315 research outputs found

    Optimization and validation of a method for extraction and quantification of ochratoxin A in black pepper

    Get PDF
    The extraction method for the determination of ochratoxin A (OTA) in black pepper was optimized. The influence of three variables, i.e., type of solvent, solvent-volume-to-sample-size ratio (v/w) and amount of sodium chloride (NaCl) (g), on OTA recovery was evaluated. Analysis of variance was used to compare recovery values obtained from different solvents, and response surface methodology (RSM) was used to determine the optimum amount of NaCl and the solvent-volume-to-sample-size ratio. The concentration of OTA was determined by high-performance liquid chromatography with fluorescence detection. The highest recovery (95.2 %) was obtained when methanol/water (80:20, v/v) was used as the solvent. The RSM results showed that the experimental data could be adequately fitted to a second-order polynomial model with multiple regression coefficients (R2) of 0.962. The optimum amount of NaCl was determined to be 3 g, whereas the optimum solvent-volume-to-sample-size ratio (v/w) was found to be 4. The proposed method was applied to 20 samples, and the presence of OTA was found in 8 (40%) samples ranging from 0.11 to 3.16 ng g-1

    Effect of initial aflatoxin concentration, heating time and roasting temperature on aflatoxin reduction in contaminated peanuts and process optimisation using response surface modelling.

    Get PDF
    Response surface methodology was applied to optimise the aflatoxin reduction in both naturally and artificially contaminated samples using dry oven. The effect of initial aflatoxin concentration (0-400ngg-1), heating time (30-120min) and temperature (90-150°C) was evaluated. The maximum reduction of AFB1 (78.4%) and AFB2 (57.3%) of artificially contaminated samples with initial aflatoxin concentration of 237 and 68ngg-1, and those of AFG1 (73.9%) and AFG2 (75.2%) with initial aflatoxin concentration of 215 and 75ngg-1 was obtained at 150°C. The maximum reduction of AFB1 (80.2%) and AFB2 (69.7%) of naturally contaminated samples with initial aflatoxin concentration of 174 and 25ngg-1 was obtained at 150°C and 130°C, respectively

    Optimisation of the determination of deoxynivalenol in wheat flour by HPLC and a comparison of four clean-up procedures.

    Get PDF
    The determination of deoxynivalenol (DON) in wheat flour by liquid chromatography with photodiode array (PDA) detection was optimised. Response surface methodology (RSM) was used to determine the optimum chromatographic conditions for the determination of DON. The influence of three variables, acetonitrile (ACN) volume in mobile phase (9.5-24.5, v/v), flow rate (0.5-1.5 ml min-1) and wavelength (215-221 nm) on DON peak area was evaluated. The best separation was achieved using a symmetry column (150×3.9 mm; particle size 5 µm) by isocratic elution (1.0 ml min-1) and a mobile phase consisting of ACN/water in the ratio 17:83 (v/v). UV detection was performed at 218 nm. Linear calibration curves were constructed in the concentration range 1-1000 ng ml-1. The detection limit measured as the signal-to-noise ratio (3:1) was 0.03 ng ml-1. RSM results showed that the experimental data could be adequately fitted to a second-order polynomial model with multiple regression coefficients (R2) of 0.968. The efficiency of four clean-up procedures for wheat flour extract was compared. Recovery of DON using a Mycosep #225 column was highest with a value of 99%, while that of Mycosep #227 was 65%. In contrast, DON recovery using immunoaffinity columns (IAC) and an Oasis® HLB column was only 53 and 42%, respectively. The trueness of the method using the Mycosep #225 column was established with a certified reference material CRM 379. The result obtained from three replicates was 0.66±0.04 µg g-1 and the certified value was 0.67 µg g-1

    Kandungan Kapsaisin dalam Kultivar Capsicum annum

    Get PDF
    Thirteen cultivars of chilli Capsicum annum were used for the determination of capsaicin obtained from two stages of maturation, 25 and 40 days after flowering. The results showed that there was a significant difference (p > 0.05) in the capsaicin content among different cultivars for both stages. The range of capsaicin concentration for day 25 was 6.14 - 26.6 mg/g and 6.3 - 106.42 mg/g (dry weight) for day 40. Except for KA2 dan Abheim, other cultivars contained significantly higher concentration of capsiasin in day 40 compared to those in day 25. The range of capsaicin located in the placenta, the pericarp and the seeds was 47 - 60%, 27 - 41 %, 6 - 16%, respectively

    Effects of washing pre-treatment on mercury concentration in fish tissue.

