Lipid Oxidation as a Source of Off‐flavour Development During the Storage of Dairy Products

Abstract

Summary The suggested mechanism for the formation of oct‐l‐en‐3‐one and malonaldehyde, two lipid oxidation products, is diagrammatically summarized. The thiobarbituric acid (TBA) and peroxide methods are critically evaluated as standard chemical indices of oxidative rancidity in dairy products. Some recent results on the effect of copper contamination, light exposure and storage temperatures on the oxidative stability of butter, cheese and UHT cream are discussed.

Oxidative pathways to the formation of off-flavours

“…2-trans-Hexen-I-ol has a sweet wine odour and the higher C8-C12 2-alken-l-0Is have fatty odours (Forss, 1972). The low flavour threshold vinyl alcohol, l-octen-3-01, has been reported to be responsible for the mushroom note in deteriorated milk fat and dairy products (Downey, 1969). Many workers (Hoffmann, 1962;Badings, 1970;Stark and Forss, 1964;Frankel, 1983) have identified the presence of l-octen-3-01 from oxidised methyllinoleate, Kellard et al (1985); d Badings (1970); < Evans et al (1971) deteriorated butter and soyabean oil.…”

Physical and Chemical Changes in Vacuum Packaged Parmigiano Reggiano Cheese During Storage at 25, 2 and −25c

“…As a general trend, the TBA number decreased in the first period of storage (until about 40 days for all the temperatures), then remained at a quite constant value during the subsequent storage time. This parameter to evaluate the lipid oxidation of cheese was used by Downey (1969) who found an increase in the TBA value in cheese and in other dairy products in relation to the type of packaging and atmosphere ; nevertheless, other authors were not able to find an increase in the TBA value in cheese in relation to storage time and temperature (Kajs et al 1979;Sherif et al 1977;Hellerup-Nielsen 1973). In our samples the TBA values were less than 2, proposed by Hamilton and Rossel (1986) as the threshold value above which a fatty food can be considered oxidized.…”

The flavors of dairy fats—A review

“…In addition to review papers already discussed, one from Ireland deals with off flavors in dairy products caused by lipid oxidation (96). Another from Norway presented at the 4th Scandinavian Symposium on Fats and Oils discusses oxidized flavors arising in milk during its production (97).…”

“…Malonaldehyde has no flavor itself but its measurement through various TBA tests has been a means of measuring oxidation and oxidized flavors. The value of the TBA test as an index of oxidation has been compared with various (hydro) peroxide tests 9 A paper from Ireland discusses the formation and importance in oxidized flavors of 1-octen-3-one and malonaldehyde (96). A paper from the Netherlands lists aroma compounds mostly carbonyt, isolated from or expected to occur in butter with cold storage defects and from autoxidized fatty acids.…”