Abstract In the baking industry, different processes and methods of freezing have been used for breadmaking to preserve a quality comparable to that of fresh bread. In this study, the effect of part-baking time, freezing rate, and frozen storage time on part-baked French bread quality was determined. The bread was part-baked for 0, 3 and 6 min, frozen at slow (0.15 °C/min) and fast (1.75 °C/min) freezing rates, stored under freezing conditions for up to 56 days and thawed every 14 days. Part-baked bread was rebaked, and the SV and firmness at 2, 24 and 48 h were obtained. An experiment with a factorial design of 3×2×5 (3 part-baking time, 2 freezing rates and 5 frozen storage times) with analysis of variance (ANOVA) at a confidence level of 95% was carried out. The highest SV was obtained at 6 min of part-baking at a slow freezing rate and decreased as the frozen storage time increased. In contrast, TPA showed that bread firmness increases when the specific volume decreases, and the highest firmness is at 0 min of part-baked time. Relatively long part-baking times allow for firm crumb formation with limited damage to the structure and therefore bread with optimal quality.

Abstract The study aims to investigate the effects of mixing on the protein solubility and secondary structure in corn dough during processing for tortilla production. To evaluate how mixing affects dough rheology, the storage moduli (G´), loss moduli (G´´) and tangent of the phase angle (Tan δ) dependent on frequency and texture profile analysis (TPA) were determined. HPLC-SEC showed an increased proportion of soluble polymeric proteins (soluble high molecular weight species). FT-IR results revealed that mixing promotes an increase of the β-sheet structure and a reduction of α-helix proportion, which suggests protein aggregation. Rheological data showed that the elastic prevailed over the viscous behavior (G´ > G´´) in the corn dough, with a soft solid material and an ordered and stable structure. Mixing, an intermediate step for dough production had important effects in protein structure and dough rheological properties. The increased Tan δ ( G´´/ G´) is consistent with an increased viscous character and polymers aggregation that was demonstrated in this case for proteins.

Resumen El estudio tiene como objetivo investigar los efectos del mezclado sobre la solubilidad de las proteínas del maiz y su estructura secundaria, en masas de maíz durante el procesamiento para la producción de tortillas. Para evaluar cómo el mezclado afecta la reología de la masa, se determinaron los módulos de almacenamiento (G´), los módulos de pérdida (G´´) y el ángulo de fase (Tan δ) dependientes de la frecuencia y el perfil de textura (TPA). Los análisis cromatográficos (HPLC-SEC) mostraron una mayor proporción de proteínas poliméricas solubles (especies solubles de peso molecular alto). Los resultados de FT-IR revelaron que la mezcla promueve el aumento de la estructura de la hoja β y la reducción de la proporción de la hélice α, lo que sugiere la agregación de las proteínas. Los datos reológicos mostraron que en las masas de maíz prevaleció el comportamiento elástico sobre el viscoso (G´ > G´´), un material sólido, blando con una estructura ordenada y estable. El mezclado, un paso intermedio para la producción de masa, tuvo efectos importantes en la estructura de la proteína y las propiedades reológicas de la masa, el aumento de Tan δ es consistente con un mayor carácter viscoso y agregación de polímeros que se demostró en este caso para las proteínas.

