Oxalate contents in green juice prepared using either a high-speed blender or a masticating juicer

Abstract

Green vegetables are very beneficial for health, but sometimes it is not understood that some vegetables also contain anti-nutrients. For example, oxalic acid can be found in some green vegetables, such as spinach. Oxalic acid can be absorbed from food and as it is a toxin it has to be removed from the body via the kidneys. Under certain conditions, oxalate can combine with calcium in the kidneys forming stones which can lead to impaired kidney function. This study aims to compare two techniques for making vegetable juice, using a high-speed blender or a masticating juicer. The content of oxalic acid, calcium, pH and titratable acidity (TA) was measured in both juices. Total oxalic acid was measured using HPLC, calcium content was analyzed using a Coupled Plasma Optical Emission Spectrophotometer. Dry matter, pH and TA were measured based on AOAC methods. The highest total oxalate (OA) was found in juice made using a masticating juicer of 7638.27 mg OA/100 g dry weight. The highest calcium content was found in the fiber fraction or in the remaining juice using the masticating juicer technique, which was 10.04 mg/100 g juice. Meanwhile, the TA value of the thick juice produced by the high speed blender was not significantly different from the runny juice produced by the masticating juicer. The smoothie-like green juice prepared using a high-speed blender was healthier as the soluble and insoluble oxalate extracted in the juice was lower than in the clear juice prepared using a masticating juicer.

Physicochemical and Anti-nutrients Analysis of Pasteurised and Unpasteurised Underutilised Sweet Potato Haulm Juice Powder

“…The total amount of oxalate in blended and masticated spinach juice was much higher (3302.58-7638.27 mg/100g dw) than unpasteurised and pasteurised SPHJP [36]. Spinach is usually used as green juice because of its availability and lowpriced; hence, this study provides another alternative for green spinach, with a much lower level of oxalic acid.…”

“…In this study, haulm dregs (byproduct) were not included in the juice, lowering the oxalic acid levels. It had been proved that the discarded fibre spinach juice had reduced oxalates compared to the thick blended juice [36]. Meanwhile, more analysis on the total, soluble, and insoluble oxalates in sweet potato haulm must be determined in the future.…”

Circular bioprocess for phosphorus nutrient recovery to grow lettuce in lunar space

“…Novitasari et al reported juice extraction using a high-speed blender and a masticatory juicer from a mixture of spinach (40% m/m), apple (15%), celery (11.25%), cucumber (11.25%), green pepper (7.5%), red pepper (7.5%), lemon (6%) and parsley (1.5%). 33 We therefore used a spiral oil press for extraction and total oxalic acid concentration was confirmed using 0.2 M hydrochloric acid to dissolve insoluble salts as described by Hönow et al 34 Some 0.33 mmol g −1 and 0.45 mmol g −1 of oxalic acid were extracted which was, respectively, 73 and 54% of the soluble fraction using high-speed blender and masticating juicer.…”