William Jeffrey Hurst- PhD
- Professor (Associate) at University of New Mexico
William Jeffrey Hurst
- PhD
- Professor (Associate) at University of New Mexico
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122
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Introduction
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Publications
Publications (122)
HPLC profiling of phenolics in grape seed extracts revealed a prominent peak of an unknown substance with concentrations up to 5.3%. Spectroscopic data allowed the identification of the compound 1 as 1-(3′,4′-dihydroxyphenyl)-3-(2″,4″,6″-trihydroxyphenyl)-propan-2-ol. 1 is known to be produced from catechin and epicatechin through anaerobic bacteri...
When man evolved from a hunter gatherer they began to grow crops for food. They found that selection of crops improved the quality and yield of foods for food production. The selection of seeds led to the evolution of new crops that are more productive and nutritious crops.
Documentary and archaeological evidence suggests that populations throughout North and South America created and drank caffeinated concoctions. Made of leaves, stems or seeds of various plants, these drinks had economic and ritual importance, and typically medicinal and cosmological importance as well. In this paper, we discuss the proliferation of...
The U.S. Pharmacopeia has led an international collaborative project to develop a tool-box of screening methods and reference standards for the detection of milk powder adulteration. During the development of adulterated milk powder reference standards, blending methods used to combine melamine and milk had unanticipated strong effects on the NIR s...
Adding to a thus far limited number of archaeological identifications of cacao residues in pottery in ancient Mesoamerica, this study presents the first such evidence from the southern Guatemalan piedmont in the Southern Maya Region. To save on cost, an original sample of 150 vessels from the site of Chocolá was reduced to 43 using semi-quantitativ...
Proanthocyanidins (PACs) are naturally occurring flavonoids possessing health beneficial bioactivities. Their quantification often utilizes the 4-dimethylaminocinamaldehyde (DMAC) spectrophotometric assay with the assumption that molar absorption coefficients (MACs) are similar across the various PAC species. To assess the validity of this assumpti...
s document is an introduction to the issue focusing on ISCHOM.
Significance
This article presents the results of a large-scale National Science Foundation-funded study of organic residues from archaeological sites in the US Southwest/Mexican Northwest. It reveals widespread use of two different caffeinated plants, cacao and holly, as the basis for drinks used in communal, ritual gatherings. This is the largest...
The use of cacao in ancient Mesoamerica is widely known. This paper contributes to better characterize the early stages of its use and cultivation in the Pacific Piedmont of Guatemala. The detection of Cacao in archaeological ceramics, is usually done through sophisticated and expensive analysis, such as the high-performance liquid chromatography (...
The invention provides methods for isolating and enhancing the levels of jasmonates from cacao plant sources. In a preferred embodiment, jasmonic acid and 12-hydroxy jasmonate sulfate are detected in various cocoa products, and the levels of these compounds can be manipulated to increase the beneficial health effects of a food product made with the...
Cocoa is derived from the seeds of the fruit of the Theobroma cacao tree and has a complex chemical composition. A number of compounds found in cocoa have documented physiological effects. In particular, a significant body of literature supports the role of cocoa polyphenols in maintaining cardiovascular health. Future studies on cocoa should be ai...
Although it has been happening to some degree for centuries, food adulteration is increasingly becoming a worldwide epidemic, as evidenced by the melamine scandal of 2008 and recent meat and fish substitutions at major food chains. Analysts are applying more sophisticated chromatographic, spectroscopic, and enzymatic analytical techniques to monito...
Background
Alzheimer’s disease (AD) is the most common age-related neurodegenerative disorder, characterized by pathological aggregates of amyloid peptide-β (Aβ) and tau protein. Currently available therapies mediate AD symptoms without modifying disease progression. Polyphenol-rich diets are reported to reduce the risk for AD.
Objective
In the pr...
As dates of earliest use of Theobroma cacao in ancient Mesoamerica are established, interest is shifting to how cacao was used. One approach is to consider combinations of ingredients— the recipes for ancient cacao use. Beverages made from cacao seeds and maize have
a long history in Mesoamerica. We began testing the hypothesis that there is qualit...
