Observation of the sweating in lipstick by scanning electron microscopy

The relationship between the wax matrix in lipstick and sweating has been investigated by observing the change of size and shape of the wax matrix due to sweating by Scanning Electron Microscopy (SEM). For observation by SEM, a lipstick sample was frozen in liquid nitrogen. The oil in the lipstick was then extracted in cold isopropanol (-70 degrees C) for 1-3 days. After the isopropanol was evaporated, the sample was sputtered with gold and examined by SEM. The change of wax matrix underneath the surface from fine, uniform structure to coarse, nonuniform structure resulted from the caking of surrounding wax matrix. The oil underneath the surface migrated to the surface of lipstick with sweating; consequently the wax matrix in that region was rearranged into the coarse matrix. In case of flamed lipstick, sweating was delayed and the wax matrix was much coarser than that of the unflamed one. The larger wax matrix at the surface region was good for including oil. The effect of molding temperature on sweating was also studied. As the molding temperature rose, sweating was greatly reduced and the size of the wax matrix increased. It was found that sweating was influenced by the compatibility of wax and oil. A formula consisting of wax and oil that have good compatibility has a tendency to reduce sweating and increase the size of the wax matrix. When pigments were added to wax and oil, the size of the wax matrix was changed, but in all cases sweating was increased due to the weakening of the binding force between wax and oil. On observing the thick membrane of wax at the surface of lipstick a month after molding it was also found that sweating was influenced by ageing. In conclusion, the structure of the wax matrix at the surface region of lipstick was changed with the process of flaming, molding temperature, compatibility of wax and oil, addition of pigment, and ageing. In most cases, as the size of the wax matrix was increased, sweating was reduced and delayed.     

Application of high-angle annular dark field scanning transmission electron microscopy,scanning transmission electron microscopy-energy dispersive X-ray spectrometry,and energy-filtered transmission electron microscopy to the characterization of nanoparticles in the environment

A major challenge to the development of a fundamental understanding of transport and retardation mechanisms of trace metal contaminants (<10 ppm) is their identification and characterization at the nanoscale. Atomic-scale techniques, such as conventional transmission electron microscopy, although powerful, are limited by the extremely small amounts of material that are examined. However, recent advances in electron microscopy provide a number of new analytical techniques that expand its application in environmental studies, particularly those concerning heavy metals on airborne particulates or water-borne colloids. High-angle annular dark field scanning transmission electron microscopy (HAADF-STEM), STEM-energy-dispersive X-ray spectrometry (EDX), and energy-filtered TEM (EFTEM) can be effectively used to identify and characterize nanoparticles. The image contrast in HAADF-STEM is strongly correlated to the atomic mass: heavier elements contribute to brighter contrast. Gold nanocrystals in pyrite and uranium nanocrystals in atmospheric aerosols have been identified by HAADF-STEM and STEM-EDX mapping and subsequently characterized by high-resolution TEM (HRTEM). EFTEM was used to identify U and Fe nanocrystals embedded in an aluminosilicate. A rare, As-bearing nanophase, westerveldite (FeAs), was identified by STEM-EDX and HRTEM. The combined use of these techniques greatly expands the effective application of electron microscopy in environmental studies, especially when applied to metals of very low concentrations. This paper describes examples of how these electron microbeam techniques can be used in combination to characterize a low concentration of heavy metals (a few ppm) on nanoscale particles.     

Thermally treated soya bean oleosomes: the changes in their stability and associated proteins

Oleosomes are subcellular organelles present naturally in plant seeds for storing lipids. Oleosomes can be used in the preparation of various food products, such as creams, salad dressings, mayonnaise and emulsion. However, food products are always subjected to thermal processing, and therefore, the evaluation of the thermal stability of oleosomes is of great important. The present work aimed to understand the effect of soya bean oleosome-associated proteins (SOAPs) on the thermal stability of soya bean oleosome emulsion (SOE). SOE was thermally treated for 15 min at different temperatures of 65, 75, 85 and 95 °C. The confocal laser scanning microscope (CLSM) and Cryo-SEM of SOE, and as well as fluorescence spectroscopy, circular dichroism of SOAPs were investigated. The stability of SOE was significantly affected by thermal treatments, by modulating the conformational structures of SOAPs, while the composition changed slightly. The results of particle size, zeta potential and CLSM showed that thermal treatments caused aggregations of oleosomes especially at high temperatures (75–95 °C). Thermally treated oleosomes were observed to have a rough surface. Results of this work are useful for understanding the underlying mechanisms of SOAPs in maintaining the thermal stability of SOE.     

