Chlorophyll‐bound Magnesium in Commonly Consumed Vegetables and Fruits: Relevance to Magnesium Nutrition

Abstract

Magnesium is bound as the central atom of the porphyrin ring of the green plant pigments chlorophyll a and b. It has been suggested that chlorophyll-bound magnesium may play an important role in magnesium nutrition because when iron is similarly bound in the porphyrin ring of heme, it is absorbed to a greater extent than non-heme iron. We have analyzed 22 frequently consumed fruits and vegetables for the chlorophyll content by high-pressure liquid chromatography and for magnesium with atomic absorption spectroscopy. Chlorophyll concentrations ranged from 6 g/g (grape) to 790 g/g (spinach) (median 63 µg/g). Magnesium concentrations ranged from 48 g/g (grape) to 849 g/g (spinach) (median 122 g/g). In the green leafy vegetables, such as spinach and lettuce, chlorophyll-bound magnesium represented 2.5% to 10.5% of total magnesium whereas other common green vegetables, pulses and fruits contained <1% chlorophyll-bound magnesium. The chlorophyll content of spinach was further decreased by about 35% on thawing frozen spinach or on chopping fresh spinach, and this degradation increased to about 50% after boiling and steaming. Based on the present results and published food consumption data, we estimate that chlorophyll-bound magnesium represents a very low fraction of total magnesium intake in industrialized countries, less than 1% in the case for data obtained from Switzerland. Thus, chlorophyll-bound magnesium is of little relevance to magnesium nutrition.

Modelling kinetics of watercress (Nasturtium officinale) colour changes due to heat and thermosonication treatments

“…These results are in agreement with Bohn, Walczyk, Leisibach, and Hurrell (2004), that reported for raw spinach a total chlorophylls content of 790 μg g − 1 . Nevertheless, these are higher than the values of 68 μg g − 1 for chlorophyll a and 29 μg g − 1 for chlorophyll b in raw green beans (Oruña-Concha, González-Castro, López-Hernández, & Simal-Lozano, 1997).…”

The Effect of Magnetized Water on Physiological and Agronomic Traits of Cowpea (Vigna unguiculata L.)

“…It was noticed that, irrigation with magnetically treated water lead to an increase in all elements such as calcium, magnesium and potassium content except sodium [13]. Magnesium ions are found in the centre of chlorophyll molecules, and chlorophyll is an essential component in the reaction of photosynthesis, which produces energy for growth [20]. This agrees with the Results of [21] and [22] who found an increase in photosynthetic rate and influx of water as a result of magnetic treatments.…”

Antioxidant and antibacterial properties of guava leaf extracts as affected by solvents used for prior dechlorophyllization

“…Naturally, they are largely biosynthesized in plants and can be used in food industry as a colorant (Roca, Chen, & Pérez-Gálvez, 2016). It is partially soluble in a polar solvent because of the presence of magnesium in the porphyrin ring of chlorophyll central atom (Bohn, Walczyk, Leisibach, & Hurrell, 2004). Consequently, chlorophyll is inevitably co-extracted into plant extracts.…”