RESUMO
BACKGROUND: Chronotype has been related to obesity and metabolic disturbances. However, little is known about the relationship between circadian preferences and genetic background in CLOCK genes with obesity and weight loss among severely obese patients after bariatric surgery. OBJECTIVES: The research goals were (1) to examine whether evening chronotype is related to obesity and weight loss evolution in severely obese followed during 6 years after bariatric surgery and (2) to examine potential interactions between circadian preferences and CLOCK 3111T/C for obesity in this population. SUBJECTS/METHODS: Participants (n=252, 79% female; age (mean±s.d.): 52±11 years; body mass index (BMI): 46.4±6.0 kg m-2) were grouped into evening and morning types. Obesity and weight loss parameters, energy and macronutrients intake, energy expenditure, chronotype, meal timing, sleep duration and CLOCK genotype were studied. RESULTS: Evening-type subjects showed significantly higher initial body weight (P=0.015) and BMI (P=0.014) than morning types. Moreover, evening-type, when compared with morning types, lost less weight (percentage of excess weight loss) after bariatric surgery (P=0.015). Weight-loss progression between the two chronotype groups differed significantly from the fourth year after the bariatric surgery toward a higher weight regain among evening types (P<0.05). We also detected a significant interaction between CLOCK 3111T/C SNP and chronotype for body weight at baseline (P<0.001). Specifically, among carriers of the risk allele C, evening types showed higher body weight than morning types (P=0.012). In addition, CLOCK 3111T/C SNP significantly associated with obesity and sleep duration in the older subjects. CONCLUSIONS: Evening chronotype is associated with higher obesity in severely obese subjects and with lower weight loss effectiveness after bariatric surgery. In addition, circadian preferences interact with CLOCK 3111T/C for obesity. The circadian and genetic assessment could provide tailored weight loss recommendations in subjects who underwent bariatric surgery.
Assuntos
Proteínas CLOCK/metabolismo , Ritmo Circadiano , Obesidade Mórbida/metabolismo , Adulto , Cirurgia Bariátrica , Ritmo Circadiano/genética , Metabolismo Energético/fisiologia , Comportamento Alimentar , Feminino , Seguimentos , Frequência do Gene , Variação Genética , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade Mórbida/genética , Obesidade Mórbida/cirurgia , Estudos Prospectivos , Espanha/epidemiologia , Redução de Peso/genéticaRESUMO
Major brands of cocoa powder products present in the Spanish market were analyzed for monomeric flavanols [(+)-catechin and (-)-epicatechin] and flavonols [quercetin-3-glucuronide, quercetin-3-glucoside (isoquercitrin), quercetin-3-arabinoside, and quercetin]. In addition, the influence of the manufacturing process of cocoa powder products, in particular, the alkalinization treatment ( Dutching), on the original content of these flavonoids has been studied. (-)-Epicatechin was in the range of 116.02-730.26 microg/g, whereas (+)-catechin was in the range of 81.40-447.62 microg/g in the commercial cocoa products studied. Among flavonols, quercetin-3-arabinoside and isoquercitrin were the major flavonols in the cocoa powder products studied, ranging from 2.10 to 40.33 microg/g and from 3.97 to 42.74 microg/g, respectively, followed by quercetin-3-glucuronide (0.13-9.88 microg/g) and quercetin aglycone (0.28-3.25 microg/g). To our knowledge, these results are the first quantitative data in relation to the content of individualized flavonol derivatives in commercial cocoa powder products. The alkalinization treatment resulted in 60% loss of the mean total flavonoid content. Among flavanols, (-)-epicatechin presented a larger decline (67%, as a mean percentage difference) than (+)-catechin (38%), probably because of its epimerization into (-)-catechin, a less bioavailable form of catechin. A decline was also confirmed for di-, tri-, and tetrameric procyanidins. In the case of flavonols, quercetin presented the highest loss (86%), whereas quercetin-3-glucuronide, quercetin-3-arabinoside, and isoquercitrin showed a similar decrease (58, 62, and 61%, respectively). It is concluded that the large decrease found in the flavonoid content of natural cocoa powder, together with the observed change in the monomeric flavanol profile that results from the alkalinization treatment, could affect the antioxidant properties and the polyphenol biovailability of cocoa powder products.