Proanthocyandins (PACs) , polymeric flavan- 3- ols, are recognized for their bioactivities including: bacterial anti- adhesion, biofilm inhibition, cytotoxicity to cancer cells, and anti- inflammatory activities. Quantification of PACs, by both HPLC and spectrophotometric methods, has been problematic due to the lack of readily available pure stds....
Previous methods for the quantitative analysis of phytosterols have usually used GC-MS and require elaborate sample preparation including chemical derivatization. Other common methods such as HPLC with absorbance detection do not provide information regarding the identity of the analytes. To address the need for an assay that utilizes mass selectiv...
The use of cacao, in its familiar food and beverage form, dates back about 3,800 years. By the time of the discovery of America by Europeans, the Aztecs and Mayans had developed methods for drying, roasting and grinding cacao beans for use in beverages and foods. Today, the same processes are used, but have been adapted to modern machinery. The cur...
Chemical analyses of organic residues in fragments of pottery from the large site of Cahokia and surrounding smaller sites in Illinois reveal theobromine, caffeine, and ursolic acid, biomarkers for species of Ilex (holly) used to prepare the ritually important Black Drink. As recorded during the historic period, men consumed Black Drink in portions...
Flavanols such as epicatechin occurring in the seeds of Theobroma cacao (cocoa beans) are associated with beneficial health effects. When cocoa seed-based products are ingested, epicatechin is absorbed and converted into epicatechin glucuronide, epicatechin sulfates, and epicatechin methylsulfates, which can be found in human serum. A UHPLC-MS-MS m...
ABSTRACT: This paper reports a systematic study of the level of flavan-3-ol monomers during typical processing steps as cacao beans are dried, fermented and roasted and the results of Dutch-processing. Methods have been used that resolve the stereoisomers of epicatechin and catechin. In beans harvested from unripe and ripe cacao pods, we find only...
This study determined the in vitro inhibitory effects of cocoa extracts and procyanidins against pancreatic α-amylase (PA), pancreatic lipase (PL), and secreted phospholipase A(2) (PLA(2)) and characterized the kinetics of such inhibition. Lavado, regular, and Dutch-processed cocoa extracts as well as cocoa procyanidins (degree of polymerization (D...
Numerous popular media sources have developed lists of "Super Foods" and, more recently, "Super Fruits". Such distinctions often are based on the antioxidant capacity and content of naturally occurring compounds such as polyphenols within those whole fruits or juices of the fruit which may be linked to potential health benefits. Cocoa powder and ch...
Low molecular weight flavan-3-ols are thought to be responsible, in part, for the cardiovascular benefits associated with cocoa powder and dark chocolate. The levels of epicatechin and catechin were determined in raw and conventionally fermented cacao beans and during conventional processing, which included drying, roasting, and Dutch (alkali) proc...
A simple, specific, high-throughput colorimetric method based on the reaction of 4-dimethylaminocinnamaldehyde (DMAC) with flavan-3-ols was developed to determine total procyanidins in selected cacao-based products. Extracts of defatted samples were dispensed into a 96-well plate and reacted with DMAC. The absorbance of the reaction products was me...
Several recent reports have been published indicating that the antioxidant activity of olive oil and tea leaves is not stable over product shelf lives of about one year. We have measured the antioxidant activity, total polyphenols, flavan-3-ols monomers, and procyanidin levels in milk and dark chocolate, in cocoa powder, and in cocoa beans. Results...
This report describes the characterization of a series of commercially available procyanidin standards ranging from dimers DP = 2 to decamers DP = 10 for the determination of procyanidins from cocoa and chocolate. Using a combination of HPLC with fluorescence detection and MALDI-TOF mass spectrometry, the purity of each standard was determined and...
Little is known about the effects of common cooking processes on cocoa flavanols. Antioxidant activity, total polyphenols (TP), flavanol monomers, and procyanidin oligomers were determined in chocolate frosting, a hot cocoa drink, chocolate cookies, and chocolate cake made with natural cocoa powder. Recoveries of antioxidant activity, TP, flavanol...
A survey of a broad range of chocolate- and cocoa-containing products marketed in the United States was conducted to provide a more detailed analysis of flavan-3-ol monomers, oligomers, and polymers, which can be grouped into a class of compounds called procyanidins. Samples consisted of the three or four top-selling products within the following s...
