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Human exposure to persistent, nonbiological nanoparticles and microparticles via the oral route is continuous and large scale (10 12 -10 13 particles per day per adult in Europe). Whether this matters or not is unknown but confirmed health risks with airborne particle exposure warns against complacency. Murine models of oral exposure will help to identify risk but, to date, lack validation or relevance to humans. This work addresses that gap. It reports i) on a murine diet, modified with differing concentrations of the common dietary particle, food grade titanium dioxide (fgTiO 2 ), an additive of polydisperse form that contains micro- and nano-particles, ii) that these diets deliver particles to basal cells of intestinal lymphoid follicles, exactly as is reported as a "normal occurrence" in humans, iii) that confocal reflectance microscopy is the method of analytical choice to determine this, and iv) that food intake, weight gain, and Peyer's patch immune cell profiles, up to 18 weeks of feeding, do not differ between fgTiO 2 -fed groups or controls. These findings afford a human-relevant and validated oral dosing protocol for fgTiO 2 risk assessment as well as provide a generalized platform for application to oral exposure studies with nano- and micro-particles., (© 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Background: Pigment-grade titanium dioxide (TiO 2 ) particles are an additive to some foods (E171 on ingredients lists), toothpastes, and pharma-/nutraceuticals and are absorbed, to some extent, in the human intestinal tract. TiO 2 can act as a modest adjuvant in the secretion of the pro-inflammatory cytokine interleukin 1β (IL-1β) when triggered by common intestinal bacterial fragments, such as lipopolysaccharide (LPS) and/or peptidoglycan. Given the variance in human genotypes, which includes variance in genes related to IL-1β secretion, we investigated whether TiO 2 particles might, in fact, be more potent pro-inflammatory adjuvants in cells that are genetically susceptible to IL-1β-related inflammation., Methods: We studied bone marrow-derived macrophages from mice with a mutation in the nucleotide-binding oligomerisation domain-containing 2 gene (Nod2 m/m ), which exhibit heightened secretion of IL-1β in response to the peptidoglycan fragment muramyl dipeptide (MDP). To ensure relevance to human exposure, TiO 2 was food-grade anatase (119 ± 45 nm mean diameter ± standard deviation). We used a short 'pulse and chase' format: pulsing with LPS and chasing with TiO 2 +/- MDP or peptidoglycan., Results: IL-1β secretion was not stimulated in LPS-pulsed bone marrow-derived macrophages, or by chasing with MDP, and only very modestly so by chasing with peptidoglycan. In all cases, however, IL-1β secretion was augmented by chasing with TiO 2 in a dose-dependent fashion (5-100 μg/mL). When co-administered with MDP or peptidoglycan, IL-1β secretion was further enhanced for the Nod2 m/m genotype. Tumour necrosis factor α was triggered by LPS priming, and more so for the Nod2 m/m genotype. This was enhanced by chasing with TiO 2 , MDP, or peptidoglycan, but there was no additive effect between the bacterial fragments and TiO 2 ., Conclusion: Here, the doses of TiO 2 that augmented bacterial fragment-induced IL-1β secretion were relatively high. In vivo, however, selected intestinal cells appear to be loaded with TiO 2 , so such high concentrations may be 'exposure-relevant' for localised regions of the intestine where both TiO 2 and bacterial fragment uptake occurs. Moreover, this effect is enhanced in cells from Nod2 m/m mice indicating that genotype can dictate inflammatory signalling in response to (nano)particle exposure. In vivo studies are now merited.