Assuntos
Cacau/química , Flavonoides/análise , Manipulação de Alimentos/métodos , Disponibilidade Biológica , Catequina/análise , Flavonoides/farmacocinética , Flavonóis/análise , Conservação de Alimentos , Concentração de Íons de Hidrogênio , Quercetina/análogos & derivados , Quercetina/análiseRESUMO
BACKGROUND: Food iron fortification can be a good strategy to prevent iron deficiency. Iron bioavailability from cocoa powder enriched with ferric pyrophosphate encapsulated in liposomes or ferrous fumarate was assessed in rats. METHODS: Three groups of rats consumed during 28 days either a control diet or two diets prepared with ferric pyrophosphate- or ferrous fumarate-enriched cocoa powder as the unique source of iron. Body weight and food intake were monitored and last-week feces were collected. On day 28, animals were sacrificed and livers and spleens were removed. Hemoglobin and total iron binding capacity (TIBC) were determined. RESULTS: There were no significant differences in body weight and food intake. Apparent iron absorption and % absorption/intake were significantly lower in rats consuming enriched cocoa compared to the control group, without significant differences due to the iron form. Enriched cocoa groups showed significantly lower spleen iron content and concentration than the control. Liver iron was lower in the ferric pyrophosphate group compared to the other two groups. Hemoglobin and TIBC values showed a deficient iron status in ferric pyrophosphate rats. CONCLUSION: Cocoa powder is a good vehicle for iron fortification when enriched with ferrous fumarate compared to ferric pyrophosphate encapsulated in liposomes.
Assuntos
Cacau , Difosfatos/farmacocinética , Compostos Ferrosos/farmacocinética , Ferro da Dieta/farmacocinética , Ferro/farmacocinética , Fígado/metabolismo , Baço/metabolismo , Anemia Ferropriva/prevenção & controle , Anemia Ferropriva/terapia , Animais , Disponibilidade Biológica , Dieta , Feminino , Alimentos Fortificados , Hemoglobinas/análise , Ferro da Dieta/sangue , Lipossomos , Masculino , Distribuição Aleatória , Ratos , Ratos WistarRESUMO
OBJECTIVES: The aim of this study was to characterize the physico-chemical properties of cocoa fibre (CF), to analyze its polyphenolic content and antioxidant capacity in vitro, and to investigate the effect of the administration of a polyphenolic extract of this cocoa fiber on the antioxidant capacity of the serum in rats. METHODS AND MATERIALS: Dietary fiber (DF) composition and polyphenolic (PP) content of the cocoa fiber were analyzed. The antioxidant capacity of the CF was determined by means of its reduction power (FRAP) and the capacity to scavenge free radicals (ABTS). To evaluate the bioavailability and the antioxidant capacity in vivo of the phenolic compounds of CF, an extract of these compounds was administred in the stomach of the rats with a gastric probe (100 mg PP/kg), taking blood samples at different time intervals. Sera were analyzed by HPLC to determine the presence/absence of PP or PP-metabolites. In orther to evaluate the antioxidant capacity of the serum FRAP and ABTS methods were used. RESULTS: Cocoa fiber was an excellent source of DF, with a high content of total dietary fiber (TDF), over 60% of the dry matter, made up mainly of insoluble dietary fiber (IDF; 83% of TDF). This fiber had just 1.15% of polyphenols, with low antioxidant activity. After intragastric administration of the PP-rich fraction a fast and measurable absorption of the CF polyphenols was observed, being epicatechin the main PP in blood. The absorption of this PP confers a significant, although transitory increase of the serum antioxidant capacity 10-45 minutes post-gavage; after this time, the antioxidant capacity progressively decreased reaching basal levels after 6 h. CONCLUSIONS: Cocoa fiber can be considered as an excellent source of DF, mainly insoluble dietary fiber; therefore, it could be used as an ingredient in fiber-rich functional foods. Besides the benefits derived from its high fiber content, the CF would provide protection against oxidative damage by means of its content in phenolic compounds (epicatechin) wich are absorbed maintaining the antioxidant properties in vivo.
