The determination of dehydrated apple shelf-life using accelerated assays

preview a food shelf-life is essential to evaluate the kinetics of degradation reactions beyond the orientation of the more appropriate conservation conditions of the products. For the dehydrated apple shelf-life estimative, the product was packed in PE film of 140 and stored at 5 degrees C (control), 25 degrees C (room) and 35 degrees C (accelerated) temperatures and then evaluated based on objective color readings of L, a and b Hunter during 6 months at a 15-day interval. Experimental data showed that the color degradation follows the model of a zero order kinetic reaction. The Arrhenius model was applied to reaction rates (k) at each temperature and an activation energy (E-a) of 7.6 kcal.mol(-1) and Q(10) of = 2.0 was obtained. Shelf-life evaluation was based on subjective (Difference from Control Sensorial Discriminative Test) measurements over 4 months at 15 day intervals. The results suggest that the product stored at 35 T has 100 days shelf-life time; Since Q(10)= 2.0, the product stored at room temperature might be 200 days shelf-life time.27114114

Color degradation kinetics in low-calorie strawberry and guava jellies

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The purpose of this study was to follow-up color changes in low-calorie strawberry and guava jellies during storage. To this end, one formulation of each flavor was prepared varying the application of hydrocolloids (pectin and modified starch). The jellies were studied regarding pH, soluble solids, water activity and syneresis. In order to follow-up color changes, the samples remained stored for 180 days in chambers with controlled temperatures of 10 degrees C (control) and 25 degrees C (commercial), and color instrumental analyses (L*, a*, and b*) were performed every 30 days. Arrhenius model was applied to reaction speeds (k) at different temperatures, where light strawberry and guava jellies showed greater color changes when stored at 25 degrees C compared to the samples stored at 10 degrees C. Activation energy values between 13 and 15 kcal.mol(-1) and Q(10) values between 2.1 and 2.3 were obtained for light strawberry jelly and light guava jelly, respectively. Therefore, it was concluded that, with respect to color changes, every 10 degrees C temperature increase reduces light jellies shelf-life by half.313758764Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Degradation Kinetics of Anthocyanin of Traditional and Low-Sugar Blackberry Jam

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The objective of this study was to monitor the stability of anthocyanin and phenolic compounds contained in two formulations of blackberry jam (traditional and low-sugar) during storage. For that purpose, jams were prepared with varying amounts of hydrocolloids and investigated as to pH, total soluble solids, water activity, total acidity, total anthocyanins and total polyphenols. In order to accompany and assess the levels of phenolic compounds and colour (L*, a* and b*) changes, the samples were stored for 180 days at two different temperatures (10 and 25 degrees C). The Arrhenius model was used to determine the relationship between the reaction rate (k) at the different storage temperatures, yielding activation energy values of 19 and 12 kcal/mol and Q(10) values of 3.0 and 2.0 for traditional and low-sugar jams, respectively. The results show that by the end of the storage time investigated, the anthocyanin compounds had been partially degraded, with the greatest loss being observed in traditional jam stored at 25 degrees C. Colour stability was also lower in traditional jam as compared to the low-sugar product.5624882496Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq