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Development of microwave drying technology for swiftlet bird’s nest at low pressure

June 6, 2012.

 

        Swiftlet bird’s nest, as shown in Fig.1, is an internationally well known product for its functional and healthy food, a great tonic to make a healthy skin, to cure respiratory symptoms and sinusitis etc.

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          Swiftlet bird’s nest, as shown in Fig.1, is an internationally well known product for its functional and healthy food, a great tonic to make a healthy skin, to cure respiratory symptoms and sinusitis etc.

         The nest has been consumed and known as Eastern Caviar. The swiftlet bird’s nest consists of 0.14-1.28% of fat, 25-27% of carbohydrate and 62-63% of protein[1]. The protein of the nest, which is a glycoprotein, possesses precursor substance for boosting immunity and stimulating skin cell growth. It has higher nutritional value than normal protein, can inhibit growth of bacteria, fungi and virus. To make food product from the bird’s nest, it will be soaked in water to clean up contaminated matter, and then the clean and white fiber-like nest is dried up as shown in Fig.2.

          Traditionally, warm air circulation is used to dry the nest, taking too long drying time more than 22 hours, which is not practical for industrial production. New drying technologies are critically needed by local industries for value-added of the dried nest and reduction of transportation cost. Plasma technology for agricultural application research laboratory, Thailand Center of Excellence in Physics (ThEP Center), have been developing low pressure microwave drying system for bird’s nest. Figure 3 shows the low-pressure microwave drying system, which is composed of adjustable microwave power source, vacuum system, oil trap and water condenser.

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          Figure 4 shows that drying time of bird’s nest by low-pressure microwave system has been reduced drastically. At 100 watts, the drying time is less than 2 hours. The color of the nest, dried by microwave, is preserved as original, as shown in Fig.5.

 

 

 

          The percentages of protein, which is shown in Table 1, are higher for the bird’s nests  which are dried by low-pressure microwave system, compared with other methods.

          In this research, it is verified that low-pressure microwave drying technique is suitable to dry heat sensitive substance, such swiftlet bird’s nest. The qualities of the dried products, such as color, texture and nutrition, are preserved. The low-pressure microwave drying system, developed in this research, can be applied to dry other heat sensitive substances. It also can be developed for industrial prototype of the drying system.

 

Acknowledgement

We would like to thank the Network for Commercialize Research and Development of Government-Private Sector Joint Mission, and Thailand Center of Excellence in Physics,
Commission on Higher  Education (CHE), for their financial support.

 

Reference
1. Glai-more Magazine , Vol.23 , No.2 , February 1998

Reported by
Assistant Professor Dr. Mudtorlep  Nisoa
Plasma Technology for Agricultural Applications Research Laboratory
Division of Physics, Faculty of Science
Walailak  University ,  Nakhon-si-thammarat  80160
Tel: +66 7567 3229, Fax: +66 7567 2004
Email: nmudtorl@wu.ac.th