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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research » Research » Research Project #414320


Location: Horticultural Crops Research

2009 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.

3. Progress Report
An important aspect of the nutrition industry is the dried powders made from fruits, vegetables, and plant extracts found in many nutraceutical products. In the nutrition industry, powders are typically made by manufacturers and sold in bulk quantities to companies that then use them in consumer products. A key component that has been severely lacking in this market is economical powders that are also high quality. The majority of puree powders on the market are low quality because they contain high amounts of additives (up to 80%) such as maltodextrin or cornstarch, are heat damaged, or oxidized. In order to address this need for high quality nutritional supplement powders, whole blueberries and strawberries were pureed and low quantities of additives (cornstarch and maltodextrin) were added to the blueberry at 40% weight / weight of solids and no additives were added to the strawberry. The blueberry was dried on a pilot Radiant Zone Dryer TM (Columbia PhytoTechnology, LLC, Dallesport, WA) and the strawberry was dried on a commercial sized Radiant Zone Dryer TM and a pilot freeze dryer (WSU, Pullman, WA). The starting liquid puree and dried powder was analyzed for total phenolics, total anthocyanins, total antioxidant activity, and anthocyanin profile and the data was compared to determine losses on drying. The Radiant Zone TM dried blueberry and strawberry powders were milled using a commercial sized Quadro-Comil and evaluated for physical characteristics including moisture content, water activity, flowability, and potential for clumping. The freeze dried powder is currently being prepared for similar analysis. Thus far, both modes of drying liquids appear to produce relatively high quality powders that retain nutrients and are suitable for encapsulation or tableting by the nutritional supplement industry. Production of high quality, value-added berry powders using freeze drying and/or Radiant Zone TM drying may also be a first step in establishing the Northwest as a producer of premium nutritional supplement powders as both of these drying technologies are located at companies in the Pacific Northwest. This type of research provides a use for damaged, bruised, or over-produced fruit that may not be suitable for sale in the fresh and frozen market as well as for berry waste streams from the juicing industry. Methods of ADODR monitoring included meetings, e-mail, and phone calls.

4. Accomplishments