Date of Award

8-2011

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Packaging Science

Advisor

COOKSEY, KAY

Committee Member

DARBY , DUNCAN O

Committee Member

WHITESIDE , WILLIAM S

Abstract

Thermally processed (TP) baby carrots were packaged in pouches with varying oxygen transmission rate (OTR) pouches. The pouches were four layer laminate (PET-Nylon-Barrier-CPP) with barrier layer being foil, aluminum oxide (AlOx), ethylene vinyl alcohol (EVOH), and nylon. Retort pouches were placed in boxes that were stored in an environmental chamber (43 °C, 50%RH). The objective of the study was to determine an alternative barrier retort pouch that is microwavable and still had similar barrier functions to foil for baby carrots and determine how the alternative compare with regard to shelf life. Instrumental analysis of color (L*, a*, b*) and texture (firmness) was performed on TP baby carrots in the different oxygen barrier pouches. OTR of pouches were measured pre-, post- processing, and at week 14. Sensorial analysis was performed with frequent panelists. The results were correlated to determine if there was a relationship between instrumental measurements and sensory analysis of TP baby carrots packed in varying OTR pouches for color and texture.
Firmness of the retorted carrots did not change drastically over time, but showed some difference within each week. There was a weak correlation (R 2 = 0.2329) between instrumental texture measurement to sensory analysis. The instrumental color analysis showed a clear trend of split between foil and AlOx barrier materials with the other 2 materials starting week 6. Overall, TP baby carrots in EVOH and nylon pouches were significantly darker (decreasing L*), less red (decreasing a*), and less yellow (decreasing b*) than the carrots in foil and AlOx throughout the study after week 4. The higher OTR of EVOH and nylon allows more oxygen to go through the pouch; thus driving the reaction that changes the color of carrots. Color of carrots in foil and AlOx were ranked significantly higher than the carrots in EVOH and nylon pouches for sensory.
Due to the high OTR of EVOH and nylon, the carrots had less liking and acceptability over time. These two barrier pouches did not provide adequate barrier for maximum shelf life when compared to foil and AlOx barrier pouches. The carrots in foil and AlOx had a predicted shelf life of at least 24.5 weeks or more; however, the carrots in EVOH and nylon only lasted half that time.

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