Assuntos
Antioxidantes/fisiologia , Fenômenos Fisiológicos Sanguíneos/efeitos dos fármacos , Cacau , Fibras na Dieta/farmacologia , Animais , Cacau/química , Fenômenos Químicos , Físico-Química , Masculino , Ratos , Ratos WistarRESUMO
BACKGROUND: Recent research has demonstrated a relationship between the timing of food intake and weight loss in humans. However, whether the meal timing can be associated with weight loss in patients treated with bariatric surgery is unknown. OBJECTIVE: To evaluate the role of food-timing in the evolution of weight loss in a sample of 270 patients that underwent bariatric surgery with a follow-up of 6 years. METHODS: Participants (79% women; age [mean ± SD]: 52 ± 11 years; BMI: 46.5 ± 6.0 kg/m2) were classified according their weight loss response patterns after bariatric surgery: good weight-loss-responders (67.8%), primarily poor weight-loss-responders (10.8%) or secondarily poor weight-loss-responders (21.4%). Then, they were grouped in early-eaters and late-eaters, according to the timing of the main meal (before or after 15:00 h). Obesity and biochemical parameters, energy and macronutrients intake, energy expenditure, sleep duration, and chronotype were studied. RESULTS: The percentage of late eaters (after 15:00 h) was significantly higher in the primarily poor weight-loss-responders (â¼70%) than in both secondarily poor weight-loss-responders (â¼42%) and good weight-loss-responders (â¼37%) (p = 0.011). Consistently, primarily poor weight-loss-responders had lunch later as compared to good and secondarily poor weight-loss-responders (p = 0.034). Age, gender and type of surgery were not determining. Surprisingly, obesity-related variables, biochemical parameters, pre-surgical total energy expenditure, sleep duration, chronotype, calorie intake and macronutrients distribution, were similar among groups. CONCLUSIONS: Weight loss effectiveness after bariatric surgery is related to the timing of the main meal. Our preliminary results suggest that the timing of food intake is important for weight regulation and that eating at the right time may be a relevant factor to consider in weight loss therapy even after bariatric surgery.
Assuntos
Cirurgia Bariátrica , Ingestão de Alimentos , Obesidade Mórbida/cirurgia , Redução de Peso , Adulto , Índice de Massa Corporal , Ingestão de Energia , Metabolismo Energético , Feminino , Humanos , Masculino , Refeições , Pessoa de Meia-Idade , Sono , Fatores de Tempo , Resultado do TratamentoRESUMO
A rapid, simple and reliable liquid chromatographic method has been developed for the simultaneous determination of nicotinamide, thiamin, riboflavin, pyridoxine, pyridoxal, pyridoxamine, cyanocobalamine and folic acid in liquid and powdered infant milk. Ion-pair chromatography with a reversed-phase C18 column is used. Six vitamins were resolved in a single analysis; total analysis time never exceeded 55 min. A mobile phase of methanol-water (15:85), 5 mM octanesulfonic acid, with 0.5% triethylamine at pH 3.6 and a flow-rate of 1.0 ml/min gave the most satisfactory separation of these vitamins using a UV detector set at different wavelengths. Sample preparation involves acidification to precipitate proteins, and centrifugation followed by gravity filtration. Linearity, precision, recovery and sensitivity were always satisfactory. Detection limits ranged from 0.02 to 0.10 microgram/ml and determination limits ranged from 0.03 to 0.25 microgram/ml.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Alimentos Infantis/análise , Complexo Vitamínico B/análise , Animais , Humanos , Lactente , Modelos Lineares , Leite/química , Reprodutibilidade dos Testes , Solubilidade , Espectrofotometria Ultravioleta , Complexo Vitamínico B/química , Água/químicaRESUMO
