Lemon oil solubilization in mixed surfactant solutions: Rationalizing microemulsion & nanoemulsion formation

Lipophilic functional ingredients are usually incorporated into aqueous-based foods and beverages in the form of colloidal dispersions. In this study, we investigated the rate and extent of solubilization of emulsified lemon oil in mixed non-ionic surfactant solutions (buffer: propylene glycol = 2:1): sucrose monopalmitate (SMP) and/or Tween 80 (T80). The influence of surfactant concentration, type, and mixing ratio on lemon oil solubilization was investigated, with the aim of identifying suitable conditions for preparing stable microemulsions and nanoemulsions. Solubilization was monitored by measuring changes in light scattering by lemon oil droplets after they were dispersed in surfactant solutions (pH 7). The solubilization process was rapid (<few minutes), with the rate increasing with increasing surfactant concentration. For a particular surfactant type and concentration, lemon oil was transferred from nanoemulsion droplets into microemulsion droplets until a critical lemon oil concentration (C_sat) was reached, after which it remained as nanoemulsion droplets. The value of C_sat increased with increasing surfactant concentration and was higher for SMP than Tween 80. The impact of storage at pH 3.5 on the physical stability of microemulsions and nanoemulsions was examined. Acid stable colloidal dispersions could not be formed using SMP alone. However, relatively stable nanoemulsions and microemulsions could be formed when ≥75 or 50 wt% Tween 80 was incorporated into the surfactant phase, respectively. This study provides important information for the rational design of food-grade colloidal delivery systems for encapsulating and delivering functional lipids for food and beverage applications.     

TBARs distillation method: Revision to minimize the interference from yellow pigments in meat products

The aim was to study the effect of the incubation method and TBA reagent (concentration/solvent) on yellow pigment interference in meat products. Distillates from red sausage, sucrose, malondialdehyde and a mixture of sucrose–malondialdehyde were reacted with four different TBA solutions at five different temperature/time relations. Two TBA solutions were prepared at 20 mM using 90% glacial acetic acid or 3.86% perchloric acid. In addition, an 80 mM TBA solution was prepared using distilled water adjusted to pH 4 and another using 0.8% TBA in distilled water. The temperature/time relations were: (1) 35 min in a boiling water bath; (2) 70 °C/30 min; (3) 40 °C/90 min; (4) room temperature (r.t.) (24 °C) in dark conditions for 20 h; and (5) 60 min in a boiling water bath. The results showed that aqueous or diluted acid solutions of TBA reagent and the application of 100 °C for less than 1 h provided the best conditions to minimize the presence of yellow pigments and maximize pink pigment formation in meat products.     

Oral and intestinal digestion of oligosaccharides as potential sweeteners: A systematic evaluation

The utilisation of oligosaccharides by oral microorganisms and intestinal enzymes are important factors in determining their effectiveness as alternative sweeteners. In this study, classes of naturally occurring sugars were assessed using in vitro models for oral and intestinal digestibility, in order to test the influence of chemical structure on functional properties. Amongst the classes of sucrose isomers, α-glucobioses, β-glucobioses and sucrose-based oligosaccharides, structures were identified that were not utilised by the common oral bacterium Streptococcus mutans, and would therefore contribute to the non-cariogenic potential of a sweetener. Analysis of the rate and products of digestion by a rat glucosidase mixture was used to determine the relative intestinal digestibility. The results showed that oligosaccharides containing a (1 → 6)-β-Glc group, including gentiobiose and gentiobiitol, together with melezitose, a sucrose-derived oligosaccharide containing a α-Glc-(1 → 3)-Fru moiety were resistant to digestion by both S. mutans and mammalian intestinal enzymes, highlighting their potential as dietary sugar substitutes.     

Effect of successive stimuli on sweetness intensity of gels and custards

Variations of tastant concentration during the consumption of food products were shown to enhance taste intensity. The aim of this study was to investigate the relation between the frequency at which tastant concentration is varied during the consumption of products and the occurrence of taste enhancement. For this purpose, the sweetness intensity of sequences of 4 successive sweet stimuli represented by cubes of a semi-solid gel or spoons of a model custard dessert was assessed. The intensity and the order of the stimuli within the sequences were varied to obtain 4 types of sucrose concentration profile (decreasing, increasing, middle peak and boundary peak) at 2 magnitudes of concentration differences (small and large). Sequences of 4 stimuli containing a constant sucrose concentration were used as a reference. The sweetness intensity of the sequences of successive stimuli was assessed using line scale and time-intensity ratings.Line scale ratings showed that the type of sequence had an effect on sweetness intensity. A sweetness enhancement relative to the reference was observed in sequences that ended with high-intensity stimuli, whereas sweetness suppression was observed in sequences that ended with low-intensity stimuli. The observed sweetness enhancement and suppression were attributed to serial position effects (i.e. recency effects).Time-intensity ratings indicated that each stimulus in the sequences was evaluated individually by the assessors. Sequential effects seem to have occurred during the continuous evaluation of successive stimuli, since preceding stimuli in the sequences affected the evaluation of posterior stimuli. Furthermore, the overall sweetness intensity of the different sequences was not enhanced in relation to the reference. The lack of taste enhancement in sequences exhibiting variations of sucrose concentration was attributed mainly to the long period at which sucrose concentration was varied during the evaluation of the sequences. It was confirmed that the frequency of variation of tastant concentration affects the occurrence of taste enhancement.     

