Olive oil phenolics: Where do we stand? Where should we go?

The formulation of an antioxidant/atherosclerosis hypothesis stimulated experimental and epidemiological studies on the possible role of micronutrients, including olive oil phenolics, in the protection from cardiovascular disease observed in the Mediterranean area. This article prospectively summarises our current knowledge of olive phenolics, underscore our gaps in information, and brings forward areas that are, as yet, to be explored.     

Corneal staining: Do we really understand what we are seeing?

Sodium fluorescein (‘fluorescein’) is widely utilised for the evaluation of ocular surface integrity. It is particularly well suited to this task due to its fluorescent properties and its high visibility at low concentrations. Ocular surface fluorescence observed clinically is affected by a number of factors including concentration of fluorescein, thickness of the fluorescein layer, the wavelength of the exciting light source and whether or not a barrier filter is used as part of the viewing system. In this review we have attempted to provide a critical evaluation of the published literature relating to three potential cellular mechanisms involved in corneal surface fluorescence: surface pooling, uptake by cells and ingress around cells. Despite the widespread adoption of use of fluorescein for the assessment of the ocular surface, we contend that the clinical understanding and interpretation of corneal surface fluorescence is based upon assumption, extrapolation and clinical intuition rather than solid evidence-based science underpinning the basic causative mechanisms of this phenomenon. Further research in order to understand the basic interactions between the ocular surface cells and fluorescein should be made a priority in the fields of optometry and ophthalmology.     

Non-cigarette tobacco products: what have we learnt and where are we headed?

A wide variety of non-cigarette forms of tobacco and nicotine exist, and their use varies regionally and globally. Smoked forms of tobacco such as cigars, bidis, kreteks and waterpipes have high popularity and are often perceived erroneously as less hazardous than cigarettes, when in fact their health burden is similar. Smokeless tobacco products vary widely around the world in form and the health hazards they present, with some clearly toxic forms (eg, in South Asia) and some forms with far fewer hazards (eg, in Sweden). Nicotine delivery systems not directly reliant on tobacco are also emerging (eg, electronic nicotine delivery systems). The presence of such products presents challenges and opportunities for public health. Future regulatory actions such as expansion of smoke-free environments, product health warnings and taxation may serve to increase or decrease the use of non-cigarette forms of tobacco. These regulations may also bring about changes in non-cigarette tobacco products themselves that could impact public health by affecting attractiveness and/or toxicity.     

Can plant phenolic compounds reduce Fusarium growth and mycotoxin production in cereals?

ABSTRACT

To assess the in vitro activity of three phenolic acids (ferulic acid, p-hydroxybenzoic acid, vanillic acid) and two flavonols (quercetin, rutin) on mycelial growth and mycotoxin accumulation of Fusarium graminearum (FG), F. langsethiae (FL) and F. poae (FP), two different approaches were chosen. First, grains from oat varieties were inoculated with a suspension of three FL isolates to determine the influence of phenolic compounds on the accumulation of mycotoxins. The oat variety Zorro showed a tendency for lower accumulation of T-2/HT-2, diacetoxyscirpenol and neosolaniol. Second, a mycelium growth assay was conducted to follow FG, FL and FP growth on cereal based media supplemented with phenolic compounds. Increasing concentrations of ferulic acid substantially inhibited growth of FG and FL, while FP growth was reduced to 57%. In contrast, p-hydroxybenzoic acid, vanillic acid, quercetin, and rutin slightly stimulated mycelium growth. Results about mycotoxin production in cereal based media were less conclusive.     

In vitro digestibility of phenolic compounds from edible fruits: could it be explained by chemometrics?

The health benefits of phenolic compounds depend on the ingested amount, molecular diversity and gastrointestinal digestibility. The phenolic profile of eight fruits (blackberry, blueberry, strawberry, raspberry, mulberry, pomegranate, green and red globe grapes) was chemometrically associated with their in vitro digestibility (oral, gastric, intestinal). Extractable phenols, flavonoids and anthocyanins strongly correlated with each other (r ≥ 0.84), proanthocyanidins with anthocyanins (r = 0.62) and hydrolysable phenols with both extractable phenols (r = 0.45) and proanthocyanidins (r = ?0.54). Two principal components explained 93% of the variance [61% (free‐phenols), 32% (bounded‐phenols)], and four clusters were confirmed by hierarchical analysis, based in their phenolic richness (CLT 1‐4: low to high) and molecular diversity. In vitro digestibility of extractable phenols and flavonoids was blackberry (CLT‐4)> raspberry (CLT‐2)> red grape (CLT‐1) related to their phenolic richness (r ≥ 0.96; P < 0.001), but anthocyanins’ digestibility was pH‐dependent. Chemometrics is useful to predict the in vitro digestibility of phenolic compounds in the assayed fruits.     