ABSTRACT The rhamnogalacturonan I (RGI) is part of pectin plant cell wall, and currently there is scarce information about the elicitor effect of its fragments in the fruit defense mechanism. In this work, the effect of the fragments of RGI on the defense mechanism in tomato (Solanum lycopersicum L.) fruits was evaluated. Three fragments of RGI released from enzymatic degradation by RG lyase were characterized according to their physical-chemical and structural characteristics. Two of RGI fragments (F-1 and F-2) were selected and applied on tomato fruits during 48 h. At different exposure times (0, 0.5, 1, 6, 24, and 48 h) tomato samples were taken, and the enzymatic activity of chitinase was assessed by fluorometry, and β-1,3-glucanase and peroxidase by spectrophotometry (UV-visible). The absorption bands determined by Fourier transform infra-red (FT-IR) spectroscopy in the RGI fragments, was different concerning RGI no fragmented. The RGI had a molecular weight of 64 kDa and an intrinsic viscosity of 40.9 mL g-1; while the molecular weight of F-1 and F-2 fragments were 20 and 16 kDa, and an average intrinsic viscosity of 27 and 26 mL g-1, respectively. The content of galacturonic acid decreased, and the neutral sugars increased concerning the time of enzymatic degradation. F-1 and F-2 fragments induced an increase in the level of β -1,3-glucanase activity in tomato fruits; however, an increase in the enzymatic activity of chitinase and peroxidase was observed after 0.5 h of exposure to F-2 fragment. It was concluded that the RGI fragments were structurally different from the RGI no fragmented and induced the natural defense mechanism of the tomato fruit.

Fruit thinning is a regular practice in apple (Malus x domestica Borkh.) orchards to increase fruit size and to promote blooming. This practice generates immature, small (10 to 40 mm diameter) fruits, which are occasionally used as cattle feed. The use of thinned apples for pectin extraction could increase orchards profitability and promote development of new transformation processes. Pectin is a polysaccharide located on the cell wall of plant tissues. Commercial pectins are extracted from different plant sources and have been mainly used in the food industry. The present research aimed to extract pectin from thinned Golden Delicious (GD) and RedChief Delicious (RChD) immature fruits and determine the effect of de-esterification on pectin gelling properties. Pectin was extracted using a controlled acid hydrolysis. Extraction yields were 12 and 11 % (w/w) for GD and RChD, respectively. De-esterified pectins were obtained by alkaline hydrolysis and showed an esterification degree of 35 and 42 % for GD and RChD, respectively. Using a polysaccharide concentration of 2 % (w/v), both de-esterified pectins formed ionic gels induced by calcium, which presented an elasticity of 147 and 90 Pa for GD and RChD, respectively. In short, thinned GD and RChD immature fruits are a source of pectin with yield and properties similar to commercially available pectins.

El raleo de frutos es una práctica común en los huertos de manzana (Malus x domestica Borkh.) para obtener frutos de mayor tamaño y promover el retorno de la floración. Esta práctica genera manzanas inmaduras y de diámetro pequeño (10 a 40 mm) que son utilizadas ocasionalmente como alimento para ganado. La utilización de la manzana de raleo como fuente alternativa de pectina podría incrementar la rentabilidad de los huertos y el desarrollo de nuevos procesos de transformación. La pectina es un polisacárido localizado en la pared celular de los tejidos vegetales, que se ha extraído de distintas fuentes y utilizado exitosamente en la industria alimentaria. Este trabajo de investigación tuvo como objetivo extraer la pectina de manzanas de raleo de las variedades Golden Delicious (GD) y RedChief Delicious (RChD), y determinar las propiedades gelificantes del polisacárido. La pectina fue extraída mediante hidrólisis ácida controlada, con un rendimiento de 12 y 11 % (p/p) para GD y RChD, respectivamente. Las pectinas obtenidas fueron desesterificadas por vía alcalina y presentaron grados de esterificación de 35 % (GD) y 42 % (RChD). Ambas pectinas formaron geles iónicos inducidos por calcio, con una elasticidad de 147 y 90 Pa para GD y RChD, respectivamente, a una concentración de polisacárido de 2 % (p/v). La pectina desesterificada de manzanas inmaduras de raleo presenta propiedades físico-químicas y gelificantes que podrían ser de interés para las industrias alimentaria, farmacéutica y cosmética.

