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[EN] Due to the high dependence of ruminant feeding systems on the use of soybean meal as source of protein, insect meals have been suggested as a promising alternative. However, a high rumen degradability might be a drawback for its utilisation. In this regard, tannins are known to be able to exert beneficial effects on the digestive utilization of protein-rich feeds due to a reduction of their degradation in the rumen, especially of the protein, although they might also restrict intestinal digestibility. Therefore, this experiment was conducted to examine if tannins could improve the digestive utilization of 4 insect meals (from Acheta domesticus, Alphitobius diaperinus, Tenebrio molitor and Zophobas morio). To this aim, four ruminally cannulated sheep were used to study the ruminal degradation and intestinal digestibility of these feedstuffs as well as those of soybean meal, which was used as a reference. The five substrates were treated with either 0% (control) or 15% DM of commercial tannin extracts from oak (OAK) or quebracho (QUE), and incubated in situ for 16 h. Afterwards, the intestinal digestibility of non-degraded protein was estimated in vitro. Both oak and quebracho tannins were able to protect the protein of insect meals from ruminal degradation, following a similar pattern than that observed in soybean meal. On average, reductions were about 15%, with no significant differences between oak and quebracho effects. On the opposite, the OAK treatment might offer advantages over QUE in terms of intestinal protein digestibility, as the latter caused a lower value in A. domesticus compared with the control. More research would be advisable to confirm these results, particularly in vivo, [FR] . En raison de la forte dépendance à l’utilisation de tourteau de soja comme source de protéines dans les systèmes d’alimentation des ruminants, la farine d’insectes a été suggérée comme une alternative prometteuse. Cependant, une forte dégradation de sa protéine dans le rumen pourrait constituer un inconvénient à son utilisation. À cet égard, les tanins peuvent avoir des effets bénéfiques sur l’utilisation digestive des aliments riches en protéines, en réduisant leur dégradation dans le rumen, même si ils peuvent limiter la digestibilité intestinale. Par conséquent, cet essai a été mené afin d’examiner si les tanins pouvaient améliorer l’utilisation digestive de 4 farines d’insectes (provenant d’Acheta domesticus, Alphitobius diaperinus, Tenebrio molitor et Zophobas morio). Pour ce faire, quatre moutons munis d’une canule ruminale ont été utilisés afin d’étudier la dégradation ruminale et la digestibilité intestinale de ces aliments, en comparaison avec celles du tourteau de soja (aliment de référence). Les cinq substrats ont été traités avec 0 (témoin) ou 15% MS des extraits commerciaux de tanin de chêne (OAK) ou de quebracho (QUE) et par la suite ils ont été incubés in situ pendant 16 h. Ensuite, la digestibilité intestinale de la protéine non dégradée a été estimée in vitro. Les tanins de chêne et de quebracho ont permis de protéger la protéine des farines d’insectes de la dégradation ruminale, en suivant une tendance similaire à celle observée pour le tourteau de soja. En moyenne, la réduction de la dégradation protéique a été d’environ 15%, sans différence significative entre les effets du chêne et du quebracho. Au contraire, en termes de digestibilité intestinale des protéines, le traitement OAK pourrait offrir des avantages par rapport à QUE, puisque ce dernier a entrainé une valeur inférieure pour A. domesticus par rapport au contrôle. D’autres recherches seraient requises pour confirmer ces résultats, particulièrement en conditions in vivo

BACKGROUND:The outer peels of pomegranate (Punica granatum L.) possess two groups of polyphenols that have health beneficial properties: anthocyanins (ATs, which also affect peel color); and hydrolysable tannins (HTs). Their biosynthesis intersects at 3-dehydroshikimate (3-DHS) in the shikimate pathway by the activity of shikimate dehydrogenase (SDH), which converts 3-DHS to shikimate (providing the precursor for AT biosynthesis) or to gallic acid (the precursor for HTs biosynthesis) using NADPH or NADP+ as a cofactor. The aim of this study is to gain more knowledge about the factors that regulate the levels of HTs and ATs, and the role of SDH. RESULTS:The results have shown that the levels of ATs and HTs are negatively correlated in the outer fruit peels of 33 pomegranate accessions, in the outer peels of two fruits exposed to sunlight, and in those covered by paper bags. When calli obtained from the outer fruit peel were subjected to light/dark treatment and osmotic stresses (imposed by different sucrose concentrations), it was shown that light with high sucrose promotes the synthesis of ATs, while dark at the same sucrose concentration promotes the synthesis of HTs. To verify the role of SDH, six PgSDHs (PgSDH1, PgSDH3-1,2, PgSDH3a-1,2 and PgSDH4) were identified in pomegranate. The expression of PgSDH1, which presumably contributes to shikimate biosynthesis, was relatively constant at different sucrose concentrations. However, the transcript levels of PgSDH3s and PgSDH4 increased with the accumulation of gallic acid and HTs under osmotic stress, which apparently accumulates to protect the cells from the stress. CONCLUSIONS:The results strongly suggest that the biosynthesis of HTs and ATs competes for the same substrate, 3-DHS, and that SDH activity is regulated not only by the NADPH/NADP+ ratio, but also by the expression of the PgSDHs. Since the outer peel affects the customer's decision regarding fruit consumption, such knowledge could be utilized for the deve

