Nutritional and chemical profiling of UK-grown potato bean (Apios americana Medik) reveal its potential for diet biodiversification and revalorisation

Apios americana Medik, a native American plant has potential as a commercially viable Northern European-grown motcrop, mainly due to its resistance to extreme climate and nutritional quality. Analysis of A. americana sourced from two UK sites; South (51.4690 degrees N, 1.1150 degrees W) and North (55.9661 degrees N, 3.2063 degrees W) showed that the tubers were a complete source of amino acids (UPLC-TUV analysis), were rich in protein (15.0 +/- 0.0160 and 17.3 +/- 0.0779%; Vario Max CN analysis), fibre (total non-starch polysaccharides, 10.4 +/- 0.570 and 10.6 +/- 0.280%; GC analysis) and micronutrients (calcium, manganese, iron, zinc, molybdenum, potassium and phosphorus; ICP-MS analysis). Apios americana tubers were also rich in bioactive phytochemicals. From the 156 plant metabolites measured using LC-MS/MS analysis, genistein was the major phytophenol in both the Southern- and Northern UK tubers (259 +/- 12.2 mg Kg(-1) and 356 +/- 29.9 mg Kg(-1) respectively); the peel having similar phytochemical profiles. The protein and fibre content of the leaves (17.3 +/- 0.0434% and 11.7 0.0445%) and rhizomes (18.4 +/- 0.0152% and 13.5 +/- 0.590%) were significantly higher (p <0.05) than the tubers. The leaves were also a good source of anthocyanins; delphinidin and cyanidin (840 +/- 137 and 3934 +/- 176 mg Kg(-1) respectively). Cultivation of A. americana as a high-protein staple-crop has enormous potential in Northern European countries for human nutrition, diet diversification, and use in livestock diets.