Iron binding characteristics of phenolic compounds: some tentative structure–activity relations

Two mechanisms are commonly proposed to explain the antioxidant role of phenolic compounds; these are metal chelation and/or free radical scavenging. However, the structural requirements for each may not be the same. This paper describes the determination of iron-binding efficiencies (in vitro) for a series of pure phenolics of known structure [gallic acid, tannic acid, catechin, epicatechin (EC), epicatechingallate (ECG), epigallocatechin (EGC), epigallocatechingallate (EGCG) and quercetin] and of tea beverages of known flavonoid composition. Iron-binding efficiency was measured as catechin equivalents or tannic acid equivalents using the two wavelength assay. High catechin equivalents require the presence of a 3′,4′ dihydroxy (catechol ) group on flavanoid ring B. In contrast, the presence of a 3′,4′,5′-trihydroxy (galloyl) group of ring B (epigallocatechin) or ring C (epicatechin gallate) was associated with reduced Fe-binding. The extent of Fe-binding was also found to be lower for quercetin than catechin, which is probably due to the presence of conjugation extending from the C4-keto group, via C2-3 to the 3′-OH group (rings B and C). For the polyphenols examined, catechin equivalents were inversely correlated with tannic acid equivalents and with antioxidant activity of flavonoids, as measured by the TEAC assay. Requirements for efficient iron-binding are discussed.     

Sustainable sunflower processing — II. Recovery of phenolic compounds as a by-product of sunflower protein extraction

A process for the recovery of polyphenol-rich extracts from the production of light colored sunflower protein isolates by combining mild-acidic protein extraction with adsorptive removal of phenolic compounds has been developed. In preliminary trials, different solvents were examined to evaluate their suitability for an exhaustive desorption of the polyphenols from a food-grade adsorbent resin. For this purpose, the elution behavior of different solvent–water mixtures was assessed at identical temperatures and flow rates. Besides methanol and ethanol, 2-propanol showed the most promising results. Furthermore, a D-optimal experimental design was applied to further optimize desorption of phenolic compounds from the adsorbent resin. Optimal conditions were deduced from experiments performed at different temperatures and flow rates and with varying solvent concentrations also evaluating the phenolic compound profiles at each step of the recovery process. Finally, antioxidant capacity of the polyphenol-enriched eluates was determined using the Folin–Ciocalteu and FRAP (ferric ion reducing antioxidant power) assays with ascorbic acid and trolox, respectively, as reference compounds.Industrial relevanceProtection against oxidation is a major challenge for the retention of sensory quality of processed foods. Since consumers generally reject artificial food additives, their substitution by natural counterparts is of increasing relevance. Phenolic compounds of different plant sources such as grape and apple pomace are known as potent antioxidants and radical scavengers. Consequently, to achieve sustainability of sunflower processing and complete utilization of by-products arising from sunflower oil production, polyphenols co-extracted during sunflower protein recovery from the expeller were recovered by adsorption technology. After their exhaustive desorption from the adsorber resin, the polyphenol enriched eluate may be used as a natural antioxidant due to its high antioxidant activity as demonstrated by this study.     

Agroterrorism: where are we in the ongoing war on terrorism?

The U.S. agricultural infrastructure is one of the most productive and efficient food-producing systems in the world. Many of the characteristics that contribute to its high productivity and efficiency also make this infrastructure extremely vulnerable to a terrorist attack by a biological weapon. Several experts have repeatedly stated that taking advantage of these vulnerabilities would not require a significant undertaking and that the nation's agricultural infrastructure remains highly vulnerable. As a result of continuing criticism, many initiatives at all levels of government and within the private sector have been undertaken to improve our ability to detect and respond to an agroterrorist attack. However, outbreaks, such as the 1999 West Nile outbreak, the 2001 anthrax attacks, the 2003 monkeypox outbreak, and the 2004 Escherichia coli O157:H7 outbreak, have demonstrated the need for improvements in the areas of communication, emergency response and surveillance efforts, and education for all levels of government, the agricultural community, and the private sector. We recommend establishing an interdisciplinary advisory group that consists of experts from public health, human health, and animal health communities to prioritize improvement efforts in these areas. The primary objective of this group would include establishing communication, surveillance, and education benchmarks to determine current weaknesses in preparedness and activities designed to mitigate weaknesses. We also recommend broader utilization of current food and agricultural preparedness guidelines, such as those developed by the U.S. Department of Agriculture and the U.S. Food and Drug Administration.     