转谷氨酰胺酶及非肉蛋白在重组碎羊肉卷加工中的应用

在原料肉中添加0.04%转谷氨酰胺酶,分别与0、0.2%、0.4%、0.6%、0.8%、1.0%酪蛋白、淀粉、大豆分离蛋白组成3个试验组,在6℃条件下催化反应138min,经过成型、解冻,以保形性作为指标,并用扫描电子显微镜(SEM)观察其微观结构。结果表明:大豆分离蛋白(0.8%)和酪蛋白(0.2%)都可以提高原料肉的保形性。SEM分析结果表明,转谷氨酰胺酶的加入可使碎肉形成致密的凝胶网络结构,在3个实验组中转谷氨酰胺酶与酪蛋白结合效果更好。     

Microbial degradation of normal maize and bm3 maize in the rumen observed by scanning electron microscopy

Samples of internodes and leaf blades from normal and bm3 maize (Zea mays L) harvested at dough to glazing stage were studied separately to determine their dry matter content, wall composition (NDF, ADF and ADL) and digestibility in sacco. For examination by light and scanning electron microscope, fragments 0·5 cm long were cut halfway along the internode beneath the female ear and on the corresponding blade. The wall and lignin contents of the bm3 maize were lower than in normal maize. The bm3 maize had a greater extent and faster rate of internode and blade disappearance in the rumen than normal maize samples. The histological structure of the two maizes was the same, but after 24 h in the rumen the parenchyma of the bm3 maize had degraded faster and the secondary walls of the fibres of its vascular bundles were degraded whereas those of normal maize had remained intact. After 72 h in the rumen the sclerenchyma of normal maize had changed little whereas that of the bm3 maize had much thinner walls and was abundantly colonised by rumen bacteria.     

Use of microbial transglutaminase and nonmeat proteins to improve functional properties of low NaCl, phosphate-free patties made from channel catfish (Ictalurus punctatus) belly flap meat

ABSTRACT:  This study was aimed at developing value-added low sodium chloride (NaCl), phosphate-free restructured patties using minced channel catfish ( Ictalurus punctatus ) belly flap meat. The effect of microbial transglutaminase (MTGase) and nonmeat proteins (isolated soy protein, ISP, and whey protein concentrate, WPC; 1.7%, respectively) alone and in combination were evaluated to improve cooking yield and textural properties in patties with reduced NaCl and no phosphate. The concentration effect of MTGase (0.05% to 0.7%) was also studied. The addition of MTGase increased textural properties such as binding strength, hardness, cohesiveness, chewiness, and springiness, but decreased cooking yield of the patties ( P < 0.05). Isolated soy protein increased cooking yield ( P < 0.05), but did not affect textural properties. Inclusion of WPC did not increase cooking yield or impact textural properties of patties. The combination of MTGase and ISP significantly increased both the cooking yield and textural properties of patties. As the concentration of MTGase increased at constant ISP, the textural properties of cooked patties significantly increased, but cooking yield decreased ( P < 0.05). In conclusion, we suggest that the combination of 0.05% to 0.1% of MTGase with 1.7% ISP is optimal for development of a low NaCl, phosphate-free patty using minced catfish belly flap meat.     

肌红蛋白在加工贮藏过程中结构与功能特性的变化及其对肉制品色泽的影响研究进展

肌红蛋白是一种主要存在于肌浆中的色素蛋白质,可以赋予和提升肉及肉制品在加工、贮藏和消费过程中的色泽。在肉制品加工过程中,引起肌红蛋白结构变化的因素有很多,而蛋白质结构的改变会引起其功能特性的改变,从而对肉制品的色泽产生影响。本文主要介绍肉及肉制品中肌红蛋白在加工和贮藏过程中的结构变化,并综述了结构变化引起的肌红蛋白功能特性改变,以期为肉及肉制品的品质控制提供参考。     

Immunocytochemical and biochemical studies of the mobilisation of storage oil-bodies and proteins in germinating cotyledons of oilseed rape,Brassica napus