A high-performance liquid chromatography (HPLC) method to determine available lysine is proposed. Available lysine was measured by an optimised fluorodinitrobenzene method on the basis of the reactivity of the free epsilon-amino group of the lysine. The classical acid hydrolysis has been improved and shortened from the usual time of 12 h to 2 h 30 min using an oil bath. Optimal resolution and quantitation of Nn-dinitrophenyllysine was obtained with a Nova-Pak C18 column using an isocratic elution with 35% methanol and 65% 0.01 M sodium acetate buffer (pH 4.5) and a flow-rate of 1 ml/min. Satisfactory results were obtained for the reliability of the method in terms of linearity from 0.1 to 5.0 mg/l of lysine-free base, precision (R.S.D. values between 4.3% and 7.8%), recovery (91.5%) and sensitivity (detection limit of 0.02 mg/l). The proposed method has also been checked for lack of interferences from other dinitrophenyl-amino acids.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Alimentos Infantis/análise , Lisina/análise , Ácidos/química , Animais , Humanos , Hidrólise , Lactente , Leite/química , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Fatores de TempoRESUMO
The interaction between tyrosine-decarboxylase and proteolytic activities of a Lactobacillus curvatus and Staphylococcus xylosus, respectively, on biogenic amine production during the ripening and the storage of dry fermented sausages was investigated. Water content, pH, proteolysis parameters, microbial counts, and biogenic amine contents were monitored in spontaneously and starter fermented sausages. The use of proteolytic staphylococci as starter resulted in a higher content of non-protein nitrogen and total free amino acids. Tyramine was the main amine produced in all batches. However, tyrosine-decarboxylase activity of the L. curvatus starter strain was weak and yielded lower amounts of tyramine than those produced by the wild mioroflora in the control batch. Association between tyramine production and proteolysis could only be established in a defectively dried batch. Putrescine and cadaverine accumulation was efficiently reduced in the starter-mediated fermentation, in agreement with the lower development of enterobacteria. Phenylethylamine and tryptamine were only detected in the spontaneously fermented sausages, while histamine, spermine and spermidine did not vary during the ripening. Biogenic amine levels and related parameters showed significant changes during the storage of dry sausages depending on the temperature and the batch. As a general rule, changes in the pH, proteolysis, microbial counts, and biogenic amine contents were stronger at 19 degrees C than at 4 degrees C. The results suggest that refrigeration would be advisable for preventing further accumulation of biogenic amines during the storage of dry fermented sausages.
Assuntos
Aminas Biogênicas/biossíntese , Conservação de Alimentos , Lactobacillus/metabolismo , Produtos da Carne/microbiologia , Staphylococcus/metabolismo , Contagem de Colônia Microbiana , Fermentação , Manipulação de Alimentos , Concentração de Íons de Hidrogênio , Temperatura , Tiramina/biossíntese , ÁguaRESUMO
The effect of proteolytic starter cultures of Staphylococcus carnosus and Staphylococcus xylosus on biogenic amine production was examined during the fermentation process of dry sausages. Microbial counts (lactic acid bacteria, Micrococcaceae and Enterobactenaceae), pH, moisture and proteolysis-related parameters were also studied. The polyamines spermine and spermidine were the main amines found in the raw material and they only showed slight fluctuations during the fermentation. The four elaborated batches presented a significant (P < 0.001) formation of tyramine and putrescine. The main rate of amine production was during the first three days, when a sharp pH decrease and the development of lactic acid bacteria occurred. Sausages fermented with starters had lower amounts of tyramine than naturally fermented sausages (control), but differences in the Micrococcaceae counts were only significant during the first week of the ripening process. A slight formation of diaminopropane, cadaverine, agmatine, tryptamine and phenylethylamine was observed. The amounts of histamine were constant and remained below 0.5 mg/kg of dry matter, while serotonin, octopamine and dopamine were not detected. The sausages with Staphylococcus as starter culture showed strong proteolysis that was correlated with higher pH values than those of the control sausages. However, no positive correlation was found between the proteolysis index and biogenic amine production. Since proteolysis was stronger during the second half of the ripening process, the release of free amino acids as amine precursors occurred later than the early amine production.
