Identification by NMR of key compounds present in beer distillates and residual phases after dealcoholization by vacuum distillation.

BACKGROUND: Nowadays, low alcohol and non-alcohol beer intake has increased due to expanding concerns about healthy diets. However, there are still appreciable differences between non-alcoholic beer and conventional beer, particularly regarding flavor. Vacuum distillation is commonly used to remove ethanol from the beer in industrial processes and it is used here. RESULTS: The presence of n-propanol, isobutanol, 3-methylbutanol, 2-methylbutanol, 2-phenylethanol, ethyl acetate, isoamyl acetate, and acetaldehyde, which are key compounds responsible for aroma and flavor of beer, have been analyzed using nuclear magnetic resonance (NMR) spectroscopy in commercial beers and also in the corresponding distillates and residual phases after dealcoholization. CONCLUSION: The compounds present in each phase were identified by monodimensional and bidimensional NMR spectra. The compounds that are completely removed or that remain in the residue of the conventional beers studied are described in detail. The presence of these compounds in dealcoholized beer would be beneficial in keeping the aroma and flavor in dealcoholized beer. © 2020 Society of Chemical Industry.

Field-Evolved Mode 1 Resistance of the Fall Armyworm to Transgenic Cry1Fa-Expressing Corn Associated with Reduced Cry1Fa Toxin Binding and Midgut Alkaline Phosphatase Expression.

Insecticidal protein genes from the bacterium Bacillus thuringiensis (Bt) are expressed by transgenic Bt crops (Bt crops) for effective and environmentally safe pest control. The development of resistance to these insecticidal proteins is considered the most serious threat to the sustainability of Bt crops. Resistance in fall armyworm (Spodoptera frugiperda) populations from Puerto Rico to transgenic corn producing the Cry1Fa insecticidal protein resulted, for the first time in the United States, in practical resistance, and Bt corn was withdrawn from the local market. In this study, we used a field-collected Cry1Fa corn-resistant strain (456) of S. frugiperda to identify the mechanism responsible for field-evolved resistance. Binding assays detected reduced Cry1Fa, Cry1Ab, and Cry1Ac but not Cry1Ca toxin binding to midgut brush border membrane vesicles (BBMV) from the larvae of strain 456 compared to that from the larvae of a susceptible (Ben) strain. This binding phenotype is descriptive of the mode 1 type of resistance to Bt toxins. A comparison of the transcript levels for putative Cry1 toxin receptor genes identified a significant downregulation (>90%) of a membrane-bound alkaline phosphatase (ALP), which translated to reduced ALP protein levels and a 75% reduction in ALP activity in BBMV from 456 compared to that of Ben larvae. We cloned and heterologously expressed this ALP from susceptible S. frugiperda larvae and demonstrated that it specifically binds with Cry1Fa toxin. This study provides a thorough mechanistic description of field-evolved resistance to a transgenic Bt crop and supports an association between resistance and reduced Cry1Fa toxin binding and levels of a putative Cry1Fa toxin receptor, ALP, in the midguts of S. frugiperda larvae.

Low-alcohol Beers: Flavor Compounds, Defects, and Improvement Strategies.

Beer consumers are accustomed to a product that offers a pleasant and well-defined taste. However, in alcohol-free and alcohol-reduced beers these characteristics are totally different from those in regular beer. Therefore, it is important to evaluate and determine the different flavor compounds that affect organoleptic characteristics to obtain a product that does not contain off-flavors, or taste of grass or wort. The taste defects in alcohol-free beer are mainly attributed to loss of aromatic esters, insufficient aldehydes, reduction or loss of different alcohols, and an indeterminate change in any of its compounds during the dealcoholization process. The dealcoholization processes that are commonly used to reduce the alcohol content in beer are shown, as well as the negative consequences of these processes to beer flavor. Possible strategies to circumvent such negative consequences are suggested.

