Page Banner

United States Department of Agriculture

Agricultural Research Service

2012 Annual Report

1a.Objectives (from AD-416):
1) Evaluate liquid dehydration methods, freeze drying and Radiant Zone Drying, to produce a pure powder with no maltodextrin or 20% maltodextrin (w/w of puree solids) from purees of whole blueberry and strawberry. 2) Measure phenolic composition, total phenolics, total anthocyanins, and total antioxidant activity of dried powder as compared to the fresh berry. Additionally, for strawberry determine ascorbic acid and volatile losses on drying. 3) Evaluate dried powder for suitability for use as a nutritional supplement ingredient by measuring microbiological content moisture content, water activity, bulk density, hygroscopicity, degree of caking, and flowability. 4) Evaluate shelf-life of powders at 1 year by measuring parameters listed in 2 and 3 above.

1b.Approach (from AD-416):
Whole blueberries and strawberries will be pureed and if not immediately dried will be frozen at -4ºC until drying. The berry puree will be dried without maltodextrin (carrier-free) or blended with 20% maltodextrin based on the solids content of the berry. The carrier-free and maltodextrin blend will be dehydrated at optimum drying conditions based on previous literature and operator experience. Using drying conditions that achieve a dry powder, the trials will be conducted in triplicate and the resulting data subjected to analysis of variance (ANOVA). Drying parameters such as time, temperature and yield will be recorded to determine throughput and estimate cost of production. The dried puree powders will be milled and sifted to obtain a homogenous 100% through a 40 mesh screen powder. Powders will be stored in moisture proof HDPE (high density polyethylene) metalized packaging in a dehumidified room at room temperature to replicate typical storage treatments in the Industry. Blueberry and strawberry puree samples and powder samples will be evaluated and compared for total antioxidant activity. Phenolic profiles will be measured using High Performance Liquid Chromatography (HPLC) to determine loss on drying and changes in phenolic profile. Two additional analyses will be performed on strawberry, volatiles using gas chromatography and ascorbic acid content using a spectrophotometer. Analysis will be run in triplicate on homogenous puree and dried samples. Dried powder samples will be stored for one year and all analysis will be repeated to evaluate storage /shelf life on these parameters. Documents Grant with Washington State University. Formerly 5358-21000-037-09G (8/2011).

3.Progress Report:

This research was conducted in support of objective 305 1B Perennial Crops of the parent project. Small fruit and wine grape pomace has been collected. Pomace has been separated into seed and skin/pulp components and the skin/pulp components dried using radiant zone heating and, for selected pomaces, also by freeze drying. The resulting dried fruit powders are being analyzed for their phytonutrient content.

Last Modified: 7/28/2015
Footer Content Back to Top of Page