Influence of cultivar and germination on bioactive amines in soybeans (Glycine max L. Merril)

The levels of amines in soybeans as affected by cultivar in two consecutive years and by germination were investigated. Spermidine, spermine, putrescine, agmatine, and cadaverine were detected, whereas tyramine, histamine, tryptamine, serotonine, and phenylethylamine were not. Spermidine was the predominant amine followed by spermine. High concentrations of these amines confirmed soybean as a rich source. Cadaverine was confirmed to be inherent to soybean. The percent contribution of spermidine and spermine to total levels was not affected by cultivar in either years. However, amine levels were affected by cultivars in different ways in the consecutive years. Cadaverine was affected more by the cultivar, whereas spermidine, spermine, and agmatine were affected by harvest year. During germination the levels of amines from soybean increased significantly, except for agmatine. Spermidine and spermine accumulated in the cotyledon, whereas cadaverine and putrescine accumulated in the radicle and hypocotyl.     

Biogenic amine formation and nitrite reactions in meat batter as affected by high-pressure processing and chilled storage

Changes in biogenic amine formation and nitrite depletion in meat batters as affected by pressure-temperature combinations (300 MPa/30 min/7, 20, and 40 degrees C), cooking process (70 degrees C/30 min), and storage (54 days/2 degrees C) were studied. Changes in residual nitrite concentration in raw meat batters were conditioned by the temperature and not by the pressure applied. Cooking process decreased (P < 0.05) the residual nitrite concentration in all samples. High-pressure processing and cooking treatment increased (P < 0.05) the nitrate content. Whereas protein-bound nitrite concentration decreased with pressure processing, no effect was observed with the heating process of meat batters. High-pressure processing conditions had no effect on the rate of residual nitrite loss throughout the storage. The application of high pressure decreased (P < 0.05) the concentration of some biogenic amines (tyramine, agmatine, and spermine). Irrespective of the high processing conditions, generally, throughout storage biogenic amine levels did not change or increased, although quantitatively this effect was not very important.     

Determination of biogenic amines in squid and white prawn by high-performance liquid chromatography with postcolumn derivatization

A simple method was developed for the determination of biogenic amines in aquatic food products using a reverse-phase high-performance liquid chromatography with postcolumn automatic o-phthalaldehyde derivatization and fluorescence detection. The linearity, repeatability, and recovery of the method for seven amines (tyramine, putrescine, cadaverine, histamine, agmatine, spermidine, and spermine) were evaluated. This optimized method was applied to detect biogenic amines in squid and white prawn during refrigerated storage. Sensory analysis, pH value, and total volatile base nitrogen value were combined to evaluate the freshness quality of these two raw materials. Agmatine and cadaverine in squid, cadaverine, and putrescine in white prawn were the most obviously changed amines during the storage at two different temperatures, and these biogenic amines could be the effective quality indicators for the freshness of the raw aquatic materials.     

Relation of biogenic amines' formation with microbiological and sensory attributes in Lactobacillus-inoculated vacuum-packed rainbow trout (Oncorhynchus mykiss) fillets

The biogenic amine (BA) content of vacuum-packed filleted rainbow trout (Oncorhynchus mykiss) inoculated or not with two different Lactobacillus strains, individually or in combination, was monitored during refrigerated storage for 20 days and related to respective bacteriological and sensory changes occurring during the same period. Eight amines, namely putrescine, cadaverine, tyramine, tryptamine, beta-phenylethylamine, histamine, spermine, and spermidine, were determined, whereas agmatine was not detected in any of the samples. In all cases, BA concentration was higher (P < or = 0.05) in the controls compared to all inoculated treatments, whereas the trend with regard to the bacterial populations (Enterobacteriaceae, pseudomonads, and H2S-producing bacteria) and the off-odor scores was similar. Inoculation with Lactobacillus sakei CECT 4808 showed the best preservative effect among inoculated treatments. Concentrations of putrescine and cadaverine, the main BAs formed, correlated well with both spoilage bacterial counts and off-odor scores and can be useful indicators of shelf life. Spermine and spermidine contents decreased during storage, while levels of the other determined BAs remained below 10 mg/kg even after sensory rejection.     

