Nitrogenous compounds are considered very important in beer playing a key role in determining the quality and stability of the finished product. They include amino acids, peptides, polypeptides, proteins, nucleic acids and their degradation products. These compounds affect flavor, foam stability, haze formation, color, yeast nutrition and biological stability. The nitrogenous compounds in beer are derived mainly from barley malt and its adjuncts. Moreover the brewing process may have an important role in determining complex profile of nitrogenous compounds present in the final beer. The content of nitrogen compounds in barley depends on variety and on environmental condition in cultivation. During malting the storage proteins are degraded to amino acids and other peptides. These amino acids are important in wort to promote a good fermentation and the yeast budding. During fermentation amino acids are used in different ways by yeasts and may have many effects on the final quality of beer: in particular the amino nitrogen content influences the flavor profile of beer. The amino acids present in final beer could influence negatively the stability of product promoting haze formation. Nitrogen compounds may also play an important role influencing the foam quality and stability.
Isohumulones, which impart bitter flavor and an antibacterial property to beers, are generated from humulones (also known as alpha acids) in the hop plant (Humulus lupulus L.) during the brewing process. The three major types of isohumulones are isohumulone, isocohumulone, and isoadhumulone, all of which are structurally related. The presence of isohumulones has long been noted in beers, but their physiologic actions remained curiously obscure. However, their unexpected pleiotropic effects on glucose and lipid metabolism in the body have recently been uncovered due to the availability of isomerized hop extract (IHE) that primarily contains isohumulones. Oral administration of IHE or isohumulones to mice results in significantly decreased blood triglyceride and non-esterified free fatty acid (NEFA) levels, adipose tissue weight, and hepatic cholesterol content. Microarray analysis and quantitative real time PCR (QPCR) have indicated that IHE dose-dependently upregulated the expression of hepatic genes involved in microsomal co-oxidation and peroxisomal and mitochondrial beta-oxidation. These effects are very similar to those that follow administration of hypolipidemic drugs with the potential of activating the peroxisome proliferator-activated receptor alpha (PPAR alpha). Moreover, these effects are not seen in PPAR alpha-deficient mice. An in vitro reporter assay also indicates the activation of PPAR alpha by isohumulone and isocohumulone. These observations strongly suggest that isohumulones upregulate the expression of key genes in hepatic fatty acid oxidation, and that they ameliorate blood and hepatic lipid profiles through activation of PPAR alpha. This review focuses primarily on the effects of isohumulones on lipid metabolism through PPAR alpha activation. Several PPAR alpha independent functions are also described. These physiologic actions of isohumulones may be potentially therapeutic for the prevention of dyslipidemia in metabolic syndrome and alcoholic fatty liver disease.
Brazzaville is the capital of Congo, which is a central African country with a population of around 3 million. Alcohol consumption has been prevalent in the Brazzaville since the colonial period. Beer was introduced to the region during the 1950s. The annual consumption of alcohol is estimated to be 5.2l per person over the age of 15 years, however, a large proportion of the population are teenagers. Following a study done by our group we identified the extent of beer consumption amongst the teenage population. Factors such as non-schooling teenagers and orphans have a higher beer intake than teenagers attending school or teenagers with parents. Furthermore, those who practice religion have a significantly lower prevalence of beer consumption than those who do not. Within 15-19 year old age groups, the consumption of beer is marked and this leads to concerns about long-term health implications. In view of the high incidence of beer consumption, efforts to control drinking patterns amongst teenagers in Brazzaville would be prudent.
