No abstract

No abstract

In this work was evaluated the effect of lactic acid treatment method in pork Serratus ventralis muscle on meat quality parameters pH, color, weight loss, cooking loss, hardness, and taste. The treatment was performed by immersing the sample in lactic acid solutions at two concentrations (1 and 3% v v -1 ) for 1 and 3 min., immediately the samples were stored at 4 °C during 7 days. The taste was evaluated employing trained and untrained judges. Only hardness, weight loss and cooking loss, were affected by lactic acid concentration (p<0.05). The perception of lactic acid taste to trained judges was higher in samples of major concentration and immersion time. To untrained judges the sample treated with 3% lactic acid for 1 minute, had the best acceptation. Both judges reported that the taste of meat was delicious. Therefore, lactic acid treatment may be an alternative to extend pork shelf life.

Specific heat capacity (CP) is regarded as a fundamental parameter for the design, operation, and optimization of the heat transfer equipment widely used in the food industry. Using the calorimetric ASTM E1269‐11 standard procedure, the CP–temperature (CPfalse(Tfalse)) curves of fruit juice model systems prepared at different mass fractions of fructose/glucose/sucrose/citric acid/pectin and water were measured. Thus, experimental data of CP for solid samples in crystalline and amorphous states from −80 °C up to the melting temperature range and for aqueous samples from −80 to 110 °C were generated. In the tested temperature interval, the CP of crystalline, amorphous, and aqueous samples were found to be in the ranges of 0.037 ± 0.020 to 5.61 ± 0.04; 0.061 ± 0.004 to 3.12 ± 0.19, and 0.363 ± 0.05 to 3.24 ± 0.14 kJ/kg °C, respectively. Also, a generalized empirical equation based on the type and concentration of components was developed to predict the CPfalse(Tfalse) curves of the studied samples. The proposed equation exhibited a low error sum of squares (SSE <  57.3) and a high coefficient of determination (R2 > 0.927). An analysis of variance (ANOVA) was performed with a confidence level of 95% (p < 0.05). The CPfalse(Tfalse) curves were influenced by temperature, thermal transitions, water, solid types, and compound interactions. Glucose was one of the solids that most significantly influenced the CP values of samples. Practical Application The experimental specific heat capacity data and empirical equation proposed in this study are relevant to the design, evaluation, and optimization of heat transfer equipment involved in many foods and biochemical industrial processes such as cryopreservation, frozen storage, freezing, chilling, drying, and the cooking of hard candies.

Entomophagy or consumption of insects has significantly increased worldwide, either for pleasure or to satisfy the food needs in developing countries. There are approximately 2,000 species of edible insects distributed in 120 countries. From these 2,000 species, about 540 are located in Mexico; one of the most consumed are the escamoles. Escamoles are larvae and pupae of the ant Liometopum apiculatum. Escamoles are nutritious because of their high content of protein, fat, carbohydrates and vitamin. However, during storage the quality of escamoles changes rapidly which affects the acceptability by the consumer. This loss of quality is probably a result of proteolytic activity of endogenous proteases. Therefore, the objectives of this study were to identify the classes of proteases in escamoles as well as to evaluate the effect of proteolytic activity on physicochemical and structural changes during storage. Proteases identification was conducted using specific inhibitors; structural changes, texture, and proteolytic activity were monitored at different days of storage. The highest proteolytic activities (P<0.05) were observed at pH 8, 9 and 10 and at 37 and 50 °C. Proteases were mainly inhibited by iodoacetic acid and soybean trypsin inhibitor showing that cysteine and serine proteases were dominant. High proteolytic activity, significant (P<0.05) reduction in texture and weight loss was observed during storage. The deterioration of escamoles was evident in analyses of images, where initial structure was lost during storage. These results indicate that different groups of proteases are associated with rapid deterioration of escamoles.