Biogenic amine profile in unripe Arabica coffee beans processed according to dry and wet methods

Immature coffee fruit processing contributes to a high amount of defective beans, which determines a significant amount of low-quality coffee sold in the Brazilian internal market. Unripe bean processing was tested, taking the levels of bioactive amines as criteria for evaluating the extent of fermentation and establishing the differences between processing methods. The beans were processed by the dry method after being mechanically depulped immediately after harvest or after a 12 h resting period in a dry pile or immersed in water. Seven bioactive amines were quantified: putrescine, spermine, spermidine, serotonin, cadaverine, histamine, and tyramine, with global amounts ranging from 71.8 to 80.3 mg/kg. The levels of spermine and spermidine were lower in the unripe depulped coffee than in the natural coffee. The specific conditions of dry and wet processing also influenced cadaverine levels, and histamine was reduced in unripe depulped coffee. A resting period of 12 h does not induce significant alteration on the beans and can be improved if performed in water. These results confirm that peeling immature coffee can decrease fermentation processes while providing more uniform drying, thus reducing the number of defects and potentially increasing beverage quality.     

Grain-size effect on the structure and antiobesity activity of konjac flour

The effect of high-frequency oscillatory type ball-mill treatment on the structure and antiobesity activity of konjac flour was investigated. The grain size of konjac flour changed from 657.3 microm (d(50)) to 23.7 microm (d(50)) after 4 h of treatment. The structural change of the konjac flour with different grain size was characterized by using X-ray diffraction (XRD) differential scanning calorimetry (DSC). The results indicated that the crystallinity decreased and the diffraction peak drifted not only by when the crystallization region was reduced but also when the crystalline structure was changed. With the decrease of the grain size and crystallinity, the konjac flour grain, especially the 4 h milled konjac flour, swelled more rapidly and led to the improvement of the antiobesity effect. Compared with the native konjac flour, the 4 h milled konjac flour could significantly decrease the body weight and total wet weight of fat of nutritional obese rats (P < 0.05) and also decreased the contents of triglyceride, glucose, and high-density lipoprotein in blood of nutritional obese rat significantly (P < 0.05), which meant the grain-size effect of konjac flour improved its antiobesity activity notably.     

Changes in polyamines and ethylene during the development and ripening of eggplant fruits (Solanum melongena)

The levels of free polyamines in the endocarpium of eggplants (Solanum melongena) cv. Black Nite were studied during fruit growth and ripening. Other parameters such as weight and volume variation, respiratory intensity, ethylene production, and sugar content were determined. The polyamines found were putrescine and spermidine, with a higher amount of the former. No spermine, agmatine, or cadaverine were found during the development and ripening period of eggplant. At the beginning of fruit development, the levels of putrescine and spermidine observed were 1.67 nmol/g of fresh tissue. Putrescine levels peaked at 17.4 nmol/g of fresh tissue on the ninth day after petal fall, decreasing later to the initial levels. No significant changes in spermidine were observed during the growth period of the fruit. Beginning 9 days after petal fall, there was a rapid increase in fruit weight and volume, which coincided with the maximum content of free polyamines. At the same growth stage, total sugar content was maximum. Ethylene production decreased rapidly from 14.23 to 1.5 microL/kg.h and remained low during the whole growth period.     

不同亲水胶体对带鱼鱼糜凝胶品质的影响

为确定合适的亲水胶体种类及其添加量,以带鱼鱼糜为原料,通过测定凝胶强度、质构(硬度、粘聚性、弹性和咀嚼性)、白度、持水性和凝胶溶解度等指标,分析瓜尔胶、魔芋胶和沙蒿胶3种亲水胶体对带鱼鱼糜凝胶品质的影响。结果表明,瓜尔胶、魔芋胶和沙蒿胶均能提高带鱼鱼糜凝胶强度,但相同添加量下魔芋胶的改善效果最好,而瓜尔胶对鱼糜凝胶强度的影响不显著。魔芋胶能显著改进带鱼鱼糜凝胶的质构特性;瓜尔胶添加量为2.0%时鱼糜凝胶硬度、弹性、咀嚼性、粘聚性比对照组低;沙蒿胶对鱼糜凝胶的粘聚性影响显著,当添加量为1.5%或2.0%时,带鱼鱼糜凝胶的咀嚼性、硬度增加,弹性下降。瓜尔胶、魔芋胶和沙蒿胶均能提高带鱼鱼糜持水性,降低鱼糜凝胶白度和溶解度,但对鱼糜凝胶色泽的影响不显著。扫描电镜结果显示,1.5%魔芋胶处理组形成的鱼糜凝胶表面规则有序、网络结构致密均一。综合比较,添加1.5%魔芋胶能有效改善带鱼鱼糜的凝胶品质。本研究结果为提高带鱼鱼糜制品品质及生产研发提供了一定的理论依据。     

Carotenoid content, physicochemical, and sensory qualities of deep-fried carrot chips as affected by dehydration/rehydration, antioxidant, and fermentation.