Seeds of Brassica napus L cv Mikado contain about 25% w/w protein in addition to 40–50% w/w storage oil. About 50% of the seed protein is the legumin-like neutral protein, cruciferin, and a further 20% is the small basic protein, napin. The only other major seed protein (20% of total) is a polypeptide of apparent molecular mass (M_r) 19 000±200, which is associated with the membranes of the storage oil-bodies. The purification of this protein and preparation of monospecific antibodies have recently been reported. The kinetics of protein and oil mobilisation and the subcellular distribution of the M_r 19 000 oil-body protein have been studied by techniques including sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), gas-liquid chromatography (GLC), sucrose density gradient fractionation, and electron microscop-immunocytochemistry. The results show that the mobilisation of the storage products of rapeseed occurs in at least three distinct phases: (1) a lag phase of 10–15 h, (2) breakdown of cruciferin and napin from 12 h until day 3, (3) breakdown of storage oil and oil-body membranes from day 2 until day 7. The M_r 19000 protein was localised on oil-body membranes in early stages of germination but was later associated with a light membrane fraction, which probably contained oil-body ghosts. Relatively little difference in the kinetics of the mobilisation of storage oils and proteins was found whether seedlings were grown in the light or in the dark. The implications of these results for the mechanism of storage oil mobilisation in oilseeds are discussed.     

Use of casein micelles to improve the solubility of hydrophobic pea proteins in aqueous solutions via low-temperature homogenization

The dairy industry struggles to maintain consumer attention in the midst of declining fluid milk sales. Current trends create an opportunity to incorporate plant-based proteins with milk to produce a high-protein, multisourced, functional food product. Plant-based proteins, such as those in peas, can be challenging to use in food systems because of their low solubility and undesirable off-flavors. Casein micelles have unique structural properties that allow for interactions with small ions and larger macromolecules that aid in their noteworthy ability as a nanovehicle for hydrophobic compounds. The objective of this study was to use the inherent structure of the casein micelle along with common dairy processing equipment to create a stable colloidal dispersion of casein micelles with pea protein to improve its solubility in aqueous solutions. We created 3 blends with varying ratios of casein-to-pea protein (90:10, 80:20, 50:50). We subjected the mixtures to 3 cycles of homogenization using a bench-top GEA 2-stage homogenizer at 27,580 kPa maintained at 4°C, followed by pasteurization at 63°C for 30 min. The resulting blends were homogeneous liquids with increased stability due to the lack of protein precipitation. Further protein analysis by HPLC and AA sequencing revealed that vicilin, an insoluble storage protein, was the main pea protein incorporated within the casein micelle structure. These results supported our hypothesis that low-temperature homogenization can successfully be used to create a colloidal dispersion with increased stability, in which insoluble plant-based proteins may be incorporated with casein micelles in an aqueous solution. Additionally, 3-dimensional microscope images of the blends indicated a noticeable difference between the surface roughness upon addition of pea protein to the casein micelle matrix. This research highlights a promising application for other plant-based proteins to be used within the dairy industry to help drive future product innovation while also meeting current processing conditions and consumer demands.     

Issues Related to the Use of Blood in Food and Animal Feed

Blood has traditionally been used as a high protein ingredient in both human food and animal feed, with resulting economic, environmental and nutritional benefits. However, potentially serious health and safety issues related to blood consumption, particularly the risk of pathogenic or harmful metabolic materials, the infectivity of prion diseases, and the presence of identified allergens such as bovine serum albumin (BSA), are causing many consumers to shy away from any product containing either animal blood or ingredients derived from animal blood. Thus, despite the significant volumes of blood produced by slaughterhouses, blood is currently underutilized as a food ingredient. This article reviews the use of animal blood as an ingredient in food intended for human consumption or for animal feed and discusses the related consumer concerns.     

Multivariate optimisation of a capillary electrophoretic method for the separation of glutenins. Application to quantitative analysis of the endosperm storage proteins in wheat

A capillary electrophoretic method has been designed to allow separation of glutenins with high resolution. Several factors, such as buffer composition, running voltage and capillary temperature were optimised using factorial design and response surface methodology. On the other hand, quantification of content of glutenins and gliadins of different wheat varieties were achieved for the first time using a glutenin extract of wheat gluten and a gliadin extract as external standards, respectively, and using the lys-tyr-lys tripeptide as internal standard. The optimised method and an early reported method for the gliadin separation were validated by evaluating linearity, sensitivity, detection and quantitation limits, repeatability and precision.     

Towards a routine application of vibrational spectroscopy to the detection of bone fragments in feedingstuffs: Use and validation of a NIR scanning microscopy method

The possibility to use NIR scanning microscopy for the detection of bone fragments in feedingstuffs has been evaluated analysing sediments derived from commercial feedingstuffs samples spiked with MBM. The method appeared sensitive enough to reveal the presence of bone fragments for MBM concentration in the feedingstuffs as low as 0.05 wt.%. The identification of MBM is done versus vegetable ingredients.     

