Volatile compounds associated with the off-flavour in stored casein

Abstract

SummaryCompounds associated with the ‘gluey’ off-flavour in stored casein have been isolated and identified by a combination of gas chromatography and mass spectrometry. Most of the flavour was found in the non-acid steam-volatile fraction which contained many compounds including n-alkanals, n-alkan-2-ones, furfural and other furan derivatives, benzaldehyde, dimethyl disulphide and benzthiazole. No single compound had the typical gluey flavour, which must be a complex sensation in which the quantities of minor components may determine the specific gluey character. o-Aminoacetophenone was present in the casein in subthreshold amounts. This compound has some gluey flavour and may have a synergistic effect in enhancing the total flavour.

Steam volatile constituents of stale nonfat dry milk. Role of the Maillard reaction in staling

“…As to the role of the Maillard reaction, it is significant that at least five of the 12 constituents more likely to make a contribution to the stale flavor originate from nonenzymatic browning. Among them, 2-furaldehyde, and possibly benzaldehyde have also been implicated in the stale or gluey flavor of stored casein (Ramshaw and Dunstone, 1969b). A tentative conclusion from the above is that control of the Maillard reaction is likely to result in better keeping qualities of dry skim milk.…”

The flavors of dairy fats—A review

“…The acids, alkanals, 2-alkanones and alkanols are all common products of lipid oxidation and are likely to result from the degradation of the small amounts (1-2%) of milk fat remaining in commercial casein. The steam distillate from gluey casein contained 25-30 ~g of volatile components per gram of casein of which 20 ~g consisted of acids (93). However, it was concluded that the presence or absence of fat plays only a minor role in off flavor development and that greatest improvement in flavor was achieved by removal of some other component, probably lactose during preparation (94).…”

Non-Enzymatic Degradation Pathways of Lactose and Their Significance in Dairy Products

“…Furfuryl alcohol is probably formed on reduction of furfural. Furfural and furfuryl alcohol are also formed in stored casein (Ramshaw and Dunstone, 1969). Patton (1950a) suggested that HMF in heated milk systems is formed largely via the Maillard reaction since it could not be detected on heating lactose solutions in the absence of casein or glycine.…”