Perceptions of production methods for organic and conventional milk are changing, with consumers prepared to pay premium prices for milk from either certified organic or conventional grass-fed cows. Our study investigated whether chemical composition differed between milk produced by these two farming systems. Sampling was conducted on two farms sets, each comprised of one organic and one conventional farm. All farms applied year-round pasture grazing. Milk samples were collected throughout the milking season and analysed for free oligosaccharides, fatty acids, major casein and whey proteins, and milk fat volatiles. Fatty acids were influenced by breed and fertilizer application. Oligosaccharides differed between farming systems, with causes presently unknown, while farm set was the dominant influence factor on protein composition. Factors identified in this study influencing milk composition are not exclusive to either farming system, and pasture feeding conventional cows will remove differences previously reported for organic and conventionally produced milk., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

A bovine milk oligosaccharide (BMO) library, prepared from cow colostrum, with 34 structures was generated and used to rapidly screen oligosaccharides in domestic animal milks and a whey permeate powder. The novel library was entered into a custom Personal Compound Database and Library (PCDL) and included accurate mass, retention time, and tandem mass spectra. Oligosaccharides in minute-sized samples were separated using nanoliquid chromatography (nanoLC) coupled to a high resolution and sensitive quadrupole-Time of Flight (Q-ToF) MS system. Using the PCDL, 18 oligosaccharides were found in a BMO-enriched product obtained from whey permeate processing. The usefulness of the analytical system and BMO library was further validated using milks from domestic sheep and buffaloes. Through BMO PCDL searching, 15 and 13 oligosaccharides in the BMO library were assigned in sheep and buffalo milks, respectively, thus demonstrating significant overlap between oligosaccharides in bovine (cow and buffalo) and ovine (sheep) milks. This method was shown to be an efficient, reliable, and rapid tool to identify oligosaccharide structures using automated spectral matching.

Ruminant animals contribute significantly to the global value of agriculture and rely on a complex microbial community for efficient digestion. However, little is known of how this microbial-host relationship develops and is maintained. To begin to address this, we have determined the ability of three Bifidobacterium species isolated from the faeces of newborn calves to grow on carbohydrates typical of a newborn ruminant diet. Genome sequences have been determined for these bacteria with analysis of the genomes providing insights into the host association and identification of several genes that may mediate interactions with the ruminant gastrointestinal tract. The present study provides a starting point from which we can define the role of potential beneficial microbes in the nutrition of young ruminants and begin to influence the interactions between the microbiota and the host. The differences observed in genomic content hint at niche partitioning among the bifidobacterial species analysed and the different strategies they employ to successfully adapt to this habitat.

Differing amounts of fresh forage and concentrates fed, and level of input contributes to the differences reported in fatty acid (FA) composition of organic and conventionally produced cow milk. In many previous studies designed to investigate this phenomenon, comparisons were made between grazed organic cows and housed conventional cows. In the present study, we have investigated differences between organic and conventional milk produced using year-round pasture grazing, as practiced in New Zealand. The FA composition was determined in milk sampled at morning and evening milking in both spring and autumn. Samples were taken from 45 cows from the Massey University organic herd and compared with 50 cows from the corresponding conventional herd grazed and managed similarly at the same location. Forty-three out of 51 analyzed FA were influenced by season, whereas 28 were different between production systems. In addition, one-half were also different due to time of milking. Levels of linoleic acid and α-linolenic acid were higher in organic milk, whereas conjugated linoleic acid (CLA) and vaccenic acid were higher in conventional milk. The first 3 FA (linoleic acid, α-linolenic acid, and CLA) were more abundant in milk harvested during autumn, and the CLA concentration was also significantly influenced by time of milking. Our results confirm reports that the FA profile is affected by season and time of milking, and we also showed an effect due to the production system, when both sets of cows were kept continuously on pasture, even after taking milking time and seasonal effect into account., (Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Consumer perception of organic cow milk is associated with the assumption that organic milk differs from conventionally produced milk. The value associated with this difference justifies the premium retail price for organic milk. It includes the perceptions that organic dairy farming is kinder to the environment, animals, and people; that organic milk products are produced without the use of antibiotics, added hormones, synthetic chemicals, and genetic modification; and that they may have potential benefits for human health. Controlled studies investigating whether differences exist between organic and conventionally produced milk have so far been largely equivocal due principally to the complexity of the research question and the number of factors that can influence milk composition. A main complication is that farming practices and their effects differ depending on country, region, year, and season between and within organic and conventional systems. Factors influencing milk composition (e.g., diet, breed, and stage of lactation) have been studied individually, whereas interactions between multiple factors have been largely ignored. Studies that fail to consider that factors other than the farming system (organic vs. conventional) could have caused or contributed to the reported differences in milk composition make it impossible to determine whether a system-related difference exists between organic and conventional milk. Milk fatty acid composition has been a central research area when comparing organic and conventional milk largely because the milk fatty acid profile responds rapidly and is very sensitive to changes in diet. Consequently, the effect of farming practices (high input vs. low input) rather than farming system (organic vs. conventional) determines milk fatty acid profile, and similar results are seen between low-input organic and low-input conventional milks. This confounds our ability to develop an analytical method to distinguish organic from conventionally produced milk and provide product verification. Lack of research on interactions between several influential factors and differences in trial complexity and consistency between studies (e.g., sampling period, sample size, reporting of experimental conditions) complicate data interpretation and prevent us from making unequivocal conclusions. The first part of this review provides a detailed summary of individual factors known to influence milk composition. The second part presents an overview of studies that have compared organic and conventional milk and discusses their findings within the framework of the various factors presented in part one., (Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