Ferul Ferulated arabinoxylans are the primary non-starch polysaccharides in cereal grains. They are located in thecell walls of endosperm, aleurone layer and pericarp. There are reports of their presence in major cereal grains including wheat (Triticum aestivum L.), rye (Secale cereale L. M. Bieb.), barley (Hordeum vulgare L.), oat (A. Sativa), rice (Oryza sativa L.), sorghum (Sorghum vulgare), maize (Zea mays L.) and millet (Panicum miliaceum L.). Recent research has focused on arabinoxylan extraction from low-value cereal byproducts in the food industry, such as bran cereal and 'nejayote' (maize nixtamalization wastewater). Ferulated arabinoxylans form highly viscous solutions, and they can form gels in the presence of certain oxidizing agents. Gelling capability of cereal arabinoxylans is determined by inherent physicochemical properties. Arabinoxylan gels are receiving increasing attention due to characteristics such as neutral odor and taste, stability to pH and electrolyte concentration changes, and macro porous structure. They can potentially be used as controlled-release matrices in food and non-food applications like biomedicine and cosmetics. Thus, cereal grains and by-products become more valuable. This review includes some of the most recent findings on the physicochemical properties and gelling capability of ferulated arabinoxylans from cereals.

Los arabinoxilanos ferulados son los principales polisacáridos no amiláceos de los granos de cereales, que se localizan en las paredes celulares del endospermo, en la capa aleurona y en el pericarpio de los mismos. Estos polisacáridos se han reportado en los cereales más importantes, como trigo (Triticum aestivum L.), centeno (Secale cereale L. M. Bieb.), cebada (Hordeum vulgare L.), avena (A. Sativa), arroz (Oryza sativa L.), sorgo (Sorghum vulgare), maíz (Zea mays L.) y mijo (Panicum miliaceum L.). Recientemente se han realizado esfuerzos enfocados a la extracción de arabinoxilanos ferulados a partir de subproductos de la industria procesadora de cereales, como de los pericarpios de maíz y de trigo, así como del "nejayote" que es el agua residual de la nixtamalización del maíz. Los arabinoxilanos ferulados forman soluciones viscosas y pueden formar geles bajo la acción de ciertos agentes oxidantes. Además, presentan características físico-químicas determinantes para su capacidad gelificante. Los geles de arabinoxilanos han despertado un gran interés debido a que presentan características interesantes como: olor y sabor neutro; estabilidad al pH, a los cambios de temperatura y de concentración de electrolitos; así como una estructura macroporosa. Estas características les confieren aplicación potencial como matrices para la liberación controlada de biomoléculas en aplicaciones alimentarias y no alimentarias, lo cual podría dar valor agregado a los cereales o subproductos de cereales de los cuales pueden ser extraídos estos polisacáridos. Esta revisión incluye los reportes más recientes sobre las características fisicoquímicas y la capacidad gelificante de arabinoxilanos ferulados, tema sobre el cual ha resurgido el interés en los últimos diez años. La generación de nuevo conocimiento sobre este polisacárido y sus geles podría sentar las bases para su aplicación en distintas áreas como la agroalimentaria, la biomédica y la cosmética, entre otras.

Three strains of Candida oleophila and their combination were evaluated for nutrient competition as a mode of action for the biocontrol of Penicillium expansum and Botrytis cinerea. C. oleophila treatments reduced germination of conidia of both pathogens when challenged on 1% 'Golden Delicious' apple juice. P. expansum conidia germination was 1x10(7) mL-1 and B. cinerea conidia germination was 5x10(5) mL-1. C. oleophila treatments lowered conidia germination from 2-7x10(4) mL-1 for P. expansum and from 1-4x10(4) for B. cinerea. C. oleophila treatments reduced conidia germination on an average of 99% for P. expansum and 96% for B. cinerea. Sugar consumption for L07 rugose was of 0.026 mg mL-1 against B. cinerea and of 0.056 mg mL¹ against P. expansum. Sugar consumption supports conidia germination reduction. P. expansum consumed 1.69 μg L-1 of proteins, while L07 rugose consumed the greatest amount with 47.95 μg L-1. B. cinerea consumed 8.95 μg L-1 and L06 consumed 36.89 μg L-1, which was statistically equal to that of L07 rugose with 27.96 μg L-1. C. oleophila strains biocontrol B. cinerea and P. expansum, in part, by nutrient competition.