Evidence of multiple/cross resistance to Bt and organophosphate insecticides in Puerto Rico population of the fall armyworm, Spodoptera frugiperda.

Fall armyworm (FAW) is a damaging pest of many economic crops. Long-term use of chemical control prompted resistance development to many insecticide classes. Many populations were found to be significantly less susceptible to major Bt toxins expressed in transgenic crops. In this study, a FAW strain collected from Puerto Rico (PR) with 7717-fold Cry1F-resistance was examined to determine if it had also developed multiple/cross resistance to non-Bt insecticides. Dose response assays showed that the PR strain developed 19-fold resistance to acephate. Besides having a slightly smaller larval body weight and length, PR also evolved a deep (2.8%) molecular divergence in mitochondrial oxidase subunit II. Further examination of enzyme activities in the midgut of PR larvae exhibited substantial decreases of alkaline phosphatase (ALP), aminopeptidase (APN), 1-NA- and 2-NA-specific esterase, trypsin, and chymotrypsin activities, and significant increases of PNPA-specific esterase and glutathione S-transferase (GST) activities. When enzyme preparations from the whole larval body were examined, all three esterase, GST, trypsin, and chymotrypsin activities were significantly elevated in the PR strain, while ALP and APN activities were not significantly different from those of susceptible strain. Data indicated that multiple/cross resistances may have developed in the PR strain to both Bt toxins and conventional insecticides. Consistently reduced ALP provided evidence to support an ALP-mediated Bt resistance mechanism. Esterases and GSTs may be associated with acephate resistance through elevated metabolic detoxification. Further studies are needed to clarify whether and how esterases, GSTs, and other enzymes (such as P450s) are involved in cross resistance development to Bt and other insecticide classes.

New trends in beer flavour compound analysis.

As the beer market is steadily expanding, it is important for the brewing industry to offer consumers a product with the best organoleptic characteristics, flavour being one of the key characteristics of beer. New trends in instrumental methods of beer flavour analysis are described. In addition to successfully applied methods in beer analysis such as chromatography, spectroscopy, nuclear magnetic resonance, mass spectrometry or electronic nose and tongue techniques, among others, sample extraction and preparation such as derivatization or microextraction methods are also reviewed.

Innovations in the brewing industry: light beer.

The demand for light beers has led brewers to innovate by developing light beer. However, these products are not widely accepted in Europe compared to North America and Australasia because of their lack of fullness in the taste and low bitterness compared with conventional beer. The lower levels of some important compounds, present in light beer, can explain these features since they are responsible for the characteristics of the beer. These include alcohol soluble proteins, oligosaccharides, glycerol, polyphenols, iso-α-acids, fusel alcohols and trihydroxy fatty acids. Light beer is produced by several methods, the most commonly used is the addition of glucoamylase to the wort before or during fermentation. This enzyme metabolizes residual carbohydrates (mainly dextrins) transforming them into fermentable sugars and reducing the caloric and alcohol content in this type of beer. Recently pilot studies have been carried out with genetically engineered yeast strains in which amylolytic genes are introduced into the yeast genome in order to metabolize carbohydrate residues. When introducing amylolytic genes, a better fermentability occurs although the fullness of flavor still becomes reduced.

Prediction of the ageing of commercial lager beer during storage based on the degradation of iso-α-acids.

BACKGROUND: Iso-α-acids and their chemically modified variants are responsible for the bitterness of beer and play a disproportionately large role in the final quality of beer. The current study was undertaken to predict the degradation of commercial lager beers related to changes in the concentration of trans-iso-α-acids during storage by using high-pressure liquid chromatography. RESULTS: In the analysed beers the concentration of isohumulone (average concentration 28 mg L(-1)) was greater than that of isocohumulone (20 mg L(-1)) and isoadhumulone (10 mg L(-1)). The kinetic parameters, activation energy and rate constant, of the trans-iso-α-acids were calculated. In the case of dark beers, the activation energy for the degradation of trans-isocohumulones was found to be higher than for trans-isohumulones and trans-isoadhumulones, whereas in pale and alcohol-free beers activation energies for the degradation of the three trans isomers were similar. CONCLUSION: The loss of iso-α-acids can be calculated using the activation energy of the degradation of trans-iso-α-acids and the temperature profile of the accelerated ageing. The results obtained in the investigation can be used in the beer industry to predict the alteration of the bitterness of beer during storage.

