比较不同来源钙剂对大鼠骨密度的影响

目的:研究纳米碳酸钙、微晶体羟磷灰钙、乳钙对大鼠骨密度和钙表观吸收率的影响。方法:SPF级4周龄雌性SD大鼠90只,随机分为9组,即纳米碳酸钙、微晶体羟磷灰钙、乳钙低、高剂量组和相应剂量碳酸钙对照组(低、高剂量组饲料钙含量分别为500mg/100g和1000mg/100g),以及低钙对照组(饲料钙含量为150mg/100g)。喂养13周,测钙表观吸收率、骨钙含量和骨密度。结果:不同钙剂组大鼠骨密度均明显高于低钙对照组(P0.05);不同钙剂低剂量组大鼠钙表观吸收率介于52.96%～68.16%之间,高剂量组吸收率介于41.78%～61.30%,均明显低于低钙对照组(P0.05)。结论:与低钙对照组相比,纳米碳酸钙、微晶体羟磷灰钙、乳钙均可明显改善大鼠的骨密度。     

Processing and analytical characterisation of pulp-enriched cloudy apple juices

Pulp-enriched cloudy apple juices were manufactured from two apple varieties by blending of apple puree with natural cloudy apple juice in order to enrich bioactive secondary plant substances. Finishing of the puree with a 0.6-mm mesh screen and final product homogenisation revealed as the optimum processing technology for the novel 100% fruit beverage. The presence of large particles originating from the puree prevented long-term cloud stability, but due to the proportion of cloud-stable juice a complete phase separation did not occur. Optimal drinkability was achieved at a viscosity of 11.5 mPa s. Polyphenol compositions and concentrations were determined by means of RP-HPLC/PDA. The results ranged from 109 to 610 mg/l. All samples showed the typical polyphenol pattern of apples with dominating hydroxycinnamic acids followed by flavanols and flavonols. The puree addition to the cloudy apple juices increased the polyphenol concentrations by average 100%. Relatively, the highest increase could be observed for dimeric procyanidins. Different technological variants did not affect significantly the polyphenol concentrations. The dietary fibre contents of the pulp-enriched cloudy apple juices ranged from 5.8 to 9.4 g/l.     

瞬时聚合丙烯酸酯浆料的性能研究

探讨在采用瞬时聚合法直接合成固体丙烯酸酯浆料的过程中,疏水性单体丙烯酸丁酯用量对所生成丙烯酸酯浆料性能的影响.测试了不同丙烯酸丁酯用量下反应生成物的水溶性、水溶液黏度及对涤棉粗纱黏附性,并对合成的固体丙烯酸浆料进行红外表征.结果表明:在丙烯酸的中和度为50%、氧化还原引发体系中引发剂为单体量的6%时,丙烯酸丁酯为单体量的25%时合成的浆料性能最好,所生产的浆料为丙烯酸-丙烯酸钠盐-丙烯酸丁酯共聚物.     

Effect of temperature on rheological characteristics of molasses: Modeling of apparent viscosity using Adaptive Neuro - Fuzzy Inference System (ANFIS)

In this study, the effect of temperature on the rheological characteristics of apricot and date molasses was studied separately. Rheological characteristics of both molasses were evaluated in the shear rate range of 0.1-100 s⁻¹ at different temperatures (10-40 °C). Power law model was used for the calculation of flow behavior index and consistency coefficients of molasses. Consistency coefficients of apricot and date molasses were in the range of 5.408-39.905 Pa sⁿ and 0.910-2.852 Pa sⁿ, respectively. Molasses samples showed a non-Newtonian flow behavior. The effect of temperature on apparent viscosity was described by Arrhenius equation and calculated activation energy at the shear rate of 54.2 s⁻¹ was 41.42 and 38.19 kJ/mol for apricot and date molasses, respectively. An efficient predictive model for apparent viscosity values of molasses was constructed using Adaptive Neuro - Fuzzy Inference System (ANFIS) and this model showed satisfactory prediction with high coefficient of determination (0.979-0.999) and low root mean squared error (0.12-0.46).     

酶解淀粉在纯棉纱低温上浆中的应用

探讨酶解淀粉在纯棉纱低温上浆中的应用效果。采用酶解淀粉在低温条件下煮浆和上浆,测试了浆液性能和对纯棉纱的浆纱性能,结果表明:酶解淀粉具有较低的黏度及黏度热稳定性,对纯棉纤维的黏附性较好,浆纱的强伸性能好,毛羽贴伏效果接近磷酸酯淀粉,耐磨性能略低于磷酸酯淀粉。     

