Displaying publications 1 - 20 of 50 in total

Abstract:
Sort:
  1. Amino acid composition of Ascaris lumbricoides, A. suum and Toxocara canis
    Bisseru B, Lim KG
    Med J Malaya, 1968 Mar;22(3):236.
    PMID: 4234371
    Matched MeSH terms: Amino Acids/analysis*
  2. Fatty acid and amino acid composition in haruan as a potential role in wound healing
    Jais AM, McCulloch R, Croft K
    Gen. Pharmacol., 1994 Sep;25(5):947-50.
    PMID: 7835642
    1. Two species of snakehead fish are available in Sabah, i.e. Channa striatus and Channa melanosoma, and are commonly known as haruan. Haruan is consumed by many Malaysians to induce healing after a clinical operations. However, there is no scientific evidence as yet to substantiate the claim, and so it was decided to analyse the biochemical composition in haruan to determine which compounds may have a possible role or potential in wound healing. 2. Samples (midline fillet) of both species were extracted separately in hexane for the qualitative analysis of fatty acids by a gas chromatography, Hewlett-Packard 5890A, using a 10 meter superox 11 column (Alltech) at temperature between 190 and 245 degrees C. Peak areas were calculated automatically using Hewlett-Packard 3393A computing integrator. Subsequently, the amino acid composition was analysed using a precolumn derivatization reverse phase HPLC waters PICO-TAG system. 3. Haruan is found to contain unusually high arachidonic acid (AA) but almost no eicosapentaenoic acid (EPA). AA which is a precursor of prostaglandin may initiate blood clotting and be responsible for growth. Haruan also contains all the essential amino acids for wound healing, particularly glycine which is the most important component of human skin collagen. Therefore, haruan contained all the basic biochemical requirements for wound healing.
    Matched MeSH terms: Amino Acids/analysis*
  3. Biochemical and nutritional components of selected honey samples
    Chua LS, Adnan NA
    Acta Sci Pol Technol Aliment, 2014 Apr-Jun;13(2):169-79.
    PMID: 24876312
    The purpose of this study was to investigate the relationship of biochemical (enzymes) and nutritional components in the selected honey samples from Malaysia. The relationship is important to estimate the quality of honey based on the concentration of these nutritious components. Such a study is limited for honey samples from tropical countries with heavy rainfall throughout the year.
    Matched MeSH terms: Amino Acids/analysis
  4. A comparative study of physicochemical characteristics and functionalities of pinto bean protein isolate (PBPI) against the soybean protein isolate (SPI) after the extraction optimisation
    Tan ES, Ying-Yuan N, Gan CY
    Food Chem, 2014;152:447-55.
    PMID: 24444960 DOI: 10.1016/j.foodchem.2013.12.008
    Optimisation of protein extraction yield from pinto bean was investigated using response surface methodology. The maximum protein yield of 54.8 mg/g was obtained with the optimal conditions of: temperature=25 °C, time=1 h and buffer-to-sample ratio=20 ml/g. PBPI was found to obtain high amount of essential amino acids such as leucine, lysine, and phenylalanine compared to SPI. The predominant proteins of PBPI were vicilin and phytohemagglutinins whereas the predominant proteins of SPI were glycinin and conglycinins. Significantly higher emulsifying capacity was found in PBPI (84.8%) compared to SPI (61.9%). Different isoelectric points were found in both PBPI (4.0-5.5) and SPI (4.0-5.0). Also, it was found that PBPI obtained a much higher denaturation temperature of 110.2 °C compared to SPI (92.5 °C). Other properties such as structural information, gelling capacity, water- and oil-holding capacities, emulsion stability as well as digestibility were also reported.
    Matched MeSH terms: Amino Acids/analysis
  5. Soy sauce and its umami taste: a link from the past to current situation
    Lioe HN, Selamat J, Yasuda M
    J Food Sci, 2010 Apr;75(3):R71-6.