Almonds and pecans are considered functional foods because their regular intake provides protection against several chronic-degenerative diseases. Phenolic compounds are some of the most bioactive components of these tree nuts; yet, their identification and characterization is regularly viewed as an analytical challenge. The aim of the present work was to characterize the phenolic compound profile of acetone and methanol extracts of almond and pecan nut, by using HPLC coupled to tandem mass spectrometry (MS/MS). First, high resolution MS (Q-TOF) was used to identify phenolic compounds in the extracts: 29 compounds were detected in almond (22 in acetone extract, 24 in ethanol extract) and 43 in pecan (39 in acetone extract, 37 in ethanol extract). Identity of 6 almond compounds and 20 pecan compounds was confirmed through analysis of their MS/MS fragmentation patterns. Phenolic profiles were different between pecan and almond but similar between extraction solvents for a same tree nut species. Flavonols and flavanones were the major types of phenolic compounds in almond, while pecan phenolics were mostly hydrolysable (ellagitannins acid ellagic acid derivatives) and condensed tannins (upto tetramers). Three ellagitannins are described for the first time in pecan., La almendra y nuez pecana son alimentos funcionales, cuyo consumo habitual puede prevenir el desarrollo de numerosas enfermedades crónico-degenerativas. Los compuestos fenólicos (CF) son algunos de los que poseen mayor actividad biológica en estos frutos secos, pero su identificación y caracterización siempre representa un reto analítico. El objetivo del presente trabajo fue caracterizar el perfil de los CF, mediante HPLC acoplado a espectrometría de masas en tándem (MS/MS) de dos tipos de extractos de nuez pecana y almendra, un extracto etanólico y uno acetónico. Se identificaron, mediante HPLC acoplado a espectrometría de masas de alta resolución (Q-TOF), 29 compuestos en almendra (22 estuvieron en el extracto acetónico y 24 en el etanólico) y 43 en nuez pecana (39 en el acetónico y 37 en el etanólico). La identidad de 6 compuestos de la almendra y 20 de nuez pecana se confirmó mediante el análisis de sus patrones de fragmentación en el modo MS/MS del equipo. El perfil de los CF fue claramente diferente entre almendra y nuez, pero muy parecido entre ambos tipos de solventes empleados (acetona y etanol), para un mismo fruto seco. En la almendra predominó la presencia de flavonoles y flavanonas, mientras que en nuez pecana predominaron taninos hidrolizables (sobre todo elagitaninos y derivados simples del ácido elágico) y condensados (hasta tetrámeros). En este estudio se describe por primera vez la identificación de tres elagitaninos en nuez pecana.

