The Experts below are selected from a list of 972 Experts worldwide ranked by ideXlab platform

Shao-quan Liu - One of the best experts on this subject based on the ideXlab platform.

  • Bioproduction of Natural Isoamyl Esters from Coconut Cream as
    2016
    Co-Authors: Catalysed Lipases, Shao-quan Liu, Huey Yie Lee, Philip Curran, Jingcan Sun
    Abstract:

    This study investigated the bioproduction of isoamyl esters in Coconut Cream by lipases. Five lipases (palatase 20000 L, lipase AYS “Amano”, lipase A “Amano ” 12, piccantase A and piccantase AN) were used to biosynthesize isoamyl esters in Coconut Cream supplemented with isoamyl alcohol. The lipases have different abilities to synthesize isoamyl esters with lipase AYS “Amano”, palatase 20000 L and piccantase A showing the highest potential. Bioproduction of isoamyl octanoate by palatase 20000 L was further examined under different conditions of temperature, pH, isoamyl alcohol concentration and lipase amount. Biosynthesis of isoamyl octanoate by palatase was not significantly affected at 30-50°C or pH of 4 to 7 and its maximum bioproduction was obtained at isoamyl alcohol concentration of 4 % (v/v) and lipase amount of 6 mg 100 mL-1 reaction mixture. The lipase-treated Coconut Cream may serve as a bioflavouring ingredient for food applications or for extraction of pure aroma chemicals

  • Ester Synthesis in Aqueous Media by Lipase: Alcoholysis, Esterification and Substrate Hydrophobicity
    Journal of Food Biochemistry, 2014
    Co-Authors: Jingcan Sun, Shao-quan Liu
    Abstract:

    Lipases are versatile biocatalysts commonly used for flavor ester synthesis in media with low-water activity. This research studied the mechanism of ester synthesis by lipase Palatase in Coconut Cream and phosphate buffer with alcohols and fatty acids. When ethanol was added as the alcohol substrate, hydrolysis of triglycerides dominated over synthesis of esters. When fusel alcohols (fusel oil) were used as the alcohol substrate, ester synthesis dominated over lipid hydrolysis. However, there was no visible pattern of fatty acid production and then reutilization in relation to ester synthesis in either case. Higher consumption of octanoic acid was obtained than that of butyric acid in both Coconut Cream and buffer systems spiked with the same alcohol. This indicated the preferential utilization of more hydrophobic substrates for esterification by lipase in aqueous media. These results suggest that the lipase Palatase-catalyzed ester synthesis in aqueous media was mainly hydrophobicity-dependent esterification. Practical Applications Esters are important flavor compounds that are applied in food products. The effects of substrate hydrophobicity and reaction environment on the catalytic behavior of a lipase during ester synthesis in an aqueous system of Coconut Cream and fusel oil were investigated. Useful information was obtained on the in situ generation of esters in food materials. This study has implications for lipase-catalyzed synthesis of flavor esters in other aqueous food matrices.

  • Optimization of methionol bioproduction by Saccharomyces cerevisiae using response surface methodology
    Annals of Microbiology, 2014
    Co-Authors: Heng-qian Lwa, Jingcan Sun, Shao-quan Liu
    Abstract:

    Methionol (3-methylthio-1-propanol) is an important volatile sulphur-containing alcohol that may significantly impact food flavour. The purpose of this research is to investigate the bioproduction of methionol from L-methionine catabolism by Saccharomyces cerevisiae EC-1118. The biotransformation was carried out in Coconut Cream supplemented with L-methionine. Response surface methodology was applied for the optimization of fermentation conditions to achieve a high yield of methionol. A second-order polynomial model (R2 = 0.912) was established based on the experimental data obtained in this study using multiple regression analysis. To obtain more accurate prediction results, a reduced quadratic model was obtained through backward elimination. Based on the reduced model, the optimal conditions for maximum methionol production were determined to be 0.30 % (w/v) of L-methionine, 0.10 % (w/v) of yeast extract and zero level of diammonium phosphate. Under these optimal conditions, a methionol concentration of 240.7 ± 17.4 μg/mL was achieved. This experimental result was in close agreement with the predicted value of 243.5 μg/mL, indicating that this model was adequate. These results indicate that fermentation by S. cerevisiae in L-methionine-supplemented Coconut Cream medium is an effective method for the production of methionol. Large-scale fermentation trials are needed to provide valuable information for industrial production.