    Get PDF
    The objective of this study was to examine the effect of washing pre-treatment on mercury concentration in fish fillet. Response surface methodology was used to investigate the influence of three variables, pH (1-6.5), NaCl (0-1% w/v) and exposure time (5-30 min) by using a three-factor central composite design. The aim was to obtain the best possible combination of these variables in order to reduce mercury in fish fillet. The experimental data were adequately fitted into a second-order polynomial model with multiple regression coefficients (R(2)) of 0.961. The results indicated that the reduction of mercury in fish flesh significantly depends on the pH of the solution used. The overall optimal condition resulting in the maximum mercury reduction in fish fillet was obtained at a combined level pH of 2.79, NaCl of 0.5% and exposure time of 13.5 min. The optimized protocol produced a solution that can reduce mercury from raw fish fillet up to 81%

    Cocoa - wonders for chocolate lovers

    Get PDF
    The components of cocoa attribute to the unique of flavor, texture, color characteristics and health benefits of chocolate. Cocoa flavor is very specific; therefore it cannot be replaced by sources other than cocoa. It consists of cocoa aroma which comprises volatile compounds produced through Maillard reaction and taste, a balanced combination of bitterness, sourness and sweetness derived form non-volatile compounds, such as phenols, acids and peptides, respectively. Proper handling and processing would prevent the development of undesirable properties of cocoa such as astringency, moldy, hammy, smoky and excessive sourness. Cocoa butter contributes to the unique texture of chocolate, which gives the smoothness and glossy appearance, and melts only at body temperature. The natural color of chocolate comes only from cocoa; color of cocoa can be of different shades to reflect the uniqueness of the food it contained. Genetic and origin, fermentation, drying, roasting, alkalizations, refining and conching are the main factors which influence the flavor, texture and color of cocoa and its characteristics in chocolate. Recently, cocoa and chocolate have become the objects of increased scientific research mainly because or their phytochemical composition. Cocoa is rich in polyphenol (10 – 18%) which had anti-oxidant activities, responsible for the prevention of many diseases and possible anti-cariogenic effects. Stearic acid in cocoa butter, although saturated, is neutral with respect to blood and suppresses the effect of cholesterol. Cocoa contains phenylethylalanine, which strikes the endocrine gland to secrete hormone associated with happy feeling. Research and development initiatives in the area include flavor improvement using enzymes, detection and quantification of fats other than cocoa butter, the production of polyphenol fractions, cocoa flavor from other plant proteins, fat-free cocoa powder and heat-resistant chocolates

    Analysis of Non-volatile Organic Acids in Fermented and Dried Cocoa Beans by High Performance Liquid Chromatography

    Get PDF
    A high peiformance liquid chromatographic methodfor analysis of non-volatile acids (oxalic, citric, tartaric, succinic, malic and lactic) in fermented and dried cocoa beans is described. Bean samples were pulverized in dionized water using a Polytron Homogenizer (Brinkman)for 20 sec and centrifuged at 14000 rpm for 45 min at 25°C. The extract was alkalized to pH between 8-9 and passed through intermediate base anion exchange resin; the acidic fraction was eluted after adding 10lt/o sulphuric acid to the column. Polyphenols in the fraction were then eliminated by passing the acidic fraction through a reverse phase SEP-PAK that had been pre-wet with methanol. The eluate was analyzedfor non-volatile acids using Organic Acid Column (Bio-Rad) with O.lN H SO as a mobile phase at 65°C. The acids were detected at 214nm and quantified by comparing peak 2hezght of sample to those of standards. The method demonstrated excellent reproducibility and recoveries of the added acids

    Natural occurrence of deoxynivalenol (DON) in wheat based noodles consumed in Malaysia

    Get PDF
    In this first study performed in noodle samples consumed in Malaysia for the presence of deoxynivalenol (DON), a total of 135 sample of noodles, comprised of instant noodle, yellow alkaline noodle and white salted noodle, were randomly collected from food stores and analyzed for DON using high performance liquid chromatography (HPLC) with a PDA (photodiode array) detector at 218 nm. The objective of this study was to investigate the DON contamination levels in different types of wheat-based noodle consumed in Peninsular Malaysia. An acetonitrile:water (17:83 v/v) mixture was used as a mobile phase and clean-up was accomplished with a Mycosep 225 column. There was a high variation in the DON concentrations in all types of noodle group as well as between brands. Only one sample of instant and yellow alkaline noodle each were contaminated with DON, at concentrations of 1.003 and 1.243 ng/g, respectively. The minimum detectable concentration for the DON was 0.627 ng/g in instant noodle. In the case of white salted noodle, none of the samples contained any detectable amount of DON. The results indicate a low occurrence of DON mycotoxins in commercial noodle products in Malaysia
    corecore