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Effect of calcium pretreatments, vacuum levels, and apple varieties, on the texture of vacuum microwave dehydrated apple chips

University of British Columbia

Apples were washed, sliced, steam blanched and dipped in 0-5% calcium chloride solution. These slices were air dried to a moisture content of ~50%db and then vacuum microwave dried (VMD) to a final moisture content of ~5%db. The effects of calcium pretreatment, vacuum levels, and apple varieties on the textural characteristics of VMD apple chips were determined by a TA XT2 Texture Analyzer using punch and die tests. The effect of different drying techniques (VMD, air drying and freeze drying) on apple chips' texture was also investigated. The calcium pretreated chips were found to be significantly (p<0.05) crispier than the non-treated ones. Application of vacuum during VMD was observed to have significant (p<0.05) effects on lowering the density and increasing the crispness in apple chips. Furthermore, results from instrumental analysis showed that Fuji apple chips were significantly (p<0.05) crispier than both Red Delicious and Golden Delicious apple chips. Fuji apple chips were also found to have a significantly (p<0.05) higher rating for crispness than the other two apple varieties. Results from sensory analysis illustrated that although a significant bitterness was not observed (p>0.05) in 1% CaCl₂ pretreated apple chips, this calcium pretreatment did significantly (p<0.05) affect the flavor (apple flavor, sweetness, and off flavor) of apple chips. Scaiining electron microscopy was used to exarriine the structures of the dehydrated apple chips. The calcium pretreatment, the levels of vacuum employed, and the types of drying technology were all shown to have effects on the structural characteristics of apple chips.

Thesis/Dissertation

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2009-07-09

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http://hdl.handle.net/2429/10495

Food Science

University of British Columbia

UBCV

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