Uticaj dodatka etarskih ulja na kvalitet fino usitnjenih barenih i fermentisanih suvih kobasica / Effect of essential oils addition on quality of finely comminuted cooked and dry fermented sausages

The main aim of this doctoral dissertation is to examine the influence of the addition of selected essential oils isolated from spices and medicinal herbs (caraway, juniper, and sage) on the quality of finely comminuted cooked and dry fermented sausages. Finely comminuted cooked sausages were produced with the addition of essential oils of caraway, juniper, and sage in the respective amounts of 0.1, 0.5, 1.0, 2.0, and 5.0 μl/g, as well as without the addition of essential oils (control group), while dry fermented sausages were produced with the addition of essential oils of caraway, juniper, and sage in the respective amounts of 0.01, 0.05, and 0.10 μl/g, as well as without the addition of essential oils (control group). In addition, it was decided to examine the possibility of partial or complete replacement of nitrite contents with these oils on dry fermented sausages made with three different levels of nitrite contents (0, 75, and 150 mg/kg) and two different fat contents (15 and 25%), whose quality and safety were monitored during 225 days of storage. The quality of finely comminuted cooked and dry fermented sausages was tested by determining and analysing physical [pH value, colour – instrumental (L*, a*, and b* values)], chemical [TBARS value, antiradical activity against the DPPH radical (IC50 value), total phenolic content (only for finely comminuted cooked sausages)], microbiological [the total number of aerobic mesophilic bacteria, the total number of aerobic mesophilic sporogenic bacteria, the total number of lactic acid bacteria (only for dry fermented sausages), the total number of lipolytic bacteria (only for dry fermented sausages), the total number of Enterobacteriaceae, the total number of Escherichia coli, the total number of sulphitereducing clostridia, total number of Listeria spp. (including Listeria monocytogenes) (only for dry fermented sausages), the total number of yeasts and moulds] and sensory [colour, odour (only for dry fermented sausages), flavour] quality parametres. For finely comminuted cooked sausages produced with the addition of essential oils of caraway, juniper, or sage, in comparison with finely comminuted cooked sausages produced without the addition of essential oils, independently of the added concentrations of essential oils, the following was determined: a decrease in lightness (L* values) – a darker colour was determined, an increase in redness (a* values), the decrease in yellowness (b* values), the reduction of TBARS values, a reduction of the IC50 values, an increase of total phenolic content, a reduction of the total number of aerobic mesophilic bacteria, a reduction of the total number of aerobic mesophilic sporogenic bacteria, a sensory darker colour, and a sensory higher intensity of flavour, with an increase in the concentrations of the essential oils resulting in the even more pronounced effect of decreasing the TBARS values, of decreasing the IC50 values, of increasing the total phenolic content, of decreasing the total number of aerobic mesophilic bacteria, of decreasing the total number of aerobic mesophilic sporogenic bacteria, and of increasing the intensity of flavour. In the case of dry fermented sausages produced with the addition of essential oils of caraway, juniper, or sage, in comparison with dry fermented sausages produced without the addition of essential oil, independently of the added concentrations of essential oils, the following was determined: an increase in pH values, a reduction of TBARS values, a sensory darker colour, a sensory higher intensity of odour, and a sensory higher intensity of flavour, with an increase in the concentrations of the essential oils resulting in the even more pronounced effect of decreasing the TBARS values, of increasing the intensity of odour, and of increasing the intensity of flavour. For dry fermented sausages produced with the addition of nitrite (75 and 150 mg/kg), in comparison with dry fermented sausages produced without the addition of nitrite, the following was determined: higher values of pH, lower lightness (L* values) – a darker colour was determined, which was also confirmed by sensory analysis – by ranking, higher yellowness (b* values), lower TBARS values, higher IC50 values, lower total number of lactic acid bacteria (only for dry fermented sausages produced with the addition of nitrite in the amount of 150 mg /kg), lower sensory scores for colour difference and higher sensory scores for the difference in odour, with a higher yellowness (b* value) and a lower sensory score for colour difference determined in dry fermented sausages produced with the addition of nitrite in the amount of 150 mg/kg, in comparison with dry fermented sausages produced with the addition of nitrite in an amount of 75 mg/kg. In the case of dry fermented sausages produced with 15% fat, compared to dry fermented sausages produced with 25% fat, the following was determined: a higher pH value, lower lightness (L* value) – a darker colour was determined, a higher redness (a* value), a higher yellowness (b* value), a lower IC50 value, a higher total number of aerobic mesophilic bacteria, and a lower sensory score for colour difference. During storage of dry fermented sausages (from the moment of production to 225 days), the following was determined: an increase in pH values, a decrease in lightness (L* values) – a darker colour was determined, an increase in redness (a* values), an increase in yellowness (b* values), an increase in TBARS values, an increase in IC50 values, an increase in total number of aerobic mesophilic bacteria, a decrease in total number of lactic acid bacteria, and an increase of sensory scores for colour difference, with several exceptions that do not differ greatly from the established trend.