Almonds and pecans are considered functional foods because their regular intake provides protection against several chronic-degenerative diseases. Phenolic compounds are some of the most bioactive components of these tree nuts; yet, their identification and characterization is regularly viewed as an analytical challenge. The aim of the present work was to characterize the phenolic compound profile of acetone and methanol extracts of almond and pecan nut, by using HPLC coupled to tandem mass spectrometry (MS/MS). First, high resolution MS (Q-TOF) was used to identify phenolic compounds in the extracts: 29 compounds were detected in almond (22 in acetone extract, 24 in ethanol extract) and 43 in pecan (39 in acetone extract, 37 in ethanol extract). Identity of 6 almond compounds and 20 pecan compounds was confirmed through analysis of their MS/MS fragmentation patterns. Phenolic profiles were different between pecan and almond but similar between extraction solvents for a same tree nut species. Flavonols and flavanones were the major types of phenolic compounds in almond, while pecan phenolics were mostly hydrolysable (ellagitannins acid ellagic acid derivatives) and condensed tannins (upto tetramers). Three ellagitannins are described for the first time in pecan., La almendra y nuez pecana son alimentos funcionales, cuyo consumo habitual puede prevenir el desarrollo de numerosas enfermedades crónico-degenerativas. Los compuestos fenólicos (CF) son algunos de los que poseen mayor actividad biológica en estos frutos secos, pero su identificación y caracterización siempre representa un reto analítico. El objetivo del presente trabajo fue caracterizar el perfil de los CF, mediante HPLC acoplado a espectrometría de masas en tándem (MS/MS) de dos tipos de extractos de nuez pecana y almendra, un extracto etanólico y uno acetónico. Se identificaron, mediante HPLC acoplado a espectrometría de masas de alta resolución (Q-TOF), 29 compuestos en almendra (22 estuvieron en el extracto acetónico y 24 en el etanólico) y 43 en nuez pecana (39 en el acetónico y 37 en el etanólico). La identidad de 6 compuestos de la almendra y 20 de nuez pecana se confirmó mediante el análisis de sus patrones de fragmentación en el modo MS/MS del equipo. El perfil de los CF fue claramente diferente entre almendra y nuez, pero muy parecido entre ambos tipos de solventes empleados (acetona y etanol), para un mismo fruto seco. En la almendra predominó la presencia de flavonoles y flavanonas, mientras que en nuez pecana predominaron taninos hidrolizables (sobre todo elagitaninos y derivados simples del ácido elágico) y condensados (hasta tetrámeros). En este estudio se describe por primera vez la identificación de tres elagitaninos en nuez pecana.

Almonds and pecans are considered functional foods because their regular intake provides protection against several chronic-degenerative diseases. Phenolic compounds are some of the most bioactive components of these tree nuts; yet, their identification and characterization is regularly viewed as an analytical challenge. The aim of the present work was to characterize the phenolic compound profile of acetone and methanol extracts of almond and pecan nut, by using HPLC coupled to tandem mass spectrometry (MS/MS). First, high resolution MS (Q-TOF) was used to identify phenolic compounds in the extracts: 29 compounds were detected in almond (22 in acetone extract, 24 in ethanol extract) and 43 in pecan (39 in acetone extract, 37 in ethanol extract). Identity of 6 almond compounds and 20 pecan compounds was confirmed through analysis of their MS/MS fragmentation patterns. Phenolic profiles were different between pecan and almond but similar between extraction solvents for a same tree nut species. Flavonols and flavanones were the major types of phenolic compounds in almond, while pecan phenolics were mostly hydrolysable (ellagitannins acid ellagic acid derivatives) and condensed tannins (upto tetramers). Three ellagitannins are described for the first time in pecan., La almendra y nuez pecana son alimentos funcionales, cuyo consumo habitual puede prevenir el desarrollo de numerosas enfermedades crónico-degenerativas. Los compuestos fenólicos (CF) son algunos de los que poseen mayor actividad biológica en estos frutos secos, pero su identificación y caracterización siempre representa un reto analítico. El objetivo del presente trabajo fue caracterizar el perfil de los CF, mediante HPLC acoplado a espectrometría de masas en tándem (MS/MS) de dos tipos de extractos de nuez pecana y almendra, un extracto etanólico y uno acetónico. Se identificaron, mediante HPLC acoplado a espectrometría de masas de alta resolución (Q-TOF), 29 compuestos en almendra (22 estuvieron en el extracto acetónico y 24 en el etanólico) y 43 en nuez pecana (39 en el acetónico y 37 en el etanólico). La identidad de 6 compuestos de la almendra y 20 de nuez pecana se confirmó mediante el análisis de sus patrones de fragmentación en el modo MS/MS del equipo. El perfil de los CF fue claramente diferente entre almendra y nuez, pero muy parecido entre ambos tipos de solventes empleados (acetona y etanol), para un mismo fruto seco. En la almendra predominó la presencia de flavonoles y flavanonas, mientras que en nuez pecana predominaron taninos hidrolizables (sobre todo elagitaninos y derivados simples del ácido elágico) y condensados (hasta tetrámeros). En este estudio se describe por primera vez la identificación de tres elagitaninos en nuez pecana.