Synthesis of Co-Zr doped nanocrystalline strontium hexaferrites by sol-gel auto-combustion route using sucrose as fuel and study of their structural,magnetic and electrical properties

Sol-gel auto-combustion route using sucrose as fuel has been employed to synthesize nanocrystalline particles of SrZr_xCo_xFe_(12−2x)O₁₉ (0.0≤ x ≤1.0). The characterization of these materials has been done by TGA-DTA, FT-IR, XRD and EDS. SEM and TEM techniques have been used to study the structure and morphology. Magnetic properties have been investigated by VSM and Mössbauer spectroscopy (MS). The influence of calcination temperature on morphology and magnetic properties of samples is studied in a wide temperature range of 500–1100 °C. XRD analysis indicates the formation of pure single phase hexagonal ferrites at 900 °C. The crystallite size calculated using Scherrer equation lies in a narrow range of 21–33 nm. The crystallite size is small enough to obtain a suitable signal to noise ratio in high density recording medium. Substitution of Zr and Co for Fe has been found to have a profound effect on the structural, magnetic and electrical properties. Upon substitution saturation magnetization (M_S) first increases from 62.67 emu/g to 64.84 emu/g (up to x=0.4) followed by a decrease to 49.71 emu/g at x=1.0. There is a slow fall in coercivity (H_C) from 5785.74 (x=0.0) to 1796.51 Oe (x=1.0). Dielectric constant, dielectric loss tangent and AC conductivity in the frequency range 20 Hz to 120 MHz have been studied for all the compositions (x=0–1.0). The composition and frequency dependence of these dielectric parameters has been qualitatively explained.     

Characterization of Adsorption Behavior of Sucrose Monolaurate on Gold Substrate Using the Quartz Crystal Microbalance (QCM)

One class of biodegradable surfactants, sucrose fatty acid esters (SEs), has attracted wide interest in the food and cosmetic industries due to their excellent biocompatibility, biodegradability and lower pH- and temperature-sensitivity. The objective of this study was to evaluate the adsorption behavior of pure sucrose monolaurate (SML) at the solid–liquid interface as a function of concentration, 0.02–0.5 % w/w, and medium pH, as these can be the pre-determinants of their performance. The quartz crystal microbalance (QCM), an effective and versatile surface adsorption tool with customizable surfaces, was used for the first time in real-time characterization of the adsorption behavior. Adsorption was fast, between 1 and 3 min, with a typical one-step monolayer adsorption mechanism occurring at most concentrations and medium pH used, thus justifying the application of the Sauerbrey equation to determine the deposited mass. The adsorption isotherm was likely Langmuirian and the SML deposition on gold was significantly higher, at and beyond 0.1 % w/w, in de-ionised water (pH 6.9) than in aqueous buffer (physiological pH 5.5) due to the interaction of water molecules with the adsorbed layer. The results from this work highlight the importance of media for studying the adsorption behaviors of SEs and serve as a reference for future investigations on different functionalized surfaces.     

表面活性剂对蔗糖色素物质影响的研究

本文对煮糖过程中添加表面活性剂对蔗糖晶体色值的影响进行了研究。通过实验室条件下甲膏模拟煮糖,分别对Hodag CB—6,Mazu 400,S—570,糖助剂—29和SS—02五种表面性剂做了六种添加量的对此试验。然后对晶体色值进行检测,并对影响晶体色值的几个主要因素—酚类物、氨基氮以及不同分子量色素物质的含量进行分析。结果发现,表面活性剂在改善煮糖作业的同时,对降低晶体的色值也具有良好的作用。     

蔗糖缩二脲树脂胶的合成研究

利用蔗糖为绿色原料,经酸化、脱水后以双金属为催化剂,合成不含三醛的羟甲基糖醛缩二脲树脂胶,通过单因素试验,对整个反应的pH值、反应温度、催化剂用量,反应原料配比和反应时间进行了优选,结果表明:在pH值为1.0催化剂用量为0.4g,温度95℃,物料比10:1为合成无醛树脂胶的最佳条件,得到的产品经红外分析表征,确定为目标产品,该产品在施胶过程中固化条件为:固化时间2h,温度为115℃,固化剂质量分数为8%。     

Starch,Sucrose, and Rezol® IL800 as Density Modifiers for Polyurethane Rigid Foams Formulated by Recycled Polyol

Waste polyurethane rigid foam (PUF) is recycled by the glycolysis process. The recycled product is used in a polyol blend, applied in a new foam formulation. Polyurethane rigid foams formulated by recycled polyols are highly dense compared to rigid foams formulated by virgin polyols. As these foams are mostly used in insulation, they make an extra mass to the main product or system that is insulated. Therefore, it is important to decrease their density as much as possible.

Some density modifiers such as starch, sucrose, and REZOL^® IL800 were investigated to recognize their effect on PUF's density.     

蔗糖酯的酶促合成研究进展

蔗糖酯是通过脂肪酸类化合物和蔗糖合成的一种重要食品添加剂。相对于化学催化,酶催化条件温和,操作简单,更具有高的选择性。就蔗糖酯不同位置上的选择性酶促合成进展做一综述.