    PMID: 20492309 DOI: 10.1111/j.1750-3841.2010.01529.x
    Soy sauce taste has become a focus of umami taste research. Umami taste is a 5th basic taste, which is associated to a palatable and pleasurable taste of food. Soy sauce has been used as an umami seasoning since the ancient time in Asia. The complex fermentation process occurred to soy beans, as the raw material in the soy sauce production, gives a distinct delicious taste. The recent investigation on Japanese and Indonesian soy sauces revealed that this taste is primarily due to umami components which have molecular weights lower than 500 Da. Free amino acids are the low molecular compounds that have an important role to the taste, in the presence of sodium salt. The intense umami taste found in the soy sauces may also be a result from the interaction between umami components and other tastants. Small peptides are also present, but have very low, almost undetected umami taste intensities investigated in their fractions.
    Matched MeSH terms: Amino Acids/analysis
  6. Effects of preparation methods on protein and amino acid contents of various eggs available in Malaysian local markets
    Ismail M, Mariod A, Pin SS
    Acta Sci Pol Technol Aliment, 2013 Jan-Mar;12(1):21-31.
    PMID: 24584862
    BACKGROUND:
    The effect of preparation methods (raw, half-boiled and hard-boiled) on protein and amino acid contents, as well as the protein quality (amino acid score) of regular, kampung and nutrient enriched Malaysian eggs was investigated.
    METHODS:
    The protein content was determined using a semi-micro Kjeldahl method whereas the amino acid composition was determined using HPLC.
    RESULTS:
    The protein content of raw regular, kampung and nutrient enriched eggs were 49.9 ±0.2%, 55.8 ±0.2% and 56.5 ±0.5%, respectively. The protein content of hard-boiled eggs of regular, kampung and nutrient enriched eggs was 56.8 ±0.1%, 54.7 ±0.1%, and 53.7 ±0.5%, while that for half-boiled eggs of regular, kampung and nutrient enriched eggs was 54.7 ±0.6%, 53.4 ±0.4%, and 55.1 ±0.7%, respectively. There were significant differences (p < 0.05) in protein and amino acid contents of half-boiled, hard-boiled as compared with raw samples, and valine was found as the limiting amino acid. It was found that there were significant differences (p < 0.05) of total amino score in regular, kampung and nutrient enriched eggs after heat treatments.Furthermore, hard-boiling (100°C) for 10 minutes and half-boiling (100°C) for 5 minutes affects the total amino score, which in turn alter the protein quality of the egg.
    Matched MeSH terms: Amino Acids/analysis*
  7. Application of the artificial neural network in quantitative structure-gradient elution retention relationship of phenylthiocarbamyl amino acids derivatives
    Tham SY, Agatonovic-Kustrin S
    J Pharm Biomed Anal, 2002 May 15;28(3-4):581-90.
    PMID: 12008137
    Quantitative structure-retention relationship(QSRR) method was used to model reversed-phase high-performance liquid chromatography (RP-HPLC) separation of 18 selected amino acids. Retention data for phenylthiocarbamyl (PTC) amino acids derivatives were obtained using gradient elution on ODS column with mobile phase of varying acetonitrile, acetate buffer and containing 0.5 ml/l of triethylamine (TEA). Molecular structure of each amino acid was encoded with 36 calculated molecular descriptors. The correlation between the molecular descriptors and the retention time of the compounds in the calibration set was established using the genetic neural network method. A genetic algorithm (GA) was used to select important molecular descriptors and supervised artificial neural network (ANN) was used to correlate mobile phase composition and selected descriptors with the experimentally derived retention times. Retention time values were used as the network's output and calculated molecular descriptors and mobile phase composition as the inputs. The best model with five input descriptors was chosen, and the significance of the selected descriptors for amino acid separation was examined. Results confirmed the dominant role of the organic modifier in such chromatographic systems in addition to lipophilicity (log P) and molecular size and shape (topological indices) of investigated solutes.