[EN] Due to the high dependence of ruminant feeding systems on the use of soybean meal as source of protein, insect meals have been suggested as a promising alternative. However, a high rumen degradability might be a drawback for its utilisation. In this regard, tannins are known to be able to exert beneficial effects on the digestive utilization of protein-rich feeds due to a reduction of their degradation in the rumen, especially of the protein, although they might also restrict intestinal digestibility. Therefore, this experiment was conducted to examine if tannins could improve the digestive utilization of 4 insect meals (from Acheta domesticus, Alphitobius diaperinus, Tenebrio molitor and Zophobas morio). To this aim, four ruminally cannulated sheep were used to study the ruminal degradation and intestinal digestibility of these feedstuffs as well as those of soybean meal, which was used as a reference. The five substrates were treated with either 0% (control) or 15% DM of commercial tannin extracts from oak (OAK) or quebracho (QUE), and incubated in situ for 16 h. Afterwards, the intestinal digestibility of non-degraded protein was estimated in vitro. Both oak and quebracho tannins were able to protect the protein of insect meals from ruminal degradation, following a similar pattern than that observed in soybean meal. On average, reductions were about 15%, with no significant differences between oak and quebracho effects. On the opposite, the OAK treatment might offer advantages over QUE in terms of intestinal protein digestibility, as the latter caused a lower value in A. domesticus compared with the control. More research would be advisable to confirm these results, particularly in vivo., [FR] En raison de la forte dépendance à l’utilisation de tourteau de soja comme source de protéines dans les systèmes d’alimentation des ruminants, la farine d’insectes a été suggérée comme une alternative prometteuse. Cependant, une forte dégradation de sa protéine dans le rumen pourrait constituer un inconvénient à son utilisation. À cet égard, les tanins peuvent avoir des effets bénéfiques sur l’utilisation digestive des aliments riches en protéines, en réduisant leur dégradation dans le rumen, même si ils peuvent limiter la digestibilité intestinale. Par conséquent, cet essai a été mené afin d’examiner si les tanins pouvaient améliorer l’utilisation digestive de 4 farines d’insectes (provenant d’Acheta domesticus, Alphitobius diaperinus, Tenebrio molitor et Zophobas morio). Pour ce faire, quatre moutons munis d’une canule ruminale ont été utilisés afin d’étudier la dégradation ruminale et la digestibilité intestinale de ces aliments, en comparaison avec celles du tourteau de soja (aliment de référence). Les cinq substrats ont été traités avec 0 (témoin) ou 15% MS des extraits commerciaux de tanin de chêne (OAK) ou de quebracho (QUE) et par la suite ils ont été incubés in situ pendant 16 h. Ensuite, la digestibilité intestinale de la protéine non dégradée a été estimée in vitro. Les tanins de chêne et de quebracho ont permis de protéger la protéine des farines d’insectes de la dégradation ruminale, en suivant une tendance similaire à celle observée pour le tourteau de soja. En moyenne, la réduction de la dégradation protéique a été d’environ 15%, sans différence significative entre les effets du chêne et du quebracho. Au contraire, en termes de digestibilité intestinale des protéines, le traitement OAK pourrait offrir des avantages par rapport à QUE, puisque ce dernier a entrainé une valeur inférieure pour A. domesticus par rapport au contrôle. D’autres recherches seraient requises pour confirmer ces résultats, particulièrement en conditions in vivo.

Many studies quantify total phenolics or total tannins, but understanding the ecological role of polyphenolic secondary metabolites requires at least an understanding of the diversity of phenolic groups present. We used UPLC-MS/MS to measure concentrations of different polyphenol groups - including the four most common tannin groups, the three most common flavonoid groups, and quinic acid derivatives - in foliage from 628 eucalypts from the genera Eucalyptus, Angophora and Corymbia. We also tested for phylogenetic signal in each of the phenolic groups. Many eucalypts contained high concentrations of polyphenols, particularly ellagitannins, which have been relatively poorly studied, but may possess strong oxidative activity. Because the biosynthetic pathways of many phenolic compounds share either precursors or enzymes, we found negative correlations between the concentrations of several of the constituents that we measured, including proanthocyanidins (PAs) and hydrolysable tannins (HTs), HTs and flavonol derivatives, and HTs and quinic acid derivatives. We observed moderate phylogenetic signal in all polyphenol constituents, apart from the concentration of the prodelphinidin subunit of PAs and the mean degree of polymerisation of PAs. These two traits, which have previously been shown to be important in determining plants' protein precipitation capacity, may have evolved under selection, perhaps in response to climate or herbivore pressure. Hence, the signature of evolutionary history appears to have been erased for these traits. This study is an important step in moving away from analysing “totals” to a better understanding of how phylogenetic effects influence phenolic composition, and how this in turn influences ecological processes.

