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1.
PLoS One ; 15(8): e0237844, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32834013

RESUMO

The feasibility of the production of germinated rice extracts using indigenous rice from Southern Thailand, including Khemtong (KHT) and Khai Mod Rin (KMR) from a single location at the Pak Phanang River Basin in Nakhon Si Thammarat, was investigated. The nutritional composition and bioactivity of the germinated rice extracts from both cultivars were evaluated. Optimum germination time for both rices was 96 h, leading to the highest GABA, thiamine, free amino acid, total sugar, and α-amylase activity (p<0.05). Germinated KHT had a higher α-amylase activity than germinated KMR at all germination times. Mashing at 60°C/pH 5.5 rendered the extract with the highest GABA content (p<0.05) and desirable contents of other nutrients. In comparison with germinated Sungyod (local colored rice) and Jasmine (commercial Thai rice) extracts, KHT and KMR showed a higher scavenging activity against DPPH•, OH•, and H2O2 (p<0.05) with a comparable ABTS•+ inhibition. For metal chelation, reducing power and ACE inhibitory activity, the germinated Sungyod extract was greater than KHT/KMR. The results demonstrated the potential use of germinated local Thai rice for the production of functional beverages.


Assuntos
Germinação , Fenômenos Fisiológicos da Nutrição , Oryza/química , Oryza/crescimento & desenvolvimento , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Aminoácidos/análise , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Antioxidantes/farmacologia , Compostos de Bifenilo/química , Estudos de Viabilidade , Flavonoides/análise , Depuradores de Radicais Livres/química , Minerais/análise , Fenóis/análise , Ácido Fítico/análise , Picratos/química , Açúcares/análise , Tiamina/análise , Fatores de Tempo , alfa-Amilases/metabolismo , Ácido gama-Aminobutírico/análise
2.
J Chromatogr A ; 1626: 461335, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797820

RESUMO

On-spot fixed-charge derivatization has been suggested for the modification of α-amino acids for their analysis by thin layer chromatography/matrix-assisted laser desorption ionization (TLC/MALDI) mass spectrometry. The approach was based on post-chromatographic treatment of separated analytes by tris(2,6-dimethoxyphenyl)methenium salt and triethylamine. The reaction proceeded smoothly in mild conditions and gave rise to pink-red colored derivatives, containing permanent positive charge. Their MALDI mass spectra, recorded directly from TLC plates, revealed intense peaks corresponding to decarboxylated cationic parts. All derivatives are characterized by high ionization efficiency, which indicates the high sensitivity of the developed method for analyzing amino acids. Applicability of the method to analysis of amino acids was demonstrated on artificial mixtures and dietary supplement.


Assuntos
Aminoácidos/análise , Cromatografia em Camada Delgada/métodos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Aminoácidos/química , Etilaminas/química
3.
J Oleo Sci ; 69(9): 1133-1138, 2020 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-32788514

RESUMO

To identify antioxidants for improving rough skin, we aimed to analyze the amino acid composition of fish mucus and antioxidant activity of the mucus component. Specifically, we aimed to examine the antioxidant properties of dialyzed mucus components secreted from mackerel, which can be used as raw materials for producing cosmetics. The amino acid composition of hydrolyzed mucus was examined by ultra-high-performance liquid chromatography after dialyzing mucus. In addition, the antioxidant activity of the mucus was evaluated via oxygen radical absorption capacity and Trolox equivalent antioxidant capacity assays. The amino acid composition differed between the low-molecular-weight and high-molecular-weight fractions. Moreover, the low-molecular-weight fraction of farmed mackerel mucus exhibited antioxidant activity with high specificity. The results suggest that antioxidant peptides or free amino acids are present in the low-molecular-weight fraction of farmed mackerel mucus.