Carrot slices were subjected to one of the following experiments prior to deep-frying: (A) dehydration/rehydration, (B) soaking in different antioxidants, and (C) fermentation with/without blanching. There were no significant differences (P > or = 0.05) in carotenoid contents among carrot chips treated with/without dehydration. Soaking in sodium metabisulfite resulted in the highest carotenoid content and lightness (L), redness (a), and yellowness (b) values among the antioxidant treatments. Fermentation without blanching significantly decreased (P < 0.05) carotenoid content, vitamin A activity, and fat content. Dehydration and fermentation with blanching significantly increased (P < 0.05) the lightness (L), redness (a), and yellowness (b) values of the chips. Dehydration/rehydration, but not antioxidant and fermentation, significantly decreased (P < 0.05) the water activity of the chips. The textural values of carrot chips prepared using sodium metabisulfite, without dehydration and without fermentation, were the lowest among other treatments which suggests the crispiest. Carrot chips prepared using sodium metabisulfite, without dehydration and without fermentation, had the highest carotenoid content and retention, and the highest overall acceptability score.     

High-performance liquid chromatographic determination of biogenic amines in poultry carcasses

Biogenic amines, produced by bacterial decarboxylation of amino acids, have been associated with toxicological symptoms in broilers fed various poultry byproducts. A reversed-phase high-performance liquid chromatographic method is described for the quantitation of eight biogenic amines (tryptamine, phenylethylamine, putrescine, cadaverine, histamine, tyramine, spermidine, and spermine) in chicken carcasses. Amines were extracted with perchloric acid, derivatized with dansyl chloride, separated using gradient elution (methanol and water), and detected by fluorescence. Benzylamine was used as the internal standard. Linearity, repeatability, and recovery of the method were evaluated. The method was linear for all of the amines studied at concentrations ranging from 0.05 to 25 microg/mL. Average recoveries ranged from 92.6% to 96.8% for all amines except for histamine, which was 74.6%.     

体外法添加苹果酸与不饱和脂肪酸对瘤胃发酵及瘤胃功能菌群的影响

本研究采用体外法在油酸（Oleic acid,OA）、亚油酸（Linoleic acid,LA）、亚麻酸（Linolenic acid,LNA）的基础上添加不同水平苹果酸(Malic acid, MA),研究苹果酸和不饱和脂肪酸对瘤胃发酵模式与瘤胃主要功能菌群的影响。结果表明添加不饱和脂肪酸和苹果酸后,丙酸浓度随着脂肪酸不饱和度的增加显著升高（P<0.01）,总产气量和CH4产量显著降低（P<0.01）,其它挥发性脂肪酸均随着脂肪酸不饱和度的增加显著降低（P<0.01）。添加不饱和脂肪酸LA与LNA的甲酸甲烷杆菌数量显著增加（P<0.01）;白色瘤胃细菌与黄色瘤胃细菌数量比CK组显著增加（P<0.05）;而脂解厌氧弧杆菌和溶纤维丁酸弧菌数量比CK组却显著下降（P<0.05）。联合添加苹果酸和不饱和脂肪酸组中,只有在添加10 mmol/L苹果酸的OA组的甲酸甲烷杆菌,数量明显减少（P<0.05）。结论是不饱和脂肪酸和苹果酸能够改善瘤胃发酵模式,但二者对体外CH4抑制作用之间没有直接的联系。并且联合添加二者对于瘤胃主要功能菌群没有显著影响。     