  • biosynthesis of flavor esters in Coconut Cream through coupling fermentation and lipase catalyzed biocatalysis
    European Journal of Lipid Science and Technology, 2013
    Co-Authors: Jingcan Sun, Yunwei Lim, Shao-quan Liu
    Abstract:

    The aim of this research was to study the biosynthesis of natural flavor-active ethyl esters with a commercial lipase, Palatase 20 000 L, in Coconut Cream by coupling with yeast alcoholic fermentation. Alcoholic fermentation was carried out by Saccharomyces cerevisiae, which generated ethanol as one substrate for ester synthesis. Lipase was added into the fermentation medium at three different time points (12, 24, and 48 h) during the time-course fermentation of 72 h. The concentrations of ethyl octanoate, ethyl decanoate, and ethyl laurate were the highest when lipase was added at 12 h, indicating early coupling of ethanol production with ester synthesis catalyzed by lipase. Although the growth of S. cerevisiae was slightly inhibited when lipase was added into the fermentation medium due to the formation of fatty acids, no adverse effect on ester synthesis was observed. This novel approach may be useful in the production of relevant flavors of fermented Coconut Cream with lipase treatment, which could be used as a new food ingredient. Practical applications: Esters are a group of valuable flavor compounds that have wide applications in a variety of food products. In this work, we proposed one effective approach of coupling yeast alcoholic fermentation and lipase-catalyzed biocatalysis to synthesize natural fatty acid ethyl esters in Coconut Cream. This method provides a novel application of Coconut Cream for ester synthesis. In addition, the esters formed can be considered as natural according to current regulations. The ethanol generated can be effectively utilized for ester synthesis, therefore, complying with the Halal rules. The end product can be possibly used as a natural flavoring in the food industry after sensory evaluation and proper process. The esters formed may be further separated and purified as pure flavor compounds.

  • Biosynthesis of flavor esters in Coconut Cream through coupling fermentation and lipase‐catalyzed biocatalysis
    European Journal of Lipid Science and Technology, 2013
    Co-Authors: Jingcan Sun, Yunwei Lim, Shao-quan Liu
    Abstract:

    The aim of this research was to study the biosynthesis of natural flavor-active ethyl esters with a commercial lipase, Palatase 20 000 L, in Coconut Cream by coupling with yeast alcoholic fermentation. Alcoholic fermentation was carried out by Saccharomyces cerevisiae, which generated ethanol as one substrate for ester synthesis. Lipase was added into the fermentation medium at three different time points (12, 24, and 48 h) during the time-course fermentation of 72 h. The concentrations of ethyl octanoate, ethyl decanoate, and ethyl laurate were the highest when lipase was added at 12 h, indicating early coupling of ethanol production with ester synthesis catalyzed by lipase. Although the growth of S. cerevisiae was slightly inhibited when lipase was added into the fermentation medium due to the formation of fatty acids, no adverse effect on ester synthesis was observed. This novel approach may be useful in the production of relevant flavors of fermented Coconut Cream with lipase treatment, which could be used as a new food ingredient. Practical applications: Esters are a group of valuable flavor compounds that have wide applications in a variety of food products. In this work, we proposed one effective approach of coupling yeast alcoholic fermentation and lipase-catalyzed biocatalysis to synthesize natural fatty acid ethyl esters in Coconut Cream. This method provides a novel application of Coconut Cream for ester synthesis. In addition, the esters formed can be considered as natural according to current regulations. The ethanol generated can be effectively utilized for ester synthesis, therefore, complying with the Halal rules. The end product can be possibly used as a natural flavoring in the food industry after sensory evaluation and proper process. The esters formed may be further separated and purified as pure flavor compounds.