Tres cepas de Candida oleophila y su combinación, se evaluaron para determinar la competencia por nutrientes, como modo de acción para el biocontrol de Penicillium expansum y Botrytis cinerea. Los tratamientos con C. oleophila redujeron la germinación de conidios de ambos patógenos, al ser enfrentadas en jugo de manzana 'Golden Delicious' al 1%. Conidios de P. expansum germinaron a 1x10(7) mL-1 y conidios de B. cinerea germinaron a 5x10(5) mL-1. Los tratamientos con C. oleophila disminuyeron la germinación de conidios de 2-7x10(4) mL-1 para P. expansum y de 1-4x10(4) para B. cinerea. Los tratamientos con C. oleophila redujeron la germinación de conidios con promedios de 99% para P. expansum y de 96% para B. cinerea. Los azúcares consumidos por L07 rugosa fueron de 0.026 mg mL-1 contra B. cinerea y de 0.056 mg mL-1 contra P. expansum. El consumo de azúcares corrobora la reducción de germinación de conidios. P. expansum consumió 1.69 μg L-1 de proteínas, mientras que L07 rugosa consumió la mayor cantidad con 47.95 μg L-1. B. cinerea consumió 8.95 μg L-1 y L06 36.89 μg L-1, que fue estadísticamente igual al de L07 rugosa con 27.96 μg L-1. Las cepas de C. oleophila, ejercieron un biocontrol de B. cinerea y P. expansum, en parte, por competencia de nutrientes.

Six Trichoderma spp. native strains were identified to specie and studied to determine their growth rate and antagonism against plant pathogen fungi. The strains were cultivated on Potato Dextrose Agar to determine their morphological characteristics and growth rate. Molecular analysis was carried out to identify their species. The antagonistic activity was tested by the dual cultures confrontation method. Although morphological characteristics of strains were similar to T. harzianum and T. viride, the molecular analysis showed that strains TC74, TC74M, T341, T359 and T479, were T. asperellum and T397 was T. longibrachiatum. Trichoderma strains mean growth rate at 25 °C ranged from 12 to 17 mmd-1. Inhibition of the B. cinerea growth ranged from 60% to 75% and mycelium overgrown from 25% to 100%. Inhibition of R. solani growth ranged from 34% to 52% and overgrown from 15% to 100%. Antagonistic activity of T. asperellum TC74, T341 and T359 was similar to reference strains T22 and Th. The same three strains inhibited the M. phaseolina growth from 44% to 64%, R. solani from 51% to 59%, P. omnivora 28% to 37% and Fusarium sp. 5%to 14%.

Seis cepas nativas de Trichoderma spp. se identificaron a especie y se determinó su tasa de crecimiento y antagonismo contra diferentes hongos fitopatógenos. Sus características morfológicas y tasa de crecimiento se determinaron cultivándolas en Papa Dextrosa Agar y mediante un análisis molecular se identificó la especie. El antagonismo fue evaluado mediante confrontación por cultivos duales. Morfológicamente las cepas fueron similares a T. harzianum y a T. viride; sin embargo, el análisis molecular identificó a TC74, TC74M, T341, T359 y T479, como T.asperellum y a T397 como T. longibrachiatum. La tasa de crecimiento promedio de las cepas a 25 °C varió de 12 a 17 mmd-1. La inhibición del crecimiento de B. cinerea varió 60% a 75% y el sobrecrecimiento sobre su micelio 25% a 100%. La inhibición de R. solani varió 34% a 52% y el sobrecrecimiento 15% a 100%. La actividad antagónica de T. asperellum TC74, T341 y T359 fue similar a las cepas de referencia T22 y Th. Estas tres cepas también inhibieron 44% a 64% el crecimiento de M. phaseolina, 51% a 59% el de R. solani, 28% a 37% el de P. omnivora y 5% a 14% el de Fusarium sp.