Optimization of Processing Conditions of Traditional Cured Tuna Loins–Muxama

Abstract

Muxama is a traditional highly-valued food product prepared from dry-cured tuna loins in southern Portugal and Spain. The production procedure has seen little change over the last centuries. The muxama's stability is due to reduced water activity. In addition, the drying method has secondary effects on characteristics of flavor, color, and the nutritional value of the product. Our objectives were to describe the dynamics of important physicochemical parameters such as moisture content, water activity (a W ), NaCl concentration (as water-phase salt, Z NaCl ), pH and color, during the salting and drying stages of muxama production, and to test the effect(s) of changes in the traditional processing conditions followed in southern Portugal, aiming at optimizing the production procedure. The lowest values of moisture and a W and highest Z NaCl obtained after drying tuna loins for seven days at 20 • C exceeded the values reported for commercial products and have impact on the appearance (color) of the product. Therefore, drying tuna loins at lower temperatures (ca. 14 • C) is probably more appropriate. The results obtained in this study could be used in the design of future experiments at other conditions and to assess other quality parameters, e.g., total volatile base nitrogen (TVB-N), thiobarbituric acid reactive substances (TBA-RS), microorganism abundance and sensory attributes, and subsequent validation trials.

Muxama and other traditional food products obtained from tuna in south Portugal and Spain: review and future perspectives

“…Those authors observed a clear shortening of the processing time required to obtain muxama with the simultaneous brine thawing and salting of frozen tuna loins. Moreover, Esteves and Aníbal [82] modeled the changes in physicalchemical parameters of tuna loins during the dry-salting stage and derived predictive equations to estimate parameters of interest by plugging-in values of temperature and time in the appropriate range (respectively 14 to 20°C and 4 to 7 days) during the subsequent drying stage of processing muxama. Studying the changes in quality parameters during/along processing and model the kinetics of chemical mechanisms in operation, instead of "simply" evaluating the characteristics thru analyses of end-products, as suggested by Collignan et al [112] for osmotic dehydration of fish, would provide a broader understanding of quality development.…”

“…Rahman [[75]; Table 25.1] summarizes the quality characteristics of dried foods. Furthermore, salted-dried products incorporate flavor-texture-color combinations and nutritional value that are unique and highly valued by consumers [59,63,66,67,73,76,[80][81][82][83][84][85][86][87][88][89][90]. Dried and salted fish are very popular food items worldwide.…”

“…Dried and salted fish are very popular food items worldwide. Wikipedia [91] lists more than 20, e.g., bacalhau (salteddried cod, [84]), vobla (salted-dried roach), litão seco [83,92], or muxama (salted-dried tuna, [82,92,93]).…”