Assuntos
Aminoácidos/análise , Antioxidantes/análise , Cosméticos , Muco/química , Aminoácidos/farmacologia , Animais , Cromatografia Líquida de Alta Pressão , Histidina , Metionina , Peso Molecular , Perciformes , Selenometionina
4.
J Chromatogr A ; 1625: 461255, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709316

RESUMO

A three-dimensional (3D) HPLC system in combination with fluorescence derivatization has been developed for the highly sensitive and selective analysis of chiral amino acids in extraterrestrial samples. As the targets, alanine (Ala), 2-aminobutyric acid (2AB), valine (Val), norvaline (nVal) and isovaline (iVal), frequently found chiral amino acids in the carbonaceous chondrites, were selected. These amino acids were pre-column derivatized with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F), and the target analytes were separated from other amino acids and organic compounds by a reversed-phase column in the first dimension. The targets were further separated from interferences by an anion-exchange column in the second dimension, and their enantiomers were separated and determined in the third dimension by a Pirkle-type enantioselective column. The present 3D-HPLC system was validated and applied to the Murchison meteorite and the Antarctic meteorites, and all of the target amino acid enantiomers were clearly observed (0.78-22.33 nmol/g in the Murchison meteorite and 1.79-78.84 nmol/g in the Antarctic meteorites) without severe interferences. The %L values of the non-proteinogenic amino acids were almost 50% in both meteorites, and even the proteinogenic amino acids were almost racemic in the Antarctic meteorites.


Assuntos
Aminoácidos/análise , Cromatografia Líquida de Alta Pressão/métodos , Meteoroides , Alanina/análise , Aminoácidos/química , Aminobutiratos/análise , Cromatografia por Troca Iônica , Limite de Detecção , Estereoisomerismo , Valina/análogos & derivados , Valina/análise
5.
Food Chem ; 332: 127406, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32615387

RESUMO

Hot peppers are sensitive to low temperature, and seed browning significantly reduces the fruit quality. This study aims to clarify the mechanisms of seed browning in terms of metabolite changes. Metabolites were analysed during a 30-day-storage period at 2 °C and 10 °C. Gamma-aminobutyric acid, tyrosine, phenylalanine, and isoleucine concentrations were significantly higher at 2 °C storage than at 10 °C. Reactive oxygen species (ROS) generation was associated with seed browning. Transcription of jasmonic acid synthesis and ROS scavenging genes were higher in hot peppers stored at 2 °C than those stored at 10 °C. This study elucidated the mechanisms underlying seed browning and chill damage in hot peppers during storage at low temperatures and our findings may help improve hot peppers' quality following harvesting.


Assuntos
Capsicum/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Aminoácidos/análise , Aminoácidos/metabolismo , Cromatografia Líquida de Alta Pressão , Temperatura Baixa , Ciclopentanos/metabolismo , Armazenamento de Alimentos , Frutas/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Oxilipinas/metabolismo , Análise de Componente Principal , Sementes/metabolismo , Ácido gama-Aminobutírico/análise , Ácido gama-Aminobutírico/metabolismo
6.
Food Chem ; 332: 127424, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32619947

RESUMO

Celery (Apium graveolens L. var dulce) is a widely cultivated vegetable which is popularly consumed due to its nutrient content and contains bioactive metabolites with positive effects on human physiology. In this study, 1H NMR spectroscopy coupled with multivariate statistical analyses was used to distinguish celery stem and leaf samples from different geographical origins. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were employed to investigate the differences between celery extracts from three geographical origins: Australia, Taiwan and China. Sugars, amino acids and organic acids were found to contribute significantly to the differentiation between origins, with mannitol identified as an important discriminating metabolite. It was demonstrated that NMR-based metabolomics is an effective approach for establishing reliable metabolomic fingerprints and profiles, enabling the identification of metabolite biomarkers for the possible discrimination of geographical origin.


Assuntos
Apium/química , Metabolômica/métodos , Espectroscopia de Prótons por Ressonância Magnética/métodos , Aminoácidos/análise , Apium/metabolismo , Austrália , China , Análise Discriminante , Humanos , Análise dos Mínimos Quadrados , Manitol/análise , Manitol/metabolismo , Análise Multivariada , Folhas de Planta/química , Análise de Componente Principal , Verduras/química , Verduras/metabolismo
7.
Food Chem ; 332: 127422, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32623129

RESUMO

During wheat cultivation, glyphosate-based herbicides are recommended to be applied a week prior to harvest during the ripe stage of physiological maturity. However, some grains may not be at this physiological stage due to non-uniform maturation within the field. The goal of this study was to determine the effect of glyphosate-based herbicide timing on the chemistry of wheat gluten proteins and shikimic acid accumulation. The results of the study indicate that pre-harvest glyphosate application does not impact the amino acid composition, protein secondary structure or gluten protein composition. However, pre-harvest glyphosate application decreased the molecular weight of SDS extractable and unextractable proteins, and significantly increased the amount of shikimic acid accumulation, especially when applied early. Thus, this study indicates that pre-harvest use of glyphosate-based herbicides can cause significant differences in wheat protein chemistry and shikimic acid levels, especially when applied earlier than recommended, emphasizing the importance of timely application.