Assuntos
Aminas Biogênicas/biossíntese , Endopeptidases/química , Microbiologia de Alimentos , Produtos da Carne/microbiologia , Staphylococcus/crescimento & desenvolvimento , Animais , Aminas Biogênicas/análise , Cromatografia Líquida de Alta Pressão , Contagem de Colônia Microbiana , Enterobacteriaceae/crescimento & desenvolvimento , Fermentação , Concentração de Íons de Hidrogênio , Lactobacillus/crescimento & desenvolvimento , Produtos da Carne/análise , Micrococcaceae/crescimento & desenvolvimento , Nitrogênio/análise , Putrescina/análise , Putrescina/biossíntese , Staphylococcus/química , Estatísticas não Paramétricas , Suínos , Tiramina/análise , Tiramina/biossínteseRESUMO
The occurrence of amino acid-decarboxylase activity in 92 strains of lactic acid bacteria, coagulase-negative staphylococci, and Enterobacteriaceae isolated from Spanish fermented pork sausages was investigated. The presence of biogenic amines in a decarboxylase synthetic broth was determined by ion-pair high performance liquid chromatography with o-phtalaldehyde post-column derivatization. Among the 66 lactic acid bacteria strains tested, 21 lactobacilli (in particular, Lactobacillus curvatus) and all 16 enterococci were amine producers. Tyramine was the main amine produced by these bacteria, although they also produced phenylethylamine, tryptamine, and/or the diamines putrescine and cadaverine. None of the lactic acid bacteria produced histamine. Coagulase-negative staphylococci were found to be negative amine-producers. Aromatic monoamines, apart from histamine, were not formed by Enterobacteriaceae. This family was responsible for cadaverine and putrescine production. The results obtained for biogenic amine production by bacteria in a synthetic medium suggest that amino acid-decarboxylase activity is strain dependent rather than being related to specific species.
Assuntos
Descarboxilases de Aminoácido-L-Aromático/metabolismo , Enterobacteriaceae/enzimologia , Lactobacillus/enzimologia , Produtos da Carne/microbiologia , Staphylococcus/enzimologia , Animais , Aminas Biogênicas/análise , Aminas Biogênicas/biossíntese , Cromatografia Líquida de Alta Pressão/métodos , Fermentação , Espanha , Suínos , Tiramina/biossínteseRESUMO
A survey of 21 beers produced in Spain during 1994 was conducted to assess contamination with volatile N-nitrosamines. N-Nitrosodimethylamine (NDMA), the only volatile N-nitrosamine detected, was found in 52% of Spanish beers at or above the detection level (0.05 microgram/kg). The mean NDMA level for all samples was 0.11 microgram/kg, and the range was from not detected to 0.55 microgram/kg. No differences in the NDMA content were observed between the different beer types. Individual daily intake of NDMA may reach up to 0.021 microgram/person/day for Spanish people.
Assuntos
Cerveja/análise , Carcinógenos/análise , Dimetilnitrosamina/análise , Contaminação de Alimentos/análise , EspanhaRESUMO
Refined wheat, unrefined whole wheat, and wheat bran were studied for their ability to protect against heterocyclic amines (HCAs) in vitro and in vivo. Wheat bran, which binds HCAs in vitro, as well as refined wheat and unrefined whole wheat, inhibited the mutagenic activities of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) when they were co-incubated and the supernatant (minus grain) was added to the Salmonella assay. The water-soluble fraction alone from refined and unrefined wheat, but not bran, also inhibited against these mutagens in vitro. In vivo, AIN-93G diets containing refined wheat or unrefined wheat were examined for their ability to inhibit IQ-induced colonic aberrant crypt foci (ACF) in the Fischer 344 rat. A slight increase in the number of AC/ACF (aberrant crypts/ACF) was seen after 16 weeks in rats treated post-initiation with refined wheat (P < 0.05), and fewer foci with two or three aberrant crypts (ACF-2) were found in rats given unrefined whole wheat post-initiation compared with animals treated with the same diet during the initiation phase (P < 0.05). There was no significant difference in the profile of IQ urinary metabolites or excretion of promutagens 0-48 h after carcinogen dosing, and grains had no effect on hepatic cytochrome P4501A1 (CYP1A1), CYP1A2, aryl sulfotransferase or N-acetyltransferase activities; however, a slightly higher UDP-glucuronosyl transferase activity was observed in rats fed unrefined wheat compared with refined wheat diets (P < 0.05). Thus, despite their antimutagenic activities in vitro, only marginal effects were seen with refined and unrefined wheat in vivo with respect to hepatic enzyme activities, carcinogen metabolism and IQ-induced ACF in the rat colon.
