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- Optimization of a cupuaçu (Theobroma grandiflorum) nectar formulationPublication . Vieira, M. M. C.; Silva, C. L. M.A Cupuaçu (Theobroma grandiflorum) nectar formulation was optimized, for European consumers, using an augmented simplex centroid mixture design. the working ranges, x1 (Sugar, 10–25%), x2 (Cupuaçu, 15–30%) and x3 (Water, 60–75%), were based on a common Brazilian recipe. As responses, a sensory panel evaluated taste, acidity, sweetness, viscosity, mouthfeel and overall opinion. For each response, the best mathematical predictive model was chosen, based on Response Surface statistical analysis. an optimization was then performed, and the optimum was Cupuaçu (18.5%), Sugar (11%) and Water (70.5%). Tolerance tests were carried out and, although differences were detected (= 5%), the level of acceptance remained above average.
- Mathematical-modeling of the thermal-degradation kinetics of vitamin-c In cupuaçu (theobroma-grandiflorum) nectarPublication . Vieira, M. M. C.; Teixeira, A. A.; Silva, C. L. M.The thermal degradation kinetics of both components of vitamin C, ascorbic acid (AA) and dehydroascorbic acid (DHAA), were determined in a nectar of Cupuacßu (Theobroma grandi¯orum) with 25% of pulp and 15% of sugar in water. AA was assayed by HPLC and the results showed that AA degraded into DHAA. A reversible ®rst order model described well the AA degradation data, with an activation energy of 74 5 kJ/mol and k80 C 0:032 0:003min ÿ1. DHAA kinetic behavior suggested a consecutive ®rst order reaction where DHAA was the intermediate product of AA degradation. A mechanistic model was derived to predict DHAA concentration. Rate constants were replaced by the Arrhenius equation in the model to evaluate the temperature dependence and the kinetic parameters for AA degradation, previously determined, were used. An activation energy of 65 9 kJ/mol and a k80 C of 0:013 0:003 min ÿ1 were estimated. The present ®ndings will help to predict the best Cupuacßu nectar processing conditions that minimize degradation of an important quality factor such as vitamin C.