Pre-treatments effect on pepper drying time and microstructure

Ana Sakura Zainal Abidin; Melissa Michelle Rolland; Sinin Hamdan; Rasli Muslimen; Shirley J. Tanjong; Raudhah Ahmadi

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Pre-treatments effect on pepper drying time and microstructure

Author(s)

Ana Sakura Zainal Abidin Dept. of Mechanical and Manufacturing Engineering, Faculty of Engineering, Universiti Malaysia Sarawak, 94300, Kota Samarahan, Sarawak, Malaysia

Melissa Michelle Rolland Dept. of Mechanical and Manufacturing Engineering, Faculty of Engineering, Universiti Malaysia Sarawak, 94300, Kota Samarahan, Sarawak, Malaysia

Sinin Hamdan Dept. of Mechanical and Manufacturing Engineering, Faculty of Engineering, Universiti Malaysia Sarawak, 94300, Kota Samarahan, Sarawak, Malaysia

Rasli Muslimen Dept. of Mechanical and Manufacturing Engineering, Faculty of Engineering, Universiti Malaysia Sarawak, 94300, Kota Samarahan, Sarawak, Malaysia

Shirley J. Tanjong Dept. of Mechanical and Manufacturing Engineering, Faculty of Engineering, Universiti Malaysia Sarawak, 94300, Kota Samarahan, Sarawak, Malaysia

Raudhah Ahmadi Dept. of Civil Engineering, Faculty of Engineering, Universiti Malaysia Sarawak, 94300, Kota Samarahan, Sarawak, Malaysia

Abstract

Traditional pepper drying process takes 4 to 5 days and sometimes longer, especially during rainy days. This paper presented a study on the effects of two pre-treatment methods to the improvement of the drying rate of black pepper production. Two samples of pepper berries were pre-treated by boiling and freezing, respectively. After pre-treatment, the samples must be immediately dried to prevent microbial infections. To achieve this, each sample was then spun in a rotary drum dryer at a controlled temperature. The weight of the sample was recorded at a certain time interval until the sample has achieved a 12% moisture content. Each sample was also tested using Fourier Transform Near-Infrared (FT-NIR) to check the physical and chemical specifications. Scanning Electron Microscopy (SEM) was used to observe the surface morphology of the skin and core of the samples. Pre-treated samples resulted in shorter drying time compared to untreated samples. Observation of the microstructural changes using SEM showed that the dried core of the pretreated samples was less damaged compared to untreated samples. This study demonstrated that pre-treating pepper berries prior to drying improved the drying time from 8 hours (based on an untreated sample) to 2½ hours. Dried pre-treated samples also achieved the standard moisture content. Thus, the application of a rotary drum dryer to dry the pre-treated pepper is the novelty of this research.

Publication Details

Page(s) 13-18

DOI DOI not available

Published Journal: Science International, Volume: 33, Issue: 1, Year: 2021

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Keywords

SEM, moisture content, Black pepper, freezing, Rotary drum dryer, FT-NIR, Boiling, Drying Time