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

作　　者：Thing Chai Tham Mei Xiang Ng Shu Hui Gan Lee Suan Chua Ramlan Aziz Luqman Chuah Abdullah Sze Pheng Ong Nyuk Ling Chin Chung Lim Law 

机构地区：[1]Department of Chemical Engineering The University of Nottingham,Malaysia Campus,Jaian 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

出　　处：《Chinese Journal of Chemical Engineering》2018年第2期303-316,共14页中国化学工程学报（英文版）

基　　金：Supported by the Ministry of Agriculture and Agro-Based Industry(MOA),Malaysia(NER30001)

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 H20-（g DM）-1. rain-1 to 0.212 g H20-（g DM）-1. rain 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.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 from0.054 g H_2 O·(g DM)^(-1) ·min^(-1) to 0.212 g H_2 O·(g DM)^(-1)·min^(-1) while SD had the lowest drying rate, measured at 0.042 g H_2 O·(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 

分 类 号：TQ028.67[化学工程]