    Matched MeSH terms: Amino Acids/analysis*
  8. Fulltext Evolutionary and genomic analysis of four SARS-CoV-2 isolates circulating in March 2020 in Sri Lanka; Additional evidence on multiple introduction and further transmission
    Satharasinghe DA, Parakatawella PMSDK, Premarathne JMKJK, Jayasooriya LJPAP, Prathapasinghe GA, Yeap SK
    Epidemiol Infect, 2021 03 16;149:e78.
    PMID: 33722321 DOI: 10.1017/S0950268821000583
    The molecular epidemiology of the virus and mapping helps understand the epidemics' evolution and apply quick control measures. This study provides genomic evidence of multiple severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) introductions into Sri Lanka and virus evolution during circulation. Whole-genome sequences of four SARS-CoV-2 strains obtained from coronavirus disease 2019 (COVID-19) positive patients reported in Sri Lanka during March 2020 were compared with sequences from Europe, Asia, Africa, Australia and North America. The phylogenetic analysis revealed that the sequence of the sample of the first local patient collected on 10 March, who contacted tourists from Italy, was clustered with SARS-CoV-2 strains collected from Italy, Germany, France and Mexico. Subsequently, the sequence of the isolate obtained on 19 March also clustered in the same group with the samples collected in March and April from Belgium, France, India and South Africa. The other two strains of SARS-CoV-2 were segregated from the main cluster, and the sample collected from 16 March clustered with England and the sample collected on 30 March showed the highest genetic divergence to the isolate of Wuhan, China. Here we report the first molecular epidemiological study conducted on circulating SARS-CoV-2 in Sri Lanka. The finding provides the robustness of molecular epidemiological tools and their application in tracing possible exposure in disease transmission during the pandemic.
    Matched MeSH terms: Amino Acids/analysis
  9. Comparison of physicochemical and functional properties of duck feet and bovine gelatins
    Kuan YH, Nafchi AM, Huda N, Ariffin F, Karim AA
    J Sci Food Agric, 2017 Mar;97(5):1663-1671.
    PMID: 27465360 DOI: 10.1002/jsfa.7970
    BACKGROUND: Previous studies have indicated that duck feet are a rich source of gelatin extractable from avian sources. In this study, the physicochemical and functional properties of avian gelatin extracted from duck feet (DFG) with acetic acid were compared with those of commercial bovine gelatin (BG).

    RESULTS: The yield of DFG obtained in this study was 7.01 ± 0.31%. High-performance liquid chromatography analysis indicated that the imino acid content was slightly lower for DFG compared with BG (P < 0.05). Differences in molecular size and amino acids between DFG and BG were also observed. The isoelectric points of DFG and BG were at pH 8 and 5 respectively, and the overall protein solubility of BG was higher than that of DFG. Gels prepared from BG exhibited higher bloom strength, viscosity and clarity and were darker in colour compared with DFG gels (P < 0.05). The gelling and melting points of BG were 21.8 and 29.47 °C respectively, while those of DFG were 20.5 and 27.8 °C respectively. BG exhibited slightly better emulsifying and foaming properties compared with DFG.

    CONCLUSION: Although some differences between DFG and BG were observed, the disparities were small, which indicates that DFG could be exploited commercially as an alternative source of gelatin. © 2016 Society of Chemical Industry.

    Matched MeSH terms: Amino Acids/analysis
  10. Nuclear magnetic resonance spectroscopy and liquid chromatography-mass spectrometry metabolomics studies on non-organic soybeans versus organic soybeans (Glycine max), and their fermentation by Rhizopus oligosporus
    Chong SG, Ismail IS, Ahmad Azam A, Tan SJ, Shaari K, Tan JK
    J Sci Food Agric, 2023 Apr;103(6):3146-3156.
    PMID: 36426592 DOI: 10.1002/jsfa.12355
    BACKGROUND: Soybeans (Glycine max) are high in proteins and isoflavones, which offer many health benefits. It has been suggested that the fermentation process enhances the nutrients in the soybeans. Organic foods are perceived as better than non-organic foods in terms of health benefits, yet little is known about the difference in the phytochemical content that distinguishes the quality of organic soybeans from non-organic soybeans. This study investigated the chemical profiles of non-organic (G, T, U, UB) and organic (C, COF, A, R, B, Z) soybeans (G. max [L.] Merr.) and their metabolite changes after fermentation with Rhizopus oligosporus.

