Effect of Magnesium Supply and Storage Time on Anti-Nutritive Compounds in Potato Tubers

Elżbieta Wszelaczyńska,Wojciech Kozera,Jarosław Pobereżny,Ewa Spychaj-Fabisiak,Tomasz Knapowski,Elke Pawelzik

doi:10.3390/agronomy10030339

Abstract

The nutritional quality of potato tubers is cultivar-specific and depends on climate-soil conditions and agrotechnical practices, as well as the conditions during long-term storage. Studies were performed from 2009–2011 to determine the effects of magnesium fertilisation and storage duration on the contents of the anti-nutritive compound nitrates, nitrites and total glycoalkaloids (TGA) in potato tubers of mid-early cultivar “Bila” (Solanum tuberosum L.). Magnesium (Mg) was applied in doses of 0, 20, 40, 60, 80 and 100 kg MgO ha−1, respectively, in the form of kieserite–magnesium sulphate (26% MgO). Potato quality after harvest and after three and six months of storage was determined. The content of nitrates in tubers after harvest ranged from 303 to 356 mg kg−1 FW and nitrites from 1.59 to 1.67 mg kg−1 FW. Increasing magnesium fertilisation reduced the nitrate and nitrite content of tubers but increased TGA content. Possible explanations for the TGA increase after Mg supply are discussed. Tubers that contained less TGA after harvest also had less glycoalkaloids after storage. However, physical damage during harvest or transportation, exposure to light and bad storage conditions increase the concentrations of glycoalkaloids in tubers. The consumption of cultivar “Bila” would not exceed the acceptable daily intake of harmful substances.

Highlights

Besides wheat, maize and rice, potato is one of the world’s main food crops, being cultivated in over 80% of countries [1]
The mean potato yield varied depended on mineral magnesium nutrition (Table 2)
Considering the above aspects, it seems useful to design such a growing technology that would take into account yield volumes and yield quality, including concentrations of particular forms of nitrogen [4,22,26]. This is slightly different from are the results reported by Rogozinska et al [44], who discovered that, besides nitrogen fertilisation, applications of larger quantities of magnesium led to lowered total nitrogen contents in potato tubers

Summary

Introduction

Maize and rice, potato is one of the world’s main food crops, being cultivated in over 80% of countries [1]. In addition to compounds with high nutritive value, like other vegetables, contain substances which are undesirable in human nutrition. They are the so-called “anti-nutritive compounds”, such as nitrates, nitrites and glycoalkaloids [1,2]. Vegetables including potatoes provide more than 90% of the total amount of harmful compounds in daily food intake and constitute their major source [3,4]. According to the FAO/WHO guidelines, the acceptable daily intake (ADI) by an adult with a body weight (BW) of 70 kg should not exceed 260 mg of nitrates and 4.9 mg of nitrites [5,6]

Methods

Results

Conclusion