The effect of mechanical harvesting and long-distance transport on the concentration of haze-forming proteins in grape juice

The concentration and composition of soluble, haze-forming protein in juice of hand-harvested (HH) and mechanically harvested (MH) Pinot Noir and Sauvignon Blanc grapes was determined. The major soluble proteins in both varieties were pathogenesis-related (PR) proteins, specifically thaumatin-like proteins and chitinases. Comparison among HH berries, MH intact berries and the mixture of broken fruit and juice, the predominant form of MH fruit, indicated that little if any protein was produced as a result of stress caused by MH. Nevertheless, MH coupled with long-distance transport which caused a delay in pressing the mechanically damaged fruit, resulted in juice with a higher concentration of PR proteins compared to juice obtained from pressing HH fruit. Soluble PR proteins were detected in the berry skin of both varieties. Increases in protein content of juice from MH fruit are predominantly caused by extraction of protein from skins and solids of broken grapes during transport to the winery.     

The use of mechanical analyses,scanning electron microscopy and ultrasonic imaging to study the effects of high‐pressure processing on multilayer films

The effects of high‐pressure processing (HPP) on the mechanical and physical characteristics of eight high‐barrier multilayer films were investigated. These films were PET/SiO_x/LDPE, PET/Al₂O₃/LDPE, PET/PVDC/nylon/HDPE/PP, PE/nylon/EVOH/PE, PE/nylon/PE, metallised PET/EVA/LLDPE, PP/nylon/PP and PET/PVDC/EVA. In addition, PP was evaluated as a monolayer film for comparison purposes. Pouches made from these films were filled with distilled water, sealed, then pressure processed at 600 and 800 MPa for 5, 10 and 20 min at a process temperature of 45 °C. Pouches kept at atmospheric pressure were used as controls. Prior to and after HPP, all films were tested for tensile strength, percentage elongation and modulus of elasticity (at 50 cm min^?1) and imaged by scanning electron microscopy (SEM) and C‐mode scanning acoustic microscopy (C‐SAM). Results showed no significant changes in tensile strength, elongation and modulus of elasticity of all films after HPP. However, significant physical damage to metallised PET (MET‐PET) was identified by SEM and C‐SAM. Thus it could be concluded that MET‐PET is not suitable for batch‐type high‐pressure‐processed food packaging. It can also be concluded that the other materials investigated during this study are suitable for batch‐type high‐pressure‐processed food packaging. Copyright © 2003 Society of Chemical Industry     

Regulation of peroxisomal proteins and organelle proliferation by multiple carbon sources in the methylotrophic yeast,Candida boidinii

A methylotrophic yeast, Candida boidinii, was grown on various combinations of peroxisome-inducing carbon source(s) (PIC(s)), i.e. methanol, oleate and d-alanine, and the regulation of peroxisomal proteins (both matrix and membrane ones) and organelle proliferation were studied. This regulation was followed (1) at the protein or enzyme level by means of the peroxisomal enzyme activity and Western analysis; (2) at the mRNA level by Northern analysis; and (3) at the organelle level by direct observation of peroxisomes under a fluorescent microscope. Peroxisomal proliferation was followed in vivo by using a C. boidinii strain producing a green fluorescent protein having peroxisomal targeting signal 1. When multiple PICs were used for cell growth, C. boidinii induced specific peroxisomal proteins characteristic of all PIC(s) present in the medium, responding to all PIC(s) simultaneously. Thus, these PICs were considered to induce peroxisomal proliferation independently and not to repress peroxisomes induced by other PICs. Next, the sensitivity of the peroxisomal induction to glucose repression was studied. While the peroxisomal induction by methanol or oleate was completely repressed by glucose, the d-alanine-induced activities of d-amino acid oxidase and catalase, Pmp47, and the organelle proliferation were not. These results indicate that peroxisomal proliferation in yeasts is not necessarily sensitive to glucose repression. Lastly, this regulation was shown to occur at the mRNA level. © 1998 John Wiley & Sons, Ltd.     