Oxidative stress enhances pathological processes contributing to cancer, cardiovascular disease, and neurodegenerative diseases, and dietary antioxidants may counteract these deleterious processes. Because rapid methods to evaluate and compare food products for antioxidant benefits are needed, a new assay based on liquid chromatography-mass spectro...
This chapter discusses the use and representation of cacao in Copan, Honduras, during the Classic period. Cacao in Copan, Honduras, played a significant role in rituals. In the mountains of the Copan Acropolis, Early Classic queens and kings were entombed with several comestibles containing cacao. Although cacao iconography has not been found recor...
Although the use of cacao by the Mesoamerican people has been documented since the early Colonial period, archaeologists have been hindered from discovering the breadth of its use in rituals and in the daily life of the Mesoamericans because of its rare recovery from archaeological context. In 1989, the author of this chapter determined chemically...
Chemical analyses of organic residues in fragments of ceramic vessels from Pueblo Bonito in Chaco Canyon, New Mexico, reveal theobromine, a biomarker for cacao. With an estimated 800 rooms, Pueblo Bonito is the largest archaeological site in Chaco Canyon and was the center of a large number of interconnected towns and villages spread over northwest...
Dietary resveratrol (3,4′,5-trihydroxystilbene) has been implicated in the health benefits associated with grapes and red wine, more specifically with potential benefits for metabolic syndrome, energy use, and increased endurance. Levels of trans-resveratrol and its glucoside, trans-piceid, were determined in 19 top selling commercially available c...
Cocoa is a food ingredient that is important for the contribution of flavor to foods but is also associated with potential health benefits. The chemistry thought to be responsible for its cardiovascular health benefits is the flavanol (flavan-3-ol) antioxidants. Evidence from the literature indicates that natural cocoas are high in flavanols, but w...
Chemical analyses of residues extracted from pottery vessels from Puerto Escondido in what is now Honduras show that cacao beverages were being made there before 1000 B.C., extending the confirmed use of cacao back at least 500 years. The famous chocolate beverage served on special occasions in later times in Mesoamerica, especially by elites, was...
Archaeological investigations at a mortuary cave in southern Belize recovered a bowl containing five cacao ( chocolate) seeds dating to the fourth or fifth century AD. The context of both the burial and the cacao informs our understanding of the role of chocolate as a ritual substance in pre-Columbian Mesoamerica. Most archaeologists think of cacao...
This manuscript summarizes HPLC methodologies used for the determination of selected biogenic amines in foods. It includes methods of extraction of these compounds, methods used to eliminate potential interferring compounds and the HPLC determinant step.
A rapid method for the determination of the pentapeptide, met enkephalin, in samples of rat retina is described. The method uses ultrafiltration as a sample preparation followed by free solution capillary electrophoresis with detection at 210 nm. The method is rapid with an analysis time of less than 10 minutes.
High performance liquid chromatography (HPLC) has been applied to the characterization and quantitation of the simple sugars (glucose, fructose, sucrose, maltose and lactose) present in a broad variety of food items, both fresh and processed. Following one of two simple extraction procedures, HPLC analysis is complete in 15 min. Recovery studies in...
High Performance Liquid Chromatography (HPLC) has been applied to the characterization and quantitation of tartrazine (FD&C Yellow 5) in a variety of food products. After extraction, HPLC analysis is complete within 10 min. Recovery studies of 93–97% indicate method accuracy from three food matrices. The method exhibits a %Cv of less than 5% for st...
In the United States, commercially available foods, including cocoa and chocolate, are being marketed with statements referring to the level of antioxidant activity and polyphenols. For cocoa-containing foods, there has been no comprehensive survey of the content of these and other chemistries. A survey of cocoa and chocolate-containing products ma...
A reversed phased HPLC method with photodiode array detection was used to monitor the stability of opioid growth factor (OGF; [Met]‐enkephalin) in sterile saline for 1, 2, and 8 weeks, and stored at −17°C, 4°C, and 23°C. Samples maintained at −17°C had 97% of the initial OGF concentration after 2 months, whereas those stored at 4°C had 94% of the o...