This chapter emphasizes the influence of the different phases of beer-making and the removal of pesticide residues. The effect of their presence on beer quality and health impact is also assessed. With this aim, based on the current data an overview of the behavior and fate of agrochemical residues during the brewing stages (malting, mashing, boiling, fermentation, and stabilization of the beer) is presented. The methodology for analysis of pesticide residues and their metabolites in raw materials, wort, and beer and the main aspects of the food safety and policy in the European Union (EU) are summarized. Depending on the stage involved and the physical-chemical properties (mainly K-OW [as log P] value, water solubility, vapor pressure and Henry's law constant) of the residue in the raw materials, differences in the final fate of the residues are observed. As a general rule, the malsters should devote special attention to the residues of hydrophobic pesticides with K-OW > 2 because they can remain on the malt. On the contrary, brewers should control residues of hydrophilic pesticides with K-OW < 4 because they can be carried over into beer. Thus, the monitoring and surveillance of pesticide residues with K-OW ranging from 2 to 4 (most of them) during the brewing process is essential to get a "healthy drink." Additionally, the influence of pesticide residues on flavor, sugar content, acidity, color or total polyphenol, and flavonoid contents has been pointed out. Therefore, the knowledge of the behavior of pesticide residues must be intended to (i) provide information on the transfers of residues from barley to malt, wort, and beer to calculate concentration or reduction factors during each process; (ii) achieve a realistic estimate of the dietary intake of pesticide residues; (iii) propose maximum residue limits (MRLs) for residues in beer when necessary; and (iv) avoid alterations in the beer quality.
Histamine is the major mediator in inflammation and allergy. Furthermore, histamine is a product of microbial metabolism especially during fermentation and spoiling of food. In this paper histamine is determined in beverages like beer before and after mechanical and chemical cleaning of tap installation in selected German bars and restaurants. After a couple of weeks without cleaning storage devices, tubes and taps, histamine increases up to 35 mg/l in a beer sample on-draft. However, this contamination can be significantly reduced after mechanical (35%) and after combined mechanical/chemical cleaning (93%), respectively. Beside histamine other biogenic amines, especially tyramine, are produced and must also be taken into account in the health risk assessment. Brewing, brewery location and hygienicity are most important factors for the Enterobacteriaceae, Lactobacillae, Pediococcus and Staphylococcus spp. derived biogenic contaminations. The specific mammalian histamine responses are also discussed. Special focus is laid on histamine-activated G protein coupled receptors (GPCR), the signal transduction induced by the gastro/intestinal (H2R) and the "new" lymphocyte (H4R) histamine receptor. It can be suggested that beer consumption is better than wine related to the prevalence of allergic reactions. Specific "beer allergies" are very rare, and only a few articles are published on this matter in the international literature.
The possible adverse effect of excessive alcohol consumption on the pancreas has been known since many years. Alcohol (ethanol) is generally consumed in the form of alcoholic beverages which contain numerous non-alcoholic compounds. On gastric acid secretion it has been convincingly demonstrated that alcohol and alcoholic beverages have markedly different effects. In this chapter we provide an overview about the effect of beer and different non-alcoholic constituents of beer on the pancreas and their possible interaction with molecular mechanisms leading to “alcoholic” pancreatitis, diabetes and pancreatic carcinoma. The present data indicate that pancreatic enzyme secretion in humans is stimulated by non-alcoholic constituents of beer which are generated by alcoholic fermentation of glucose. Natural phenolic compounds (e.g. quercetin, resveratrol) of beer have been shown to exert different effects on the pancreas in in vitro experiments, such as inhibition of pancreatic enzyme output, of pancreatic stellate cell activation and of pancreatic cancer growth. However, some compounds, for example resveratrol and catechins, showed also protective effects against oxidative stress and on experimentally induced acute pancreatitis or experimentally induced diabetes in rats. Bioavailability and efficacy of these compounds are summarized at the end of this chapter.
The principal ions in beer are the cations - calcium, magnesium, sodium, and potassium - and the anions - sulfate, nitrate, phosphate, chlorides, and silicate. The minor ions are iron, copper, zinc and manganese. Cereals, water, hops and adjuncts are the main sources of the minerals present in beer, while in yeast, industrial processing and the containers contribute to a lesser extent. The mineral content of the brewing water is particularly important for the brewing process and hence for the quality and flavor of the final beer. In beer most of the minerals originate from the barley. About 75% derives from the malt, while the remaining 25% originates from the water. The mineral composition of the malt depends on the variety, place where it was grown, atmospheric condition, growing techniques, harvesting, storage, and malting system. Hops contribute a negligible amount of the minerals in beer because of the small quantities used (200 g to produce 100 l beer). However hops make a notable contribution of nitrate to the beer wort. In many countries a part of the malt can be substituted with other cereals like maize grits and rice. These cereal matrices normally contain fewer minerals than malt and so the metal level is less than an all-malt wort. The large amount of minerals from the raw materials decreases during the brewing process due to some minerals being removed through precipitations.
