂SD2-2

本文简介了液态有机硼交联剂ＳＤ２２的合成和物理特性，发表了用ＳＤ２２交联的４类６种植物胶（改性魔芋胶、改性田菁胶、改性龙胶、３种改性瓜尔胶）压裂液的配方和８０℃粘时数据。这些压裂液粘度适中，保持高粘度时间长，１０—１２ｈ可彻底破胶。从这些配方中推荐了ＣＴ９１／ＳＤ２２压裂液（用于７０—９０℃井温），详尽研究了推荐配方压裂液的各项性能。通过４个井例，简介了ＳＤ２２交联羟丙基瓜尔胶、羟丙基田菁胶压裂液在新疆、四川、吉林一些地区５０余井次现场应用的良好效果     

化学剂去皮法分离香豆胶

本文报道化学剂去皮法分离香豆胶的室内实验研究结果。将香豆用化学剂浸泡、清水冲洗除去种皮，再用机械方法将去皮香豆分离为内胚乳和胚。分出的内胚乳片即香豆胶片，种皮和胚为下脚料。香豆胶的收率可高达３３％－３８％，且较纯净，不含杂质。用双化学剂脱皮后分离出的香豆胶片，其增粘能力高于现行行业标准对一级香豆胶粉规定的指标。从工艺技术、经济等方面考察，该法可以实现工业化。以去皮所用某些化学剂处理目前市售香豆胶片，可使其增粘能力接近和超过瓜尔胶片。     

Spray drying conditions for orange juice incorporated with lactic acid bacteria

This work aimed to develop an orange juice powder by spray drying with lactic acid bacteria (Lactobacillus plantarum 299v and Pediococcus acidilactici HA‐6111‐2), testing their survival both during drying and storage (room temperature and 4 °C). Initially, the best conditions for spray drying were chosen to allow the best survival of each LAB: (i) inlet air temperature of 120 °C and (ii) 0.5:2 ratio of the orange juice soluble solids and drying agent added (prebiotics: 10 DE maltodextrin or gum Arabic). Survival of LAB was not affected by drying process, and it was higher when cultures were stored at 4 °C. A slightly higher protection was conferred by 10 DE maltodextrin, in the case of L. plantarum and at 4 °C. Pediococcus acidilactici was more resistant during storage at 4 °C, with logarithmic reductions lower than 1 log‐unit. It was demonstrated that it is possible to produce a functional nondairy product, orange juice powder supplemented with prebiotic compounds, containing viable LAB for at least 7 months, when stored at 4 °C.     

Significant improvement for the functional properties of konjac glucomannan based on phase separation

Konjac glucomannan (KGM) serves as a stabiliser due to its high molecular weight and viscosity. However, these properties limit its addition in food products, especially in drinks. The main aim of this study was to improve the functional properties of KGM by a green and effective method, that is phase separation. It was found that increasing temperature accelerated phase separation of KGM/gum arabic mixture. KGM‐rich phase was characterised and its physical properties were investigated by different methods. Crystal property showed no significant changes after phase separation. Nevertheless, rheological properties indicated that the viscosities of samples after phase separation (FKGM) decreased dramatically. Their emulsifying capacities also improved. Moreover, the differences in molecular rearrangement at the oil–water interface were also studied by using interfacial rheology. These results suggested that FKGM with low viscosity had better interfacial properties, and thus may have potential applications as food ingredients.     

甘蔗糖蜜发酵产黄原胶发酵条件的优化研究

实验以甘蔗糖蜜为碳源发酵生产黄原胶,通过单因素实验和正交实验设计,确定优化的培养条件为:糖蜜酸化水解液糖度12°Bx,蛋白胨浓度8g/L,培养时96h,发酵温度28℃,接种量10%,pH7.5,在优化的培养条件下黄原胶的产量可达35.28g/L,是初始培养条件产量22.14g/L的1.59倍。     

Comparative amino acid and fatty acid compositions of edible gums kondagogu (Cochlospermum gossypium) and karaya (Sterculia urens)