To evaluate behavior ofE. coliin feces of dairy cows added with hydrolysable tannins, an experiment was conducted, in which aliquots of 100 g were randomly assigned to two hydrolysable tannins levels (0 or 10%), three values of pH 5.2, 6.5 and 8.3, and cultured at 0, 2, 6, 9, 15, 22, and 30 days after tannins addition. Feces added with HT 10% shown the highestE. coligrowth (P< 0.01) compared to those that did not received HT (Log105.071vs.Log104.401). Feces with 6.5-pH value had lower values (P< 0.01) ofE. coli(Log104.525)vs. pH 5.2 (Log104.866), and pH 8.3 (Log104.816). In all cases theE. coligrowth diminished (P< 0.01) as increased days number (Log10= 5.51 day 0; Log10= 3.36 at day 30). The results suggest that HT did not inhibitE. coligrowth in feces of cows; however, at pH values close to neutrality theE. coligrowth decreases., Para evaluar el comportamiento de E. coli en heces de vacas lecheras adicionadas con taninos hidrolizables, se llevó a cabo un experimento en el que alícuotas de 100 g de heces fueron asignadas de manera aleatoria a uno de dos niveles (0 y 10%) de taninos hidrolizables (TH), uno de tres valores de pH: 5.2, 6.5 y 8.3 y cultivados a: 0, 2, 6, 9, 15, 22 y 30 días una vez adicionados los taninos. Las heces adicionadas con 10% de TH presentaron mayor crecimiento (P < 0.01) de E. coli comparadas con las que no se les agregó TH (Log10 5.071 vs. Log10 4.401). Las heces con pH 6.5 tuvieron valores menores (P < 0.01) de E. coli (Log10 4.525) vs. pH de 5.2 (Log10 4.866) y pH 8.3 (Log10 4.816). En todos los casos el crecimiento de E. coli disminuyó (P < 0.01) conforme se incrementaron los días (Log10 = 5.51 el día 0; Log10 = 3.36 en el día 30). Los resultados sugieren que los TH no inhiben el crecimiento de E. coli en las heces de las vacas, sin embargo a valores de pH cercanos a la neutralidad el crecimiento de E. coli en heces disminuye.

Para evaluar el comportamiento de E. coli en heces de vacas lecheras adicionadas con taninos hidrolizables, se llevó a cabo un experimento en el que alícuotas de 100 g de heces fueron asignadas de manera aleatoria a uno de dos niveles (0 y 10%) de taninos hidrolizables (TH), uno de tres valores de pH: 5.2, 6.5 y 8.3 y cultivados a: 0, 2, 6, 9, 15, 22 y 30 días una vez adicionados los taninos. Las heces adicionadas con 10% de TH presentaron mayor crecimiento (P < 0.01) de E. coli comparadas con las que no se les agregó TH (Log10 5.071 vs. Log10 4.401). Las heces con pH 6.5 tuvieron valores menores (P < 0.01) de E. coli (Log10 4.525) vs. pH de 5.2 (Log10 4.866) y pH 8.3 (Log10 4.816). En todos los casos el crecimiento de E. coli disminuyó (P < 0.01) conforme se incrementaron los días (Log10 = 5.51 el día 0; Log10 = 3.36 en el día 30). Los resultados sugieren que los TH no inhiben el crecimiento de E. coli en las heces de las vacas, sin embargo a valores de pH cercanos a la neutralidad el crecimiento de E. coli en heces disminuye., To evaluate behavior ofE. coliin feces of dairy cows added with hydrolysable tannins, an experiment was conducted, in which aliquots of 100 g were randomly assigned to two hydrolysable tannins levels (0 or 10%), three values of pH 5.2, 6.5 and 8.3, and cultured at 0, 2, 6, 9, 15, 22, and 30 days after tannins addition. Feces added with HT 10% shown the highestE. coligrowth (P< 0.01) compared to those that did not received HT (Log105.071vs.Log104.401). Feces with 6.5-pH value had lower values (P< 0.01) ofE. coli(Log104.525)vs. pH 5.2 (Log104.866), and pH 8.3 (Log104.816). In all cases theE. coligrowth diminished (P< 0.01) as increased days number (Log10= 5.51 day 0; Log10= 3.36 at day 30). The results suggest that HT did not inhibitE. coligrowth in feces of cows; however, at pH values close to neutrality theE. coligrowth decreases.