Assuntos
Glicina/análogos & derivados , Herbicidas/farmacologia , Proteínas de Plantas/metabolismo , Ácido Chiquímico/metabolismo , Triticum/efeitos dos fármacos , Aminoácidos/análise , Aminoácidos/metabolismo , Glutens/análise , Glutens/metabolismo , Glicina/farmacologia , Proteínas de Plantas/análise , Ácido Chiquímico/análise , Triticum/química , Triticum/crescimento & desenvolvimento , Triticum/metabolismo
8.
Food Chem ; 332: 127388, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32603918

RESUMO

Peptidyl post-translational modifications (PTMs) could influence the final quality of processed meat. In this study, the peptide oxidative phenomena in Spanish dry-cured ham (Biceps femoris muscle) was evaluated at different ripening times (9, 12, 15, 18 and 24 months of processing) evidencing interactions amongst the lipid and protein oxidation, major peptidyl PTMs and the release of free amino acids (FAAs). Results showed that 12 months of processing enabled the most abundant protein-bound carbonyls, while TBARS value was significantly favored (p < 0.001) by ripening. However, FAAs were still intensively generated during overall ripening. Peptidomics and chemometrics further revealed that proteolysis mostly hampered the oxidized peptides rather than the deamidated ones during ripening. Myosin light chain (MYL1 and MYL3) showed high oxidative susceptibility owing to peptidyl methionine and proline oxidation as well as acetaldehyde adduct formation on lysine or histidine residues.


Assuntos
Produtos da Carne/análise , Cadeias Leves de Miosina/metabolismo , Peptídeos/análise , Aminoácidos/análise , Animais , Cromatografia Líquida de Alta Pressão , Dipeptídeos/análise , Peroxidação de Lipídeos , Cadeias Leves de Miosina/química , Oxirredução , Peptídeos/metabolismo , Análise de Componente Principal , Processamento de Proteína Pós-Traducional , Suínos , Espectrometria de Massas em Tandem
9.
An Acad Bras Cienc ; 92 Suppl 1: e20180757, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32491136

RESUMO

Pereskia grandifolia Haworth (PGH) and Pereskia aculeata Miller (PAM) are recognized sources of proteins; dietary fiber; vitamins and minerals make this plant leaves, raw, cooked, and braised, an important ally against protein and micronutrient deficiencies. One of the main problems is the presence of antinutritional factors that may interfere in the digestibility and bioavailability of some nutrients. The objective was to evaluate the amino acid profile and the chemical score of the raw leaves and the effects of heating media and time on the total dietary fiber, minerals, trypsin inhibition, oxalic acid and tannins of leaves of PGH and PAM. The samples had similar amino acid profiles and total dietary fiber. With regard to antinutritional compounds, heating the leaves of PGH led to a decrease in trypsin inhibition, primarily after the first minutes of wet cooking. Oxalic acid and tannins predominated in both species. Considering the interaction with time, the variables related to iron and zinc minimized the tannin responses in PGH and PAM, respectively. Heating media and times interfered with the chemical components present in the leaves of Pereskia species and led to high antinutrient retention after heat treatment.


