Process and formulation effects on the quality of flat plate dried pomace (abstract)

Authors: Milczarek, Rebecca; Alleyne, Fatima; FERRY, JONATHON - University Of California; Olson, Donald; WINSTON, ROLAND - University Of California

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/18/2016
Publication Date: 7/18/2016
Citation: Milczarek, R.R., Alleyne, F.S., Ferry, J.J., Olson, D.A., Winston, R. 2016. Process and formulation effects on the quality of flat plate dried pomace (abstract). Institute of Food Technologists Annual Meeting - Chicago, IL - July 16-19, 2016.

Interpretive Summary:

Technical Abstract: Pomace is a co-product of the fruit and vegetable processing industry; it has potential applications as a source of food ingredients but is currently underutilized. Drum drying is one method that could be used to dry and stabilize pomace. However, the quality effects of the dryer surface temperature, product dwell time, content of carrier, and content of added water (to aid in application of the pomace to the dryer surface), have not yet been explored . In this work, a flat plate heater was used to simulate the surface of a drum dryer. Industrially-produced carrot pomace of initial moisture content of 84.8% (wet basis) was used as the starting material. Based on a central composite response surface design, various feed blends of pomace, maltodextrin (carrier), and water were dried on the flat plate at varying surface temperatures for varying lengths of time. The heating oil feed temperature (92°C to 132°C) and drying time (2 min to 4 min, plus a 1 min heat-up time) represented conditions that would be achievable on a typical drum dryer. Regression equations were generated for the L* (lightness), a* (greenness/redness), and b* (blueness/yellowness) color values of the dried material, as well as for the overall color change (delta E). The R2 values for the fits of these quality metrics were 87.2%, 90.5%, 89.1%, and 86.9%, respectively. The significance of the various formulation and process variable terms, as well as that of their square and interaction terms, was determined. L*, b*, and delta E were significantly (p < 0.05) affected by the squared term for the pomace:water ratio and interaction term for the maltodextrin content and temperature. To minimize the color change between the wet feed and dried material, dryer surface temperature should be minimized, while dwell time, content of maltodextrin carrier, and content of added water should be maximized (while still using conditions that produce a fully-dried product). The results of this work will inform the design of a solar thermal-powered drum dryer that can produce high-quality dried specialty crop purees and pomaces.