Assuntos
Aminas/toxicidade , Antimutagênicos , Fibras na Dieta , Testes de Mutagenicidade , Triticum , Aminas/antagonistas & inibidores , Animais , Carcinógenos/toxicidade , Colo/efeitos dos fármacos , Colo/patologia , Neoplasias do Colo/induzido quimicamente , Neoplasias do Colo/prevenção & controle , Fibras na Dieta/administração & dosagem , Concentração de Íons de Hidrogênio , Imidazóis/toxicidade , Quinolinas/toxicidade , Ratos , Ratos Endogâmicos F344 , Salmonella/efeitos dos fármacos , Salmonella/genética , Solubilidade , Triticum/químicaRESUMO
The effect of the hygienic status of raw materials on biogenic amine production during ripening and storage (at 4 and 15 degrees C) of fermented sausages was studied. Two portions of fresh lean and back fat pork were stored for 5 days at -20 degrees C (treatment A) and at 4 degrees C (treatment B), respectively. Raw materials of treatment A maintained their hygienic quality high and low amine content. Raw materials of treatment B showed from 1 to 3 log (CFU/g) higher microbial counts and a biogenic amine index near 50 mg/kg, indicating poorer hygienic quality. The quality of raw materials influenced the composition and the concentration of biogenic amines produced during the ripening sausages. Sausages of treatment A (A-sausages) showed a large accumulation of tyramine (up to 100 mg/kg dm) followed by putrescine and cadaverine (<15 mg/kg). In contrast, B-sausages resulted in earlier and much greater amine production, and cadaverine, tyramine, and putrescine levels were 50-, 2.6-, and 6.5-fold higher than those of A-sausages. Other biogenic amines, such as octopamine, tryptamine, phenylethylamine, and histamine were also produced in B-sausages. The higher proteolysis and the lower pH of B-sausages might have favored the decarboxylase activity of microorganisms. Biogenic amine contents of sausages during storage depended on the raw materials used and storage temperature. No significant modification on the amine contents was observed during the storage of A-sausages at either temperature. Greater changes occurred in B-sausages stored at 15 degrees C than in those stored at 4 degrees C. Higher temperatures favored proteolytic and decarboxylase reactions, resulting in increased amine concentrations after storage.
Assuntos
Aminas Biogênicas/biossíntese , Enterobacteriaceae/crescimento & desenvolvimento , Microbiologia de Alimentos , Conservação de Alimentos/métodos , Higiene , Produtos da Carne/análise , Animais , Cromatografia Líquida de Alta Pressão , Contagem de Colônia Microbiana , Descarboxilação , Fermentação , Concentração de Íons de Hidrogênio , Produtos da Carne/microbiologia , Espanha , Suínos , Temperatura , Fatores de TempoRESUMO
Several combinations of an amine-negative Lactobacillus sakei strain, along with proteolytic Staphylococcus carnosus or Staphylococcus xylosus strains, were used to study the influence of mixed starter cultures on biogenic amine production during the manufacture of dry fermented sausages. Changes in pH, water content, proteolysis, microbial counts, and biogenic amine contents were simultaneously examined in a spontaneously fermented batch and in three mixed starter-mediated batches. A double-controlled microbial charge initially inoculated as mixed starter culture of L. sakei and Staphylococcus spp. (all amine-negative strains) drastically reduced tyramine, cadaverine, and putrescine accumulation. No production of other aromatic amines such as histamine, phenylethylamine, or tryptamine was observed in any batch. The polyamines, spermine and spermidine, were found in raw materials and their levels decreased slightly in the spontaneously fermented batch. No correlation between proteolysis and biogenic amine production was observed. The use of proper technological conditions favoring starter development and the use of the raw materials with good hygienic quality make it possible to produce fermented sausages nearly free of biogenic amines.