Assuntos
Cactaceae/química , Valor Nutritivo , Verduras/química , Aminoácidos/análise , Cactaceae/classificação , Fibras na Dieta/análise , Manipulação de Alimentos , Minerais/análise , Proteínas/análise , Taninos/análise , Verduras/classificação
10.
Food Chem ; 331: 127340, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-32569971

RESUMO

Acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC) were extracted and purified from the cartilages of skate and sturgeon. Their typical structure and physicochemical properties were evaluated by circular dichroism (CD), X-ray diffraction (XRD), and so on. Results showed that the extracted collagen was likely identified as collagen-II composed of three α-chains (135 kDa), with the typical peptide sequence of Gly-X-Y. It showed the collagen retained the native and intact triple helical structure, and its intensity ratio of the positive and negative absorption peaks (Rpn) was 0.19-0.25. In addition, the extracted collagen exhibited obvious self-assembly behavior with the concentration above 0.3 mg/mL, the adjustment of pH 7.4-7.6 and the NaCl concentration of 120 mmol/L. The critical aggregate mass concentrations of pepsin-soluble collagens from skate and sturgeon were 0.93 and 0.86 g/L, respectively. Therefore, collagens from skate and sturgeon cartilages have potential commercial application.


Assuntos
Cartilagem/química , Colágeno Tipo II/química , Proteínas de Peixes/química , Peixes , Aminoácidos/análise , Animais , Dicroísmo Circular , Colágeno Tipo II/análise , Produtos Pesqueiros , Proteínas de Peixes/análise , Concentração de Íons de Hidrogênio , Monossacarídeos/análise , Concentração Osmolar , Pepsina A/química , Conformação Proteica , Rajidae , Cloreto de Sódio/química , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
11.
Food Chem ; 331: 127369, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-32590262

RESUMO

To make better use of chicken liver, a byproduct of meat processing with rich proteins, the influence of ultrasound pretreatment on the extent of Maillard reaction (MR) and the properties of MR products (MRPs) of chicken liver protein (CLP) and its hydrolysate (CLPH) were investigated. The extent of MR of sonicated CLPH (SCLPHMs) was significantly higher than that of the other two MRPs. The decreased fluorescence intensity (FI) of the SCLPHMs indicated adequate reaction of d-xylose with sonicated CLPH (SCLPH). The particle size of the three MRPs was significantly larger than that of CLP, CLPH, and SCLPH, respectively. Ultrasound treatment increased the utilization of amino acids and enriched the variety of volatile compounds in all groups. Furfural was the main heterocyclic compound in the MRPs. Therefore, ultrasound pretreatment and enzymolysis of chicken liver may be a foundation for high-value development in flavors for the food industry.


Assuntos
Galinhas , Indústria de Processamento de Alimentos/métodos , Fígado/química , Reação de Maillard , Proteínas de Aves Domésticas/química , Compostos Orgânicos Voláteis/química , Aminoácidos/análise , Aminoácidos/química , Animais , Aromatizantes/química , Produtos Finais de Glicação Avançada/química , Produtos Avícolas , Hidrolisados de Proteína/química , Paladar , Ultrassom , Compostos Orgânicos Voláteis/análise , Xilose/química
12.
Food Chem ; 331: 127350, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-32590267

RESUMO

Fish by-products are excellent sources of collagen. Acid-soluble collagen (ASC) derived from a mixed by-product of different fish species was hydrolyzed to obtain peptide fractions and evaluate their biological and functional activities. All fractions obtained (F1: ≥30, F2: 10-30, F3: 5-10, F4: 1-5, and F5: ≤1kDa) exhibited antioxidant activity at concentrations of 5, 10, and 15 mg/mL. However, F5 registered the highest reducing power (absorbance 0.366) and hydroxyl-radical-scavenging activity (91%) at 15 mg/mL; whereas the highest DPPH scavenging activity (81%) was also detected in F5 at 5 mg/mL. The solubility of F1, F2, and F3 was ≥ 95% at pH 7. The highest foaming capacity (78%), foaming stability (60%), and emulsion stability index (42 min) were registered for F1. However, the highest emulsifying activity index (130 m2/g) was for F3. These results place collagen obtained from a mixed by-product of different fish species as a potential biotechnological alternative for the industry.