雷帕霉素靶蛋白(mTOR)信号通路参与沉默信息调节因子1(Sirt1)抑制小鼠脂肪沉积

探讨沉默信息调节因子1(Sirt1)对小鼠脂肪沉积的抑制作用和雷帕霉素靶蛋白(mTOR)信号通路的影响。用Sirt1的激动剂白藜芦醇(100mg·kg-·1d-1)和抑制剂尼克酰胺(500mg·kg-·1d-1)灌胃处理小鼠(Mus mussulus)15d,记录小鼠体质量变化,测定小鼠皮下脂肪、附睾脂肪和肾周脂肪的沉积量,试剂盒测定血脂指标,同时利用Real-timePCR分析与脂肪生成密切相关的转录因子过氧化物酶体增殖物激活受体γ(PPARγ)、固醇调节元件结合蛋白1(SREBP1)和脂解基因甘油三酯水解酶(ATGL)、激素敏感性脂肪酶(HSL)、围脂滴蛋白(Perilipin)及生脂基因脂肪酸合成酶(FAS)mRNA的表达水平,检测mTOR通路关键因子雷帕霉素靶蛋白(mTOR)、核糖体S6蛋白激酶1(S6K1)和真核启动因子4E结合蛋白1(4EBP1)mRNA表达水平。与对照组相比,白藜芦醇处理组小鼠体质量增加量和体脂含量均显著降低(P<0.01),血清中甘油三酯(TG)、总胆固醇(TC)和低密度脂蛋白(LDL-C)浓度均显著降低(P<0.01),而高密度脂蛋白(HDL-C)浓度升高(P<0.01),mTOR通路关键因子mTOR、4EBP1和S6K1mRNA表达水平降低(P<0.01),脂代谢相关基因PPARγ、SREBP1及成脂基因FASmRNA表达水平显著降低(P<0.01),脂解相关基因ATGL、HSL和PerilipinmRNA表达水平显著升高(P<0.01);烟酰胺处理组小鼠体质量、附睾脂肪以与皮下脂肪沉积量增加缓慢(P>0.05),肾周脂肪沉积量增加(P<0.05),血清中LDL-C浓度升高(P<0.05),HDL-C浓度降低(P<0.01),mTOR通路关键因子mTOR和4EBP1mRNA表达水平升高(P<0.01),而脂代谢调控相关因子PPARγ和SREBP1mRNA水平升高(P<0.05),ATGLmRNA表达量显著降低(P<0.05),FAS、HSL和PerilipinmRNA表达量变化不显著(P>0.05)。表明激活Sirt1可减少脂肪合成,增加脂肪分解,从而降低体脂沉积,而mTOR信号通路参与这个过程。     

Dietary combination of conjugated linoleic acid (CLA) and pine nut oil prevents CLA-induced fatty liver in mice

Conjugated linoleic acid (CLA) strongly prevents fat accumulation in adipose tissue of mice, even if hepatic fat deposition and insulin resistance are concomitantly observed. This study investigated the possibility of maintaining the antiadiposity properties of CLA while preventing adverse effects such as liver steatosis and hyperinsulinemia. To this end, mice were divided into three groups and fed a standard diet (control) or a diet supplemented with 1% CLA (CLA) or a mixture of 1% CLA plus 7.5% pine nut oil (CLA + P). The combination of CLA + P preserved the CLA-mediated antiadiposity properties (70% fat reduction), preventing hepatic steatosis and a sharp increase in plasmatic insulin starting from the eighth week of CLA treatment. The assay of both fatty acid synthesis and oxidation in the CLA + P mice revealed a time-dependent biphasic behavior of the corresponding enzymatic activities. A sudden change in these metabolic events was indeed found at the eighth week. A strong correlation between the changes in key enzymes of lipid metabolism and in insulin levels apparently exists in CLA-fed mice. Furthermore, lower levels of lipids, in comparison to values found in CLA-fed mice, were observed in the liver and plasma of CLA + P-fed animals.     

Biogenic amines in wines from three Spanish regions

One hundred and sixty-three wines from La Rioja, Utiel-Requena, and Tarragona were analyzed to determine if there were any differences in the concentrations of six biogenic amines that are found in these three regions. The influence of grape variety, type of vinification, wine pH, malolactic fermentation, and storage in bottle on biogenic amine concentrations was studied. Results show important differences in putrescine and histamine concentrations among regions, varieties of grape, and type of wine; differences were less appreciable for the remaining biogenic amines studied. Low pH prevented biogenic amine formation. Malolactic fermentation and short storage periods in bottle (3-6 months) showed increases in histamine concentration, whereas longer periods of storage led to a general decrease in histamine. Several strains of lactic acid bacteria were isolated in this work, and their ability to form biogenic amines was assayed in synthetic media, grape must, and wine. Grape varieties, different types of winemaking, pH, and lactic acid bacteria may be responsible for the differences observed in the biogenic amine concentrations of the wines analyzed.     

Content of biogenic amines in a Chardonnay wine obtained through spontaneous and inoculated fermentations

This paper describes the content of biogenic amines in wines obtained from a Chardonnay must inoculated with different strains of Saccharomyces cerevisiae and in a wine fermented with the indigenous yeasts (control wine). The concentrations of nonvolatile amines and phenethylamine in the wines from the inoculated must were superior to those of the control wine. This was probably due to the fact that consumption of the precursor amino acids of these amines, during fermentation, was also greater in the inoculated samples than in the control sample. Furthermore, from the results obtained it may be said that, at least to some extent, the nonvolatile amines were formed by yeasts during fermentation. The concentrations of dimethylamine, ethylamine, and pyrrolidine (volatile amines) were different for the different wines, although they did not reach concentrations sufficiently high to have any effect on the aroma.     