Jingcan Sun - One of the best experts on this subject based on the ideXlab platform.

  • Bioproduction of Natural Isoamyl Esters from Coconut Cream as
    2016
    Co-Authors: Catalysed Lipases, Shao-quan Liu, Huey Yie Lee, Philip Curran, Jingcan Sun
    Abstract:

    This study investigated the bioproduction of isoamyl esters in Coconut Cream by lipases. Five lipases (palatase 20000 L, lipase AYS “Amano”, lipase A “Amano ” 12, piccantase A and piccantase AN) were used to biosynthesize isoamyl esters in Coconut Cream supplemented with isoamyl alcohol. The lipases have different abilities to synthesize isoamyl esters with lipase AYS “Amano”, palatase 20000 L and piccantase A showing the highest potential. Bioproduction of isoamyl octanoate by palatase 20000 L was further examined under different conditions of temperature, pH, isoamyl alcohol concentration and lipase amount. Biosynthesis of isoamyl octanoate by palatase was not significantly affected at 30-50°C or pH of 4 to 7 and its maximum bioproduction was obtained at isoamyl alcohol concentration of 4 % (v/v) and lipase amount of 6 mg 100 mL-1 reaction mixture. The lipase-treated Coconut Cream may serve as a bioflavouring ingredient for food applications or for extraction of pure aroma chemicals

  • Ester Synthesis in Aqueous Media by Lipase: Alcoholysis, Esterification and Substrate Hydrophobicity
    Journal of Food Biochemistry, 2014
    Co-Authors: Jingcan Sun, Shao-quan Liu
    Abstract:

    Lipases are versatile biocatalysts commonly used for flavor ester synthesis in media with low-water activity. This research studied the mechanism of ester synthesis by lipase Palatase in Coconut Cream and phosphate buffer with alcohols and fatty acids. When ethanol was added as the alcohol substrate, hydrolysis of triglycerides dominated over synthesis of esters. When fusel alcohols (fusel oil) were used as the alcohol substrate, ester synthesis dominated over lipid hydrolysis. However, there was no visible pattern of fatty acid production and then reutilization in relation to ester synthesis in either case. Higher consumption of octanoic acid was obtained than that of butyric acid in both Coconut Cream and buffer systems spiked with the same alcohol. This indicated the preferential utilization of more hydrophobic substrates for esterification by lipase in aqueous media. These results suggest that the lipase Palatase-catalyzed ester synthesis in aqueous media was mainly hydrophobicity-dependent esterification. Practical Applications Esters are important flavor compounds that are applied in food products. The effects of substrate hydrophobicity and reaction environment on the catalytic behavior of a lipase during ester synthesis in an aqueous system of Coconut Cream and fusel oil were investigated. Useful information was obtained on the in situ generation of esters in food materials. This study has implications for lipase-catalyzed synthesis of flavor esters in other aqueous food matrices.

  • Optimization of methionol bioproduction by Saccharomyces cerevisiae using response surface methodology
    Annals of Microbiology, 2014
    Co-Authors: Heng-qian Lwa, Jingcan Sun, Shao-quan Liu
    Abstract:

    Methionol (3-methylthio-1-propanol) is an important volatile sulphur-containing alcohol that may significantly impact food flavour. The purpose of this research is to investigate the bioproduction of methionol from L-methionine catabolism by Saccharomyces cerevisiae EC-1118. The biotransformation was carried out in Coconut Cream supplemented with L-methionine. Response surface methodology was applied for the optimization of fermentation conditions to achieve a high yield of methionol. A second-order polynomial model (R2 = 0.912) was established based on the experimental data obtained in this study using multiple regression analysis. To obtain more accurate prediction results, a reduced quadratic model was obtained through backward elimination. Based on the reduced model, the optimal conditions for maximum methionol production were determined to be 0.30 % (w/v) of L-methionine, 0.10 % (w/v) of yeast extract and zero level of diammonium phosphate. Under these optimal conditions, a methionol concentration of 240.7 ± 17.4 μg/mL was achieved. This experimental result was in close agreement with the predicted value of 243.5 μg/mL, indicating that this model was adequate. These results indicate that fermentation by S. cerevisiae in L-methionine-supplemented Coconut Cream medium is an effective method for the production of methionol. Large-scale fermentation trials are needed to provide valuable information for industrial production.

