Protein modification by Amadori and Maillard reactions during seed storage: roles of sugar hydrolysis and lipid peroxidation

Abstract

The non-enzymatic modifications of proteins through Amadori and Maillard reactions play an important role in the loss of seed viability during storage. In the present study, the contribution of sugar hydrolysis and lipid peroxidation to Amadori and Maillard reactions, and to seed deterioration was investigated in mung-bean (Vigna radiata Wilczek). The contents of glucose and lipid peroxidation products in seed axes increased significantly during storage. The accumulation of Amadori products in seed axes was correlated to the lipid peroxidation, whereas the accumulation of Maillard products was closely correlated to sugar hydrolysis. The rate of accumulation of Maillard products was not well correlated to the content of Amadori products in both seed axes and protein/glucose model system, reflecting the complex nature of Amadori and Maillard reactions. The content of Amadori products in seed axes increased during the early stages of seed ageing, whereas the content of Maillard products increased steadily during the entire period of storage. The accumulation of Maillard products in seed axes was associated with the decline of seed vigour. These data suggest that, during seed ageing, sugar hydrolysis and lipid peroxidation are coupled with non-enzymatic protein modification through Amadori and Maillard reactions.

Volatile fingerprints of seeds of four species indicate the involvement of alcoholic fermentation, lipid peroxidation, and Maillard reactions in seed deterioration during ageing and desiccation stress

“…The products of both sugar hydrolysis and lipid peroxidation can initiate non-enzymatic protein and DNA degradation via Amadori and Maillard reactions. Despite reports of the inhibition of enzymatic and auto-oxidation of lipids at the seed MCs used in this study [13.2, 11.4, and 10.2% (fresh mass basis) for P. sativum , L. pratensis , and C. scoparius , respectively; Murthy and Sun, 2000], malondialdehyde and 4-hydroxynonenal were detected in aged P. sativum seeds, indicating that lipid peroxidation did occur and may have contributed to Maillard reactions.…”

“…Under such storage conditions, metabolic activity is minimal due to the low molecular mobility of cell cytoplasm. One mechanism of seed ageing is via Maillard reactions, which occur following a non-enzymatic attack on amino groups of proteins and nucleic acid–protein complexes by reducing sugars or aldehydes (Murthy and Sun, 2000). This forms advanced glycosylation end-products, which are found in both naturally and artificially aged seed tissues, and increase during storage at all MCs and temperature conditions.…”

The role of protein modifications in senescence of freeze-dried Acetobacter senegalensis during storage

“…Non-enzymatic browning may result from Maillard and Amadori reactions starting from a condensation reaction between reducing sugars and amino groups. These reactions are known to produce carbonyl intermediates which react with neighboring amino groups [36]. Protein glycation is a process in which reducing sugars interact with primary amines on the side chains of Lysine and Arginine, resulting in a chemical sequence of reactions known as “Amadori rearrangement” which leads to the formation of Amadori modified proteins (AMPs).…”

Effects of accelerated aging upon the lipid composition of seeds from two soft wheat varieties from Morocco

“…McDonald (1999) suggested that the secondary of lipid peroxidation, such as malondialdehyde, was likely to be involved in the breakdown of proteins and nucleic acids through the Amadori and Maillard reactions. However, the involvement of lipid peroxidation in seed degradation during storage is still subject to debate (Narayana Murthy and Sun, 2000).…”