Micronutrient Mineral and Folate Content of Australian and Imported Dried Fruit Products

Abstract

A selection of Australian and imported fresh and dried fruit products, including sultanas, Sunmuscats, Carina currants, Zante currants, apricots, and prunes, were analyzed for selected minerals (Ca, Mg, Na, S, B, Al, Fe, Mn, Cu, Zn, Mo, and Se), folate and vitamin C, and the capacity of dried fruits for dietary provision of these micronutrients evaluated. Micro-nutrients were concentrated by a factor of 3–5 in dried fruits compared with their fresh fruit counterparts and were consequently present in nutritionally significant levels, in contrast to fresh fruit. Australian dried sultanas, Carina currant, Zante currant, apricots, and prunes contained Cu, Fe, K, and Mn at levels of >20% of daily Required Dietary Intake (RDI, taken as the average for adult men and women as nominated by the Australian National Health and Medical Research Council) and Sunmuscats contained Cu, Fe, and K at >20% of RDI. All dried fruits studied contained boron in the range of 1.5 to 5.4 mg per 100 g; however, the RDI for boron has not been defined by the NHMRC at the present time. All sultanas and currants studied contained folate at levels of 10–20% of RDI per 100 g. Experimental drying methods significantly affected folate levels with higher folate content in non-ground versus ground-based drying methods. Of the micro-nutrients supplying >20% of RDI, folate represents a particular nutrient for which the mean daily intake of adult Australians is typically inadequate. This study shows that dried fruit consumption, in contrast with fresh fruit, can provide significant proportions of daily requirements of several micronutrients, particularly folate.

Keywords:

• dried fruit
• sultana
• Sunmuscat
• currant
• apricot
• prune
• mineral
• folate
• rack
• trellis
• ground
• emulsion

ACKNOWLEDGEMENTS

This work was co-funded by the Australian Dried Fruits Association together with Horticulture Australia Limited and the CSIRO Preventative Health National research flagship. Technical assistance of Sunanda Sudharmarajan, Katherine Robinson, Patricia Wallace, and David Emanuelli is gratefully acknowledged. Co-ordination of dried fruit sample collection by Dr. Michael Treeby and contributions to project planning by Dr. Rob Walker are also gratefully acknowledged.