This study was conducted to investigate the catabolism and fermentation of caprine milk oligosaccharides (CMO) by selected bifidobacteria isolated from 4 breast-fed infants. Seventeen bifidobacterial isolates consisting of 3 different species (Bifidobacterium breve, Bifidobacterium longum subsp. longum and Bifidobacterium bifidum) were investigated. A CMO-enriched fraction (CMOF) (50% oligosaccharides, 10% galacto-oligosaccharides (GOS), 20% lactose, 10% glucose and 10% galactose) from caprine cheese whey was added to a growth medium as a sole source of fermentable carbohydrate. The inclusion of the CMOF was associated with increased bifidobacterial growth for all strains compared to glucose, lactose, GOS, inulin, oligofructose, 3'-sialyl-lactose and 6'-sialyl-lactose. Only one B. bifidum strain (AGR2166) was able to utilize the sialyl-CMO, 3'-sialyl-lactose and 6'-sialyl-lactose, as carbohydrate sources. The inclusion of CMOF increased the production of acetic and lactic acid (P < 0.001) after 36 h of anaerobic fermentation at 37 °C, when compared to other fermentable substrates. Two B. bifidum strains (AGR2166 and AGR2168) utilised CMO, contained in the CMOF, to a greater extent than B. breve or B. longum subsp longum isolates, and this increased CMO utilization was associated with enhanced sialidase activity. CMOF stimulated bifidobacterial growth when compared to other tested fermentable carbohydrates and also increased the consumption of mono- and disaccharides, such as galactose and lactose present in the CMOF. These findings indicate that the dietary consumption of CMO may stimulate the growth and metabolism of intestinal Bifidobacteria spp. including B. bifidum typically found in the large intestine of breast-fed infants.

Oolong tea is a semi-fermented tea that is partially oxidised during the manufacturing process to create a product unique in composition. In this study, we investigated the potential of non-targeted LC-MS with two complementary chromatographic modes to provide a "comprehensive and unbiased" view of biochemical compositional changes occurring during oolong tea manufacturing in New Zealand. Tea leaf samples from throughout the manufacturing/fermentation process during three different harvest periods (spring, summer and autumn) were analysed by four different LC-MS streams. Principal component analysis revealed the de-greening stage of the manufacturing process was responsible for major changes in the biochemical profile, with the methodology detecting changes in a wide range of metabolites of differing polarities, such as flavonoids, nucleosides and primeverosides. Changes during the fermentation phase of the manufacturing process were less marked, however significant increases in levels of free amino acids, a hydroxyjasmonic acid and related metabolites were observed., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Tea is the second most consumed beverage in the world after water and there are numerous reported health benefits as a result of consuming tea, such as reducing the risk of cardiovascular disease and many types of cancer. Thus, there is much interest in the chemical composition of teas, for example; defining components responsible for contributing to reported health benefits; defining quality characteristics such as product flavor; and monitoring for pesticide residues to comply with food safety import/export requirements. Covered in this review are some of the latest developments in mass spectrometry-based analytical techniques for measuring and characterizing low molecular weight components of tea, in particular primary and secondary metabolites. The methodology; more specifically the chromatography and detection mechanisms used in both targeted and non-targeted studies, and their main advantages and disadvantages are discussed. Finally, we comment on the latest techniques that are likely to have significant benefit to analysts in the future, not merely in the area of tea research, but in the analytical chemistry of low molecular weight compounds in general.