Assuntos
Antioxidantes/farmacologia , Colágeno/química , Produtos Pesqueiros , Proteínas de Peixes/química , Peptídeos/química , Peptídeos/farmacologia , Aminoácidos/análise , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Antioxidantes/química , Emulsificantes/química , Proteínas de Peixes/farmacologia , Depuradores de Radicais Livres/química , Concentração de Íons de Hidrogênio , Hidrólise , Radical Hidroxila/química , Hidrolisados de Proteína/química , Solubilidade
13.
Food Chem ; 329: 127086, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32516706

RESUMO

Principal component analysis (PCA) and partial least squares (PLS) regression were applied to investigate the effect of glutathione-enriched inactive dry yeast (g-IDY) on the amino acids and volatile components of kiwi wine. Results indicated that the addition of g-IDY had positive effect on most amino acids of kiwi wine, especially glutamine and glycine. In case of pure juice fermentation, the concentrations of ethyl decanoate, 2-methylbutyric acid, trans-2-nonenal and hexyl butyrate had notably positive correlation with the addition of g-IDY. PLS regression indicated that the amino acids were highly interrelated to the volatile compositions, and glycine had the strongest positive impact on the concentrations of esters and total volatile components. This might explain the similar effect of g-IDY on the amino acids and volatile components of kiwi wine. Besides, PLS regression showed that E-nose was a good method to predict volatile compositions of kiwi wine, especially esters.


Assuntos
Actinidia/química , Aminoácidos/análise , Glutationa/metabolismo , Saccharomyces cerevisiae/química , Compostos Orgânicos Voláteis/análise , Vinho/análise , Actinidia/metabolismo , Nariz Eletrônico , Ésteres/análise , Fermentação , Análise Multivariada , Saccharomyces cerevisiae/metabolismo
14.
PLoS One ; 15(5): e0232880, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32401761

RESUMO

The southern king crab (SKC) Lithodes santolla is an important commercial species in southern South America. Fishing pressure has caused the deterioration of its stocks. Currently, culture techniques are being developed for producing SKC juveniles to enhance the natural population and to recover the fishing stock. Therefore, it is necessary to know about physiology, energetic and nutritional requirements for SKC maintenance in hatchery. Thus, this study aims to evaluate the biochemical and physiological changes in the midgut gland, muscle and hemolymph of juveniles, pre-adults and adults of wild SKC. The energetic reserves, digestive enzymes activity, amino acid profile and energy were quantified in twelve juveniles, ten pre-adult, and ten adult crabs. Juveniles showed high glycogen and low lipids in the midgut gland, and low proteins and low lactate in muscle. In the hemolymph, juveniles had high lipids. Pre-adults had high glycogen and lipids in the midgut gland, and both high protein and lactate in muscle. In the hemolymph, pre-adults had high lipids. Adults had low glycogen and high lipids in midgut gland, and both high proteins and high lactate in muscle. In hemolymph, adults had high glucose and lactate. Juveniles and pre-adults had high proteinase activity, whereas adults had high lipase activity. Major essential amino acids of SKC were arginine, methionine, and tryptophan, and the non-essential amino acids were glycine, aspartic acid and glutamic acid. On another hand, SKC had similar energy in the midgut gland and muscle, regardless of the ontogenetic stage. Moreover, we demonstrated that the biochemical energy calculation underestimates the actual measured values by a calorimeter. Thus, our results help to understand the physiological changes, energetic and nutritional requirements of L. santolla, and this study is a baseline for research on diet formulation for maintaining this species under culture conditions.


Assuntos
Anomuros/fisiologia , Aquicultura/métodos , Proteínas de Artrópodes/genética , Optogenética/métodos , Aminoácidos/análise , Ração Animal , Animais , Anomuros/citologia , Anomuros/crescimento & desenvolvimento , Dieta , Metabolismo Energético , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Regulação Enzimológica da Expressão Gênica , Hemolinfa , Masculino , Músculos/química
15.
PLoS One ; 15(5): e0233094, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32392267

