Keywords

1 Introduction

Homemade kulen (Fig. 1) is dry sausage produced in Croatian region Slavonija and Baranja. The production is still in small scale, so there are many producers, which use different recipes and different production procedure. Homemade kulen manufacturing is a seasonal character and beings in late fall and last until the late spring (approximately six months), due to the favorable weather conditions (temperature and relative humidity) [1]. The peculiar aroma of this dry sausage manly originates from long-term ripening (more than 3 months), smoking, lactic acid bacteria activity, and special spices used in its production (sweet paprika powder, hot paprika powder and garlic) [2, 3]. According to the actual Croatian Legislation [4] homemade kulen is a dry sausage made from coarsely chopped pork and pork back fat, salt, red spicy peppers and garlic, with the possibility of adding sugar, other spices or spice extracts, starter cultures, additives and smoke aromas. They should not contain more than 40% of moisture and must contain at least 22% of meat proteins [4].

The sausage is produced from the parts of the pig with the highest commercial value, the meat from the leg and loin with the addition of approximately 20% of shoulder and neck meat. The minced meat with the addition of max. 10% of pork back fat is seasoned with 2% of rock salt. 0.6% of sweet paprika powder, 0.6% of hot paprika powder and 0.3% of minced fresh garlic. This mixture is then stuffed in natural casing – pig appendix. The raw homemade kulen is then smoked, dried and ripened until it receives the satisfactory texture and aroma.

Fig. 1.
figure 1

Homemade kulen.

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Dry fermented sausage are usually made from pork, or combination of pork and beef, mutton rarely, horse meat and chicken. Minced meat is mixed with pork fat, salt, spices (paprika, pepper, garlic, etc.) and, especially in industrial production, nitrate/nitrite, ascorbate, sugars, etc., in different mass fraction (different recipes). Specific sensory properties of certain dry sausage in addition to being associated with the technology of production (primary the smoking) and added substances (primarily spices) are a result of fermentation and maturation (proteolysis and lipolysis due to the activity of endogenous and exogenous enzymes) or activity of technological microflora that is specific for each microclimatic location [5,6,7]. The dry sausages from different European countries (Croatia, Spain, Italy, Greece and Bosina and Hezegovina) were investigated for its physico-chemical properties with the purpose of standardization of its production [6, 8,9,10,11,12,13,14,15,16]. These study showed large variations in chemical composition and water activity and pH [17].

The small scale produces still use the traditional production without the possibility of controlled conditions (temperature and relative humidity) in smoking, drying and ripening stage. The production conditions are dependent on the weather condition in the area of production. All mentioned results in high variability in chemical composition, of homemade kulen between different producers.

2 Material and Methods

2.1 Material

The samples of homemade kulen were collected at the traditional homemade kulen competition organized by The Chamber of Commerce in Osijek, Croatia. In year 2019. 47 samples were collected, in the years 2020 and 2021, 25 samples were collected. The lower number of samples collected in years 2020 and 2021 is probably related to the COVID-19 pandemic.

In the production of homemade kulen the pig meat from the pigs of at least 12 month old and over 150 kg live weight must be used. After the slaughter, dissection and deboning the meat is cooled to temperatures of 0–4 ℃. The met pH at this stage should be from 5.6 to 5.9. The meat is then grinded trough a grinding plate with holes of 8 to 12 mm in diameter. The meat is them seasoned with 0.7% red paprika, 0.6% of hot paprika and garlic in the amount of 0.2%. Before this the salt is added in amount of 2%. After the mixing the mixture is stuffed into a pig’s appendix (lat. intestinum caecum).

Raw homemade kulen is then smoked with open fire using dry hard wood (hornbeam, beech and its sawdust) approximately six to seven times during a 14 days period. After the smoking, homemade kulan is dried and ripened. After that the homemade kulen is ready for consumption.

2.2 Physico-Chemical Analysis

After discarding the casing, the samples were cut into small pieces and homogenized in a knife mill Gridomix GM 200 (Retsch, Germany). The FoodScan Meat Analyser (Foos, Sweden) was used to determine moisture, total protein, total fat and collagen according to the AOAC 2007 04.

The pH level was measured in a homogenate of the sample mixed with distilled water (1:10) with pH/Ion 510 – Bench pH/Ion/mV Meter (Eutech Instruments Pte Ltd/Oakton Instruments, USA) according to ISO 2917:1999 (HRN ISO 2917:2000) and manufacturer instructions (pH/Ion 510 Instruction Manual).

Water activity (aw) was determined using a Rotronic Hygrolab 3 (Rotronic AG, Switzerland) according to manufacturer instructions, at room temperature (20 ± 2 ºC). All measurements were conducted in three parallel.