Factors such as fermentation methods, geographical origin and season can affect the biochemical composition of tea leaves (Camellia sinensis L.). In this study, the biochemical composition of oolong tea during the manufacturing and fermentation process was studied using a non-targeted method utilising ambient ionisation with a direct analysis in real time (DART) ion source and mass spectrometry (MS). Caffeine dominated the positive ionisation spectra throughout the manufacturing process, while the negative ion spectra collected during manufacturing were rich in ions likely to be surface lipids. Correlation analyses on the spectra revealed two volatile compounds tentatively identified as indole and geranic acid, along with ammonium and caffeine clusters/adducts with geranic acid that increased in concentration during the fermentation stages of the process. The tentative identifications were assigned using a combination of DART-ion-trap MS(n) and DART-accurate mass MS(1) and MS(2) on tea samples and standard compounds. This study highlights the potential of DART-MS to rapidly monitor the progress of complex manufacturing processes such as tea fermentation., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The gastrointestinal microbiota plays an important role in maintaining host health by preventing the colonization of pathogens, fermenting dietary compounds, and maintaining normal mucosal immunity. Particularly in early life, the composition of the microbiota profoundly influences the development and maturation of the gastrointestinal tract (GIT) mucosa, which may affect health in later life. Therefore, strategies to manipulate the microbiota during infancy may prevent the development of some diseases later in adult life. Earlier research suggested that term fetuses are sterile and that the initial bacterial colonization of the newborn GIT occurs only after the baby transits through the birth canal. However, recent studies have demonstrated that the colonization and/or contact of the fetus with the maternal GIT microbiota may start in utero. After vaginal birth, the colonization of the neonate GIT continues through contact with maternal feces and vaginal bacteria, leading to a relatively simple microbial community that is influenced by feeding type (breast vs. formula feeding). Maternal GIT microbiota, vaginal microbiota, and breast milk composition are influenced by maternal diet. Alterations of the maternal GIT microbiota composition via supplementation with probiotics and prebiotics have been shown; however, transfer of these benefits to the offspring remains to be demonstrated. This review focuses on the influence of maternal GIT microbiota during the pre- and postpartum periods on the colonization of the infant GIT. In particular, it examines the manipulation of the maternal GIT microbiota composition through the use of probiotics and/or prebiotics and subsequent consequences for the health of the offspring.