    RESULTS: A clear separation was only observed between non-organic G and organic Z, which were then selected for further investigation in the fermentation of soybeans (GF and ZF). All four groups (G, Z, GF, ZF) were analyzed using nuclear magnetic resonance (NMR) spectroscopy along with liquid chromatography-tandem mass spectrometry (LC-MS/MS). In this way a total of 41 and 47 metabolites were identified respectively, with 12 in common. A clear variation (|log1.5 FC| > 2 and P amino acids and organic acids were found in ZF. An additional four metabolites clustered as C-glycosylflavonoids were discovered from MS/MS-based molecular networking.

    CONCLUSION: Chemical profiles of non-organic and organic soybeans exhibited no significant difference. However, the metabolite profile of the unfermented soybeans, which were higher in sugars, shifted to higher amino acid and organic acid content after fermentation, thereby potentially enhancing their nutritional value. © 2022 Society of Chemical Industry.

    Matched MeSH terms: Amino Acids/analysis
  11. Reheating-induced gel properties change and flavor evolution of surimi-based seafood: Effects and mechanisms
    Bao L, Yang R, Diao D, Tian F, Chen Y, Zheng B, et al.
    Food Chem, 2025 Feb 01;464(Pt 1):141466.
    PMID: 39406135 DOI: 10.1016/j.foodchem.2024.141466
    This study investigated the effect of different reheating treatments on gel properties and flavor changes of surimi products. As the reheating temperature increased from 90 °C to 121 °C, the heat-induced proteolysis produced more abundant umami and sweet amino acids, which took part in the conversion of IMP to AMP, thus enhancing the taste profiles. Reheating increased the exposure of active -NH2 terminals in proteins, which boosted Maillard and Strecker reactions with carbonyl compounds originated from fatty acid oxidation, thus not only reducing the aldehydes and esters contents but also lowering the whiteness of surimi products. Reheating at 90 °C prohibited the production of warmed-over flavor (WOF) and well-preserved the textural characteristics, but high temperatures ≥100 °C were prone to generate furan as the major WOF substance and to destroy gel structures. Collectively, this study provides new insights on understanding the role of reheating on sensory properties of surimi products.
    Matched MeSH terms: Amino Acids/analysis
  12. RP-HPLC method using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate incorporated with normalization technique in principal component analysis to differentiate the bovine, porcine and fish gelatins
    Azilawati MI, Hashim DM, Jamilah B, Amin I
    Food Chem, 2015 Apr 1;172:368-76.
    PMID: 25442566 DOI: 10.1016/j.foodchem.2014.09.093
    The amino acid compositions of bovine, porcine and fish gelatin were determined by amino acid analysis using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate as derivatization reagent. Sixteen amino acids were identified with similar spectral chromatograms. Data pre-treatment via centering and transformation of data by normalization were performed to provide data that are more suitable for analysis and easier to be interpreted. Principal component analysis (PCA) transformed the original data matrix into a number of principal components (PCs). Three principal components (PCs) described 96.5% of the total variance, and 2 PCs (91%) explained the highest variances. The PCA model demonstrated the relationships among amino acids in the correlation loadings plot to the group of gelatins in the scores plot. Fish gelatin was correlated to threonine, serine and methionine on the positive side of PC1; bovine gelatin was correlated to the non-polar side chains amino acids that were proline, hydroxyproline, leucine, isoleucine and valine on the negative side of PC1 and porcine gelatin was correlated to the polar side chains amino acids that were aspartate, glutamic acid, lysine and tyrosine on the negative side of PC2. Verification on the database using 12 samples from commercial products gelatin-based had confirmed the grouping patterns and the variables correlations. Therefore, this quantitative method is very useful as a screening method to determine gelatin from various sources.
