Mineral content of green vegetable juice using two different juicers

Abstract

Background: Home juicing using readily available juicing machines is now commonplace. It is promoted not only as a mechanism to quench your thirst and provide refreshment, but also as a source of extra nutrients, vitamins and minerals. Vegetable juicers can be classified into two basic types; a masticating juicer (MJ), separates out the fibrous portion (pulp) of the juice, which is then discarded and a high speed blender (HSB), which retains the fibrous fraction of the juice. Methods: A vegetable juice recipe consisting of spinach, apple, celery, cucumber, green pepper, red capsicum, lemon and parsley was juiced using both juicers. A further recipe was prepared with the same proportions of ingredients except that the spinach content was doubled. Results: Fifteen different minerals were identified in measurable amounts in the juice and the discarded fibre fraction, with levels ranging from 0.001 to 359.36 mg/100 g juice FW, for Cd and K respectively. Juices prepared from mixtures containing high levels of spinach contained measurably higher amounts of all minerals except calcium. Analysis showed that these juices contained high levels of oxalates bound to calcium and therefore would be unlikely to be absorbed in the digestive tract when consumed. Conclusions: Juices prepared using a MJ juicer always contain lower levels of minerals compared to juices prepared from a HSB juicer. The lower levels of minerals in the MJ juicer contain significantly lower levels of minerals are they are discarded in the fibre fraction.