  • biosynthesis of flavor esters in Coconut Cream through coupling fermentation and lipase catalyzed biocatalysis
    European Journal of Lipid Science and Technology, 2013
    Co-Authors: Jingcan Sun, Yunwei Lim, Shao-quan Liu
    Abstract:

    The aim of this research was to study the biosynthesis of natural flavor-active ethyl esters with a commercial lipase, Palatase 20 000 L, in Coconut Cream by coupling with yeast alcoholic fermentation. Alcoholic fermentation was carried out by Saccharomyces cerevisiae, which generated ethanol as one substrate for ester synthesis. Lipase was added into the fermentation medium at three different time points (12, 24, and 48 h) during the time-course fermentation of 72 h. The concentrations of ethyl octanoate, ethyl decanoate, and ethyl laurate were the highest when lipase was added at 12 h, indicating early coupling of ethanol production with ester synthesis catalyzed by lipase. Although the growth of S. cerevisiae was slightly inhibited when lipase was added into the fermentation medium due to the formation of fatty acids, no adverse effect on ester synthesis was observed. This novel approach may be useful in the production of relevant flavors of fermented Coconut Cream with lipase treatment, which could be used as a new food ingredient. Practical applications: Esters are a group of valuable flavor compounds that have wide applications in a variety of food products. In this work, we proposed one effective approach of coupling yeast alcoholic fermentation and lipase-catalyzed biocatalysis to synthesize natural fatty acid ethyl esters in Coconut Cream. This method provides a novel application of Coconut Cream for ester synthesis. In addition, the esters formed can be considered as natural according to current regulations. The ethanol generated can be effectively utilized for ester synthesis, therefore, complying with the Halal rules. The end product can be possibly used as a natural flavoring in the food industry after sensory evaluation and proper process. The esters formed may be further separated and purified as pure flavor compounds.

  • Biosynthesis of flavor esters in Coconut Cream through coupling fermentation and lipase‐catalyzed biocatalysis
    European Journal of Lipid Science and Technology, 2013
    Co-Authors: Jingcan Sun, Yunwei Lim, Shao-quan Liu
    Abstract:

    The aim of this research was to study the biosynthesis of natural flavor-active ethyl esters with a commercial lipase, Palatase 20 000 L, in Coconut Cream by coupling with yeast alcoholic fermentation. Alcoholic fermentation was carried out by Saccharomyces cerevisiae, which generated ethanol as one substrate for ester synthesis. Lipase was added into the fermentation medium at three different time points (12, 24, and 48 h) during the time-course fermentation of 72 h. The concentrations of ethyl octanoate, ethyl decanoate, and ethyl laurate were the highest when lipase was added at 12 h, indicating early coupling of ethanol production with ester synthesis catalyzed by lipase. Although the growth of S. cerevisiae was slightly inhibited when lipase was added into the fermentation medium due to the formation of fatty acids, no adverse effect on ester synthesis was observed. This novel approach may be useful in the production of relevant flavors of fermented Coconut Cream with lipase treatment, which could be used as a new food ingredient. Practical applications: Esters are a group of valuable flavor compounds that have wide applications in a variety of food products. In this work, we proposed one effective approach of coupling yeast alcoholic fermentation and lipase-catalyzed biocatalysis to synthesize natural fatty acid ethyl esters in Coconut Cream. This method provides a novel application of Coconut Cream for ester synthesis. In addition, the esters formed can be considered as natural according to current regulations. The ethanol generated can be effectively utilized for ester synthesis, therefore, complying with the Halal rules. The end product can be possibly used as a natural flavoring in the food industry after sensory evaluation and proper process. The esters formed may be further separated and purified as pure flavor compounds.

Naresh Magan - One of the best experts on this subject based on the ideXlab platform.