Genetic structure and gene flow among Brazilian populations of Heliothis virescens (Lepidoptera: Noctuidae).

Population genetic studies are essential to the better application of pest management strategies, including the monitoring of the evolution of resistance to insecticides and genetically modified plants. Bacillus thuringiensis Berliner (Bt) crops have been instrumental in controlling tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), a pest that has developed resistance to many common insecticides once used for its management. In our study, microsatellite markers were applied to investigate the genetic structure and patterns of gene flow among Brazilian populations of H. virescens from cotton, Gossypium hirsutum L., and soybean, Glycine max (L.) Merr., fields, aiming to propose means to improve its management in the field. In total, 127 alleles were found across nine microsatellites loci for 205 individuals from 12 localities. Low levels of gene flow and moderate to great genetic structure were found for these populations. Host plant association, crop growing season, and geographic origin were not responsible for the genetic structuring among Brazilian populations of H. virescens. Other factors, such as demographic history and seasonal variability of intrapopulation genetic variation, were suggested to be molding the current pattern of genetic variability distribution.

Bread as a Valuable Raw Material in Craft Ale Beer Brewing.

One of the ingredients used for brewing is barley, which should be malted; it is considered the most polluting agricultural input. On the other hand, food wastage is today a widespread problem that causes significant environmental damage and also generates large economic losses worldwide. One of the most wasted food products is bread; it is estimated that hundreds of tons of bread are wasted every day worldwide. In this study, the brewing of ale beers with bread was carried out. For this purpose, up to 50% of the malt weight was replaced by different types of bread: wheat bread, whole wheat bread, rye bread, and corn bread. A physicochemical and sensory comparison was made with 100% malt ale beer. All beers brewed with bread had an alcoholic strength similar to that of the control beer, except the corn beer. Beers brewed with whole grain bread showed a higher antioxidant capacity and a higher total polyphenol content. The sensory analysis presented different profiles depending on the type of bread; in general, the addition of bread created a greater olfactory intensity in nose. Thus, it was found that it is possible to brew beer with bread substituting up to 50% of the malt. In addition, it was also shown that the beer brewed with whole wheat bread had similar characteristics to the control beer, even improving some beneficial health properties, representing a great advantage for the brewing industry all over the world.

The evolutionary process of invasion in the fall armyworm (Spodoptera frugiperda).

The fall armyworm (FAW; Spodoptera frugiperda) is one of the major agricultural pest insects. FAW is native to the Americas, and its invasion was first reported in West Africa in 2016. Then it quickly spread through Africa, Asia, and Oceania, becoming one of the main threats to corn production. We analyzed whole genome sequences of 177 FAW individuals from 12 locations on four continents to infer evolutionary processes of invasion. Principal component analysis from the TPI gene and whole genome sequences shows that invasive FAW populations originated from the corn strain. Ancestry coefficient and phylogenetic analyses from the nuclear genome indicate that invasive populations are derived from a single ancestry, distinct from native populations, while the mitochondrial phylogenetic tree supports the hypothesis of multiple introductions. Adaptive evolution specific to invasive populations was observed in detoxification, chemosensory, and digestion genes. We concluded that extant invasive FAW populations originated from the corn strain with potential contributions of adaptive evolution.

Improving gluten-free bread quality by enrichment with acidic food additives.