Gum karaya and gum kondagogu are the two important commercial tree gums of India. The amino acids and fatty acid profiles of gum kondagogu and gum karaya were investigated by preparing their corresponding N-O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) derivatives for amino acids and direct trans-esterification of methyl esters for fatty acids and their subsequent analysis by a GC–MS method. The amino acids, such as, alanine, valine, methionine, tyrosine and tryptophan, were not detected in gum karaya as they were in gum kondagogu. Interestingly, the aspartic acid content (72.8 ± 3.45 μg/g) of gum kondagogu was higher than that of gum karaya (64.2 ± 2.44 μg/g). The ratios of saturated to unsaturated fatty acid in gum kondagogu and gum karaya were found to be 5:1, and 6.6:1, respectively. Among the unsaturated fatty acids, linoleic acid (1.8 ± 0.12 μg/g) and γ-linolenic acid (0.8 ± 0.05 μg/g) were detected only in gum kondagogu. Arachidic acid was not detected in gum karaya. Additionally, the presence of linoleic acid and γ-linolenic acid in gum kondagogu reinforces its nutritional value.     

Synthesis and characterization of a novel soil stabilizer based on biodegradable poly(aspartic acid) hydrogel

A novel soil stabilizer based on poly-amino acid - polyaspartic acid (PASP) and its copolymer which modified by xanthan gum (XG) was studied to increase soil particle compressive strength and resistance to wind erosion. Due to its unique property, the stabilizer aggregated individual soil particles and formed crust. The sample compressive strength increased from 0.175 to 0.612 MPa and the wind erosion modulus reduced from 22.43 to 10.56 g·m⁻²·min⁻¹ after the 1% PASP hydrogel was applied by 1.67 Lm⁻² (1 cm of crust). The soil water content was higher than the control due to the polymer’s excellent water-retaining property. The polymer had no negative influence on seed germination and growth. The biodegradability experiment showed that PASP was easy to biodegrade and therefore it was safe to apply in the field. This work was presented at 13 ^th YABEC symposium held at Seoul, Korea, October 20–22, 2007.     

On the stabilization mechanism of Doogh (Iranian yoghurt drink) by gum tragacanth

Serum separation in Doogh, a favorite acidic dairy drink in the Middle East, is a major problem which happens due to low pH (≤4.00) and aggregation of caseins. Therefore, in the present study the influence of gum tragacanth (GT) and its soluble and insoluble fractions on prevention of serum separation as well as stabilization mechanisms were investigated using rheological, zeta potential and microscopic measurements. According to our findings, the soluble tragacanthin (T) and GT prevented serum separation at concentrations of 0.100 and 0.200%, respectively. Furthermore, the proper rheological model for control was Newtonian whereas for the others it was Power law. Based on viscoelastic experiments, Dooghs containing T and GT exhibited dominant viscose and elastic behaviors, respectively. In addition, the presence of T and GT changed the zeta potential values from positive to negative. It was elucidated that T adsorbs onto casein and induces stabilization via electrostatic and steric repulsions. Moreover, the insoluble bassorin (B) may assist stabilization by increasing the viscosity.     

Intra-species variation of the properties of gum exudates from two Acacia species of the series Gummiferae

Gum exudates from Acacia drepanolobium and A. kirkii ssp. kirkii var. kirkii from Tanzania have been analyzed and the intra-species variation of their properties evaluated. The results show that inter-species variation of the properties of the gum exudates from the two species exist, whereas only some parameters show intra-species variation. The specific optical rotations of the gum exudates varied from +72.0° to +94.6° for A. drepanolobium and +29.2° to +38.0°, for A. kirkii ssp. kirkii var. kirkii. Likewise, the acid equivalent weights (AEWs) varied from 832 to 1659 for A. drepanolobium and 663 to 1199 for A. kirkii ssp. kirkii var. kirkii. Intra-species variation for the tannin content was also observed for the species studied, whereas no intra-species variation was observed for the nitrogen and methoxyl contents. The results in this study show that the variation of the properties among the batches of commercial Acacia gum may be due to admixture of gums from different Acacia species, as well as intra-species variation.