SCN 2.2 cultures were stably transfected with luciferase reporter constructs driven by Ca(2+)/cAMP response element, E-box, or vasoactive intestinal peptide promoter to probe the circadian properties of this clock cell line. SCN 2.2 reporter lines displayed approximately 24-h rhythms of transcriptional activation after serum-shock. Serum-shocked cu...
The Maya archaeological site at Colha in northern Belize, Central America, has yielded several spouted ceramic vessels that contain residues from the preparation of food and beverages. Here we analyse dry residue samples by using high-performance liquid chromatography coupled to atmospheric-pressure chemical-ionization mass spectrometry, and show t...
Spouted vessels are diagnostic forms of Middle Preclassic (1000-400 B.C.) and Late Preclassic (400 B.C.-A.D. 250) Maya ceramic assemblages. Mayanists have traditionally called these vessels "chocolate pots," but until recently there has been little direct evidence to support this interpretation. In fact, few studies have focused on the role these s...
The Maya archaeological site at Colha in northern Belize, Central America, has yielded several spouted ceramic vessels that contain residues from the preparation of food and beverages. Here we analyse dry residue samples by using high-performance liquid chromatography coupled to atmospheric-pressure chemical-ionization mass spectrometry, and show t...
Placental transfer of the pentapeptide [Met5]-enkephalin, known to function as a growth regulating factor and neuromodulatory agent, was studied in pregnant Sprague-Dawley rats. Using separation by reversed phase high-performance liquid chromatography, and analysis by derivative spectroscopy, [Met5]-enkephalin was detected in 20-day-old fetal tissu...
The fatty acids from a series of milk-chocolate-based confectionery samples were analyzed as methyl esters by GC to determine the presence and amount of conjugated linoleic acid (CLA). A single peak corresponding to the 9-cis,11-trans isomer and ranging from less than 0.1% to nearly 0.2% of the total fatty acids, corresponding to up to 0.3 mg per g...
HPLC with UV and electrochemical detection has routinely been employed for the determination of the opioid antagonist naltrexone in serum. Sample preparation protocols range from liquid/liquid to solid phase extraction. The sample preparation described in this communication uses ultrafiltration as the mode of sample preparation prior to HPLC analys...
A HPLC method is described for the analysis of ochratoxin A at low-ppb levels in samples of artificially contaminated cocoa beans. The samples are extracted in a mixture of methanol-water containing ascorbic acid, adjusted to pH and evaporated to dryness. Samples in this state are then placed onto a Benchmate sample preparation workstation where C1...
Extracts of brain and heart from rats at birth and postnatal days 2 and 10 were evaluated for naltrexone following maternal injection of 50 mg/kg opioid antagonist throughout gestation. Samples were prepared by ultrafiltration, lyophilized, reconstituted in mobile phase, and separated by reversed-phase high performance liquid chromatography with ul...
In its early days, laboratory automation was thought by some to provide a panacea for the analytical laboratory. It was not uncommon to hear about 24-hour-a-day operations, no coffee breaks, and increased productivity, and while much of this is true, it is necessary to balance the excitement of laboratory automation with its place in the laboratory...
Extracts of fetal (20 days gestation) brain, heart, and liver were evaluated for naltrexone in rats 1 hour following maternal injection of 50 mg/kg opioid antagonist; adult plasma from the pregnant rats was analyzed. Samples were prepared by ultrafiltration, lyophilized, reconstituted in mobile phase, and separated by reversed phase high-performanc...
Extracts of adult corneal epithelium, and developing and adult cerebellum, aorta, and heart, from rats were evaluated for [Met5]-enkephalin. Samples were prepared by ultrafiltration and solid phase extraction with a C-18 Sep-pak, separated by reversed phase high-performance liquid chromatography, and analyzed by radioimmunoassay (RIA). This qualita...
The neuropeptides present challenges to the scientist interested in their analysis. These compounds while structurally similar have different functions. These are a series of peptides synthesized within three systems: proopiomelanocortin, proenkephalin, prodynorphin. High Performance Liquid Chromatography (HPLC) and Capillary Electrophoresis (CE) a...
The endogenous opioid peptide [Met5]-enkephalin is a tonically active opioid growth factor (OGF) with an inhibitory action on DNA synthesis in the developing rat retina. In this study, the ontogeny of the spatial and temporal expression of OGF and its binding activity was examined. OGF-like immunoreactivity was detected in the retina at gestation d...
