L. A. de la Rosa

Preserving quality of fresh-cut products using safe technologies.

Food preservation is critical for keeping the global food supply safe and available for consumers. Food scientists study production and processing to develop new technologies that improve the quality and quantity of healthy food products, with the main objective of increasing food production without affecting food quality and environment, while fulfilling consumer expectations. Nowadays consumers want their food to be fresh, nutritious, safe, and attractive, low priced, and ready-to-eat. That is the case of fresh-cut products; however, maintaining the quality of these products is not an easy task, since minimally processed products experience increased ethylene production and respiration rates, with the consequent lost of quality. New effective and inexpensive technologies to safely preserve the quality of fresh-cut products are needed. In the last two decades, food scientists have attempted to solve problems in fresh-cut processing and quality preservation, and rapid advances in scientific knowledge on fresh-cut product preservation have been developed. The present review describes the use of emerging technologies such as ultraviolet irradiation (UV-C), edible coatings, active packaging and natural additives, to preserve the quality of fresh-cut fruits; highlighting the areas in which information is still lacking, and commenting on future trends.

TOTAL PHENOLS AND ANTIOXIDANT ACTIVITY OF COMMERCIAL AND WILD MUSHROOMS FROM CHIHUAHUA, MEXICO FENOLES TOTALESY CAPACIDAD ANTIOXIDANTE DE HONGOS COMERCIALESY SILVESTRES DE CHIHUAHUA, MÉXICO

Abstract Three wild edible mushrooms (Agaricus sp., Boletus sp., and Macrolepiota sp.) from the North of Mexico (Chihuahua state) and two commercial species (Agaricus bisporus white strain and Portabella: Agaricus bisporus brown strain) were analyzed to determine their proximate composition, total phenols and antioxidant activity. Wild mushrooms presented lower humidity values with respect to commercial species. Other proximate parameters such as total protein, lipids, ashes and carbohydrates were similar to those reported for edible mushrooms. Total phenols and antioxidant activity (Ferric Reducing/Antioxidant Power assay, FRAP) were determined from 80% methanol extracts. Wild Mushrooms had higher phenol content and antioxidant capacity than commercial mushrooms. A direct correlation between phenols and antioxidant activity (r2 = 0.986) was observed. Due to these characteristics, wild mushrooms could be considered as a complement in the diet for the health benefits they present. Resumen Se analizó la composición proximal, fenoles totales y capacidad antioxidante, de tres hongos silvestres (Agaricus sp., Boletus sp., and Macrolepiota sp.) del norte de México (Chihuahua) y dos comerciales (Agaricus bisporus cepa blanca and Portalella: Agaricus bisporus cepa café). Los hongos silvestres presentaron valores menores de humedad que los comerciales. Los demás parámetros proximales (proteínas, lípidos, cenizas y carbohidratos totales) fueron similares a los reportados para hongos silvestres. La concentración de fenoles totales y actividad antioxidante (Ferric Reducing/Antioxidant Power assay, FRAP) se determinaron a partir de extractos con metanol al 80%. Los hongos silvestres presentaron valores más altos en fenoles totales y actividad antioxidante, frente a los hongos comerciales. Se observó una correlación directa (r2 = 0,986) entre fenoles totales y actividad antioxidante. Estas características de los hogos silvestres hacen que puedan ser considerados, como complemento de la dieta ya que puede presentar buenos beneficios en la salud. Palabras clave: Hongos comestibles, análisis proximal, polifenoles, actividad antioxidante, FRAP

Evaluation of antioxidant enzymes in response to predator odor stress in prefrontal cortex and amygdala

Conditions of stress can originate from diverse stimuli including physical, chemical, antigenic and psychological. The latter is processed in part via the hypothalamic-pituitary-adrenal (HPA) axis, with input from and communication between the amygdala (AM) and prefrontal cortex (PFC). The HPA axis generates an increase in circulating glucocorticoids, augmenting metabolism and, consequently, oxygen consumption, increasing the production of free radicals and reactive oxygen species (ROS). Exposure to predator odor as a model of non-invasive acute stress was used to evaluate the hypothesis that psychogenic stress can modify enzymatic antioxidant responses. The activities of various enzymes, catalase (CAT), cytosolic and mitochondrial superoxide dismutase (Cu, Zn-SOD and Mn-SOD, respectively) and glutathione S-transferase (GST), were determined in AM and PFC. Acute psychogenic stress inhibited CAT activity in the AM and PFC, and increased Mn-SOD activity in the PFC. These results demonstrate that different responses can be elicited by the same stressor in two separate brain regions involved in processing emotional stimuli, and that changes in specific antioxidant enzymatic responses can be seen with exposure to acute psychogenic stress.

Effect of harvest date and storage duration on chemical composition, sugar and phenolic profile of ‘Golden Delicious’ apples from northwest Mexico

The chemical composition, sugars profile, total phenolic compounds, phenolic profile and antioxidant activity of ‘Golden Delicious’ apples during storage under controlled atmospheres were evaluated. Total lipids and proteins slightly decreased during storage, while total carbohydrate and mineral content remained constant. The content of total phenolic compounds ranged from 564–748 mg gallic acid equivalents per 100 g of dry apple. Epicatechin, chlorogenic acid, catechin, phloridzin, cyanidin-3-galactoside, quercetin-3-galactoside and quercetin-3-glucoside were the seven major phenolic compounds identified in all samples. Their content was modified by harvest date and in late harvested apples was increased by controlled atmosphere storage. Antioxidant activity, evaluated by ferric reducing antioxidant power (FRAP), radical 2,2-diphenyl-1-picrylhydrazyl scavenger capacity (DPPH) and TROLOX equivalent antioxidant capacity (TEAC), remained unchanged during the whole storage for both harvest dates. The concentration of sucrose decreased, while glucose increased and fructose remained unchanged during the storage time for both harvest dates. The present results suggest that, under the storage conditions used, nutrients and bioactive compounds of apples were maintained for at least 8 months and phenolic profile was modified by harvest date and storage.