Nutrient composition and the use of solubility to estimate rumen degradability of food proteins in cattle

The use of protein solubility to estimate protein degradability in cattle was tested using 12 by‐products representing agricultural and distillers' food raw materials (RM). Agricultural RM included cereals (rice bran, maize gluten feed), legumes (field beans, soybean hulls) and oil‐seeds (rape meal, sunflower meal). Distillers' RM involved dark grains (DG1, DG2, DG3) and malts (MT1, MT2, MT3). Soluble proteins, as proportions of total soluble N (TSN), were extracted from RM and their undegraded residues (RU) after 18 h of in sacco rumen incubation in cattle (dg₁₈) by using water (albumin), salt (globulin), acid (glutalin 1) and alkali (glutalin 2) in succession. RM and RU differed significantly for all soluble proteins (P < 0.001). While albumin was the major protein in legume RM (0.74TSN), glutalin 1 was the major protein in legume RU (0.54TSN). Cereals were the most variable group, where maize gluten contained five times more albumin and two times more TSN in RM and three times more glutalin 1 + 2 in RU than those in rice bran. Distillers' RM contained slightly less albumin (0.53 vs 0.56TSN) but over twice as much glutalin 1 (0.29 vs 0.12TSN) as agricultural RM. Albumins were the most (0.55TSN, RM; 0.16TSN, RU) and glutalin 1 the least (0.21TSN, RM; 0.48TSN, RU) degradable proteins. There were moderate to strong correlations between protein solubility, dg₁₈ and acid detergent‐insoluble N (ADIN). ADIN correlated satisfactorily with glutalin 1 + 2 (r = ?0.55, RM and ?0.70, RU), TSN (r = ?0.75, RM and RU) and slowly degradable N, (SDN; r = ?0.70, all). TSN in all RM related well with SDN (r = 0.65) and dUN (r = 0.72). TSN in distillers' RM correlated closely with SDN (r = 0.91) and dUN (r = 0.96). Glutalin 1 in distillers' foods correlated extremely well (r = 0.94, RM and 0.93, RU) with dUN. Globulins correlated most consistently with SDN (r = 0.82, all; r = 0.77, agricultural; r = 0.92, distillers' RM). It is possible to predict protein degradability from the presence or absence of soluble proteins in various foods. While ADIN may be more suitable to predict DUN, globulins showed more potential to predict SDN in various foods. However, it may be necessary to be selective in choosing solvents for various foods. Further studies must validate this method by using a greater range of foods before suggesting its routine use for food evaluation. © 2001 Society of Chemical Industry     

Investigation of the activity of cathepsin B in red shrimp (Solenocera crassicornis) and its relation to the quality of muscle proteins during chilled and frozen storage

Cathepsin B is a cysteine protease that has important effects on the quality of muscle products. In this study, the changes of cathepsin B activity and its relation to muscle proteins were investigated in intact and beheaded shrimp during chilled and frozen storage. The obtained results indicated that the water holding capacity (WHC), shear force, hardness, and myofibrillar protein (MP) content all significantly decreased in both the intact and beheaded shrimp samples with increasing storage period (p < 0.05). Specifically, beheading shrimp exhibited much more stable characteristics than intact shrimp samples during both chilled and frozen storage. The enzyme activity results suggested that cold temperature and storage induced the release of cathepsin B from the lysosomes to the mitochondria, sarcoplasm, and myofibrils in the muscle tissues. Furthermore, SDS-PAGE and transmission electron microscopy (TEM) analysis revealed that beheading the shrimp greatly inhibited the dissociation of shrimp muscle proteins during storage. The current findings suggest that cathepsin B located in the head of shrimp was likely transferred to the muscle through the first abdominal segment during storage, accelerating the dissociation of the muscle proteins. Therefore, beheading the shrimp was conducive to prolonging the shelf-life of stored shrimp products.     

A DSC study on the effects of various maltodextrins and sucrose on protein changes in frozen‐stored minced blue whiting muscle

A DSC heat denaturation study on the effects of various maltodextrins and sucrose on protein changes in minced blue whiting muscle during frozen storage at −10 and −20 °C was carried out. All maltodextrins slowed down the decreases in the denaturation enthalpies (ΔH_d) ascribed to myosin and actin, making evident a noticeable effectiveness against protein denaturation, especially at −20 °C. Sucrose was as effective as maltodextrins at −20 °C, but was the least effective treatment at −10 °C. Significant correlations between both ΔH_ds and either protein solubility or formaldehyde production were found at each storage temperature. A low protein sensitivity to the small amounts of formaldehyde produced during the first weeks of storage and errors associated with the determination of enthalpies led to poorer correlations at −20 °C. Maximum denaturation temperatures (T_max) correlated with protein solubility only at −20 °C. No clear relationship between either T_max and the effectiveness of cryostabilisation was found, as T_max also depends on the effectiveness of the treatments against the thermal denaturation of proteins. © 2001 Society of Chemical Industry