High Performance Liquid Chromatography(HPLC) and Capillary Electrophoresis (CE) are valuable analytical techniques for the determination of neuropeptides in biological fluids. A crucial aspect of HPLC and CE analyses is the preparation of samples. This review outlines sample preparation protocols for HPLC and CE methods that have been used for this...
A capillary electrophoretic technique was developed to monitor patterns of hemoglobin production in young calves subjected to multiple phlebotomies. The method is similar to one previously described for the determination of human hemoglobin variants in whole blood using isoelectric focusing. After a single collection of one-half the circulating blo...
Specific guidelines for the optimal collection of blood from calves maintained as donors do not exist. This investigation was conducted to document erythrocytic changes in calves subjected to controlled blood loss. Two groups of Holstein calves ranging in age from 2 to 5 months were compared. Six animals were designated controls and six were subjec...
An HPLC/Thermospray MS method is described for the determination of aflatoxins B1, B2, G1 and G2 in peanut extracts. Samples are extracted and prepared for analysis using an SPE method. The final determination utilizes reversed phase HPLC with a thermospray MS detector. The use of the MS allowed for unequivocal identification of aflatoxins in the e...
Results of chemical analyses on residues collected from ceramic vessels found in an Early Classic period Maya tomb revealed that certain of the residues contained theobromine and caffeine, a clear indication that the corresponding vessels once contained cacao in some form. One of the vessels yielding cacao residues is decorated with hieroglyphs, tw...
Samples of a dry residue collected from the interiors of ceramic vessels at the Maya site of Rio Azul in northeastern Guatemala were analyzed by a variety of high-performance liquid chromatographic techniques. Archeologists at the site had strong indications that the vessels contained cocoa. Since the literature indicated that cocoa would tend to b...
Topical application of tincture of iodine (I) was found to be effective in blocking the thyroid uptake of orally administered 131I in humans. Abdominal skin application of tincture of I resulted in an approximately 82% reduction in the uptake of 131I by the thyroid gland. The effectiveness varied among individuals and may have depended on the quant...
The Need for Robotics in the Laboratory Automation through Laboratory Unit Operations The Justification of a Laboratory Robot Applications for Laboratory Robotics Getting Started in Laboratory Robotics Programming the Robot The Future of Laboratory Robotics Glossary References Index.
Topical application of povidone I solution in dogs has been found to be effective in producing significant elevations in serum iodide concentrations within 2 h after application. Among dogs treated with this preparation 2 h before oral administration of 131I, significant thyroid blocking persisted for at least 72 h.
Topical application of povidone I solution in dogs has been found to be effective in producing significant elevations in serum iodide concentrations within 2 h after application. Among dogs treated with this preparation 2 h before oral administration of ¹³¹I, significant thyroid blocking persisted for at least 72 h.
The occurrence of antibiotic-related enterocolitis in guinea pigs restricts the use of many common antibiotics in this species. Cephaloridine, an antibiotic frequently recommended for this species, is no longer available and a substitute has yet to be explored. In this study, the potential therapeutic efficacy of cefazolin, also a first generation...
Sodium ampicillin was administered subcutaneously to 350-550 g male Dunkin Hartley guinea pigs at doses of 6, 8 and 10 mg/kg tid for 5 days. Over a period of 12 days, the lowest ampicillin dose appeared to be tolerated well. However, significant body weight reduction and mortality occurred with the two higher dosage regimens. Cecal cultures of dead...
The HPLC separation of phospholipid mixtures was investigated on silica, amino, and diol columns, using mobile phases consisting of acetonitrile, methanol, and phosphoric or trifluoroacetic acids in varying proportions. An explanation of the mechanism of these separations is given with regard to the individual column types. It is shown that substit...
Uridine has been identified as a minor component of defatted Ecuadorian cacao liquor through reverse phase HPLC of aqueous extracts. The nucleoside was identified by comparison of its behavior in a variety of mobile phases and column types as well as its absorbance ratios at 245 and 270 nm. This work has extended the previously reported methodology...