一株产常温葡甘聚糖酶的芽孢杆菌的分离、鉴定及产酶发酵条件的研究

以魔芋生粉为唯一碳源的筛选培养基,从魔芋废渣中分离筛选出一株可以降解魔芋生粉的细菌菌株,编号为LS-6。根据16SrDNA序列和生理生化特性,将该菌株鉴定为枯草芽孢杆菌Bacillus subtilis。胞内外葡甘露聚糖酶酶活分析结果表明,LS-6产生的葡甘聚糖酶为胞外酶。LS-6产生葡甘聚糖酶的最佳培养基组分和条件是：1%魔芋生粉,0.5%酵母粉,0.5%NaCl,培养基初始pH为6.0,最佳发酵条件是25℃,摇床转速200r/min,培养48h。酶解产物的高效液相色谱分析结果表明,LS-6粗酶液的酶解产物主要为葡萄糖和甘露糖。LS-6的分离为进一步克隆常温葡甘聚糖酶基因和产酶工程菌的构建奠定了基础。     

Influence of lupin (Lupinus luteus L. cv. 4492 and Lupinus angustifolius L. var. zapaton) and fenugreek (Trigonella foenum-graecum L.) germination on microbial population and biogenic amines

Microbial population and bioactive amine profile and levels of two lupin species (Lupinus luteus L. cv. 4492 and Lupinus angustifolius L. var. zapaton) and fenugreek (Trigonella foenum-graecum L.) seeds as affected by germination were investigated. Microbial population increased considerably mainly in the first stage of germination (2 days), then small changes in bacterial numbers were observed up to 5 days to levels between 7.8 and 8.9 log colony-forming units/g. Microorganisms belonging to the Enterobacteriaceae family were dominant for the legumes tested. Ungerminated legume seeds contained putrescine, cadaverine, histamine, tyramine, spermidine, and spermine. Bioactive amine levels found in fenugreek seeds were between 3- and 4-fold higher than those found in lupin seeds. The highest total amine levels were found in fenugreek seeds [162 mg/kg of dry weight (dw)], followed by L. angustifolius var. zapaton seeds (84 mg/kg of dw) and, finally, L. luteus cv. 4492 (46 mg/kg of dw) seeds. The concentration of individual amines showed a gradual rising trend during the germination period in all tested sprouts, reaching levels >3 times higher than those found in ungerminated seeds. After 5 days of germination, the fenugreek sprouts contained the highest amount of total bioactive amines. Tyramine was the predominant amine in both lupin varieties, whereas cadaverine was the main bioactive amine detected in fenugreek. The results of this work thus indicated that microbial population and biogenic amine levels in the studied lupin and fenugreek sprouts are not a risk for healthy consumers or for individuals with restricted activity of detoxification enzymes.     

Relationship between kinase phosphorylation, muscle fiber typing, and glycogen accumulation in longissimus muscle of beef cattle with high and low intramuscular fat

The objective of this study was to examine the association of adenosine monophosphate (AMP)-activated protein kinase (AMPK) with glycogen content in bovine muscle and their links with intramuscular fat (IMF) and muscle fiber type composition. Five steers with high intramuscular fat (High IMF, IMF content is 5.71 +/- 0.36%) and five steers with low intramuscular fat (Low IMF, IMF content is 2.09 +/- 0.19%) in the longissimus thoracis muscle (LM) were selected for immunoblotting, glycogen, and myofiber type composition analyses. The glycogen content was higher in Low IMF muscle than in High IMF muscle (1.07 +/- 0.07 versus 0.85 +/- 0.08 g/100 g muscle, P < 0.05). Phosphorylation of the AMPK alpha subunit at Thr 172, which is correlated with its activity, was lower (P < 0.05) in High IMF compared to Low IMF. In agreement with the lower AMPK phosphorylation in High IMF muscle, the phosphorylation of acetyl-CoA carboxylase (ACC) was also lower (P < 0.05) in High IMF muscle than in Low IMF muscle. Glycogen synthase kinase 3 (GSK3) down-regulates glycogen synthesis through phosphorylation of glycogen synthase. The phosphorylation of GSK3 in High IMF was lower (P < 0.05) than that in Low IMF, which should down-regulate glycogen synthase activity and reduce the glycogen content in High IMF beef. Type IIB myosin isoform was absent in beef muscle. No noticeable difference in myosin isoform composition was observed between Low and High IMF muscle. In summary, High IMF cattle had lower LM glycogen levels than low IMF cattle, and AMPK activity was less in High IMF than in Low IMF cattle. The difference in glycogen content between Low and High IMF muscle was not correlated with muscle fiber composition. This data shows that LM lipid and glycogen metabolisms are affected by AMPK activity. Thus, AMPK may be a molecular target to alter IMF and glycogen levels in beef muscle.