The effects of thymus, rosemary and basil extracts on frozen (-18°c) and chilled (4±2°c), vacuumeed mackerel balls (scomber scombrus) quality parameters

In this work, the addition of 0.05% of natural antioxidant extracts in mackerel balls, obtained from thymus (Thymbra spicata), rosemary (Rosmarinus officinalis) and basil (Ocimum basilicum L.) by means of solvent extraction method, during frozen (-18oC) (Trial I) and chilled vacuumed storage (+4±20C) (Trial II) were investigated in terms of sensory (raw and cooked), biochemical (total volatile basic nitrogen (TVB-N), thiobarbituric acid (TBA), peroxide value (PV), free fatty acids (FFA), pH and fatty acids) and microbiological analyses (total viable count (TVC)). The results of Trial I showed that the shelf life of raw fish ball was found as 8 months for the control and basil groups, 10 months for rosemary and thymus groups. According to Trial II, the shelf life of fish ball (raw and cooked) was found as 25 days for the control and basil groups, 28 days for rosemary and thymus groups. TVB-N, TBA, FFA, PV ve pH values remained below the acceptable limit during storage period in all groups in the Trial I and II. Statistical differences (p<0.05) were observed among fatty acids for all groups during the storage period. In the Trial I, TVC remained lower than the acceptability limit of 107 log cfu/g at the end of storage period. However, TVC in Trial II were found 7.19 log cfu/g and 6.95 log cfu/g for control and basil group, respectively at the end of storage period. Rosemary and thymus extracts, in combination with vacuum pack were effective in controlling the growth of bacteria and biochemical parameters.