3 Results and Discussion

In the Table 1 the general composition pH and aw of the 47 samples of homemade kulen were presented. The moisture were from 25.92 to 44.13%.

Table 1. General composition, pH and aw of homemade kulen in year 2019.
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Relatively large differences are related to the defend stages ripening of homemade kulen. According to the official Croatian legislative the maximal prescribed value of moisture content for this kind of sausage is 40%. The six samples of homemade kulen were not in agreement with prescribed values (HK3, HK5, HK6, HK22, HK26 and HK27).

The fat content ranged from 13.22 to 36.27% with the average value of 23.04%. Protein content of examined samples were from 26.07 to 38.48%, collagen content ranged from 0.27 to 4.96%. pH values were in interval from 5to 6.09 and aw 0.80 to 0.91.

In the year 2020 two samples had a higher moisture content then prescribed (HK2 and HK3) (Table 2). Fat content ranged from 11.99 to 38.41%. Mass fraction of protein ranged from 26.94 to 40.15% and collagen from 1.10 to 5.13%. pH ranged from 5.09 to 6.19 and aw 0.78 to 0.89.

Table 2. General composition, pH and aw of homemade kulen in year 2020.
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Table 3. General composition, pH and aw of homemade kulen in year 2021.
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Basic chemical composition, pH and aw of 25 samples of homemade kulen in year 2021 are presented in Table 3. The moisture content varied from 25.35 to 41.51%. Four samples showed higher values then legally prescribed level. Mass fraction of fat were in range from 12.22 to 38.09%. Protein content of investigated samples were 24.08 to 37.72% and collagen from 0.85 to 4.01%. pH ranged from 5.12 to 6.15 and aw 0.81 to 0.90.

Table 4. Average, minimum and maximum values of general composition, pH and aw of homemade kulen in years 2019–2021.
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In Table 4 the average, minimum and maximum values of examined physical-chemical parameters for each production year are presented. Average values of fat content were from 22.85 to 23.15% and showed little variations. Moisture content varied from 32. 02 to 35.52%. Protein contents were from 33.26 to 34.26. Ambrosiadis et al. [18] reported higher values for moisture (38.74%), fat (40.75%) content and aw (0.931) for Greek dry sausage. Also, the protein content (16.41%) and pH (4.88) were lower.

Similar as Greek dry sausages the Spanish dry sausage Iberian chorizo showed lower values for moisture content (18.6–19.42%), protein content (27.22–28.68%) and aw (0.77–0.88), but higher values for fat content (33.50–35.98%) [9, 19]. pH values in the investigation by [18] (5.25–5.80) were similar to values presented in Table 4.

De Nobile et al. [20] reported higher protein (38.52%) and fat (27.98) content but lower moisture content (26.01) for Italian salami.

Croatian dry sausage Istarska kobasica showed higher fat content (49.01%), but lower protein (23.36%) and moisture content (22.31%) [12]. Other Croatian dry sausage such as Slavonska kobasica and Kulenova seka showed similar values of physical-chemical parameters as homemade kulen [21].

Portuguese Chorizo had higher pH of 5.78, aw 0,94, higher mass fraction of water 50.40% and fat 25.60%, but lower protein content 19.10% [22].

Traditional Spanish dry sausage Fuet had similar moisture content 33.09% higher fat content 26.83% and lower mass fraction of protein 29.14%. Values of pH were similar 5.44 but water activity showed lower values (0.763) [23].

Martin et al. reported lower moisture content of 26.04%, lower water activity 0.785 but higher pH of 5.08 for Spanish dry sausage salchichón [24].

And Turkish-style fermented sausage, also known as sucuk had higher fat content (41.55%) but lower mass fraction of water (20.01%) and protein (34.77%). Sucuk showed lower pH value of 4.82 [25].

Jahic and Pracic [11] reported higher values of moisture of 43.58% but lower fat content (17.10%) and protein content (31.47%) for dry sausage Bosnian sudžuk.

This discrepancies between the homemade kulen and other European dry sausages may be related to smoking (most of the mentioned sausages are not smoked) and the by longer ripening stage of homemade kulen [1, 5].

4 Conclusions

Fat, moisture, collagen, protein content, pH and water activity of homemade kulen showed large variation between producers for all investigated years. This shows that producers still use very different recipes in production and that the samples homemade kulen were in different stage of production (different ripening stage).

The work on the standardization of production is needed. This can be achieved by using the controlled condition (temperature 15–17 ℃, and relative humidity around 75%) of homemade kulen production. The small scale producers should use the automatic chambers for smoking, drying and ripening.