Tea is the second most consumed beverage in the world and its consumption has been associated with numerous potential health benefits. Factors such as fermentation methods, geographical origin and season can affect the primary and secondary metabolite composition of tea. In this study, a hydrophilic interaction liquid chromatography (HILIC) method coupled to high resolution mass spectrometry in both positive and negative ionisation modes was developed and optimised. The method when combined with principal component analysis to analyse three different types of tea, successfully distinguished samples into different categories, and provided evidence of the metabolites which differed between them. The accurate mass and high resolution attributes of the mass spectrometric data were utilised and relative quantification data were extracted post-data acquisition on 18 amino acids, showing significant differences in amino acid concentrations between tea types and countries. This study highlights the potential of HILIC chromatography combined with non-targeted mass spectrometric methods to provide a comprehensive understanding of polar metabolites in plant extracts., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Amino acids (AA) are essential nutritional components of a balanced diet and occur in foods in either the free AA form or as the building blocks of proteins. The analysis of AAs in foods is composed of a number of unit operations; the release of the AAs from the food matrix, the separation of the individual AAs and their quantification using calibration standards. Each of these steps has their own idiosyncrasies, e.g. different hydrolysis conditions are required for the optimal release of different AAs and there are a diverse number and type of food matrices, such that most laboratories adapt methods to best suit their applications. There is currently no official standardised method for AA analysis, although the Association of Analytical Communities (AOAC) has validated methods for a number of individual AA components. The established analytical techniques of HPLC (ion exchange or reversed phase) and GC-MS have recently been supplemented by a number of new methods. These include capillary electrophoresis MS and Ultra HPLC-MS, and LC with other detectors. This review will address the intricacies and concerns of the protein hydrolysis step, discuss what specifications or prerequisites need to be placed on the existing and new methods and laboratories using these methods, comment on whether one method can successfully satisfy the exacting requirements of the various unit operations, and finally pose the question 'Is there any merit in 'developing' a validated (e.g. AOAC) official method of analysis for AAs in food?'

The immunoprotective properties of bovine milk immunoglobulin G (IgG) have led to a recent proliferation of nutritional products incorporating this protein. It has therefore become critical that reliable analytical techniques for the measurement of the IgG content in such products are available. This literature review surveys current methods of analysis for IgG, including separation-based or immuno-based concentration analysis. The review also discusses nutraceutical applications, regulatory issues, stability of IgG and the significance of primary reference material in IgG analysis.

An affinity liquid chromatography (LC) method for the determination of bovine immunoglobulin G (IgG), using protein G coupled to an agarose support, was modified to permit the quantification of IgG in colostrum-based powders. Sample preparation included pH adjustment to 4.6 to precipitate casein and denatured whey protein. The method was applied to a range of colostrum powders and was compared with the alternative independent methods of surface plasmon resonance immunoassay, radial immunodiffusion, and reversed-phase LC. The method was rapid, and performance parameters included a working range of 10-150 microg IgG and precision relative standard deviation values of <10%.

Extensive hydrolysis of whey protein isolate by Alcalase was shown to induce gelation mainly via hydrophobic interactions. The aim of this work was to characterize the peptides released in order to better understand this phenomenon. The apparent molecular mass distribution indicated that aggregates were formed by small molecular mass peptides (<2000 Da). One hundred and thirty peptides with various lengths were identified by reversed-phase high-performance liquid chromatography coupled with electrospray ionization mass spectrometry. Alcalase was observed to have a high specificity for aromatic (Phe, Trp, and Tyr), acidic (Glu), sulfur-containing (Met), aliphatic (Leu and Ala), hydroxyl (Ser), and basic (Lys) residues. Most peptides had an average hydrophobicity of 1-1.5 kcal/residue and a net charge of 0 at the pH at which gelation occurred (6.0). Therefore, an intermolecular attractive force such as hydrophobic interaction suggests the formation of aggregates that further leads to the formation of a gel.

Extensive hydrolysis of whey protein isolate by Alcalase 2.4L produces a gel. The objectives of this study were to compare enzyme-induced gelation with the plastein reaction by determining the types of interactions involved in gelation. The average chain length of the peptides did not increase during hydrolysis and reached a plateau after 30 min to be approximately 4 residues, suggesting that the gel was formed by small molecular weight peptides held together by non-covalent interactions. The enzyme-induced gel network was stable over a wide range of pH and ionic strength and, therefore, showed some similarities with the plastein reaction. Disulfide bonds were not involved in the gel network. The gelation seems to be caused by physical aggregation, mainly via hydrophobic interactions with hydrogen bonding and electrostatic interactions playing a minor role.