A high-performance liquid chromatographic (HPLC) method has been developed to allow the determination of patulin, penicillic acid, sterigmatocystin and zearalenone in samples of cocoa beans. When this method is combined with a method that was reported earlier for the determination of ochratoxin A [W. J. Hurst and R. A. Martin, Jr., J. Chromatogr.,...
Lecithins are a constituent of all living membranes. While lecithins are found in both plants and animals, the specific fatty acid subunits vary considerably between plants and animals. The lecithins of plant origin are chiefly derived from soy but other vegetable phospholipids are also used. World consumption of these compounds was estimated @ ove...
An HPLC method is described for the determination of oxalic acid in cocoa and milk chocolate. Samples are extracted using 6N HCI; after extraction the pH of an aliquot is adjusted to 6.0 and interfering substances are eliminated through the use of a C18 Sep-pak®. The final HPLC determination uses a monolayer reversed phase column with an ion-pairin...
Adenosine has been identified as a component of defatted chocolate liquor through HPLC of aqueous extracts. The nucleoside was identified by comparing its behavior with an authentic sample in a variety of mobile phases, column types, and absorbance ratios at 254 and 245 nm.
An HPLC method is presented which allows for the determination of cholesterol content which serves as an indicator of egg solids. The method involves the extraction of the noodles with methanolic KOH and the removal of interfering substance by the use of a commercially available Sep-pak. The final HPLC determination uses a reversed-phase column wit...
Hydrogen nuclear magnetic resonance (NMR) has been used for the determination of unsaturation in natural fats and oils with good agreement to more conventional techniques. This technical note reports an extension and modification of the technique to the determination of iodine number by NMR in a series of lubricant base stocks. This technique diffe...
A high performance liquid chromatography (HPLC) method is described for the HPLC analysis of major phospholipids in soy lecithin.
The method entails dissolving soy lecithin in chloroform prior to analysis. The HPLC determination uses a normal phase column
and a mobile phase of acetonitrilemethanol-H3PO4 with detection at 205 nm. The data presented...
HPLC utilizing paired ion chromatography with electrochemical detection is used for the determination of iodide in serum. Serum samples are prepared by precipitation of protein, centrifugation and removal of Interfering substances with a bonded phase column. The resulting sample is then analyzed. The method has successfully been applied to human se...
A method using liquid chromatography was developed for the analysis of cholesterol in milk chocolate products. The method involves saponification of the sample with methanolic KOH followed by extraction with ether. Potentially interfering components are eliminated through the use of a silica Sep-Pak cleanup step before injection. The nonaqueous rev...
The methylxanthines can be determined in foods and biological systems by the chromatographic methods of TLC, GC, and HPLC. Ultraviolet spectroscopy following a separation procedure is also still used. More recently immunoassay methods have been developed. There is no single best method; the analyst must balance the features of each assay with the f...
An HPLC method for the determination of aflatoxins is described. The aflatoxins are extracted with aqueous acetone and interfering compounds precipitated with CuCO3. After defatting, the aflatoxins are extracted into CH2Cl2 for cleanup with silica Sep-pak® which eliminates other interfering compounds. The resulting extract is then treated with TFA...
A method was developed for analysis of cholesterol in whole milk powder and commercial liquid milk products. High performance liquid chromatography employed a nonaqueous reversed phase chromatographic system. Sample preparation was by saponification with methanolic potassium hydroxide followed by extraction with ether. Potential interfering substan...
Questions
Question (1)
📷
Dear Colleague,
I hope that you will forgive this email blast. I have been approached by Taylor and Francis to develop a 3rd edition of th e book, Methods of Analysis of Functional Foods and Nutraceuticals. The previous editions have received very positive reviews and while I realize that your schedule is likely full, I hope that you might be interested in participating. A list of chapters follows. We would hope for chapters to be completed by the of 2019. Please send me your choice of chapter and I will confirm by return email as we don’t want to have multiple chapters on a single topic but should you have another topic you feel appropriate please feel free to include it. Should you have any questions or wish to discuss, I am available by email FdsFunctional@aol.com, gretnasci@aol.com or phone at 717-964-3481. I look forward to your participation and hearing from you.
Kindest personal regards,
Jeff
W Jeffrey Hurst, PhD, FAIC
Editor