Can phytochemical antioxidant rich foods act as anti-cancer agents?

The search for therapeutic anticancer agents from plant-based foods became the work of numerous researchers when epidemiological studies showed a relationship between the low incidence of cancer and the intake of plant-based foods. These researchers were especially interested in plant-based foods with high antioxidant capacities because of the important role antioxidants have been postulated to play in the prevention and treatment of certain cancers. However, at present there is no conclusive proof that high antioxidant activity is a good indicator of high anticancer activity. This poses a challenge for researchers to directly test this hypothesis and resolve the debate. This review summarized the data on both sides of the debate.     

Functional implications of bound phenolic compounds and phenolics–food interaction: A review

Sizeable scientific evidence indicates the health benefits related to phenolic compounds and dietary fiber. Various phenolic compounds-rich foods or ingredients are also rich in dietary fiber, and these two health components may interrelate via noncovalent (reversible) and covalent (mostly irreversible) interactions. Notwithstanding, these interactions are responsible for the carrier effect ascribed to fiber toward the digestive system and can modulate the bioaccessibility of phenolics, thus shaping health-promoting effects in vivo. On this basis, the present review focuses on the nature, occurrence, and implications of the interactions between phenolics and food components. Covalent and noncovalent interactions are presented, their occurrence discussed, and the effect of food processing introduced. Once reaching the large intestine, fiber-bound phenolics undergo an intense transformation by the microbial community therein, encompassing reactions such as deglycosylation, dehydroxylation, α- and β-oxidation, dehydrogenation, demethylation, decarboxylation, C-ring fission, and cleavage to lower molecular weight phenolics. Comparatively less information is still available on the consequences on gut microbiota. So far, the very most of the information on the ability of bound phenolics to modulate gut microbiota relates to in vitro models and single strains in culture medium. Despite offering promising information, such models provide limited information about the effect on gut microbes, and future research is deemed in this field.     

Plant phytochemicals as new potential drugs for immune disorders and cancer therapy: really a promising path?

Plant phytochemicals represent an exciting opportunity to maintain best health conditions through a balanced and properly administered daily nutrition or dietary supplement and have often been considered a good option for obtaining a few promising, expensive new drugs from plants. Several polyphenolic compounds, such as resveratrol, tea catechins and flavonoids, which are commonly found in vegetables, fruits and plant-derived juices or beverages, exert well-evidenced cardioprotective, neuroprotective, chemopreventive and anti-inflammatory properties, but, nevertheless, further clinical and epidemiological research is required. Most of these botanical byproducts are produced as noxious components by plants, in order to prevent pathogen colonization, insect-mediated damage and also to discourage animals from eating them. An evolutionary theory of stress adaptation would explain how these toxic substances from nature act as protective molecules. A future challenge to achieve a rather complete understanding of these chemical phenol derivatives for human health should deal with the complexity of cellular signalling networks, the epigenetic machinery endowment of the cell and the nonlinear relationship between dose and effectiveness.     

Can phenolic compounds be used for the protection of corn from fungal invasion and mycotoxin contamination during storage?

The effect of natural phenolic compounds (vanillic and caffeic acid) and water activity (a(w)) on the growth and mycotoxin production on corn by Fusarium and Aspergillus isolates was investigated. Large differences were observed in the response of the Fusarium and Aspergillus isolates to the phenolic compounds, mostly determined by their genus. Generally for both F. verticillioides and F. proliferatum, an increase in concentration of either caffeic or vanillic acid resulted in a decrease in the colony growth rate and increase in the lag phase duration. Growth of the Fusarium isolates was not completely inhibited at the highest a(w) value evaluated of 0.967, with complete inhibition only being observed at combinations of high phenolic acid concentrations (> or =2000 microg g(-1)) and low a(w) values (0.948). Within the experimental limits investigated, growth of the Aspergillus species was not affected by the phenolic compounds. Application of the phenolic compounds significantly reduced fumonisin B(1) and aflatoxin B(1) production. Although the effects noted in artificial media appear to be carried over to corn, rather high concentrations are required to observe similar effects on corn and to completely inhibit growth where possible. This implies the occurrence of interactions of the phenolic compounds with some matrix components which may reduce their overall effectiveness.     