In the screening test for the substance to inhibit bone resorption, we found that humulone (HU) from beer hop extracts showed a strong inhibitory activity to bone resorption. The value of IC50 (50% inhibition of bone resorption) was 5.9 nM in pit formation assay. To study the mechanism of the action of HU, we studied the biological activity of HU as a bone resorption inhibitor with reference to prostaglandin biosynthesis. We found that HU inhibited the transcription of cyclooxygenase-2 (COX-2) gene of osteoblast MC3T3-E1 with an IC50 of 30 nM. The recent reports demonstrated a close relationship between COX enzymes and angiogenesis. We showed also that HU as a COX-2 inhibitor inhibited angiogenesis in chick embryo chorioallantoic membrane (CAM).The value of ED50 was 1.5 mu g/CAM. HU enhanced effectively the differentiation-inducing action of vitamin D to myelogenous leukemia cells in the concentration of 0.5-2.5 mu M. HU also induced apoptosis (DNA fragmentation and cell death) in HL-60 cells in the concentration of 1-100 mu g/ml.
It is well known that antioxidants are able to confer some protective effect against numerous pathologies such as cardiovascular disease. Alcoholic beverages such as red wine have thus attracted particular attention in recent years due to their high concentration of antioxidants such as phenolic compounds. However, research and information on the in vitro total antioxidant capacity (TAC) of beer has been limited, despite human studies suggesting that antioxidants in such beverages are bioavailable.In this chapter, we provide comprehensive protocols for four commonly used assays for TAC: the oxygen radical absorbance capacity (ORAC), ferric reducing ability of plasma (FRAP), Trolox (R) equivalent antioxidant capacity (TEAC) and total phenols by Folin-Ciocalteu reagent (TP-FCR) assays. We have tested these assays for linearity and precision, finding excellent correlations and coefficients of variation, and furthermore applied these assays to measure the TAC of beers, red wines and orange juices. We found that the mean TAC of a number of ales (mean TEAC, 7.02 +/- 0.08 mM Trolox (R) equivalents (TE); FRAP, 2.71 +/- 0.18 mM; ORAC, 7,516 +/- 404 mu M TE; TP-FCR, 398 +/- 30 mg/l) was several-fold lower than that of red wines (mean TEAC, 36.87 +/- 1.04 mM TE; FRAP, 19.77 +/- 1.25 mM; ORAC, 27,963 +/- 908 mu M TE; TP-FCR, 1,807 +/- 94 mg/l) but comparable to that of commercially available orange juices (mean TEAC, 6.86 +/- 0.28 mM TE; FRAP, 2.88 +/- 0.94 mM; ORAC, 5,662 +/- 630 mu M TE; TP-FCR, 648 +/- 45 mg/l). In addition, all of the assays showed strong linear correlations with one another (mean r(2) = 0.96, range 0.91-0.99).The availability of comprehensive protocols for these assays will enhance research into TAC of beers and augment the evidence base for their benefit in health and wellbeing.
There is increasing support for an important biological role of the trace element, silicon, in the optimal health of connective tissue, especially bone. Beer contains high levels of dietary silicon, in the well absorbed and biologically active form of orthosilicic acid [Si(OH)(4)]. It is widely accepted that barley, especially following malting and maceration, provides the major source of silicon within beer. However, how the different aspects of the brewing process then influence the final beer-silicon concentration is not known. Here we describe the findings of two previously unreported studies. First, we confirm that beer contains a high level (typically around 20 mg/l) of silicon. Secondly, from a pilot brewing trial, we show that barley is the major source of silicon in beer. Two different malts (malted barley) had distinctly different silicon concentrations, presumably because silicon levels of barley vary genetically. Silicon levels of the final product also depended on mashing and rinsing (sparging) conditions during the brewing process while filtration was also shown to affect (reduce) silicon levels of the beer, probably due to adsorption of orthosilicic acid onto material that is trapped by or that comprises the filter. Silicon levels of the water used for brewing are likely to have a small additional influence on the final beer-silicon levels, but in this particular work were negligible.