Assuntos
Aminas Biogênicas/biossíntese , Lactobacillus/crescimento & desenvolvimento , Produtos da Carne/microbiologia , Staphylococcus/crescimento & desenvolvimento , Animais , Aminas Biogênicas/análise , Cadaverina/análise , Cadaverina/biossíntese , Cromatografia Líquida de Alta Pressão , Contagem de Colônia Microbiana , Fermentação , Concentração de Íons de Hidrogênio , Higiene , Lactobacillus/química , Produtos da Carne/análise , Putrescina/análise , Putrescina/biossíntese , Staphylococcus/química , Suínos , Fatores de Tempo , Tiramina/análise , Tiramina/biossíntese , ÁguaRESUMO
The effectiveness of an amine-negative starter culture (Lactobacillus sakei CTC494) in the reduction of biogenic amine production during the ripening of fermented sausages was examined. Four batches were manufactured in parallel: spontaneously fermented and starter-mediated sausages were manufactured from two lots of raw materials of different hygienic quality. Besides the biogenic amine contents, changes in the microbial counts, nitrogenous fractions, pH, and water content were measured at several sampling points during the ripening process. In sausages manufactured from good quality meat, the starter strain of L. sakei reduced and even inhibited biogenic amine accumulation during sausage fermentation, the end products showing extremely low biogenic amine contents (tyramine levels less than 15 mg/kg of dry matter and putrescine and cadaverine levels less than 5 mg/kg of dry matter). Nevertheless, starter-mediated sausages made from poorer-quality raw materials showed much higher amine contents (308, 223, and 36 mg/kg of dry matter of cadaverine, tyramine, and putrescine, respectively), which were only slightly lower than those of the spontaneously fermented sausages made from the same raw materials. The relatively high bacterial numbers of raw materials of poorer-hygienic quality diminished the beneficial effect of the starter strain. Therefore, the effectiveness of the starter was strongly dependent on the hygienic quality of the raw materials used.
Assuntos
Aminas Biogênicas/metabolismo , Manipulação de Alimentos , Higiene , Lactobacillus/metabolismo , Produtos da Carne/microbiologia , Animais , Contagem de Colônia Microbiana , Fermentação , Microbiologia de Alimentos , Concentração de Íons de Hidrogênio , Nitrogênio/análise , Controle de Qualidade , Refrigeração , Fatores de Tempo , Água/análiseRESUMO
The ability of Lactobacillus sakei CTC494, a negative amino acid-decarboxylase starter culture, to reduce biogenic amine accumulation during sausage fermentation and storage at 4 and 19 degrees C was studied. The effect on the amine formation of the tyramine producer Lactobacillus curvatus CTC371, as a positive strain, was also examined in comparison to a spontaneous fermentation process without starter culture (control batch). The polyamines spermine, spermidine, and diaminopropane were not influenced by the ripening, and their levels slightly decreased in all the batches throughout the storage. Tyramine, cadaverine, and putrescine were the main amines formed during the ripening. The addition of starter culture resulted in a decrease on the biogenic amine formation, depending on the strain inoculated. A great reduction in tyramine content was achieved when L. sakei CTC494 was inoculated, whereas L. curvatus CTC371 only attenuated tyramine accumulation compared with the control batch. Both starters were able to significantly limit the production of putrescine and cadaverine, and they inhibited tryptamine and phenylethylamine formation by the wild microbial flora. Tyramine levels of the control sausages rose during the storage at both temperatures, whereas those of cadaverine only increased at 19 degrees C. On the contrary, sausages manufactured through the starter controlled fermentation did not show changes of amine contents during the storage. The addition of a proper selected starter culture is advisable to produce safer sausages with low contents of biogenic amines.
Assuntos
Descarboxilases de Aminoácido-L-Aromático/metabolismo , Aminas Biogênicas/biossíntese , Fermentação , Lactobacillus/metabolismo , Produtos da Carne/microbiologia , Animais , TemperaturaRESUMO
The effect of sugar omission on biogenic amine contents of slightly fermented sausages during ripening and storage was evaluated. Two batches of spontaneously fermented sausages were produced with and without sugars in two different trials at pilot-plant scale. Ripened sausages were stored at 4 and 19°C for a further 20 days. Tyramine and cadaverine were the main amines formed during ripening, their contents being significantly higher in batches without sugar. High counts of LAB and Enterobacteriaceae could be associated with the production of tyramine and cadaverine, respectively. The occurrence of putrescine depended on the trial and batch. Sausages without sugar contained more putrescine than those with sugar in trial 1, but this was not repeated in trial 2, in which a high production of agmatine occurred. Tryptamine and phenylethylamine were only detected in the later stages of ripening, their contents also being higher in sausages without sugar. Biogenic amine contents generally rose during storage at 19°C, the increase being especially important for cadaverine and tyramine in sausages without sugar. Levels of spermidine and spermine remained constant during ripening and decreased slightly during storage. Sugar omission is not recommended because it might increase biogenic amine accumulation during the manufacture and storage of slightly fermented sausages.
