Carbohydrate polymers in food preservation: an integrated view of the Maillard reaction with special reference to discoveries of preserved foods in Sphagnum-dominated peat bogs

Well-preserved human bodies more than 2000 years old have been found in peat bogs derived mainly from sphagnum mosses. Preservation is correlated with the occurrence of -keto-carboxylate groups in a glycuronoglycan (‘sphagnan') that comprises 60% of the holocellulose in the hyaline cell walls of the mosses [Painter (1991b). Carbohydr. Polym., 15, 123–142]. There is now renewed interest in other biodegradable materials that have been found preserved in peat, including carcasses of domestic animals, loaves of bread, dried fruits, berries, and kegs of butter or cheese up to 1800 years old. This review attempts to correlate these examples of fortuitous preservation in peat with other, more familiar methods of food preservation that depend in the first instance upon the condensation of highly reactive carbonyl compounds with primary amino-groups or ammonia. The Maillard reaction inhibits microbial growth by sequestering ammonia, aminoacids and peptides, while the brown, polymeric end-products (‘melanoidins') inhibit by cross-linking polypeptide chains and sequestering essential, multivalent metal cations. These reactions could find broader or entirely new applications in food preservation.