Accumulated evidence suggests that dietary silicon (Si) is beneficial for bone and connective tissue health and that higher intakes of dietary Si are associated with higher bone mineral density (BMD) (a proxy for bone health). A major source of Si is whole grain cereals and their products, such as beer, which is brewed from macerated, malted whole grain barley. Beer is a top contributor to Si intake in men and is a source of highly bioavailable Si. Beer also has a modest alcohol content. It is well established that moderate ingestion of alcoholic beverages is associated with increased BMD but mechanisms are unknown. In a recent extensive review (Jugdaohsingh et al., 2006) we have made a case for ethanol and Si as the two major constituents of alcoholic beverages that can positively influence BMD; the latter being nearly beer-specific. Indeed in a recent report, we showed that the association between moderate beer ingestion and BMD was significantly reduced when a correction was made for Si (Tucker et al., 2004). This was not seen with the other types of alcoholic beverages (wine and liquor). In more recent detailed analyses (Tucker et al., 2007 unpublished data) we confirmed these findings and showed that while the major positive effect of moderate beer ingestion on BMD is an ethanol effect, some could be attributed to Si. Thus moderate beer ingestion (1-4 UK units/day) could be advantageous to bone health by providing both an anti-resorptive and an anabolic component, namely ethanol and silicon, respectively.
Arabinoxylans are non-starch polysaccharides (NSP) and are found in a number of tissues, primarily in the cell wall of the aleurone layers and the endosperm. Arabinoxylans are comprised of a mixed linkage between arabinose and xylose. The arabinoxylan structure is degraded, in conjunction with beta-glucan, by enzymes during the malting process to facilitate a trouble-free breakdown of the main endosperm contents (protein and starch). Low temperature mashing (< 50 degrees C) continues the breakdown of these NSP. However, arabinoxylans have been attributed to contribute to filtration problem during brewing and haze formation in beer. There is variation with a grain type as well as between grain types used for brewing, with barley having a high arabinoxylan content compared to sorghum with a low content. Further research is required to gain a more detailed understanding of the genetic control of arabinoxylan as well as the enzyme systems that degrade this NSP to ensure trouble-free brewing and consistent beer quality. Improvements in filtration technology could increase pressure on barley breeders and maltsters breeders to produce low level arabinoxylan barley and malt which could impact on other quality parameters.
Cereals provide the carbohydrates for beer production. Barley that has been malted is the most usual cereal used. However, other cereals, including wheat, rice, maize, oats, sorghum and sugar syrups, may also be used. During malting all enzymes necessary for total degradation of starch are synthesized and/or activated, together with enzymes that contribute to the hydrolysis of beta-glucans and in less extension arabinoxylans. Important transformations occur during mashing, namely, starch is converted into maltose and dextrins. Carbohydrates form 90% of the wort extract, 64-77% of which is usually fermentable by yeast to produce ethanol and carbon dioxide.Carbohydrate levels in beer range from 3 to 61 g/l. Specific data concerning the beer carbohydrate contents reported by different authors are presented. Different contents of total and fermentable sugars are reported according to beer type. Lagers are in general more fully fermented than ales. Total carbohydrate content of lager and ale beers range between 10-30 and 15-60 g/l, respectively. Lagers also contain less residual carbohydrates than ales, 1-7 g/l and 5-10 g/l, respectively. New brewing styles include fully attenuated low carbohydrate beers that contain less carbohydrate amounts (4-9 g/l) because dextrins have been more or less completely digested and fermented. In general, non-alcohol beers produced by short fermentation present higher level of fermentable sugars (about 55 g/l).
