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Progressive Screening of Thermostable Yeasts for Phytase Production
Edi Franciele Ries,Gabriela Alves Macedo 한국식품과학회 2009 Food Science and Biotechnology Vol.18 No.3
Biotechnological phytase preparations are commercially available and are currently used in animal feeding. However, thermostability constraints, low yields, and the high cost of the enzyme have limited its use. This study represents a new perspective for the food enzyme market. The research screened thermostable yeast strains for their ability to produce phytase. The screening was carried out with a gradual increase in temperature (30-48℃). Sixteen strains (1 strain identified as Saccharomyces cerevisiae) maintained the ability to produce phytase at 48℃ and their phytase activity was confirmed using 2 phytase assay methodologies. The yeast strains tested in this study seem to be potential efficient producers of phytase, indicating a possible new source of thermostable phytase of commercial interest, particularly that from S. cerevisiae.
Biochemical Characterization of Esterase from Soybean (Glycine max L.)
Márcio de Barros,Gabriela Alves Macedo 한국식품과학회 2011 Food Science and Biotechnology Vol.20 No.5
Esterases are enzymes that present good potential in industrial application, and soybean seed can represent an alternative source for this enzyme. The extraction and esterase activity of Brazilian soybean seeds (Glycine max L.) were evaluated. Esterase activity was found in both the germinated and non-germinated seeds at 2.90 and 1.70 U/mg, respectively, with a concentration in the powdered extract (freeze dried) of 100 mg/mL. The enzyme showed a preference for the hydrolysis of short chain fatty acids (120.02 U/mL) and optimum pH for activity was pH 8.0 with optimum temperatures of 40 and 80ºC. The enzyme showed stability at 70ºC showing 60%of residual activity and activity increased with the addition of the following salts: NaNO_3, K_2SO_4, and Na_2SO_4 in the reaction medium.
Biosynthesis of Oleyl Oleate Wax Ester by Non-commercial Lipase
Danielle Branta Lopes,Marta Cristina Teixeira Duarte,Gabriela Alves Macedo 한국식품과학회 2011 Food Science and Biotechnology Vol.20 No.5
Oleyl oleate can be considered a synthetic analogue of jojoba oil. This one has been the main natural source of wax esters for commercial applications since the global ban on whale hunting. Lipase catalyzed production of this ester was carried out using oleic acid and oleyl alcohol in a solvent-free system. Lipase from Rhizopus sp. CBMAI 1127 was used as the biocatalyst and commercial enzyme Lipozyme TL IM^® was used to compare results. The acid/alcohol molar ratio showed significant effects for both lipases and the amount of enzyme had a significant effect just for Lipozyme TL IM^®. The rate of the esterification reaction using lipase from Rhizopus sp. CBMAI 1127 was very similar to that obtained with commercial lipase. The present study also evaluated antimicrobial and emulsifying properties of this ester. Emulsifying capacity of the synthesized oleyl oleate was lower than Tween 80 and sodium dodecyl sulfate, and no antimicrobial activity was observed.
A New Biotechnological Process to Enhance the Soymilk Bioactivity
Lívia Dias de Queirós,Juliana Alves Macedo,Gabriela Alves Macedo 한국식품과학회 2016 Food Science and Biotechnology Vol.25 No.3
Equol, a daidzein metabolite produced exclusively by intestinal bacteria in some, but not all, humans, exhibits a wide range of beneficial health effects owing to its superior nutraceutical effect compared with isoflavones of soy. The aim of this work was to develop bioprocesses capable of increasing the bioactive properties of soymilk and, most importantly, increase the equol content by a biotechnological process in vitro. Biotransformation processes based on soymilk fermentation by probiotic lactic bacteria and application of the enzyme tannase caused an increase in the bioactive isoflavones and antioxidant capacity of soymilk. Furthermore, these processes approximately resulted in a 10-fold increase in the equol content of the soymilk. This is the first study to produce a significant equol concentration in soymilk using enzymatic processing only. The results suggest a new and effective biotechnological process, with major commercial potential, capable of producing a bioactive soy extract that intends to be “functional for everyone.”
Comparison of different Brazilian citrus by-products as source of natural antioxidants
Paula de Paula Menezes Barbosa,Amanda Roggia Ruviaro,Gabriela Alves Macedo 한국식품과학회 2018 Food Science and Biotechnology Vol.27 No.5
Significant amounts of citrus by-products remain after juice processing, which is then used to obtain pectin. The pectin industry then generates a new waste. No study has characterized this residue or suggested applications for it. The main goal of this study was to compare citrus industrial by-products that remain after juice (CJB) and pectin (CPB) extraction, aiming to obtain bioactive compounds. The residues were evaluated for their chemical composition, antioxidant capacity, and polyphenols content. CJB had 2-fold higher total phenols than CPB. Moreover, CJB exhibited higher antioxidant capacity than CPB. Nine polyphenols were detected; hesperidin was the main compound on both residues. CPB had higher content of polyphenols than CJB, which can be attributed to the industry procedure of pectin extraction. Thus, this study provides support for the reuse of CPB to obtain nutraceutical compounds, converting waste into added-value products.
Characterization of ‘Biuti’ Peach Polyphenoloxidase
Ana Silvia Fidelis Belluzzo,Luciana Francisco Fleuri,Juliana Alves Macedo,Gabriela Alves Macedo 한국식품과학회 2009 Food Science and Biotechnology Vol.18 No.4
In Brazil canned ‘Biuti’ peach is a very popular form of this sub-tropical fruit. This production represents an important economic agro-activity in Minas Gerais, Brazil during the summer period, in preparation for the Christmas celebrations. The aim of this work was to characterize the ‘Biuti’ peach polyphenoloxidase (PPO), since peach products show enzymatic oxidation of the polyphenols by oxidative enzymes, which affects the products during their shelf life. Two different hypothesis for the browning problem in processed peaches were studied: the inadequacy of the blanching treatment and the presence of a latent phenolase in the peaches. The PPO was characterized: pH optimum (5.5) and stability (5.5-6.5); optimum temperature at 20℃ and 80% of the activity retained after 30 min at 15-40℃. The test for the presence of latent PPO in the processed and canned peaches was negative. Ascorbic acid, ß-mercaptoethanol, sodium metabisulfite, and cysteine were efficient in inhibiting the PPO.