RESUMO
Three trials were carried out to study the influence of the diameter on biogenic amine contents and related parameters (pH, humidity and proteolysis) in fermented sausages. The first trial was done on three groups of Spanish dry fermented sausages with different diameter. In the second, two sections (centre and edge) of salchichón sausages were examined. The last trial consisted in the study of the ripening of two batches of sausages fermented under the same conditions but with two different diameters. Biogenic amine contents varied among the different type of products as well as among the same type of samples. Generally, amine levels in the biggest diameter sausages were higher than in the thinnest sausages. Amine contents were higher in the central part of the sausages than in the edge. During the ripening, larger tyramine amounts were formed in sausages with the biggest diameter. Statistical correlations were found among the diameter, the pH, the proteolysis and some amines. The results of the three trials agree with the hypothesis that the diameter is a factor that may affect the formation of biogenic amines during sausage fermentation.
RESUMO
Ultra high pressure liquid chromatography (UHPLC) has become a widely used technique in separation science as it can shorten analysis time while maintaining resolution and increasing sensitivity. Here we developed a UHPLC method with UV detection for the simultaneous determination of isoflavone aglycones (daidzein, glycitein and genistein), their corresponding glycoside forms (daidzin, glycitin and genistin), and acetyl and malonyl conjugate forms of glycosides (malonyldaidzin, malonylglycitin, malonylgenistin, acetyldaidzin, acetylglycitin, acetylgenistin) in soy milk. The method allowed reliable determinations of 12 isoflavones in less than 8 min of chromatographic elution. It provided a satisfactory linearity ranging from 0.1 to 5mg/L, except for daidzin and genistin, for which it ranged from 0.1 to 10mg/L. In addition, it showed acceptable chromatographic sensitivity, with a detection limit lower than 0.05 mg/L and a determination limit below 0.2mg/L. The precision, in terms of relative standard deviation, was lower than 5% and the accuracy, as mean recovery, was greater than 95%. Total isoflavone content in commercial soy milk samples (n=8) ranged from 1805.22 to 3195.59 mg/kg dw. Genistin and Daidzin were the major isoflavones in all samples. The proportion of aglycones, ß-glucosides, and acetyl and malonyl glucosides differed among the samples. ß-Glucosides were identified as the predominant forms.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Isoflavonas/química , Leite de Soja/química , Espectrofotometria Ultravioleta/métodos , Estrutura MolecularRESUMO
Previous studies have shown the down-regulating in vitro effect of cocoa flavonoids on lymphocyte and macrophage activation. In the present paper, we report the capacity of a long-term rich cocoa diet to modulate macrophage cytokine secretion and lymphocyte function in young rats. Weaned rats received natural cocoa (4% or 10% food intake), containing 32 mg flavonoids/g, for 3 weeks. Spleen immune function was then evaluated through the analysis of lymphocyte composition, their proliferative response and their ability to secrete cytokines and Ig. In addition, the status of activated peritoneal macrophages was established through tumour necrosis factor (TNF)-alpha secretion. The richest cocoa diet (10%) caused a reduction of TNF-alpha secretion by peritoneal macrophages showing anti-inflammatory activity. Similarly, although a 10% cocoa diet increased lymphocyte proliferation rate, it down-regulated T helper 2 (Th2)-related cytokines and decreased Ig secretion. These changes were accompanied by an increase in spleen B cell proportion and a decrease in Th cell percentage. In summary, these results demonstrate the functional activity of a cocoa-high dosage in down-regulating the immune response that might be beneficial in hypersensitivity and autoimmunity.