An experimental design has been developed to improve gluten-free bread formulation, on the basis of rice flour and hydroxypropylmethylcellulose (HPMC) as alternative baking ingredients. In order to improve the quality of gluten-free bread, several levels of acidic food additives (acetic acid, lactic acid, citric acid and monosodium phosphate) have been tested. The influence of these compounds on the dough and on bread properties has been determined, including a hedonic sensory test of appearance, odour, taste and texture of bread. Results suggest that monosodium phosphate yields bread producing better texture scores, associated with the highest volumes of the loaf. Discussions are made on the basis of CO2 transport pathway across the HPMC network and simultaneous interactions with acidic food additives present. Chemical properties of the acids justify the bread's alveolus size and the preservative effects of acetic acid in the dough.

Free iron in pale, dark and alcohol-free commercial lager beers.

BACKGROUND: A highly sensitive, selective, rapid, reliable and inexpensive method has been developed for the direct analysis of free iron in 40 samples of bottled lager beer. RESULTS: A differential pulse adsorptive stripping voltammetry technique at a hanging mercury drop electrode without any sample digestion was performed. The iron content in the analysed samples was in the range of 41 to 165 ppb. CONCLUSIONS: The results point out that dark beers keep the highest free iron concentrations, which may be related to the highest amounts of minor ingredients in dark beers. Meanwhile, alcohol-free beers present the lowest free iron concentrations. Some discussion is presented regarding the basis of the free and complexed iron in beer and its participation as an essential element in the human diet.

Brewing with Starchy Adjuncts: Its Influence on the Sensory and Nutritional Properties of Beer.

In brewing, the use of cereals (wheat, barley, maize, rice, sorghum, oats, rye or millet), pseudo-cereals (buckwheat, quinoa or amaranth) and tubers (sweet potato), as starch adjuncts, is being promoted for the production of a variety of high-quality beers, from sensory and nutritional points of view. The sensory properties of the obtained beer depend on the characteristics of each adjunct but also on the forms in which the adjunct is added: whole cereal, grits, malted, extruded grains, torrefied and syrup. Among these common forms, the extruded grains (maize or rice) produce a higher content of aroma compounds in beer. From a nutritional point of view, the use of non-conventional starch adjuncts, such as black rice, buckwheat or sweet potato, leads to an increase in the polyphenol content of the beer, and thus, its antioxidant capacity. Cereals such as maize, rice, sorghum or millet are the most promising for the production of gluten-free beers. A close relationship can be developed between the use of adjuncts in the beer industry and the use of commercial enzymes. Advances made by biotechnology to design new enzymes with different functionalities could be associated to a future increase in adjunct usage in brewing.

Activity of oil-formulated conidia of the fungal entomopathogens Nomuraea rileyi and Isaria tenuipes against lepidopterous larvae.

The fungi Nomuraea rileyi and Isaria tenuipes (=Paecilomyces tenuipes) are ecologically obligate, widespread pathogens of lepidopterans. Bioassays were carried out to evaluate the activity of oil-suspended conidia of N. rileyi and I. tenuipes against larvae of Spodoptera frugiperda, Spodoptera exigua, Helicoverpa zea, and Heliothis virescens. The tests consisted of two bioassay sets. In the first set, conidia of N. rileyi and I. tenuipes were suspended in water+Tween 80, and in vegetable (canola, soybean) and mineral (proprietary mixture of alkanes and cyclic paraffins) oils, and tested against S. frugiperda. Both fungi were highly compatible with oils and caused mortalities near 100% in all oil treatments; the lowest LT(50) values were 4.7 days for N. rileyi in mineral oil and 6.0 days for I. tenuipes in soybean oil. The second set included additional fungal strains and oil formulations (mineral, canola, sunflower, olive and peanut oils) tested against larvae of S. exigua, S. frugiperda, H. zea and H. virescens. The highest activity was that of N. rileyi in mineral oil against Spodoptera spp., with LT(50) values of 2.5 days (strain ARSEF 135) and 3 days (strain ARSEF 762) respectively. For two different isolates of I. tenuipes the lowest LT(50) values (5.1-5.6 days respectively) were obtained with mineral oil formulations against Spodoptera spp. and H. zea respectively. Additionally, we tested both fungi against prepupae of all four lepidopteran species. Mortalities with I. tenuipes against S. exigua ranged from 90% to 100% (strains ARSEF 2488 and 4096); N. rileyi caused 95% mortality on S. frugiperda. The activity of formulations depended on host species and oil used; Spodoptera spp. was more susceptible to these fungi than Heliothis and Helicoverpa. The results indicate that a comprehensive evaluation of these entomopathogens in agriculture using oil application technologies is advisable, particularly, in organic and sustainable settings.

