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Drying based on temperature‐detection‐assisted control in microwave‐assisted pulse‐spouted vacuum drying
Author(s) -
Cao Xiaohuang,
Zhang Min,
Qian He,
Mujumdar Arun S
Publication year - 2017
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.8040
Subject(s) - temperature control , microwave , vacuum drying , materials science , analytical chemistry (journal) , process engineering , chemistry , chromatography , freeze drying , thermodynamics , computer science , telecommunications , engineering , physics
BACKGROUND An online temperature‐detection‐assisted control system of microwave‐assisted pulse‐spouted vacuum drying was newly developed. By using this system, temperature control can be automatically and continuously adjusted based on the detection of drying temperature and preset temperature. Various strategies for constant temperature control, linear temperature control and three‐step temperature control were applied to drying carrot cubes. Drying kinetics and the quality of various temperature‐controlled strategies online are evaluated for the new drying technology as well as its suitability as an alternative drying method. RESULTS Drying time in 70 °C mode 1 had the shortest drying time and lowest energy consumption in all modes. A suitable colour, highest re‐hydration ratio and fracture‐hardness, and longest drying time occurred in 30‐40‐50 °C mode 3. The number of hot spots was reduced in 40‐50‐60 °C mode 3. Acceptable carrot snacks were obtained in 50‐60‐70 °C mode 3 and 70 °C mode 2. All temperature curves showed that the actual temperatures followed the preset temperatures appropriately. CONCLUSIONS With this system, a linear temperature‐controlled strategy and a three‐step temperature‐controlled strategy can improve product quality and heating non‐uniformity compared to constant temperature control, but need greater energy consumption and longer drying time. A temperature‐detection‐assisted control system was developed for providing various drying strategies as a suitable alternative in making a snack product. © 2016 Society of Chemical Industry