A precise, sensitive and reliable RP-HPLC method was developed to enable not only unequivocal determination of alpha-lactalbumin and beta-lactoglobulin in bovine whey samples, but also simultaneous measurement of proteose peptone, caseinomacropeptide, bovine serum albumin and immunoglobulin G. The optimised method on the Resource RPC column allowed separation of the proteins in 30 min and could be applied to the analysis of soluble proteins in a variety of commercial and laboratory whey products. Furthermore, some qualitative information on protein heterogeneity and quality could be derived from the RP-HPLC analyses with additional data available from on-line electrospray mass spectrometry. Within- and between-day repeatability over a wide range of concentrations was excellent (RSD< or =5%) for all proteins except immunoglobulin G and bovine serum albumin where RSD was 7-10%. Analysis of grouped data from whey protein concentrate and whey protein isolate samples gave a limit of detection of < or =0.3% powder mass and a limit of quantitation of < or =1.0% powder mass for all proteins except immunoglobulin G. Limits of detection and quantitation were 0.6% and 2.0%, respectively, for this protein. Quantitative data obtained by the RP-HPLC method compared very favourably with data obtained by alternative methods of whey protein analysis.

An enzymatic method for hydrolyzing bovine milk proteins was developed. Purified milk proteins (alpha-lactalbumin, beta-lactoglobulin, and beta-casein) were hydrolyzed in 0.1 M Hepes buffer (pH 7.5) containing pronase E, aminopeptidase M, and prolidase at 37 degrees C for 20 h. Free glutamine and other amino acids were derivatized with phenylisothiocyanate and separated using a C18 Pico-Tag column. Amino acids were eluted from the column with an aqueous sodium acetate-acetonitrile gradient with detection at 254 nm. Glutamine recoveries from hydrolyzed alpha-lactalbumin, beta-lactoglobulin, and beta-casein were 78 +/- 4, 98 +/- 3, and 101 +/- 3% of the theoretical values, respectively. The recoveries of most amino acids were comparable with those obtained using acid hydrolysis, except for the recoveries of proline and acidic amino acids. These peptide bonds appeared to be resistant to enzymatic hydrolysis and also to inhibit the hydrolysis of adjacent amino acids. Free glutamine was found to be very stable (97% recovery) under the enzymatic hydrolysis conditions., (Copyright 1999 Academic Press.)

Two major caseins have been isolated from the milk of the common brushtailed possum (Trichosurus vulpecula). These have been identified as alpha- and beta-casein on the basis of the similarity of their N-terminal sequences to those of the caseins of another marsupial (Macropus eugenii). Both proteins appear to exist in multiple forms. Possum alpha-casein is glycosylated mainly in the form of sialic acid residues and was shown by electrospray mass spectrometry to have multiply phosphorylated forms of three families with molecular masses 22700 and 23200 Da that may represent genetic variants. Two-dimensional electrophoresis showed that beta-casein exists as a complex of five or six proteins of identical N-terminal sequence but differing pI. Electrospray mass spectrometry indicated that the beta-caseins also are multiply phosphorylated with masses between 32300 and 32600 Da. A subfamily with mass values 1530 greater was also detected. The patterns were not affected by stage of lactation and quantitative analysis of two-dimensional gels of whole milk shows that alpha- and beta-caseins are present at a constant ratio throughout lactation. cDNA clones for the possum alpha- and beta-caseins have been isolated from an early lactation mammary cDNA library and sequenced.

A method for the separation of the beta-LG variants A, B, and C was developed using free zone capillary electrophoresis. A separation buffer consisting of 50 mM 2-(N-morpholino)ethane sulfonic acid (pH 8.0) and polyoxyethylene (20)-sorbitan monolaurate was used for the separation. Milk samples from 424 Jersey cows were phenotyped using this method, and the gene frequencies for beta-LG A, B, and C were .41, .53, and .06, respectively. These frequencies were different from those found in studies of Jersey populations in other countries, where the beta-LG B allele had a significantly higher frequency, and the beta-LG A allele a significantly lower frequency, than those of this present study. The frequency of the beta-LG C allele was intermediate to those of other studies. The concentration of beta-LG in the milk was different among the beta-LG phenotypes and was, from greatest to least: AA, AB, AC, BB, and BC.

