Lipolytic Changes in Fermented Sausages Produced with Turkey Meat: Effects of Starter Culture and Heat Treatment

Effect of Starter Cultures on Quality of Fermented Sausages

The expansion and advancement of the meat product market have increased the demand for fermented sausages. A typical method for manufacturing high-quality fermented sausages is using a starter culture, which improves the taste, aroma, and texture. Currently, the starter culture for manufacturing fermented sausages is mainly composed of microorganisms such as lactic acid bacteria, yeast, and fungi, which generate volatile compounds by the oxidation of fatty acids. In addition, protein decomposition and changes in pH occur during the fermentation period. It can positively change the texture of the fermented sausage. In this review, we discuss the requirements (improving food safety, the safety of starter culture, enzyme activity, and color) of microorganisms used in starter cultures and the generation of flavor compounds (heptanal, octanal, nonanal, hexanal, 2-pentylfuran, 1-penten-3-ol, and 2-pentanone) from lipids. Furthermore, quality improvement (hardness and chewiness) due to texture changes after starter culture application during the manufacturing process are discussed.

Engineered Biofilm: Innovative Nextgen Strategy for Quality Enhancement of Fermented Foods

Microbial communities within fermented food (beers, wines, distillates, meats, fishes, cheeses, breads) products remain within biofilm and are embedded in a complex extracellular polymeric matrix that provides favorable growth conditions to the indwelling species. Biofilm acts as the best ecological niche for the residing microbes by providing food ingredients that interact with the fermenting microorganisms' metabolites to boost their growth. This leads to the alterations in the biochemical and nutritional quality of the fermented food ingredients compared to the initial ingredients in terms of antioxidants, peptides, organoleptic and probiotic properties, and antimicrobial activity. Microbes within the biofilm have altered genetic expression that may lead to novel biochemical pathways influencing their chemical and organoleptic properties related to consumer acceptability. Although microbial biofilms have always been linked to pathogenicity owing to its enhanced antimicrobial resistance, biofilm could be favorable for the production of amino acids like l-proline and L-threonine by engineered bacteria. The unique characteristics of many traditional fermented foods are attributed by the biofilm formed by lactic acid bacteria and yeast and often, multispecies biofilm can be successfully used for repeated-batch fermentation. The present review will shed light on current research related to the role of biofilm in the fermentation process with special reference to the recent applications of NGS/WGS/omics for the improved biofilm forming ability of the genetically engineered and biotechnologically modified microorganisms to bring about the amelioration of the quality of fermented food.

Microbial Fermentation and Its Role in Quality Improvement of Fermented Foods

Fermentation processes in foods often lead to changes in nutritional and biochemical quality relative to the starting ingredients. Fermented foods comprise very complex ecosystems consisting of enzymes from raw ingredients that interact with the fermenting microorganisms’ metabolic activities. Fermenting microorganisms provide a unique approach towards food stability via physical and biochemical changes in fermented foods. These fermented foods can benefit consumers compared to simple foods in terms of antioxidants, production of peptides, organoleptic and probiotic properties, and antimicrobial activity. It also helps in the levels of anti-nutrients and toxins level. The quality and quantity of microbial communities in fermented foods vary based on the manufacturing process and storage conditions/durability. This review contributes to current research on biochemical changes during the fermentation of foods. The focus will be on the changes in the biochemical compounds that determine the characteristics of final fermented food products from original food resources.

Biogenic Amine Formation in "Bez Sucuk," a Type of Turkish Traditional Fermented Sausage Produced with Different Meat: Fat Ratios

This study aims to evaluate biogenic amine levels of bez sucuks (BS) produced with different meat:fat ratios. For this, three BS groups were manufactured with meat:fat ratios of 90:10 (BS10), 80:20 (BS20), and 70:30 (BS30). The pH and water activity values and biogenic amine amounts of sucuk samples were determined during processing and storage periods and the pH values of the initial mixtures of BS samples were in the range 5.51-5.74, decreasing to 4.72-4.94 by the 14^th day. The water activity values of BS samples showed significant decreases as a result of the drying stage and reached to range 0.913-0.935 on the 14^th day of processing (p<0.05). Although BS10 had the highest tyramine (434.12 mg/kg), histamine (5.69 mg/kg), cadaverine (12.48 mg/kg), putrescine (17.83 mg/kg), 2-phenylethylamine (15.43 mg/kg), and tryptamine (122.41 mg/kg) levels at the end of processing stage (p<0.05), spermine and spermidine levels did not differ between the BS samples due to their utilization of different meat:fat ratios (p>0.05). Similarly, the tryptamine (205.11 mg/kg), putrescine (43.57 mg/kg), and tyramine (766.23 mg/kg) levels of BS10 were higher than BS20 and BS30 samples at the end of storage (p<0.05). The results showed that BS10 with the highest meat ratio had the highest tryptamine, putrescine, and tyramine levels at the end of the processing and storage period.