To evaluate behavior ofE. coliin feces of dairy cows added with hydrolysable tannins, an experiment was conducted, in which aliquots of 100 g were randomly assigned to two hydrolysable tannins levels (0 or 10%), three values of pH 5.2, 6.5 and 8.3, and cultured at 0, 2, 6, 9, 15, 22, and 30 days after tannins addition. Feces added with HT 10% shown the highestE. coligrowth (P< 0.01) compared to those that did not received HT (Log105.071vs.Log104.401). Feces with 6.5-pH value had lower values (P< 0.01) ofE. coli(Log104.525)vs. pH 5.2 (Log104.866), and pH 8.3 (Log104.816). In all cases theE. coligrowth diminished (P< 0.01) as increased days number (Log10= 5.51 day 0; Log10= 3.36 at day 30). The results suggest that HT did not inhibitE. coligrowth in feces of cows; however, at pH values close to neutrality theE. coligrowth decreases., Para evaluar el comportamiento de E. coli en heces de vacas lecheras adicionadas con taninos hidrolizables, se llevó a cabo un experimento en el que alícuotas de 100 g de heces fueron asignadas de manera aleatoria a uno de dos niveles (0 y 10%) de taninos hidrolizables (TH), uno de tres valores de pH: 5.2, 6.5 y 8.3 y cultivados a: 0, 2, 6, 9, 15, 22 y 30 días una vez adicionados los taninos. Las heces adicionadas con 10% de TH presentaron mayor crecimiento (P < 0.01) de E. coli comparadas con las que no se les agregó TH (Log10 5.071 vs. Log10 4.401). Las heces con pH 6.5 tuvieron valores menores (P < 0.01) de E. coli (Log10 4.525) vs. pH de 5.2 (Log10 4.866) y pH 8.3 (Log10 4.816). En todos los casos el crecimiento de E. coli disminuyó (P < 0.01) conforme se incrementaron los días (Log10 = 5.51 el día 0; Log10 = 3.36 en el día 30). Los resultados sugieren que los TH no inhiben el crecimiento de E. coli en las heces de las vacas, sin embargo a valores de pH cercanos a la neutralidad el crecimiento de E. coli en heces disminuye.

Intoxication of grazing cattle occurs repeatedly when they consume large amounts of young oak leaves (OL), that are rich in hydrolysable tannins (HT), due to a shortage of other feed resources. The HT are antimicrobial, although some rumen bacteria can resist or degrade them into potentially toxic or harmless metabolites. To study the effect of the administration of HT-rich OL (Quercus pyrenaica) after a severe feed restriction on the rumen bacterial community and monitor the variations in some bacterial groups that are potentially able to resist or metabolize tannins, 3 ruminally cannulated bulls were initially fed grass hay and then subjected to a severe 8-day feed restriction period, before receiving OL for 6 days. Then, the animals were offered again grass hay for 12 more days. Rumen contents were sampled throughout the experiment. Quantitative real-time PCR and terminal restriction fragment length polymorphism (T-RFLP) were used to monitor the bacterial dynamics. Animal 1 was not intoxicated and showed lower relative abundances of Streptococcus bovis initially and after the OL administration than animals 2 and 3, which showed acute signs of intoxication. The genus Prevotella increased its abundance with the OL administration, whereas Selenomonas ruminantium was reduced. The bacterial T-RFLP profile of animal 1 clustered initially separately from the animals 2 and 3 and was less affected by the feed restriction period. These results showed that the effect of the consumption of HT-rich OL after a severe feed restriction is highly variable in cattle and might rely on the individual composition of the microbiota colonizing the rumen.