Many thousands of different beer brands are produced worldwide and most of them can be classified into defined beer styles which have developed over the course of time in different countries or regions. Depending on the process used, a first classification can be made according to the fermentation process in top and bottom fermentation beers. Top fermented beers represent only a small percentage of the total beer consumption. Top fermented beers are very common in Britain, Germany, Canada's eastern provinces, United States and, last but not least, Belgium. However, lager (the term generally used for bottom fermented beer) is the dominant style in almost all countries and represents more than 90% of the beer produced worldwide. Until the sixteenth century, ale (the term generally used for top fermentation beers) was the main type of beer in Europe. Traditionally, ales are fermented with the use of top-cropping yeasts which rise to the top of the beer in the head of foam at temperatures between 16 degrees C and 24 degrees C. At these temperatures, the yeast produces significant amounts of esters and other secondary flavor and aromatic products, and the result is often a beer with slightly "fruity" compounds. Typical ales have a sweeter, fuller body than lagers.
The study of beer consumption and the risk of lung cancer is complicated by the fact that beer drinkers have increased rates of cigarette smoking. Nonetheless, roughly one-half of all the retrospective case control and prospective cohort studies performed, in which the confounding effects of cigarette smoking have been carefully adjusted for, demonstrate a significant increase in the risk of the development of lung cancer among beer drinkers compared to non-drinkers. The increased risk is relatively moderate, odds ratio/relative risks between 1.3 and 2. The increased risk of lung cancer is most often limited to the heaviest beer consumers. Similar increases in lung cancer risk are demonstrated for consumers of hard liquor (whiskey, vodka, "spirits "). Moderate consumption of red wine clearly decreases the risk of lung cancer. Alcohol consumption is associated with worse outcomes among patients with established lung cancer. Data regarding lung cancer treatment outcomes and specific beer consumption are not available. Heavy alcohol consumption leads to more postoperative complications, primarily respiratory and infectious, among patients undergoing resection for early stage lung cancer. Further, heavy alcohol consumption correlates with less response to chemotherapy and worse survival in patients treated for advanced lung cancer. There are a number of molecular mechanisms that account for the increased risk of lung cancer among alcohol and beer consumers and the poor outcomes among alcohol consumers with lung cancer.
Beer is one of the world's oldest alcoholic beverages. Brewing industry is a huge global business, consisting of several multinational companies and many thousands of smaller producers ranging from brewpubs to regional breweries. A great many of different types, or style, of beer are brewed across the world. For this reason, it is difficult to generalize on the relationship between beer and relative impact on nutrient intake because the composition of beers will range quite considerably depending on raw materials and how they are produced. Lager represents more than 90% of beer produced worldwide. It is typically brewed at low temperatures (bottom fermentation) in cool conditions using a particular yeast, and then stored (the word "lager" comes from the German lagern meaning "to store") in cool conditions to have maturation or improvement of its organoleptic characteristics. Until the sixteenth century ale (top fermentation) was the main type of beer in Europe. So it is only a myth that lager-style products have always been the characteristic beer in Germany. The monks of Bavaria were responsible for an innovation that was to change the face of beer brewing, the "bottom fermentation." The Bavarian monasteries first attempted to store beer for long periods in cool cellar. At lower temperatures, instead of frothing to the top of the fermenting vessel, the yeast sank to the bottom end fermenting more slowly. The Bavarian lager was still different from the widely known modern lager. They remained a fairly conventional dark brown or amber-red color, until 1842, when Joseph Groll mashed his first batch of beer in Plzen (in Czech Republic) and the world's first ever golden colored lager was born.
The trends in beer drinking worldwide were assessed from the food balance sheets of the Food and Agriculture Organization, together with available national or international studies. Overall, the data indicate that beer consumption is decreasing in industrialized countries such as Australia, Canada, Japan, New Zealand and the United States, whereas the opposite trend is observed for developing countries. This increase is particularly strong in Asia, namely in China and Thailand. Conversely, no definite trends were found in other regions such as Latin America or Africa. Although social and religious factors considerably influence alcohol and beer drinking, their effects appear to be lessening in the younger generations, which appear as the major consumers of beer.
