Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Photosynthetic assimilation of 14C into amino acids in potato (Solanum tuberosum) and asparagine in the tubers
AU - Muttucumaru, Nira
AU - Keys, Alfred J.
AU - Parry, Martin A J
AU - Powers, Stephen J.
AU - Halford, Nigel G.
PY - 2014/1/1
Y1 - 2014/1/1
N2 - Asparagine is the predominant free amino acid in potato tubers and the present study aimed to establish whether it is imported from the leaves or synthesised in situ. Free amino acid concentrations are important quality determinants for potato tubers because they react with reducing sugars at high temperatures in the Maillard reaction. This reaction produces melanoidin pigments and a host of aroma and flavour volatiles, but if free asparagine participates in the final stages, it results in the production of acrylamide, an undesirable contaminant. 14CO2 was supplied to a leaf or leaves of potato plants (cv. Saturna) in the light and radioactivity incorporated into amino acids was determined in the leaves, stems, stolons and tubers. Radioactivity was found in free amino acids, including asparagine, in all tissues, but the amount incorporated in asparagine transported to the tubers and stolons was much less than that in glutamate, glutamine, serine and alanine. The study showed that free asparagine does not play an important role in the transport of nitrogen from leaf to tuber in potato, and that the high concentrations of free asparagine that accumulate in potato tubers arise from synthesis in situ. This indicates that genetic interventions to reduce free asparagine concentration in potato tubers will have to target asparagine metabolism in the tuber.
AB - Asparagine is the predominant free amino acid in potato tubers and the present study aimed to establish whether it is imported from the leaves or synthesised in situ. Free amino acid concentrations are important quality determinants for potato tubers because they react with reducing sugars at high temperatures in the Maillard reaction. This reaction produces melanoidin pigments and a host of aroma and flavour volatiles, but if free asparagine participates in the final stages, it results in the production of acrylamide, an undesirable contaminant. 14CO2 was supplied to a leaf or leaves of potato plants (cv. Saturna) in the light and radioactivity incorporated into amino acids was determined in the leaves, stems, stolons and tubers. Radioactivity was found in free amino acids, including asparagine, in all tissues, but the amount incorporated in asparagine transported to the tubers and stolons was much less than that in glutamate, glutamine, serine and alanine. The study showed that free asparagine does not play an important role in the transport of nitrogen from leaf to tuber in potato, and that the high concentrations of free asparagine that accumulate in potato tubers arise from synthesis in situ. This indicates that genetic interventions to reduce free asparagine concentration in potato tubers will have to target asparagine metabolism in the tuber.
KW - Acrylamide
KW - Amino acid transport
KW - Crop quality
KW - Food safety
KW - Free amino acids
KW - Maillard reaction
KW - Nitrogen transport
KW - Solanum
KW - Thin-layer chromatography
UR - http://www.scopus.com/inward/record.url?scp=84891597690&partnerID=8YFLogxK
U2 - 10.1007/s00425-013-1967-0
DO - 10.1007/s00425-013-1967-0
M3 - Journal article
C2 - 24126722
AN - SCOPUS:84891597690
VL - 239
SP - 161
EP - 170
JO - Planta
JF - Planta
SN - 0032-0935
IS - 1
ER -