No abstract

(2016) Use of response surface methodology to compare vacuum and atmospheric deep-fat frying of papaya chips impregnated with blackberry juice, CyTA -Journal of Food, 14:4, 578-586, DOI: 10.1080/19476337.2016 To link to this article: https://doi.org/10. 1080/19476337.2016 Vacuum and atmospheric deep-frying were employed to obtain blackberry-based snacks using unripe papaya as matrix. Papaya slices were osmotically impregnated with blackberry juice and fried between 126°C and 154°C at atmospheric pressure and between 110°C and 127°C under vacuum conditions. A response surface methodology (RSM) was used to define which responses (water activity, moisture and oil content, L*, C*, H*, hardness and degree of liking (DOL)) were significantly related to frying parameters (time and temperature). Then a principal component analysis (PCA) was applied to choose which ones related to DOL. PCA demonstrated that hardness and hue were the main drivers of liking for atmospheric frying, while for vacuum frying they were color and oil content. A second RSM was calculated to choose optimal processing conditions. Optimum conditions were 6 min at 117°C in vacuum frying and 6 min at 130°C and 3 min at 150°C in atmospheric pressure.Utilización de la metodología de superficie de respuesta para comparar la fritura por inmersión a presión atmosférica y al vacío de hojuelas de papaya impregnadas con jugo de mora RESUMENSe obtuvo una hojuela de papaya verde, como matriz, aplicando una fritura por inmersión al vacío y otra a presión atmosférica. La papaya verde rebanada se impregnó osmóticamente con jugo de mora y se frió entre 126-154°C a presión atmosférica y entre 110-127°C a condiciones de vacío (24 kPa). Una metodología de superficie de respuesta se usó para definir cuál de las variables respuesta del producto (actividad de agua (Aw), contenido de humedad, contenido de aceite, color L*, C*, H*, dureza and agrado) se relacionaban significativamente con las variables estudiadas de fritura (tiempo y temperatura). Posteriormente un análisis de componentes principales se aplicó a los parámetros significativos para escoger los que se relacionaban con el agrado. La dureza y la tonalidad se relacionaron con agrado de la hojuela frita a presión atmosférica y el color y contenido de aceite para la fritura al vacío. Tomando en cuenta agrado, color, dureza y contenidos de humedad y grasa, una segunda superficie de respuesta se aplicó para escoger las condiciones óptimas de cada proceso, que fueron freír por 6 min a 117°C al vacío y freír por 6 min a 130°C y freír 3 min a 150°C en fritura atmosférica.ARTICLE HISTORY

The nature and occurrence of carry-over effects, i.e. the response to a stimulus is influenced by previous samples, were examined for selected bitter compounds. A time-intensity procedure was used to rate the bitterness of six compounds (caffeine, denatonium benzoate, limonin, naringin, quinine and sucrose octa-acetate). For each subject concentrations of these compounds were determined that were approximately equal in intensity to 1.18 x 10(-5) M limonin. To test carry-over effects of each compound the 36 paired sequences (pairs) were evaluated. Within a session three pairs were tested, between which two-stage rinses were used to remove any effects of the previous pairs. Within a pair only water rinses were used between stimuli. For all compounds carry-over or sensitization effects were observed in which values for maximum intensity, rate of onset and total area under the time-intensity curve were higher for a compound when tested in the second position than in the first. In addition, the degree of sensitization and susceptibility to sensitization were compound-specific. Caffeine increased the bitterness by the largest amount for all other compounds, while it was least affected. Regardless of the compound in the first position, the bitterness of quinine and denatonium were most enhanced.

Introducción. El huevo de gallina (Gallus gallus domesticus) es un alimento nutritivo de la dieta de millones de personas. Su producción mundial se obtiene con el empleo de jaulas convencionales, aunque existen sistemas alternativos como el pastoreo. Objetivo. Comparar la calidad microbiológica, fisicoquímica y el sabor de huevos provenientes de granjas con sistemas productivos convencionales o de pastoreo en Costa Rica. Materiales y métodos. El trabajo se realizó en Alajuela, Costa Rica de octubre del 2016 a mayo del 2017. Se muestrearon superficies y huevos de gallinas Isa Brown en granjas con sistemas productivos convencionales o de pastoreo y se determinó el recuento de coliformes totales, Escherichia coli, mohos y levaduras y ausencia/presencia de Salmonella sp. Además, se analizaron parámetros fisicoquímicos (unidades Haugh, índice de yema, pH, color de yema y dureza de cáscara) y se realizó una prueba sensorial de discriminación con consumidores. Resultados. Los sistemas de producción de pastoreo tienen superficies en contacto con los huevos con recuentos de coliformes totales y E. coli significativamente mayores que las superficies del sistema convencional. Los huevos de pastoreo presentaron recuentos de coliformes totales (3,2 log10 UFC huevo-1) significativamente mayores que los huevos convencionales (2,3 log10 UFC huevo-1). Salmonella sp. estuvo presente en 8 % de las muestras de pastoreo (incidencia no diferente de 0) y ausente en las convencionales. Se encontró diferencia en el color de la yema (más oscura en los huevos convencionales). Además, hubo diferencia significativa en el sabor de ambos tipos de huevo. Conclusión. En general, existió diferencia en la calidad microbiológica, fisicoquímica y el sabor de huevos producidos en granja de tipo convencional o pastoreo.

Introduction: Rice is a staple food in Costa Rica representing almost 24 % of the total calorie intake in the diet. Consumers have become more quality conscious about the rice consumed, so producers need to focus on the quality of rice along with production. Objective: The aim of this study was to investigate the physicochemical profile and consumer preference of five Costa Rican rice varieties: Palmar 18, Basmatico, Chin Chin, INTA-Miravalles, and CR- 5272. Materials and methods: Proximate analysis, amylose, and mineral content were performed in the raw grain. Two different sessions were performed (n=120 each) to evaluate consumer preference measurements using the John Brown R-Index (RJB) index. The first sensory panel selected the best cooking preparation and the second, the preferred rice variety. Instrumental color measurements (L*, C*, hº, DE) were applied to the cooked rice varieties (76-96ºC for 38 min). Results: Regarding the physicochemical characterization, INTAMiravalles showed the highest protein content (8.2%), while Basmatico and Chin Chin, the lowest. Four varieties presented high amylose content (AC) and INTA-Miravalles reported an intermediate AC. The mineral content varied among varieties. INTA-Miravalles showed the highest N, followed by Palmar 18. The cooking preparation from the regulatory agency was preferred by consumers. The consumers’ preference of the varieties ranked from high to low: Basmatico>Chin Chin=CR5772>Palmar 18=INTA-Miravalles. Conclusions: This study suggests that consumer preference for cooked rice was influenced by physicochemical characteristics such as protein, AC, mineral content, and aromatic attributes. Consumer acceptance is an important factor to consider when new varieties are developed. The water-to-rice ratio during cooking played an important role in cooked rice sensory quality.