RESUMO

Sweet corn juice is becoming increasingly popular in China. In order to provide valuable health-related information to consumers, the nutritional and physicochemical characteristics of raw and boiled purple sweet corn juices were herein investigated. Sugars, antinutrients, total free phenols, anthocyanins, and antioxidant activity were analyzed by conventional chemical methods. The viscosity and stability of juices were determined by Ubbelohde viscosity meter and centrifugation, respectively. Boiling process could elevate viscosity, stability and sugar content, and reduce antinutrients, total free phenols, anthocyanins, and antioxidant activity in corn juice. In addition, short time boiling efficiently reduced the degradation of anthocyanins during subsequent refrigeration. The content of amino acids, vitamin B1/B2 and E were detected by High Performance Liquid Chromatography. Gas Chromatography Mass Spectrometry was used for the analysis of fatty acids and aroma compounds. Several aroma compounds not previously reported in corn were identified, including 1-heptanol, 2-methyl-2-butenal, (Z)-3-nonen-1-ol, 3-ethyl-2-methyl-1,3-hexadiene, and 2,4-bis(1,1-dimethylethyl)phenol. Interestingly, the boiling process had no apparent effect on the amino acids profile, but it caused a 45.8% loss of fatty acids in the juice by promoting the retention of fatty acids in the corn residue. These results provide detailed information that could be used for increasing consumers' knowledge of sweet corn juice, further development of sweet corn juice by food producers, and maize breeding programs.


Assuntos
Zea mays/química , Aldeídos/análise , Aminoácidos/análise , Antocianinas/análise , Antioxidantes/análise , Cromatografia Líquida de Alta Pressão , Cromatografia Gasosa-Espectrometria de Massas , Heptanol/análise , Fenóis/análise , Extratos Vegetais/análise , Riboflavina/análise , Tiamina/análise
16.
Food Chem ; 327: 126998, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32438264

RESUMO

Cold-pressed rapeseed meal with high protein content (38.76% protein dry weight basis) was used to prepare rapeseed protein isolates (RPIs) by alkaline extraction (pH 8.0, 9.0, 10.0, 11.0, 12.0 and 13.0) and acid precipitation (pH 3.0, 3.5, 4.0, 4.5, 5.0 and 5.5). The protein with an intact structure and the highest yield (65.08%) was obtained at extraction pH 9.0 and precipitation pH 4.5, accompanied by the lowest D-amino acid content, the lightest colour and the lowest contents of glucosinolates (2.85 mmol/kg), phytic acid (1.05 mg/g) and sinapine (0.68 mg/g). Additionally, water/oil absorption, foaming and emulsifying capacities decreased with decreasing precipitation pH, while the solubility showed the reverse trend. During gastric simulation digestion, the α-polypeptide of cruciferin and napin in the RPIs showed digestive resistance. Overall, pH regulation might be an effective method to isolate high quality RPIs for use in the food processing industry.


Assuntos
Brassica napus/química , Proteínas de Plantas/isolamento & purificação , Proteínas de Plantas/farmacocinética , Albuminas 2S de Plantas/farmacocinética , Aminoácidos/análise , Aminoácidos/química , Antígenos de Plantas , Precipitação Química , Cor , Digestão , Emulsificantes/química , Indústria de Processamento de Alimentos/métodos , Glucosinolatos/análise , Concentração de Íons de Hidrogênio , Ácido Fítico/análise , Proteínas de Plantas/química , Óleo de Brassica napus/química , Proteínas de Armazenamento de Sementes/farmacocinética , Solubilidade
17.
Food Chem ; 326: 126940, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32413751

RESUMO

Silverskin, the main coffee roasting by-product, is rich in fiber, protein and antioxidants. Its protein fraction was studied regarding total, protein and non-protein nitrogen content. Amino acids were analysed after automated on-line derivatization. The method showed to be precise (<6.9%) and accurate (recoveries using a certified reference material and spiked blanks: 90-102%; for spiked samples: 73-113%). The real protein content of silverskin was 12%. One quarter of the total nitrogen corresponded to the non-protein fraction. All essential amino acids were present in the free form, except methionine. Regarding total amino acids, aspartic and glutamic acids (9-10 mg/g) were the major compounds. Branched chain amino acids (leucine, isoleucine and valine) were also present in substantial amounts (5-8 mg/g), as well as proline and arginine (~5 mg/g). Concluding, silverskin is a source of amino acids with relevance for the improvement of cognitive and physical performances.