Tannins are a unique group of phenolic metabolites with molecular weights between 500 and 30000 Da, which are widely distributed in almost all plant foods and beverages. Proanthocyanidins and hydrolysable tannins are the two major groups of these bioactive compounds, but complex tannins containing structural elements of both groups and specific tannins in marine brown algae have also been described. Most literature data on food tannins refer only to oligomeric compounds that are extracted with aqueous-organic solvents, but a significant number of non-extractable tannins are usually not mentioned in the literature. The biological effects of tannins usually depend on their grade of polymerisation and solubility. Highly polymerised tannins exhibit low bioaccessibility in the small intestine and low fermentability by colonic microflora. This review summarises a new approach to analysis of extractable and non-extractable tannins, major food sources, and effects of storage and processing on tannin content and bioavailability. Biological properties such as antioxidant, antimicrobial and antiviral effects are also described. In addition, the role of tannins in diabetes mellitus has been discussed. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Searching for simple analytical techniques to characterize polyphenol rich vegetable materials, a technique was standardized for spectrophotometric estimation of hydrolysable and condensed tannins. The technique was applied to the analysis of leaves of 14 species of melastomataceous plants. Dried and milled leaves were extracted with i-PrOH-Water (65:35) to be next hydrolysed in i- PrOH-HCl (65:35) mix. Condensed tannins were quantified by interpolation in a calibration curve of malvidin and hydrolysable tannins in a calibration curve with ellagic acid. Among the 14 studied species, 7 contain hydrolysable tannins (HT), 4 contain condensed tannins (CT) and 2 contain both types of tannins., En la búsqueda de técnicas analíticas sencillas para la caracterización de materiales vegetales ricos en polifenoles, se estandarizó una técnica para estimación espectrofotométrica de taninos hidrolizables y taninos condensados. La técnica se aplicó al análisis de las hojas de 14 especies de plantas melastomatáceas. Las hojas secas y molidas se extrajeron con i-PrOH-Agua (65:35) para luego ser hidrolizadas en una mezcla i-PrOH-HCl (65:35). Los taninos condensados se cuantificaron por interpolación en una curva de calibración de malvidín y los hidrolizables en una curva de calibración con ácido elágico. De las 14 especies estudiadas, 7 contienen taninos hidrolizables (TH), 4 contienen taninos condensados (TC) y 2 contienen los dos tipos de taninos.

The term tannin was historically coined by the empirical use that occurred to some vegetal extracts for the process of tanning or conversion of the animal skins to leather more than one hundred years ago. The development of the modern instrumental techniques for the structural elucidation of organic substances, allowed to the scientific beginning in the area of vegetable polyphenols, term suggested by doctor Edwin Haslam instead of tannins. In this revision some historical facts, definitions, techniques of isolation and structural elucidation, classification and applications of these compounds are discussed, from the tannery to the nutritional industry., El término tanino se acuñó históricamente por el uso empírico que se daba a algunos extractos vegetales para el proceso de tanaje o conversión de las pieles de animales en cuero desde hace más de cien años. El desarrollo de las modernas técnicas instrumentales para la elucidación estructural de sustancias orgánicas, permitió el inicio científico en el área de polifenoles vegetales, término sugerido por el doctor Edwin Haslam en lugar de taninos. En esta revisión se discuten algunos hechos históricos, definiciones, técnicas de aislamiento y elucidación estructural, clasificación y aplicaciones de estos compuestos, desde la curtiembre hasta la industria alimenticia.

Searching for simple analytical techniques to characterize polyphenol rich vegetable materials, a technique was standardized for spectrophotometric estimation of hydrolysable and condensed tannins. The technique was applied to the analysis of leaves of 14 species of melastomataceous plants. Dried and milled leaves were extracted with i-PrOH-Water (65:35) to be next hydrolysed in i- PrOH-HCl (65:35) mix. Condensed tannins were quantified by interpolation in a calibration curve of malvidin and hydrolysable tannins in a calibration curve with ellagic acid. Among the 14 studied species, 7 contain hydrolysable tannins (HT), 4 contain condensed tannins (CT) and 2 contain both types of tannins., En la búsqueda de técnicas analíticas sencillas para la caracterización de materiales vegetales ricos en polifenoles, se estandarizó una técnica para estimación espectrofotométrica de taninos hidrolizables y taninos condensados. La técnica se aplicó al análisis de las hojas de 14 especies de plantas melastomatáceas. Las hojas secas y molidas se extrajeron con i-PrOH-Agua (65:35) para luego ser hidrolizadas en una mezcla i-PrOH-HCl (65:35). Los taninos condensados se cuantificaron por interpolación en una curva de calibración de malvidín y los hidrolizables en una curva de calibración con ácido elágico. De las 14 especies estudiadas, 7 contienen taninos hidrolizables (TH), 4 contienen taninos condensados (TC) y 2 contienen los dos tipos de taninos.

The term tannin was historically coined by the empirical use that occurred to some vegetal extracts for the process of tanning or conversion of the animal skins to leather more than one hundred years ago. The development of the modern instrumental techniques for the structural elucidation of organic substances, allowed to the scientific beginning in the area of vegetable polyphenols, term suggested by doctor Edwin Haslam instead of tannins. In this revision some historical facts, definitions, techniques of isolation and structural elucidation, classification and applications of these compounds are discussed, from the tannery to the nutritional industry., El término tanino se acuñó históricamente por el uso empírico que se daba a algunos extractos vegetales para el proceso de tanaje o conversión de las pieles de animales en cuero desde hace más de cien años. El desarrollo de las modernas técnicas instrumentales para la elucidación estructural de sustancias orgánicas, permitió el inicio científico en el área de polifenoles vegetales, término sugerido por el doctor Edwin Haslam en lugar de taninos. En esta revisión se discuten algunos hechos históricos, definiciones, técnicas de aislamiento y elucidación estructural, clasificación y aplicaciones de estos compuestos, desde la curtiembre hasta la industria alimenticia.

