Chard powder as natural source of nitrites for fermented dried sausages: physicochemical and microbiological studies

Abstract

Nitrites are added to sausage products to accelerate ripening, improve color and microbiological indicators. Chard (Beta vulgaris var. cicla) is one of the best natural sources of nitrites, as it contains a lot of nitrates – 1680 mg/kg in a fresh vegetable. However, chard has not been used as a source of nitrites in sausage technology and in cooking it is used only in fresh, boiled or sautéed form. There are no technologies for industrial drying and processing of chard into powder. Chard powder was obtained by microwave vacuum drying and grinding to 200 microns, which was determined by the appropriate sieve size. Five samples of fermented dried sausages were prepared and evaluated during the ripening process: C1 (without nitrite and sodium nitrate), C2 (100 mg/kg sodium nitrite and 100 mg/kg sodium nitrate), M1 (0.5 % chard powder), M2 (1 % chard powder) and M3 (1.5 % chard powder). With the addition of 1.5 % chard powder (Sample M3), the protein content increased by 22.74 %, ash content increased by 41.82 %, and dietary fiber content increased by 93.75 % compared to the control sample C2. Nitrite was formed from chard powder during the ripening process, especially in treatments M2 and M3. After the entire production process of fermented dried sausages for 35 days, nitrates were detected only in sample C2. The yield of fermented dried sausages enriched with chard powder decreased by 15.95 % compared to the control sample C2. Chard powder improved the microbiological parameters of sausage products, especially in sample M3. The content of aerobic mesophilic bacteria increased by 5.84 % and the content of lactic acid bacteria increased by 8.96 % in sample M3 compared to control C2 after 35 days of fermentation and drying, which is related to the activity of the starter. The organoleptic parameters of fermented dried sausages enriched with chard powder for samples M2 and M3 were better in terms of color and texture. The results of the analysis of nutritional value, pH, nitrites and nitrates indicate the effectiveness of adding 1.5 % chard powder (Sample M3) obtained by microwave vacuum drying as a potential source of nitrites in fermented dried sausages.