Use of air classification technology as green process to produce functional barley flours naturally enriched of alkylresorcinols, β-glucans and phenolic compounds

In the last years, food researchers and food industries focused their attention on the content of bioactive compounds in food and in the re-use of food wastes. Sometimes, these goals can be obtained at the same time by the use of sustainable technologies. Cereal milling processes generate large amounts of cereal by-products that usually were used in zootechny or they represented the raw material for the extraction of bioactive compounds using solvents or expensive processes. The aim of this study is to propose air classification as a green technology for the production of barley flours using the whole grain and avoiding by-products production. Three non-waxy and one waxy barley cultivars were air-classified.The results demonstrate that barley coarse fraction showed high amounts of β-glucans (until two-fold higher than whole meal). The same fraction showed concentration of free and bound phenolic compounds that were 1.2–1.3 times higher than whole meal. This improvement was confirmed by the antioxidant activity of barley fraction; in fact, both DPPH and ABTS tests reported the highest values when coarse fraction was analyzed. Moreover, as far as we are concerned, alkylresorcinols were determined in barley air classified fractions for the first time. As reported for phenolic compounds, their content increased 1.2–1.4 times in coarse fraction compared to whole meal.In conclusion, air classification allows the production of two fractions from whole grain. Coarse fraction resulted naturally enriched in bioactive compounds.     

Ovarian gonadotrophin surge-attenuating factor (GnSAF): where are we after 20 years of research?

When gonadotrophin-stimulated IVF methods were being developed in the 1970s and 1980s, understanding of the physiology of FSH improved. In addition to its classic actions of stimulating aromatase activity and oestradiol secretion by ovarian granulosa cells, FSH was found to stimulate the ovarian production of an uncharacterized hormone known by its specific effect of reducing pituitary responsiveness to GnRH. This hormone has been called gonadotrophin surge-attenuating factor (GnSAF), gonadotropin surge-inhibiting factor (GnSIF), various abbreviations (GnSAF/IF, GnSIF/AF) and also attenuin. Although first described in the 1980s, GnSAF has still not been convincingly characterized and no published candidate amino acid sequences conclusively relate to GnSAF bioactivity. On the basis of superovulation studies and in vitro experimentation into the roles of steroids in regulating LH, GnRH and GnRH self-priming, the concept that GnSAF has a role in the regulation of LH secretion, the timing of the LH surge and the prevention of premature luteinization developed. For at least a decade, understanding of the specific GnSAF effects of reducing pituitary sensitivity to GnRH, especially GnRH self-priming and antagonizing the stimulatory effects of oestradiol on GnRH-induced LH secretion, supported this concept. However, improved knowledge of the changes in GnSAF bioactivity in follicular fluid and serum in women requires revision of this concept. The present authors propose that the main role of GnSAF is probably the negative regulation of pulsatile LH secretion, mainly during the first half of the follicular phase, indicating a critical role in the regulation of folliculogenesis and oestradiol secretion.     

Calf management and welfare in the Canadian and US dairy industries: Where do we go from here?

The objective of this narrative review was to compare the results of the 2015 Canadian National Dairy Study and the 2014 US National Animal Health Monitoring System (NAHMS) Dairy Studies, with a specific focus on calf management and welfare, and to interpret these findings within more recent calf health research to describe where we need to go next in the North American dairy industry. Situating results of periodic national studies within the context of past and recent research provides an opportunity to gauge adoption of recommendations and best practices and to help identify persistent and new challenges that the industry is wrestling with to help guide research needs. Through this review of the 2 national studies, we identified several strengths of the Canadian and US dairy industries. In each area of calf health management, improvements relative to previous NAHMS studies and the published literature have been found in the level of mortality, amount of colostrum fed, housing, and the number of producers using pain control for disbudding and dehorning. There were, however, some areas that present clear opportunities for improvement. Specifically, although mortality levels have improved, a large number of calves die at birth, within the first 48 h of life, and during the preweaning period. To improve the health of calves in early life, producers could look at feeding high-quality colostrum at 10% of body weight in the first feeding, as well as feeding a larger amount of milk during the preweaning period. The barriers to making these management changes and improving overall calf health need to be identified in future studies. The majority of preweaning calves in Canada and the United States are housed in individual housing. This represents a clear opportunity for improvement because recent research has identified the positive aspects of group housing. Finally, with respect to pain control, improvements are needed (particularly in the United States) to ensure that pain management is provided when disbudding and dehorning calves. Although the science is clear on pain management, discussions with producers are needed to identify reasons for the lack of uptake.