In the field of plant-herbivore interactions research methods manipulating plant secondary metabolites are becoming more and more popular. In most cases food offered to herbivores is manipulated with commercially available compounds, or more specifically, compound mixtures. Among the most commonly used is tannic acid, the almost sole commercial source of hydrolysable tannins. However, recent studies have shown that different tannic acid preparations are not comparable in their tannin structures. While tannic acids are meant to contain only gallotannins (GTs), some commercial preparations compose mainly of more simple galloglucoses (that have e.g. much lower protein precipitation capacity than GTs) or even of gallic acid (the hydrolysis product of GTs). Another commonly used group of tannins used in feeding trials is condensed tannins (CTs), usually in the form of quebracho tannin. One of the problems in using quebracho is that it contains different CT structures than e.g. leaves of many deciduous trees. Additionally, when analysed with the common acid-butanol assay for total CTs, quebracho tannins give even 30-fold lower absorbance than the CTs of those deciduous trees. This dilemma is highlighted by the fact that quebracho tannin is commonly used as a standard when analysing CT concentrations in plant tissues. In addition to above problems, different herbivore species are known to react differently to varying tannin structures. Therefore, ecologically the most serious concern lies in that our commercial tannin compounds might have biological activities highly different from the tannins of our study plants. Below we discuss these problems, as well as some means to deal with them.

[EN] Tannins are a complex group of polyphenolic compounds found in a wide range of plant species commonly consumed by ruminants. They are conventionally classified into two major groups: the hydrolysable and the condensed tannins. Although for a long time tannins were thought to be detrimental to ruminants, their effect may be either beneficial or harmful depending on the type of tannin consumed, its chemical structure and molecular weight, the amount ingested, and the animal species involved. High concentrations of tannins reduce voluntary feed intake and nutrient digestibility, whereas low to moderate concentrations may improve the digestive utilisation of feed mainly due to a reduction in protein degradation in the rumen and a subsequent increase in amino acid flow to the small intestine. These effects on nutrition are reflected in animal performance., [ES] Los taninos son un grupo muy diverso de compuestos fenólicos que aparecen en una amplia variedad de plantas consumidas por los rumiantes. Tradicionalmente se han dividido, de forma simplista, en hidrolizables y condensados. Aunque durante mucho tiempo se pensó que los taninos eran negativos para los rumiantes, su efecto puede ser beneficioso o perjudicial dependiendo del tipo de tanino, de su estructura y peso molecular, de la especie animal que los consuma y, de modo fundamental, de la cantidad ingerida. Se sabe que el consumo de cantidades elevadas reduce la ingestión voluntaria y la digestibilidad de los nutrientes, en tanto que el consumo de cantidades pequeñas o moderadas puede mejorar la utilización digestiva, debido, principalmente, a una reducción de la degradación ruminal de la proteína y, en consecuencia, a una mayor disponibilidad de aminoácidos susceptibles de ser absorbidos en el intestino delgado. Estos efectos sobre la nutrición se ven reflejados en el rendimiento productivo de los animales.

Batch cultures of rumen microorganisms, using rumen fluids from 4 ruminant species, sheep, goats, cows, and deer, were used to study the ability of polyethylene-glycol (PEG 6000) to inhibit the effect of 2 types of tannins, quebracho (QUE, a condensed tannin) and tannic acid (TA, a hydrolysable tannin) on several in vitro rumen fermentation characteristics. Both QUE and TA were able to impair ruminal fermentation (they reduced gas production, extent of degradation, ammonia-N, and volatile fatty acid concentrations, etc.; P < 0.05), with differences depending on the inoculum donor. The clearest effect of tannins was the reduction of the rates of fermentation, which was observed in all species (P < 0.05). The detrimental effects of tannins were removed by the presence of PEG in most cases, but there were important variations and noticeable exceptions. Thus, for instance, PEG failed to revert the negative effect of TA on the rate of fermentation and the extent of degradation (P < 0.05). The extent of the limited ability of PEG to completely inhibit the negative effects of tannins on in vitro ruminal fermentation seems to depend both on the type of tannin and the species of the rumen inoculum donor.