Effect of water activity in tortilla and its relationship on the acrylamide content after frying

The objective of this study was to relate the tortilla minimum integral desorption entropy with acrylamide content during processing of tortilla chips. Tortilla pieces were stored at 30 °C at aw of 0.11-0.84 for 4 days and fried later in soybean oil at 180 °C for 25 s. The lowest acrylamide content was observed in tortilla chips made of non-stored tortilla (aw = 0.98) as well as in those prepared from tortilla stored in the minimum integral entropy (aw = 0.53). In addition, the color and texture values were similar in both cases. These results suggest that the reduction of the acrylamide content during processing of tortilla chips and other tortilla based foods thermally processed might be modified by factors such as moisture content, aw, and the physical state of water in the tortilla. Thus, the minimum integral entropy showed to be a reliable indicator to establish the most appropriate moisture conditions to obtain tortilla chips with reduced level of acrylamide when tortilla is dehydrated. © 2014 Elsevier Ltd. All rights reserved.We are indebted to Juan Veles, Edmundo Gutierrez, Carlos Alberto Ávila, Araceli Mauricio and Veronica Flores from CINVESTAV Querétaro for their technical assistance.Peer Reviewe

Role of enthalpy and entropy in moisture sorption behavior of pineapple pulp powder produced by different drying methods

Sorption mechanisms of pineapple powders produced by vibro-fluidized drying (VFD), spray drying (SD), freeze drying (FD) or vacuum drying (VD) were interpreted through enthalpy/entropy variations with respect to equilibrium moisture content (EMC) at 20, 30, 40 and 50 degrees C and water activity (a(w)) between 0.059 and 0.907. Powders from SD and VFD were more hygroscopic and integral properties indicated higher stability at changing a, compared to powders from VD and FD. Powders showed an enthalpy driven zone with equal isokinetic temperature (T-BI = 499.0 +/- 4.8 K) due to their same composition, and an entropy controlled zone with different isokinetic temperature, T-B2 (VD: 116.0 +/- 40.6 K; FD: 118.3 +/- 24.1 K; SD: 95.8 +/- 23.4 K; VFD: 81.8 +/- 6.3 K), caused by different microstructures resulting from different drying methods. Powders from SD and VFD presented larger entropic zones that shifted the minimum integral entropy to higher a(w), improving storage stability. (C) 2011 Elsevier B.V. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Physicochemical and antioxidant properties of jalapeño pepper (Capsicum annuum var. annuum) during storage

El chile jalapeño se consume en estado verde (inmaduro) y rojo (maduro); por lo que es importante evaluar los componentes presentes en ambos. El objetivo de este estudio fue determinar el efecto del tiempo de almacenamiento (30 días) a temperatura ambiente (25 °C), sobre los cambios fisicoquímicos, antioxidantes y los parámetros texturales de Capsicum annuum var. annuum. Durante este periodo, se produjo un aumento significativo (P ≤ 0.05) en el contenido de sólidos solubles, acidez y azúcares reductores; mientras que la humedad, las cenizas y el pH, disminuyeron. La firmeza del pericarpio varió de 5.17 a 2.88 N. La capsaicina en estado verde fue menor que la encontrada en estado rojo. Algunos de los compuestos antioxidantes mostraron incremento significativo (P ≤ 0.05) a partir del día 15 de almacenamiento. La captura de radical DPPH fue mayor (58.35 %) en el estado rojo, en comparación con el estado verde de madurez (19.42 %). Algunas de las propiedades analizadas mostraron cambios significativos entre los días 15 y 20 de almacenamiento, coincidiendo con el cambio de color de verde a rojo. El chile jalapeño en estado rojo es una buena fuente de antioxidantes, incluyendo ácido ascórbico, carotenoides y polifenoles

Biofunctionality of native and nano-structured blue corn starch in prediabetic Wistar rats

The biofunctionality of native and nanostructured starch obtained from blue corn was evaluated on prediabetic Wistar rats. The surface of both types of starch was analyzed by atomic force microscopy (AFM). Total polyphenols content, antioxidant activity and digestibility were also evaluated. Prediabetes was induced by feeding a diet high in fat, carbohydrates and the administration of streptozotocin. Experimental design included a control group, prediabetic group and two prediabetic groups, one supplemented with native starch and the other with nanostructured starch. AFM analysis showed nano-cavities <5 nm in nanostructured starch. Nanostructured starch also had a higher content of total polyphenols, higher antioxidant activity and higher percentage of slow digestibility starch compared to native starch. Glucose, triglycerides 34 and insulin in the plasma increased significantly in the prediabetic group. Nanostructured starch administration decreased the levels of glucose and insulin in the plasma and therefore has potential as functional ingredient