L. Bruunjensen et al., THE COMBINED EFFECT OF TOCOPHEROLS, L-ASCORBYL PALMITATE AND L-ASCORBIC-ACID ON THE DEVELOPMENT OF WARMED OVER FLAVOR IN COOKED, MINCED TURKEY, Food chemistry, 55(1), 1996, pp. 41-47
The combined effect of a natural mixture of tocopherols (extracted fro
m soybean oil), L-ascorbyl palmitate and L-ascorbic acid on oxidation
of cooked, minced turkey meat, measured as 2-thiobarbituric acid react
ive substances (TEARS) after reheating, was studied for three concentr
ations of each additive in a total of 19 combinations plus two control
batches, each at two different oxygen pressures (21 and 1% O-2), duri
ng 9 days of chilled storage (5 degrees C), and compared with an accel
erated oxygen-bomb test at 90 degrees C. For initial screening of anti
oxidative activity, the latter test has been found to be a valuable an
alytical tool. The effect of the additives from the storage experiment
could be measured by two parameters; (i) M, the maximal level of TBAR
S, and (ii) r, a first-order rate constant for development of TEARS. T
ocopherols reduced M most significantly, L-ascorbyl palmitate to a les
ser degree, and L-ascorbic acid increased M, in effect acting as a pro
oxidant. For 21% O-2 packaging, the effect on M of the three additives
and their concentrations was multiplicative and could be quantified b
y a protection factor, P-(i . x,P-j . y,P-k . z), obtained by multipli
cation of the relative protection obtained by each additive at the low
est concentration used. In contrast to M, r was reduced more by L-asco
rbyl palmitate than by tocopherols, while L-ascorbic acid had only a s
mall effect on r. The combined use of tocopherols and L-ascorbyl palmi
tate in cooked, minced turkey meat products, optimises oxidative prote
ction as a result of indirect synergism, i.e. tocopherols reduced main
ly the maximum level of oxidation, while L-ascorbyl palmitate reduced
the rate at which the maximum level of oxidation is approached.