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United States Department of Agriculture

Agricultural Research Service

Title: Quality of Frozen Fruit Bars Manufactured through Infrared Pre-dehydration

Authors
item Tian, Hongping - UC DAVIS, DAVIS, CA
item Pan, Zhongli
item Zhu, Yi - UC DAVIS, DAVIS, CA
item McHugh, Tara

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 28, 2008
Publication Date: N/A

Interpretive Summary: There is great interest in producing healthful, frozen whole fruit- and vegetable-based bars, to promote consumption of the fruits and vegetables so important to human health. One concern is that fruits and vegetables with high moisture content may not have the desired hardness after being frozen. In this study, restructured apple and strawberry bars were manufactured by pre-dehydration, using infrared (IR) heating, followed by restructuring and freezing. The conclusion of this study is that frozen fruit bars produced with the method developed in the study are healthful alternative fruit products.

Technical Abstract: There is great interest in producing healthful, frozen whole fruit- and vegetable-based bars, to promote consumption of the fruits and vegetables so important to human health. One concern is that fruits and vegetables with high moisture content may not have the desired hardness after being frozen. In this study, restructured apple and strawberry bars were manufactured by pre-dehydration, using infrared (IR) heating, followed by restructuring and freezing. The objective of this investigation was to determine the effect of IR pre-dehydration on the quality of restructured frozen apple and strawberry bars. Apples and strawberries were cut into 6 mm thick slices before being dried at 50°C to various moisture levels: 89.0% to 75.3% for apples and 92.7% to 75.3% (wet basis) for strawberries. To prevent enzymatic browning, the apple slices were dipped in a solution containing 0.5% ascorbic acid and 0.5% sodium chloride for 5 minutes before the drying. IR drying reduced the moisture in the fruits quickly and caused partial degradation of total phenolic and vitamin C. However, the final product concentration of total phenolic and vitamin C significantly increased in the finished fruit bars due to the moisture removal. Both frozen apple and strawberry bars had desirable appearance and hardness when their water activities were below 0.97. The conclusion of this study is that frozen fruit bars produced with the method developed in the study are healthful alternative fruit products.

Last Modified: 12/18/2014
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