    Matched MeSH terms: Amino Acids/analysis*
  13. Fulltext HLA-A SNPs and amino acid variants are associated with nasopharyngeal carcinoma in Malaysian Chinese
    Chin YM, Mushiroda T, Takahashi A, Kubo M, Krishnan G, Yap LF, et al.
    Int J Cancer, 2015 Feb 1;136(3):678-87.
    PMID: 24947555 DOI: 10.1002/ijc.29035
    Nasopharyngeal carcinoma (NPC) arises from the mucosal epithelium of the nasopharynx and is constantly associated with Epstein-Barr virus type 1 (EBV-1) infection. We carried out a genome-wide association study (GWAS) of 575,247 autosomal SNPs in 184 NPC patients and 236 healthy controls of Malaysian Chinese ethnicity. Potential association signals were replicated in a separate cohort of 260 NPC patients and 245 healthy controls. We confirmed the association of HLA-A to NPC with the strongest signal detected in rs3869062 (p = 1.73 × 10(-9)). HLA-A fine mapping revealed associations in the amino acid variants as well as its corresponding SNPs in the antigen peptide binding groove (p(HLA-A-aa-site-99) = 3.79 × 10(-8), p(rs1136697) = 3.79 × 10(-8)) and T-cell receptor binding site (p(HLA-A-aa-site-145) = 1.41 × 10(-4), p(rs1059520) = 1.41 × 10(-4)) of the HLA-A. We also detected strong association signals in the 5'-UTR region with predicted active promoter states (p(rs41545520) = 7.91 × 10(-8)). SNP rs41545520 is a potential binding site for repressor ATF3, with increased binding affinity for rs41545520-G correlated with reduced HLA-A expression. Multivariate logistic regression diminished the effects of HLA-A amino acid variants and SNPs, indicating a correlation with the effects of HLA-A*11:01, and to a lesser extent HLA-A*02:07. We report the strong genetic influence of HLA-A on NPC susceptibility in the Malaysian Chinese.
    Matched MeSH terms: Amino Acids/analysis
  14. Validation of a reverse-phase high-performance liquid chromatography method for the determination of amino acids in gelatins by application of 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate reagent
    Azilawati MI, Hashim DM, Jamilah B, Amin I
    J Chromatogr A, 2014 Aug 1;1353:49-56.
    PMID: 24797394 DOI: 10.1016/j.chroma.2014.04.050
    In-house method validation was conducted to determine amino acid composition in gelatin by a pre-column derivatization procedure with the 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate reagent. The analytical parameters revealed that the validated method was capable of selectively performing a good chromatographic separation for 18 amino acids in less than 40 min; the overall detection and quantitation limit for amino acids fell into ranges of 5.68-12.48 and 36.0-39.0 pmol/μl, respectively; the matrix effect was not observed, and the linearity range was 37.5-1000 pmol/μl. The accuracy (precision and recovery) analyses of the method were conducted under repeatable conditions on different days in random order. Method precision revealed by HorRat values was significantly less than 2, except for histidine with a precision of 2.19, and the method recoveries had a range of 80-115% except for alanine which was recovered at 79.4%. The findings were reproducible and accurately defined, and the method was found to be suited to routine analysis of amino acid composition in gelatin-based ingredients.
    Matched MeSH terms: Amino Acids/analysis*
  15. Acetylation of glycerol to biofuel additives over sulfated activated carbon catalyst
    Khayoon MS, Hameed BH
    Bioresour Technol, 2011 Oct;102(19):9229-35.
    PMID: 21840708 DOI: 10.1016/j.biortech.2011.07.035
    Oxygenated fuel additives can be produced by acetylation of glycerol. A 91% glycerol conversion with a selectivity of 38%, 28% and 34% for mono-, di- and triacetyl glyceride, respectively, was achieved at 120 °C and 3 h of reaction time in the presence of a catalyst derived from activated carbon (AC) treated with sulfuric acid at 85 °C for 4h to introduce acidic functionalities to its surface. The unique catalytic activity of the catalyst, AC-SA5, was attributed to the presence of sulfur containing functional groups on the AC surface, which enhanced the surface interaction between the glycerol molecule and acyl group of the acetic acid. The catalyst was reused in up to four consecutive batch runs and no significant decline of its initial activity was observed. The conversion and selectivity variation during the acetylation is attributed to the reaction time, reaction temperature, catalyst loading and glycerol to acetic acid molar ratio.
