Title : The effect of chia seeds addition on selected quality features of fermented sheep's milk
Abstract:
The aim of the study was to investigate the effect of chia seed addition on selected features of fermented sheep milk. Milk from organic farming was used for the research, the starter cultures were: Streptococcus salivarius subsp. thermophilus, Lactobacillus delbrueckii subsp. bulgaricus. The following milk variants were obtained: 0.5%, 1.0%, 1.5%, 2.0%, and 2.5% of the chia additive, control sample without the additive. All variants were obtained in three independent replication series. The milk was analyzed immediately after obtaining, as well as 24 hours and 7 days after. Adding chia seeds to yogurt increased the product's protein content. The addition of chia also resulted in an increase in fat content compared to the control sample. The fat content of fermented milk without the addition was on average 6.44%, while that with 1% and 2% chia was 6.58% and 6.56%, respectively. The dry matter content in the fermented milk with the addition of 2% and 2.5% chia seeds was higher than in the remaining samples and it was 18% and 18.15%, respectively (while in the control sample this value was approximately 17%). The lowest hardness parameter was observed in the control samples (1.46N) and those with 1% chia (1.45N). The highest hardness was observed in the sample with 2% chia (3.38N). The adhesiveness values of individual variants of fermented milks did not differ statistically significantly. The lowest value was found in the control sample (5.47 mJ), while the highest in the variants with 0.5% and 2.5% chia added (11.13 mJ and 11.07 mJ, respectively). The individual variants of fermented sheep milks did not differ statistically significantly in terms of springiness (ranged from 2.92 mm for the sample with 1% chia seed addition to 4.13 mm for the control). Single-factor analysis of variance revealed no significant differences in organoleptic characteristics between the individual variants after either one or 10 days of storage (p<0.05). After one day of storage, appearance and aroma were rated as very good in all variants. Consistency was rated as very good and good, with the highest rating for the sample with 2% chia. Taste also received the highest ratings for this sample. On the first day of storage, the highest average rating was given to the sample with 2% chia added. After 10 days of storage, appearance and aroma were also rated as very good in all samples. In terms of consistency, the sample with 2% chia added received the highest rating, while the sample with 1.5% chia added received the lowest. Taste after 10 days of storage was rated as very good and good. The sample with 2% chia added received the highest average rating.In summary of the obtained results it can be concluded that, the addition of chia seeds did not significantly affect the fermentation process of sheep's milk. Fermented sheep's milk with chia was very well-rated by respondents in a sensory survey. Therefore, it's likely that such a product would find supporters and could be a valuable source of nutrients in the daily diet.
Research financed by the Ministry of Science and Higher Education of Poland as part of the targeted subsidy "Research network of natural science universities for the development of the Polish dairy sector - research project" (SUP-RIM) (MEiN/2023/DPI/2866).
