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Quality and Drying Characteristics of Apple Cubes Subjected to Combined Drying ( FD Pre‐Drying and HAD Finish‐Drying)
Author(s) -
Antal Tamás,
Kerekes Benedek,
Sikolya László,
Tarek Mohamed
Publication year - 2015
Publication title -
journal of food processing and preservation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.511
H-Index - 48
eISSN - 1745-4549
pISSN - 0145-8892
DOI - 10.1111/jfpp.12313
Subject(s) - blanching , malus , water content , shrinkage , moisture , food science , chemistry , freeze drying , materials science , mathematics , pulp and paper industry , horticulture , composite material , chromatography , geotechnical engineering , biology , engineering
The drying methods tested were hot‐air drying ( HAD ) and freeze‐drying ( FD ), as well as a combination of blanching (100C, 1 min) prior to FD pre‐drying and HAD finish drying. The effect of drying methods on moisture content, temperature, energy consumption, duration of drying, rehydration properties, color, texture and sensory were determined. Apple's HAD and FD kinetics was described by an exponential and third‐degree polynomial model, while the combined drying‐blanching prior to freeze pre‐drying and hot‐air finish‐drying (BFD‐HAD) kinetics consisted of two periods: polynomial until a converting point and exponential beyond that point. Among the products, the quality of apple samples processed by FD was the best, followed by BFD ‐ HAD , whereas the products made using HAD were the worst. The drying times obtained for HAD and BFD ‐ HAD were shorter than the drying times obtained for FD . The best BFD ‐ HAD process, from quality and energy consumption considerations, was found to a moisture content of 30% w.b. ( BFD time: 12 h), followed by 3 h of HAD . It was observed that BFD ‐ HAD can reduce by about 8 h the time needed for FD . Practical Applications Apple ( M alus domestica L .) is one of the most widely grown fruit crops in the world. Available in fresh and processed forms, apples are rich source of vitamins, organic acids, polyphenols, anthocyanins and minerals. Currently, dehydrating is a frequent practice since dried apples are included in numerous processed foods such as snack products, integral breakfast foods, etc. The aim of this article is to examine the effectiveness of freeze‐drying enhanced with two‐stage vacuum freeze and hot‐air drying. It can be suggested to apply the blanching as pretreatments and combined drying ( FD ‐ HAD ) for reduction of operational cost. Our research work confirmed that BFD ‐ HAD is a good alternative instead of the FD . The development of new drying techniques possibility for apple with good physical, chemical properties may be of interest in order to the market supply (food supplement, functional food, etc.).