DISCUSSION 



The variables that were compared through- 

 out the experiment included (1) methods of 

 applying the antioxidants and EDTA and (2) 

 the packaging method (vacuum-packaging 

 compared to glazing). Samples dipped or in- 

 jected showed the same trends in peroxide and 

 free fatty acid content throughout the exper- 

 iments. Organoleptic evaluation of these sam- 

 ples was almost identical. 



•4 5 6 



TIMEIMONTHSI 



Figure 4. — Free fatty acid content of the oil fraction 

 from Spanish maclverel fillets. 



A difference in organoleptic scores between 

 samples packed in vacuum or glazed was noted 

 throughout the storage period. Samples 

 packed in vacuum were rated organoleptically 

 superior to glazed samples (Tables 1, 2, 3). 



Samples treated with Tenox 4, Tenox 6, 

 Tenox 4 plus EDTA, and Tenox 6 plus EDTA 

 develo])ed rancid flavors and odors after 6 

 months' frozen storage. Peroxide and FFA 

 content of samples treated with these com- 

 pounds did not correlate with the rancid flavors 

 and odors that developed. This would indicate 

 a deterioration similar to the observations of 

 Ca.stell et al. (1965), who reported that many 

 off -odors are not usually identified with the de- 

 velopment of oxidative rancidity. Castell et al. 

 found that a considerable diffei'ence occurred 

 in early developing off -odors when rancidity 

 was activated by different chemical compounds, 

 and they observed a different off-odor associ- 

 ated with the addition of different trace min- 

 erals. Castell et al. concluded that the mixture 

 of trace minerals on fish acquired through en- 

 vironment and handling could account for the 

 varied off-odors from deterioration found in 

 commercial samples. 



Castell and Spears (1968) observed a rapid 

 increase in rancidity development with the ad- 

 dition of minute quantities of trace minerals. 



Table 7. — Free fatty acid content of Spanish mackerel (Scomberomorus 

 maculatus) fillets packed in vacuum-sealed bags. 



2 weeks 



2 months 



3 months 



6 months 



9 months 



Control 



% oleic 

 1.55 



Tenox 4: 



Injected 1.25 



Dipped 1.12 



Tenox 6: 



Injected 



Dipped 1.46 



EDTA: 



Injected 2.58 



Dipped 2.98 



Tenox 4 + EDTA: 



Injected 1.25 



Dipped 1.35 



Tenox 6 + EDTA: 



Injected 1.24 



Dipped 1.31 



% oleic 

 1.54 



2.54 

 1.85 



1.89 

 1.85 



2.11 

 2.61 



1.80 

 1.94 



2.79 



2.45 



% oleic 

 4.15 



3.04 

 6.21 



3.16 



2.73 



2.44 



2.54 



3.56 

 4.26 



2.56 

 2.62 



% oleic 

 4.60 



6.00 

 3.51 



3.92 

 6.65 



8.46 

 8.84 



9.93 

 3.87 



4.75 

 7.63 



% oleic 

 4.45 



7.61 

 3.70 



4.48 

 12.51 



5.78 

 5.21 



8.37 

 7.00 



10.76 

 7.05 



