Amylase for Apple Juice Processing: Effects of pH, Heat, and Ca2+ Ions
The aim of this paper was to evaluate the effects of pH, heat, and Ca2+ ions on the α-amylase activities in a commercial amylolytic enzyme (Tyazyme L300), used for apple juice processing. Kinetics of thermal inactivation was studied in acetate and citrate/phosphate buffers at different temperatures...
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| Format: | Article |
| Language: | English |
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University of Zagreb Faculty of Food Technology and Biotechnology
2002-01-01
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| Series: | Food Technology and Biotechnology |
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| Online Access: | http://hrcak.srce.hr/file/262935 |
| _version_ | 1827610152423915520 |
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| author | Liliana N. Ceci Jorge E. Lozano |
| author_facet | Liliana N. Ceci Jorge E. Lozano |
| author_sort | Liliana N. Ceci |
| collection | DOAJ |
| description | The aim of this paper was to evaluate the effects of pH, heat, and Ca2+ ions on the α-amylase activities in a commercial amylolytic enzyme (Tyazyme L300), used for apple juice processing. Kinetics of thermal inactivation was studied in acetate and citrate/phosphate buffers at different temperatures (55–70 °C) and enzyme concentrations (0.276 and 0.552 mL/100 mL). Maximum α-amylase activity was observed at pH=3.4 in both buffers. Effects of the addition of calcium chloride during and after thermal treatments were also investigated. α-amylase activities were measured by an iodometric method and thermal inactivation constants and D values (time for reducing 90 % of the enzymatic activity) were estimated. The enzyme was more sensible to pH changes and heat when citrate ions were present in the reaction medium. If Ca2+ in the enzyme structure is bound to citrate then the resistance of the enzyme to pH changes and heat is lowered. Kinetics obtained according to Arrhenius equation and two enzymatic fractions (thermo-labile and thermoresistant) were observed too. In citrate buffer the following relation was observed for thermo-labile fraction: log (D value) = -0.144 t/°C + 12.992. The level of thermal inactivation also depended on the enzyme concentration. Higher thermal inactivation rates were obtained by increasing the enzyme concentration in the case when citrate was present. It was also found that the addition of calcium chloride (1 g/L) after thermal treatment in median containing citrate reactivated the enzyme treated at 60 and 65 °C. The possible implications of these findings in apple juice processing were discussed. |
| first_indexed | 2024-03-09T07:44:46Z |
| format | Article |
| id | doaj.art-cf192c7eb9524a44bf3467169abb8258 |
| institution | Directory Open Access Journal |
| issn | 1330-9862 1334-2606 |
| language | English |
| last_indexed | 2024-03-09T07:44:46Z |
| publishDate | 2002-01-01 |
| publisher | University of Zagreb Faculty of Food Technology and Biotechnology |
| record_format | Article |
| series | Food Technology and Biotechnology |
| spelling | doaj.art-cf192c7eb9524a44bf3467169abb82582023-12-03T03:58:26ZengUniversity of Zagreb Faculty of Food Technology and BiotechnologyFood Technology and Biotechnology1330-98621334-26062002-01-014013338Amylase for Apple Juice Processing: Effects of pH, Heat, and Ca2+ IonsLiliana N. Ceci0Jorge E. Lozano1PLAPIQUI (UNS-CONICET) Camino La Carrindanga Km.7, C.C. 717 8000 Bahía Blanca – ArgentinaPLAPIQUI (UNS-CONICET) Camino La Carrindanga Km.7, C.C. 717 8000 Bahía Blanca – ArgentinaThe aim of this paper was to evaluate the effects of pH, heat, and Ca2+ ions on the α-amylase activities in a commercial amylolytic enzyme (Tyazyme L300), used for apple juice processing. Kinetics of thermal inactivation was studied in acetate and citrate/phosphate buffers at different temperatures (55–70 °C) and enzyme concentrations (0.276 and 0.552 mL/100 mL). Maximum α-amylase activity was observed at pH=3.4 in both buffers. Effects of the addition of calcium chloride during and after thermal treatments were also investigated. α-amylase activities were measured by an iodometric method and thermal inactivation constants and D values (time for reducing 90 % of the enzymatic activity) were estimated. The enzyme was more sensible to pH changes and heat when citrate ions were present in the reaction medium. If Ca2+ in the enzyme structure is bound to citrate then the resistance of the enzyme to pH changes and heat is lowered. Kinetics obtained according to Arrhenius equation and two enzymatic fractions (thermo-labile and thermoresistant) were observed too. In citrate buffer the following relation was observed for thermo-labile fraction: log (D value) = -0.144 t/°C + 12.992. The level of thermal inactivation also depended on the enzyme concentration. Higher thermal inactivation rates were obtained by increasing the enzyme concentration in the case when citrate was present. It was also found that the addition of calcium chloride (1 g/L) after thermal treatment in median containing citrate reactivated the enzyme treated at 60 and 65 °C. The possible implications of these findings in apple juice processing were discussed.http://hrcak.srce.hr/file/262935α-amylaseapple juicestarch hydrolysis |
| spellingShingle | Liliana N. Ceci Jorge E. Lozano Amylase for Apple Juice Processing: Effects of pH, Heat, and Ca2+ Ions Food Technology and Biotechnology α-amylase apple juice starch hydrolysis |
| title | Amylase for Apple Juice Processing: Effects of pH, Heat, and Ca2+ Ions |
| title_full | Amylase for Apple Juice Processing: Effects of pH, Heat, and Ca2+ Ions |
| title_fullStr | Amylase for Apple Juice Processing: Effects of pH, Heat, and Ca2+ Ions |
| title_full_unstemmed | Amylase for Apple Juice Processing: Effects of pH, Heat, and Ca2+ Ions |
| title_short | Amylase for Apple Juice Processing: Effects of pH, Heat, and Ca2+ Ions |
| title_sort | amylase for apple juice processing effects of ph heat and ca2 ions |
| topic | α-amylase apple juice starch hydrolysis |
| url | http://hrcak.srce.hr/file/262935 |
| work_keys_str_mv | AT liliananceci amylaseforapplejuiceprocessingeffectsofphheatandca2ions AT jorgeelozano amylaseforapplejuiceprocessingeffectsofphheatandca2ions |