The effects of some natural antimicrobial substances and potassium sorbate superficial application on the heat-treated sucuks quality characteri̇sti̇cs

In this study, the surface of heat-treated sucuk samples were treated with thyme (Thymus vulgaris L.) hydrosol, chebulic myrobalan (Terminalia chebula) dried fruit extract, commercial vegetable extract containing common yarrow (Achillea millefolium), sheep's sorrel (Rumex acetosella) and English plantain (Plantego lanceolata) and potassium sorbate solution (20%). After the treatment physical, chemical and color values, microbiological and sensorial properties of sucuk samples were analysed during 90 days. While potassium sorbate provided reduction of 0.57 log cfu/g in yeast-mould counts during storage periods, thyme hydrosol, chebulic myrobalan dried fruit extract and commercial vegetable extract provided reductions of 0.23, 0.15 and 0.31 log cfu/g respectively. While potassium sorbate provided reduction of 0.87 log cfu/g in total aerobic mesophilic bacteria (TMAB) counts after storage periods thyme hydrosol, chebulic myrobalan dried fruit extract and commercial vegetable extract caused reductions of 1.49, 0.86 and 1.24 log cfu/g respectively. It was determined that total psychrophilic aeorobic bacteria (TPAB) results which changed between 5.06 and 6.32 log cfu/g at the beginning of storage, decreased during storage periods. The numbers of TPAB were ranged from 3.92-5.38 log kob/g after storage periods. The highest reduction was observed in the number of TPAB (1.55 log cfu/g) of sucuk samples treated with thyme hydrosol whereas the highest reduction was observed in the number of TPAB (0.86 log cfu/g) of sucuk samples treated with chebulic myrobalan dried fruit extract. It was determined that the values of thiobarbituric acid (TBA), which ranged from 0.48 to 0.61 mg manolaldehit/kg at beginning of the storage (day 0), ranged from 0.72-0.98 mg manolaldehit/kg in the end of the storage periods (day 90). The value of TBA (0.72 mg manolaldehit/kg) was the lowest in the sucuk samples treated with commercial vegetable extract whereas the highest value (0.98 mg manolaldehit/kg) was observed in the control groups. The content of dry matter of sucuk samples increased during storage periods and the highest value (69.40%) was observed in the control group sucuk samples. The values of water activity (aw) of sucuk samples decreased during storage periods. After colour analysis, it was observed that the values of L* (lightness), a*(redness) and b* (yellowness) of the cross section and exterior surface of the sucuk samples decreased compared with the threshold values. As a result of sensory analysis, the highest general acceptability was observed in the sucuk samples treated with thyme hydrosol.