Manganese screening of pineapple by total-reflection X-ray fluorescence (TXRF) spectroscopy

Manganese is regarded as an essential trace element for human nutrition and is found in pineapple fruits in elevated concentrations. In this study, the manganese content of pineapple and pineapple juice was analysed by total-reflection X-ray fluorescence (TXRF) spectroscopy. The manganese concentration in whole fruits was highly variable, however, inside the individual fruit there is an increase from the fruit flesh to the skin of the pineapple. Looking at industrially processed pineapple products, purees (n = 12) have the lowest manganese content with a median of 4.9 mg/kg compared with pineapple juices (10.5 mg/kg, n = 17) and concentrates (15.5 mg/kg; n = 48, calculated to 12.8 degrees Brix). Depending on the concentration of the product, the tolerable daily intake of manganese is nearly reached with only one glass (200 mL) of pineapple juice.