The determining role of bolus rheology in triggering a swallowing

Swallowing is the final stage of an eating process. Even though individuals know exactly when and how to swallow, the controlling mechanisms and the determining criteria of bolus swallowing are still not yet clear. One hypothesis is that bolus rheology, i.e. its flow-ability and stretch-ability, determines the triggering of a swallowing and the main aim of this work was to test this hypothesis. A wide range of fluid foods, including 18 commercial products and 10 lab-constituted foods, were examined for easiness of swallowing by a panel of 19 subjects. Oral residence time, defined as the time from the ingestion till the completion of swallowing, was determined for each eating process. It was observed that the oral residence time had a linear relationship with the sensed difficulty of swallowing. That is a food sensed difficult-to-swallow tends to stay longer in the oral cavity. Rheological properties (both shear and stretching flow) of these foods and their simulated boluses (mixture of food and simulated saliva) have also been determined at body temperature. The apparent shear viscosity showed a positive correlation with the sensed difficult of swallowing. However, the stretching behaviour of a fluid food, characterised by the maximum stretching force and the work of stretching showed much improved correlation to the sensory perceived easiness of swallowing. It was concluded that bolus rheology, in particular its extensional stretch-ability, had the most important influence on the ease of swallowing.     

Formation of nanoemulsions stabilized by model food-grade emulsifiers using high-pressure homogenization: Factors affecting particle size

Nanoemulsions are finding increasing utilization in the food and beverage industries for certain applications because of their unique physicochemical and functional properties: high encapsulation efficiency; low turbidity; high bioavailability; high physical stability. In this study, we examined the impact of system composition and homogenization conditions on the formation of nanoemulsions using a high-pressure homogenizer (microfluidizer). The mean particle diameter decreased with increasing homogenization pressure and number of passes, with a linear log–log relationship between mean particle diameter and homogenization pressure. The minimum droplet diameter that could be produced after 6 passes at 14 kbar depended strongly on emulsifier type and concentration: SDS < Tween 20 < β-lactoglobulin < sodium caseinate. Small-molecule surfactants formed smaller droplets than proteins, which was attributed to their ability to rapidly adsorb to the droplet surfaces during homogenization. The impact of phase viscosity was examined by using different octadecane-to-corn oil ratios in the oil phase and different glycerol-to-water ratios in the aqueous phase. The minimum droplet size achievable decreased as the ratio of disperse phase to continuous phase viscosities (η_D/η_C) decreased for SDS-stabilized emulsions, but was relatively independent of η_D/η_C for β-lactoglobulin-stabilized emulsions. At low viscosity ratios, much smaller mean droplet diameters could be achieved for SDS (d ∼ 60 nm) than for β-lactoglobulin (d ∼ 150 nm). The information reported in this study will facilitate the rational design of food-grade nanoemulsions using high-pressure homogenization methods.     

Rheological properties of Salecan as a new source of thickening agent

Salecan is a novel soluble glucan produced by Agrobacterium sp. ZX09, displaying the ability to inhibit pancreatic amylase and reduce postprandial glucose. The research here provides an investigation of the rheological properties of Salecan solution over a wide range of shear rate (0.001–1000 s⁻¹), frequency (0.1–100 rad/s), concentrations (0.3%, 0.5%, 1.0% and 1.5%), temperature (5–95 °C) and pH (1.0–13.0). The power law model well described the rheological behavior of the solutions, in the shear-thinning region, with high determination coefficients, R². Salecan solutions showed a non-Newtonian viscosity behavior at all concentrations and temperatures. The solutions exhibited excellent stability below 55 °C. Viscosities were not affected after being frozen (−20 °C). Over a wide pH range from 6.0 to 12.0, the viscosity almost kept invariant. With increasing frequency, the storage and loss moduli G′ and G″ of Salecan solution increased and complex viscosities decreased continuously, which showed an elastic behaviour. All data indicated that Salecan has excellent rheological properties and could be utilized in food industry as a new source of thickening agent.     

Effect of shear thinning on aspiration – Toward making solutions for judging the risk of aspiration

Polysaccharide solutions containing a contrast medium were prepared so that their viscosity at 50 s⁻¹, which was reported as a shear rate in the oral cavity, is the same but different at other shear rates. Preparation procedure of such solutions based on heat treatment using widely used polysaccharides in foods is described, and the rheological properties of these solutions are discussed in relation with flow behaviours in the swallowing process. Videofluorographic observation was performed for healthy persons and patients and compared with rheological characteristics of these solutions to understand the mechanism of aspiration. It was shown that the degree of aspiration depended on the degree of shear thinning of polysaccharide solutions. This study showed the possibility to find what kind of fluid induces the aspiration and to reduce the risk of aspiration in dysphagic patients by controlling the food rheology.     

高压上浆工艺指标的定量定性研究

通过对高压上浆浆液含固率、压出加重率、压出回潮率、压浆力及浆液粘度等工艺指标的分析研究 ,提出了高压力、高浓度和低粘度各指标的量化标志和范围 ,分别分析了压力、浓度、粘度的影响因素 ,并给出了在一定条件下三种工艺指标相应的计算公式。