Offspring from sequential matings between Bacillus thuringiensis-resistant and Bacillus thuringiensis-susceptible Heliothis virescens moths (Lepidoptera: Noctuidae).

The tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), is an economically important pest of the Americas. Females of this species copulate multiple times during their lifetimes, and the presence of sperm from multiple males inside them could allow for a diversity of paternal genotypes in the offspring, unless there was complete precedence of sperm from the first mating. If a female copulates with a male that is insecticide-susceptible and another male that is insecticide-resistant, her progeny could vary in their resistance phenotypes. In some cases, this could impact the evolution of insecticide resistance in a population. We designed a series of experiments to determine whether Bacillus thuringiensis susceptibility is maintained when an H. virescens female that is homozygous for a genetically recessive form of B. thuringiensis resistance copulates with a Cry1Ac-susceptible and a Cry1Ac-resistant males. During the lifetime of double-copulated females, a proportion of F1 progeny were Cry1Ac-resistant. This indicates that when a B. thuringiensis-resistant H. virescens female copulates with two males, with one male being resistant to Cry1Ac, some of the progeny will carry resistance to this insecticide. Due to the polyandrous nature of this species, the above-mentioned scenario is not unrealistic; therefore, results from this study may help understand and manage the evolution of B. thuringiensis-resistance in field populations.

Phenols and Melanoidins as Natural Antioxidants in Beer. Structure, Reactivity and Antioxidant Activity.

Beer is one of the most consumed drinks around the world, containing a variety of compounds that offer both appreciated sensorial characteristics and health advantages. Important healthy compounds in beer are those with antioxidant properties that attenuate the content of free radicals produced as by-products in the human metabolism, exerting an appreciable effect against cancers or cardiovascular diseases. This work details a study of antioxidant compounds present in beer, focusing on the two main groups: phenols (including polyphenolic forms) and melanoidins, formed specifically during brewing as Maillard products. The fundaments of the most important methods to evaluate beer antioxidant activity, the main antioxidant compounds present in beer-especially those with healthy properties-and the new trends to increase beer antioxidant activity are also discussed.

Susceptibility of Fall Armyworms (Spodoptera frugiperda J.E.) from Mexico and Puerto Rico to Bt Proteins.

Fall armyworm is one of the main pests of conventional and Bacillus thuringiensis (Bt) corn in many countries in the Americas, Africa, Asia and in Australia. We conducted diet-overlay bioassays to determine the status of susceptibility to four Bt proteins (Cry1A.105, Cry2Ab2, Cry1F and Cry1Ac) in three different populations of fall armyworm from Mexico, and one population from Puerto Rico. Bioassays showed that fall armyworms from Puerto Rico were resistant to Cry1F with a resistance ratio 50 (RR50) higher than 10,000 ng/cm2 and to Cry1Ac with a RR50 = 12.2 ng/cm2, displaying the highest median lethal concentration (LC50) values to all Bt proteins tested. The effective concentration 50 (EC50) values further confirmed the loss of susceptibility to Cry1F and Cry1Ac in this population. However, LC50 and EC50 results with Cry1A.105 and Cry2Ab2 revealed that fall armyworm from Puerto Rico remained largely susceptible to these two proteins. The Mexican populations were highly susceptible to all the Bt proteins tested and displayed the lowest LC50 and EC50 values to all Bt proteins. Our results suggest that Cry1F and Cry1Ac resistance is stable in fall armyworm from Puerto Rico. However, this population remains susceptible to Cry1A.105 and Cry2Ab2. Results with Mexican fall armyworms suggest that possible deployment of Bt corn in Mexico will not be immediately challenged by Bt-resistant genes in those regions.