    Matched MeSH terms: Amino Acids/analysis
  16. Fulltext Argininosuccinic aciduria: clinical and biochemical phenotype findings in Malaysian children
    Chen BC, Ngu LH, Zabedah MY
    Malays J Pathol, 2010 Dec;32(2):87-95.
    PMID: 21329179 MyJurnal
    Argininosuccinic aciduria is an inborn error of the urea cycle caused by deficiency of argininosuccinate lyase (ASL). ASL-deficient patients present with progressive intoxication due to accumulation of ammonia in the body. Early diagnosis and treatment of hyperammonemia are necessary to improve survival and prevent long-term handicap. Two clinical phenotypes have been recognized--neonatal acute and milder late-onset form. We investigated patients with hyperammonemia by a stepwise approach in which quantitative amino acids analysis was the core diagnostic procedure. Here, we describe the clinical phenotypes and biochemical characteristics in diagnosing this group of patients. We have identified 13 patients with argininosuccinic aciduria from 2003 till 2009. Ten patients who presented with acute neonatal hyperammonemic encephalopathy had markedly elevated blood ammonia (> 430 micromol/L) within the first few days of life. Three patients with late-onset disease had more subtle clinical presentations and they developed hyperammonemia only during the acute catabolic state at two to twelve months of age. Their blood ammonia was mild to moderately elevated (> 75-265 micromol/L). The diagnosis was confirmed by detection of excessive levels of argininosuccinate in the urine and/or plasma. They also have moderately increased levels of citrulline and, low levels of arginine and ornithine in their plasma. Two patients succumbed to the disease. To date, eleven patients remained well on a dietary protein restriction, oral ammonia scavenging drugs and arginine supplementation. The majority of them have a reasonable good neurological outcome.
    Matched MeSH terms: Amino Acids/analysis
  17. Effects of ultraviolet irradiation on the physicochemical and functional properties of gum arabic
    Kuan YH, Bhat R, Senan C, Williams PA, Karim AA
    J Agric Food Chem, 2009 Oct 14;57(19):9154-9.
    PMID: 19757813 DOI: 10.1021/jf9015625
    The impact of ultraviolet (UV) irradiation on the physicochemical and functional properties of gum arabic was investigated. Gum arabic samples were exposed to UV irradiation for 30, 60, 90, and 120 min; gum arabic was also treated with formaldehyde for comparison. Molecular weight analysis using gel permeation chromatography indicated that no significant changes occurred on the molecular structure on the samples exposed to UV irradiation. Free amino group analysis indicated that mild UV irradiation (30 min) could induce cross-linking on gum arabic; this result was comparable with that of samples treated with formaldehyde. However, viscosity break down was observed for samples exposed to UV irradiation for longer times (90 and 120 min). All irradiated and formaldehyde-treated samples exhibited better emulsification properties than unirradiated samples. These results indicate that UV-irradiated gum arabic could be a better emulsifier than the native (unmodified) gum arabic and could be exploited commercially.
    Matched MeSH terms: Amino Acids/analysis
  18. Assessment of cross-linking in combined cross-linked soy protein isolate gels by microbial transglutaminase and Maillard reaction
    Gan CY, Cheng LH, Easa AM
    J Food Sci, 2009 Mar;74(2):C141-6.
