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Effect of rotation speed and steam pressure on physico-chemical properties of drum dried pitaya (Hylocereus polyrhizus) peel


Citation

Chia, Siew Lian and Chong, Gun Hean (2015) Effect of rotation speed and steam pressure on physico-chemical properties of drum dried pitaya (Hylocereus polyrhizus) peel. International Food Research Journal, 22 (1). pp. 372-376. ISSN 1985-4668; ESSN: 2231-7546

Abstract

Red pitaya (Hylocereus polyrhizus) peel is a rich source of fibre, antioxidant and betacyanin; however, it is discarded during processing, so it is able to cause environmental problems. In order to convert the fruit waste to potential by-product ingredients, drum drying is used as pre-treatment to create an ingredient which is shelf-stable. In this study, the effects of rotation speed and steam pressure of drums on the physico-chemical properties of pitaya peel that had undergone drum drying are investigated. Pitaya peel was dried in a laboratory scale double drum dryer at rotation speed of 1, 2, and 3 rpm at steam pressure of 1, 2, and 3 bar. The drum dried pitaya peel was then further analyzed based on percentage yield, moisture content, water activity, betacyanin retention and color change. Interaction of steam pressure and rotation speed gives significant effect (p < 0.05) on percentage yield, moisture content, water activity, betacyanin retention and Hunter L value, whereas it has no significant on Hunter a and b values. The best combination parameters (1 rpm and 2 bar) yield the highest betacyanin retention (80.21 mg/g of dry solid), acceptable moisture content (10.66% wet basis), water activity (aw = 0.42) and with 7.61% of yield.


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Additional Metadata

Item Type: Article
Divisions: Faculty of Food Science and Technology
Publisher: Faculty of Food Science and Technology, Universiti Putra Malaysia
Keywords: Betacyanin; Drum drying; Pitaya peel; Rotation speed; Steam pressure
Depositing User: Nabilah Mustapa
Date Deposited: 27 Jan 2016 00:11
Last Modified: 27 Jan 2016 00:11
URI: http://psasir.upm.edu.my/id/eprint/36095
Statistic Details: View Download Statistic

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