Marcos Antonio Correa Velloso, Lucia de Fatima Henriques Lourenco, Cleidiane Araujo, Eder Augusto Furtado Araujo
Purpose: The present research is on understanding the effects of the use of a starter culture, nisin and a combination of starter culture and nisin in the development and conservation of a fishburger–type product made from molded tambaqui (Colossoma macropomum). Design/methodology/approach: The products were vacuum-packed and kept at an average temperature of 6°C. The time of evaluation was 35 days. The samples were collected every five days for microbiological monitoring, which included counts of lactic acid bacteria in MRS agar. Products inoculated with starter culture showed an average lipid content of 0.86%, whereas the products without starter culture had lipid values of 2.03% (control) and 1.71% (nisin, only). This result can be attributed to the lipolytic activity of the start culture. The pH also decreased sharply in groups containing starter culture only, reaching a minimum of 5.28, whereas the lowest value for the control product was 6.12 (p<0.05). This reduction is influenced by release of organic acids produced by starter culture during fermentation process of the product. Lower growth of mesophilic bacteria and psychrophilic bacteria in relation to control product and products with nisin, may be related to its ability to prevent spoilage through formation of pores in their membranes, transmembrane potential depletion and/or pH gradient, resulting in loss of cellular material. Association between Acid lactic Bacteria and nisin was important to control the growth of spoilage. Findings: The products containing starter culture, nisin and a combination of nisin-starter culture, presented a better shelf life than control product. Practical application: Bacteriocins provide another resource for food preservation, especially when used with other barriers. The use of starters cultures with protective effects, improves security of various types of foods and prevents the proliferation of pathogens and spoilage organism, also contributing with attributes of flavor, texture and color. Most importantly, are generally regarded as safe (GRAS). Originality/value: The biopreservation of food is used to enhance food safety and extend its shelf life. The use of nisin and Lactic Acid bacteria, in products derived from fish is important in north region of Brazil, where fish exploitation is a main activity and spoilage of fish products assumes great proportion because of the lack of structure in fish production chain. In this way, this research will contribute to improve the utilization of fish through the development of new products