  • Discrimination between aflatoxigenic and non-aflatoxigenic Aspergillus section Flavi strains from Egyptian peanuts using molecular and analytical techniques
    World Mycotoxin Journal, 2011
    Co-Authors: Ahmed Abdel-hadi, David R. F. Carter, Naresh Magan
    Abstract:

    A wide range of Aspergillus section Flavi strains were isolated from Egyptian peanut samples. Eighteen of these strains were compared with two type strains (Aspergillus flavus SRRC G1907 and Aspergillus parasiticus 2747) for aflatoxin production based on (a) qualitative fluorescence using a Coconut Cream agar medium (CAM), and (b) aflatoxin production on a conducive Yeast Extract-Sucrose (YES) medium using HPLC. These results were validated by using molecular approaches (the structural genes, aflD (nor-1), aflM (ver-1) and aflP (omt A) and the regulatory gene aflR) to discriminate between aflatoxigenic and non-aflatoxigenic strains of the Aspergillus section Flavi group in vitro and on peanut seeds. Overall, 13/18 strains producing aflatoxins B1 and B2 in the range 1.27-213.35 µg/g medium were identified. In addition, 5 non-aflatoxin producing strains were found. The expression of these four genes was assessed using PCR and RT-PCR. PCR showed that all strains contained the four aflatoxin genes examined, r...

  • Mycotoxigenic fungi in peanuts from different geographic regions of Egypt
    Mycotoxin Research, 2010
    Co-Authors: Yousef Sultan, Naresh Magan
    Abstract:

    To understand the importance of mycotoxigenic fungi in Egyptian peanuts, samples from five regions (Alexandria, El-Beheira, El-Sharqiya, El-Daqahelaya in northern Egypt and Asyut, southern Egypt) in two seasons (2007, 2008) were collected. Aspergillus was consistently the most frequent genus in seeds and in-shell peanuts and was the dominant mycotoxigenic component of the mycobiota. There was no direct correlation between the moisture content of the samples and the fungal populations on peanut seeds tested from different regions. The most common species were from Aspergillus section Flavi (4.7-78.3%), Aspergillus section Nigri (9.4–52.6%) and Aspergillus section Circumdati (5.1–30.9%). In the in-shell peanut samples, the lowest populations were recorded in El-Beheira and Asyut (3.7–4.0 log_10 CFU g^-1) and the highest in Alexandria and Elsharqiya (4.1–6.0 log_10 CFU g^-1). Aspergillus section Flavi and section Nigri were the most dominant, and Aspergillus section Circumdati were only found in samples in 2008. Both qualitative (Coconut Cream agar) and quantitative analyses (HPLC) were used to analyse the potential mycotoxin production by strains isolated from peanuts. Of a total of 88 Aspergillus section Flavi strains examined, 95% were A. flavus based on production of aflatoxin B_1 on yeast extract sucrose (YES) medium and confirmation using molecular analyses. Of 64 Aspergillus section Circumdati strains only 28% produced ochratoxin A (OTA), and were identified as A. westerdijkiae . No Aspergillus section Nigri strains produced OTA, and they were identified as A. niger (uniseriate). The presence of these toxigenic fungi indicates that there is a potential risk of mycotoxin contamination in Egyptian peanuts and suggests that problems can arise from contamination with both aflatoxins and perhaps also OTA.

Luthfiana Azmi - One of the best experts on this subject based on the ideXlab platform.

  • PROSES PEMISAHAN VIRGIN Coconut OIL (VCO) DENGAN METODE SENTRIFUGASI(Separation Process Of Virgin Coconut Oil (VCO) Method With Centrifugation)
    2013
    Co-Authors: Luthfiana Azmi
    Abstract:

    Virgin Coconut Oil (VCO) is the oil produced from fesh Coconuts. Unlike the ordinary Coconut oil, Virgin Coconut Oil (VCO) is produced not by the addition of chemicals or processes that use high heat. Virgin Coconut Oil (VCO) beneficial to health, this is because Virgin Coconut Oil (VCO) contains many medium chain fatty acids (Medium Chain Fatty Acid / MCFA). MCFA are most in the Virgin Coconut Oil (VCO) iaLauric Acid (Lauric Acid). Properties that is easily absorbed MCFA will increase metabolism. The addition of energy produced by the metabolism of this produces stimulating effects in the human body there by increasing the level of energy produced. Core processes in the manufacture of Virgin Coconut Oil (VCO) is located on the separation of oil from water and protein. Many obstacles must be faced for separating oil from water and proteins, such as in the fermentation processs, the separation process takes a long time to get the Virgin Coconut Oil (VCO). While the centrifugation, the separation is done by utilizing the weight of the lighter oil. Although I do not require centrifugation long time but the way it has in the purity of the product constraints. This research was conducted by using Coconut milk is silenced for 3 hours. Then the Cream is incorporated into the instrumen with speed centrifuges spin 1000 rpm, 1200rpm and 1400rpm with variation times very; 15 minutes, 20 minutes and 25 minutes after that Coconut Cream layer divided into 3 layers of oil that is, the middle layer of protein (blondo). The results of Virgin Coconut Oil (VCO) is obtained and then analyzed with the efficiency, density, freezing pointand theVCOlevels. Separation methodused is themethod ofcentrifugation, separatingfunnelandmeasuring cupobtainedthe bestseparationmethodis the method ofcentrifugationbecausethe surface tensionof oilandthe resultingbest.

Tjatoer Welasih - One of the best experts on this subject based on the ideXlab platform.

  • PEMBUATAN VIRGIN Coconut OIL (VCO) DENGAN METODE SENTRIFUGASI
    2013
    Co-Authors: Nur Hapsari, Tjatoer Welasih
    Abstract:

    Virgin Coconut Oil (VCO) is the oil produced from fresh Coconuts. Unlike the ordinary Coconut  oil,  Virgin  Coconut  Oil  (VCO)  is  produced  not  by the  addition  of  chemicals  or processes  that  use  high  heat.  Virgin  Coconut  Oil  (VCO)  beneficial  to  health,  this  is  because Virgin Coconut Oil (VCO) contains many medium chain fatty acids (Medium Chain Fatty Acid /  MCFA).  MCFA  are  most  in  the  Virgin  Coconut Oil  (VCO)  is  Lauric  acid  (Lauric  Acid). Properties  that  is  easily  absorbed  MCFA  will  increase  metabolism.  The  addition  of  energy produced  by  the  metabolism  of  this  produces  stimulating  effects  in  the  human  body  thereby increasing the level of energy produced.  Core  processes  in  the  manufacture  of  Virgin  Coconut  Oil  (VCO)  is  located  on  the separation of oil from water and protein. Many obstacles must be faced for separating oil from water  and  proteins,  such  as  in  the  fermentation  process,  the  separation  process takes  a  long time to get the Virgin Coconut Oil (VCO). While the centrifugation, the separation is done by utilizing the weight of the lighter oil. Although I do not require centrifugation long time but the way it has in the purity of the product constraints.  This research was conducted by using Coconut Cream from Coconut milk is silenced for 3  hours.  Then  the  Cream  is  incorporated  into  the  instrument  with  speed  centrifuges  spin 600,700,800,900 and 1000 rpm with vaiasion  times very; 30, 45, 60.75 and 90 minutes after that  Coconut  Cream  layer  divided  into  3  layers  of  oil  that  is,  the  middle  layer  of  protein (blondo)  and  next  underwater  layer  silenced  for  8,10,12,14,  and  16  hours  .  The  results  of virgin  Coconut  oil  (VCO)  is  obtained  and  then  analyzed  with  the  parameters  water  content, protein content, Lauric acid, color and odor.  From the research, obtained the best conditions of rotational speed centrifuges at 1000 rpm and centrifuges turnaround time 90 minutes and 8 hours stagnand time with the quality of Virgin  Coconut  Oil  (VCO)  which  produced  yield:  Lauric  acid  yield  of  36.67%  and  52.23% results. Keywords: sentrifuge, Coconut Cream,,% yield results, VCO