A capillary zone electrophoresis (CZE) method to separate the peptide series val-glyn, where n is 1 to 4, has been evaluated and compared to separation by reversed-phase high-performance liquid chromatography (RP-HPLC). The method was able to quantitate peptides present a very low concentrations (down to 0.05 mM) with high reproducibility and accuracy and was capable of separating peptides differing in size by only a single glycine residue. It could also separate the peptides val-gly and leu-gly which differed in only a single side-chain methylene group. The method was fast, required small sample volumes, and proved to be superior to RP-HPLC. The suitability of the CZE method to analyze peptide uptake by dairy starter bacteria is discussed.

beta-Lactoglobulin is a whey protein that affects milk composition and product functionality and which can be present in up to eight genetic variant forms. A free zone capillary electrophoresis method has been developed to separate and identify the beta-lactoglobulin A, B and C variants. Three buffer systems [borate, 2-(N-morpholino)-ethanesulphonic acid (MES) and bis(2-hydroxyethyl)imino-tris(hydroxymethyl)methane (Bistris)] were examined over a range of pH values and with the addition of the separation buffer modifiers Tween 20 and/or ethanolamine. The most successful combination of these was 50 mM MES at pH 8.0 with the addition of 0.1% Tween 20 which clearly resolved the three variants from both each other and from the other whey proteins even though the MES buffer was acting well outside its pKa range (pH 5.3-7.3). The retention times and identification of the individual variants were verified by spiking with commercially purified beta-lactoglobulin A and B proteins and a beta-lactoglobulin AC whey. The method was then used to phenotype beta-lactoglobulin in a sample population of New Zealand Jersey cows.

The separation of the four major whey proteins by sodium dodecyl sulphate (SDS)-capillary gel electrophoresis (CGE) is described. Whilst commercially purified whey proteins could be analysed using the recommended protocol, the more complex nature of an acid whey and a reconstituted whey protein concentrate (WPC) powder necessitated considerable refinement of the CGE sample buffer. Individual whey proteins in the acid whey and WPC samples were then also separated and quantitated using capillary zone electrophoresis, polyacrylamide gel electrophoresis (PAGE) and HPLC methods and the results were compared. The values obtained for alpha-lactalbumin (alpha-Lac) and beta-lactoglobulin (beta-Lg) were consistent throughout the various methods, although size-exclusion HPLC, SDS-PAGE and SDS-CGE could not separate the two beta-Lg variants or the glycosylated form of alpha-Lac from the beta-Lg. There was considerable variation in the values for the bovine serum albumin and immunoglobulin determined by the different methods and it was concluded that none of the methods could satisfactorily quantitate all four whey proteins.

The desorption of Trichoderma reesei cellulase from Avicel by a wide range of desorbents was measured. Emphasis was placed on desorption at alkaline pH. A maximum desorption of 65-68% Avicelase activity was achieved by contact with NaOH, pH 10.0, at 40 degrees C for 5 min in the presence of 0.005% Triton X-100 or Tween 80. The design of a suitable desorption process using these conditions is discussed. Glycerol was also effective as a desorbent either alone or in combination with alkali and detergent. However, relatively high concentrations of glycerol were needed and the maximum desorption achieved, 68%, was not significantly greater than that with only alkali and detergent.

The size-distribution of liver glycogen was shown to be distinctly affected by the anti-inflammatory drugs salicylate and indomethacin. By measurement of the incorporation of radioactive glucose into glycogen, salicylate was shown to have a depressing effect on overall liver glycogen metabolism. These effects appear to arise from the stabilizing of the lysosome by the drugs. The incorporation, via liposomes, of purified anti-1,4-alpha-glucosidase activity and in the content of high-molecular-weight glycogen. These changes are increased by prolonged liposomal antibody treatment and suggest that a possible feedback control mechanism operates in the incorporation of glycogen into lysosomes. These experiments may be useful as a model of glycogen turnover and its failure in glycogenosis type II (Pompe's disease).