Manothermosonication (MTS) treatment of apple-carrot juice blend: effect on inactivation of Escherichia coli O157:H7 and quality attributes during storage

Kahraman, Ozan

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https://hdl.handle.net/2142/73016 Copy

Description

Title

Manothermosonication (MTS) treatment of apple-carrot juice blend: effect on inactivation of Escherichia coli O157:H7 and quality attributes during storage

Author(s)

Kahraman, Ozan

Issue Date

2015-01-21

Director of Research (if dissertation) or Advisor (if thesis)

Feng, Hao

Department of Study

Food Science & Human Nutrition

Discipline

Food Science & Human Nutrition

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Manothermosonication
• Ultrasound
• Inactivation
• Quality
• Juices
• high temperature - short time (HTST)

Abstract

With advantages such as requiring less time, saving energy and reducing the costs manothermosonication has become increasingly popular in the food processing industry in recent years. My thesis research was conducted to investigate the effect of manothermosonication (MTS) on microbial inactivation and the quality of apple-carrot blended juice during storage. To examine the effect of MTS on quality of apple-carrot blended juice samples treated with MTS and high temperature - short time (HTST) was examined during a 3-week period under refrigeration conditions. Quality attributes such as brix, total phenolic content, titratable acidity, viscosity, antioxidant capacity, turbidity, pH, and color of the samples were compared. The MTS treatment helped to achieve 5 log reduction in apple-carrot blended juice in relatively short time, especially at elevated temperatures. At 40oC, a maximum of 3.03 log CFU/ml after 75 s treatment at 300 kPa. At 50oC, 5 log reduction in the population of Escherichia coli O157:H7 was achieved in 60 s under all three pressures (100, 200, and 300 kPa). When temperature was increased to 60oC, only 30 s were needed to reduce the survival count of E. coli O157:H7 by 5 log cycles at 100, 200, and 300 kPa. MTS treatment of apple-carrot blended juice significantly affected chemical parameters such as total phenolic content, antioxidant and pH-value. The MTS treatment affected the antioxidant activities of apple-carrot blended juice during three weeks storage and a significant increase in antioxidant activity was recorded for samples treated with MTS during 3 weeks of storage. While the first day antioxidant activities of the samples were low, they were increased when measured on day 7, 14, and 21. Total phenolic content of apple-carrot blended juice treated by HTST was significantly lower compared to the samples treated with MTS. Turbidity of MTS-treated samples decreased significantly during 3 weeks of storage. Overall, apple-carrot blended juice treated with MTS showed good promise as an alternative to HTST as evidenced by effective microbial inactivation and ability to maintain juice quality.

Graduation Semester

2014-12

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http://hdl.handle.net/2142/73016

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Copyright 2014 Ozan Kahraman

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