Adaptation by copy number variation increases insecticide resistance in the fall armyworm.

Understanding the genetic basis of insecticide resistance is a key topic in agricultural ecology. The adaptive evolution of multi-copy detoxification genes has been interpreted as a cause of insecticide resistance, yet the same pattern can also be generated by the adaptation to host-plant defense toxins. In this study, we tested in the fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), if adaptation by copy number variation caused insecticide resistance in two geographically distinct populations with different levels of resistance and the two host-plant strains. We observed a significant allelic differentiation of genomic copy number variations between the two geographic populations, but not between host-plant strains. A locus with positively selected copy number variation included a CYP gene cluster. Toxicological tests supported a central role for CYP enzymes in deltamethrin resistance. Our results indicate that copy number variation of detoxification genes might be responsible for insecticide resistance in fall armyworm and that evolutionary forces causing insecticide resistance could be independent of host-plant adaptation.

Importance of tetrahydroiso alpha-acids to the microbiological stability of beer.

While beer provides a very stable microbiological environment, a few niche microorganisms are capable of growth in malt, wort, and beer. The production of off-flavors and development of turbidity in the packaged product are due to the growth and metabolic activity of wild yeast, certain lactic acid bacteria (LAB) and anaerobic Gram-negative bacteria. Beer also contains bitter hop compounds, which are toxic to Gram-positive and Gram-negative bacteria, and contribute to preventing the spoilage of this beverage. In the boiling process, the hop alpha-acids (humulones) are isomerized into iso alpha-acids. These products are responsible for the bitter taste of beer, but they also play an essential role in enhancing foam stability. Antibacterial activity of iso alpha-acids and their hydrogenated derivates (rhoiso alpha-acids and tetrahydroiso alpha-acids) in MRS broth and beer have been evaluated against different LAB (Lactobacillus and Pediococcus) for the determination of their beer-stabilizing capabilities. Besides this, we have determined the minimum inhibitory concentration and the bacteriostatic effect of each compound against Pediococcus. We found that tetrahydroiso alpha-acids (added directly to beer during production processes) are the compounds that present the greatest antibacterial activity against the main agents implicated in beer spoilage.

Response of Heliothis virescens (Lepidoptera: Noctuidae) strains to Bacillus thuringiensis Cry1Ac incorporated into different insect artificial diets.

Susceptibility to the Cry1Ac toxin from Bacillus thuringiensis in tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), is usually measured by performing bioassays under laboratory conditions. Accurate comparison of Cry1Ac susceptibility among H. virescens samples conducted in different places is challenged by several important methodological aspects, especially if different insect artificial diets are used to perform bioassays. In this study, we compared Cry1Ac susceptibility of four different-origin H. virescens colonies when challenged with this toxin incorporated into four different insect artificial diets. Our data show that Cry1Ac susceptibility was lower in all the H. virescens colonies for one of the commercial diets (Bio-Serv). Bio-Serv diet was one of the least significantly consumed diets by larvae of the four different colonies, which indicates that insects encountered less Cry1Ac toxin due to lower consumption of diet. Larvae fed Bio-Serv diet also seemed to display slower Cry1Ac toxin activation compared with larvae fed any of the other three diets tested. In contrast, a wheat germ-soybean diet (ARS) was one of the most consumed diets by the four H. virescens colonies. The increased consumption of ARS diet probably led to the high level of Cry1Ac susceptibility observed in all the H. virescens colonies. Our data highlight the importance of using common diets and use a standard tobacco budworm colony when comparing Cry1Ac susceptibility between diverse H. virescens strains or across time.