SCI和EI收录∣中国化工学会会刊

Chin.J.Chem.Eng. ›› 2018, Vol. 26 ›› Issue (2): 303-316.DOI: 10.1016/j.cjche.2017.05.011

• Separation Science and Engineering • Previous Articles     Next Articles

Impacts of different drying strategies on drying characteristics, the retention of bio-active ingredient and colour changes of dried Roselle

Thing Chai Tham1, Mei Xiang Ng1, Shu Hui Gan1, Lee Suan Chua2, Ramlan Aziz2, Luqman Chuah Abdullah3, Sze Pheng Ong1, Nyuk Ling Chin4, Chung Lim Law1   

  1. 1 Department of Chemical Engineering, The University of Nottingham, Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor D. E., Malaysia;
    2 Institute of Bioproduct Development, Universiti Teknologi Malaysia, UTM, Johor Bahru, 81310 Skudai, Malaysia;
    3 Department of Chemical and Environmental Engineering, Universiti Putra Malaysia, UPM, 43400 Serdang, Selangor, Malaysia;
    4 Department of Process and Food Engineering, Universiti Putra Malaysia, UPM, 43400 Serdang, Selangor, Malaysia
  • Received:2017-02-07 Revised:2017-05-27 Online:2018-03-16 Published:2018-02-28
  • Contact: Chung Lim Law
  • Supported by:

    Supported by the Ministry of Agriculture and Agro-Based Industry (MOA), Malaysia (NER 30001).

Impacts of different drying strategies on drying characteristics, the retention of bio-active ingredient and colour changes of dried Roselle

Thing Chai Tham1, Mei Xiang Ng1, Shu Hui Gan1, Lee Suan Chua2, Ramlan Aziz2, Luqman Chuah Abdullah3, Sze Pheng Ong1, Nyuk Ling Chin4, Chung Lim Law1   

  1. 1 Department of Chemical Engineering, The University of Nottingham, Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor D. E., Malaysia;
    2 Institute of Bioproduct Development, Universiti Teknologi Malaysia, UTM, Johor Bahru, 81310 Skudai, Malaysia;
    3 Department of Chemical and Environmental Engineering, Universiti Putra Malaysia, UPM, 43400 Serdang, Selangor, Malaysia;
    4 Department of Process and Food Engineering, Universiti Putra Malaysia, UPM, 43400 Serdang, Selangor, Malaysia
  • 通讯作者: Chung Lim Law
  • 基金资助:

    Supported by the Ministry of Agriculture and Agro-Based Industry (MOA), Malaysia (NER 30001).

Abstract: The drying kinetics of Roselle (Hibiscus sabdariffa L.) of variety Terengganu (UMKL-1) and the quality attribution of Roselle were studied. The experiments were conducted using four different drying methods, including solar greenhouse drying (SD), solar greenhouse with intermittent heat pump drying (SIHP), hot air drying (HA) and heat pump drying (HP). Among the four drying methods, HP achieved the highest drying rate at a range from 0.054 g H2O·(g DM)-1·min-1 to 0.212 g H2O·(g DM)-1·min-1 while SD had the lowest drying rate, measured at 0.042 g H2O·(g DM)-1·min-1. The analysis on colour kinetics revealed that there is no significant colour loss (p > 0.05) observed from HP's dried Roselle. Greater amount of flavonoid compounds i.e. protocatechuic acid was found in SD and SIHP dried finished product whereas HP's dried Roselle contains higher percentage of catechin as compared to other drying methods.

Key words: Hibiscus sabdariffa L., Drying, Heat pump, Total colour change, Protocatechuic acid, Catechin

摘要: The drying kinetics of Roselle (Hibiscus sabdariffa L.) of variety Terengganu (UMKL-1) and the quality attribution of Roselle were studied. The experiments were conducted using four different drying methods, including solar greenhouse drying (SD), solar greenhouse with intermittent heat pump drying (SIHP), hot air drying (HA) and heat pump drying (HP). Among the four drying methods, HP achieved the highest drying rate at a range from 0.054 g H2O·(g DM)-1·min-1 to 0.212 g H2O·(g DM)-1·min-1 while SD had the lowest drying rate, measured at 0.042 g H2O·(g DM)-1·min-1. The analysis on colour kinetics revealed that there is no significant colour loss (p > 0.05) observed from HP's dried Roselle. Greater amount of flavonoid compounds i.e. protocatechuic acid was found in SD and SIHP dried finished product whereas HP's dried Roselle contains higher percentage of catechin as compared to other drying methods.

关键词: Hibiscus sabdariffa L., Drying, Heat pump, Total colour change, Protocatechuic acid, Catechin