Assuntos
Aminoácidos/análise , Coffea/química , Nitrogênio/análise , Proteínas de Plantas/análise , Resíduos/análise , Aminoácidos de Cadeia Ramificada/análise , Antioxidantes/análise , Extratos Vegetais/análise , Sementes
18.
Nucleic Acids Res ; 48(W1): W77-W84, 2020 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-32421769

RESUMO

Low complexity regions (LCRs) in protein sequences are characterized by a less diverse amino acid composition compared to typically observed sequence diversity. Recent studies have shown that LCRs may co-occur with intrinsically disordered regions, are highly conserved in many organisms, and often play important roles in protein functions and in diseases. In previous decades, several methods have been developed to identify regions with LCRs or amino acid bias, but most of them as stand-alone applications and currently there is no web-based tool which allows users to explore LCRs in protein sequences with additional functional annotations. We aim to fill this gap by providing PlaToLoCo - PLAtform of TOols for LOw COmplexity-a meta-server that integrates and collects the output of five different state-of-the-art tools for discovering LCRs and provides functional annotations such as domain detection, transmembrane segment prediction, and calculation of amino acid frequencies. In addition, the union or intersection of the results of the search on a query sequence can be obtained. By developing the PlaToLoCo meta-server, we provide the community with a fast and easily accessible tool for the analysis of LCRs with additional information included to aid the interpretation of the results. The PlaToLoCo platform is available at: http://platoloco.aei.polsl.pl/.


Assuntos
Proteínas/química , Software , Aminoácidos/análise , Gráficos por Computador , Humanos , Proteínas de Membrana/química , Anotação de Sequência Molecular , Domínios Proteicos , Análise de Sequência de Proteína
19.
J Oleo Sci ; 69(6): 617-625, 2020 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-32404547

RESUMO

This study investigated the effect of papain on the demulsification of peanut oil body emulsion extracted using an aqueous enzymatic method and the associated mechanism. The highest free oil yield using papain (92.39%) was obtained under the following conditions: an enzymatic hydrolysis temperature of 55°C, sample-to-water ratio of 1:3, enzyme concentration of 1400 U/g, and an enzymatic hydrolysis time of 3 h. Papain degraded the peanut oil body protein to small-molecular-weight peptides (≤ 14.4 kDa). Compared to the emulsion before enzymatic hydrolysis, the amino acid content in the aqueous phase was higher after enzymatic hydrolysis, the viscosity of the oil body emulsion was lower, and the particle diameter of the emulsion was significantly larger. The following demulsification mechanism was derived. Papain degrades the protein on the peanut oil body and dissolves it in water. The outer side of the oil body loses the protection of electrostatic repulsion and steric hindrance provided by the membrane protein. This causes the viscosity of the emulsion system and the molecular steric hindrance to decrease. As a result, the oil droplets gather and eventually demulsify. The results of this study provide the theoretical basis for the instability in oil body emulsions and are expected to promote the application of enzymatic demulsification in industry.


Assuntos
Gotículas Lipídicas/química , Papaína , Óleo de Amendoim/química , Óleo de Amendoim/isolamento & purificação , Aminoácidos/análise , Emulsões , Hidrólise , Tamanho da Partícula , Peptídeos , Proteólise , Eletricidade Estática , Temperatura , Fatores de Tempo , Água
20.
Food Chem ; 328: 127110, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32464557

RESUMO

In the present work we aimed to demonstrate the influence of inoculum starter in support high quality fermentation. Cocoa fermentations were performed in wooden boxes and eight yeasts strains were used in separated fermentations of fine cocoa, type Scavina, as starter inoculum. Temperature, pH, titirable acidity, reducing sugar and free amino acids were evaluated during or after fermentation. The influence of starters yeasts on the decrease of acidity, sugar concentration and free amino acids was significant. The strains Candida parapsilosis, Torulaspora delbrueckii and Pichia kluyveri showed greater changes in the reducing sugar and free amino acids in fermented cocoa beans. These results indicate the ability of yeast used as inoculum starter to modify the end condition and further enhance the quality of fine cocoa beans.


Assuntos
Cacau , Microbiologia de Alimentos/métodos , Leveduras , Aminoácidos/análise , Aminoácidos/metabolismo , Cacau/química , Cacau/metabolismo , Candida parapsilosis/genética , Candida parapsilosis/metabolismo , Chocolate , Fermentação , Concentração de Íons de Hidrogênio , Pichia/genética , Pichia/metabolismo , Sementes/química , Sementes/microbiologia , Temperatura , Torulaspora/genética , Torulaspora/metabolismo , Leveduras/genética , Leveduras/metabolismo
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