    PMID: 19323728 DOI: 10.1111/j.1750-3841.2009.01053.x
    Soy protein isolate (SPI) gels were produced using single cross-linking agents (SCLA) of microbial transglutaminase (MTG) via incubation for 5 or 24 h (SCLA-MTG). When powdered SCLA-MTG gels were heated for 2 h with ribose (R2) (2 g/100 mL), dark brown gels were formed, and these were designated as combined cross-linking agent (CCLA) gels: MTG5(R2) and MTG24(R2). The results showed that the levels of Maillard-derived browning and cross-links of MTG5(R2) and MTG24(R2) gels were significantly (P < 0.05) lower than a control gel produced without MTG (SCLA-R2) even though the percentage of ribose remaining after heating of these gels was similar, indicating that a similar amount of ribose was consumed during heating. epsilon-(gamma-glutamyl)lysine bonds formed during incubation of SPI with MTG may have reduced the free amino group of SPI to take part in the Maillard reaction; nevertheless, ribose took part in the Maillard reaction and initiated the Maillard cross-linkings within the CCLA gels.
    Matched MeSH terms: Amino Acids/analysis*
  19. Aroma precursors and methylpyrazines in underfermented cocoa beans induced by endogenous carboxypeptidase
    Jinap S, Ikrawan Y, Bakar J, Saari N, Lioe HN
    J Food Sci, 2008 Sep;73(7):H141-7.
    PMID: 18803708 DOI: 10.1111/j.1750-3841.2008.00858.x
    Cocoa-specific aroma precursors and methylpyrazines in underfermented cocoa beans obtained from fermentation induced by indigenous carboxypeptidase have been investigated. Fermentation conditions and cocoa bean components were analyzed during 0 to 3 d of fermentation. Underfermented cocoa beans were characterized as having hydrophilic peptides and free hydrophobic amino acids much higher than unfermented ones. These 2 key components of cocoa aroma precursors may be produced from the breakdown of proteins and polypeptides by endogenous carboxypeptidase during the fermentation process. The enzyme was activated during fermentation. Polypeptides of 47, 31, and 19 kDa were observed in the samples throughout the 3-d fermentation period; however, only the first 2 polypeptides were remarkably reduced during fermentation. Since the 1st day of fermentation, underfermented cocoa beans contained methylpyrazines, a dominant group of cocoa-specific aroma. This might be due to microbial activities during fermentation, observed through a decrease of pH value and an increase of temperature of cocoa beans. The concentration of tetramethylpyrazines was significantly increased during the 3 d of fermentation. This may increase the cocoa-specific flavor to the beans.
    Matched MeSH terms: Amino Acids/analysis
  20. Alterations in juvenile diploid and triploid African catfish skin gelatin yield and amino acid composition: Effects of chlorpyrifos and butachlor exposures
    Karami A, Karbalaei S, Zad Bagher F, Ismail A, Simpson SL, Courtenay SC
    Environ Pollut, 2016 Aug;215:170-177.
    PMID: 27182978 DOI: 10.1016/j.envpol.2016.05.014
    Skin is a major by-product of the fisheries and aquaculture industries and is a valuable source of gelatin. This study examined the effect of triploidization on gelatin yield and proximate composition of the skin of African catfish (Clarias gariepinus). We further investigated the effects of two commonly used pesticides, chlorpyrifos (CPF) and butachlor (BUC), on the skin gelatin yield and amino acid composition in juvenile full-sibling diploid and triploid African catfish. In two separate experiments, diploid and triploid C. gariepinus were exposed for 21 days to graded CPF [mean measured: 10, 16, or 31 μg/L] or BUC concentrations [Mean measured: 22, 44, or 60 μg/L]. No differences in skin gelatin yield, amino acid or proximate compositions were observed between diploid and triploid control groups. None of the pesticide treatments affected the measured parameters in diploid fish. In triploids, however, gelatin yield was affected by CPF treatments while amino acid composition remained unchanged. Butachlor treatments did not alter any of the measured variables in triploid fish. To our knowledge, this study is the first to investigate changes in the skin gelatin yield and amino acid composition in any animal as a response to polyploidization and/or contaminant exposure.
    Matched MeSH terms: Amino Acids/analysis
Related Terms
Filters
Contact Us

Please provide feedback to Administrator ([email protected])

External Links