Hyperspectral Imaging to Evaluate the Effect of IrrigationWater Salinity in Lettuce

Salinity is one of the most important stress factors in crop production, particularly in arid regions. This research focuses on the effect of salinity on the growth of lettuce plants; three solutions with different levels of salinity were considered and compared (S1 = 50, S2 = 100 and S3 = 150 mM NaCl) with a control solution (Ct = 0 mM NaCl). The osmotic potential and water content of the leaves were measured, and hyperspectral images of the surfaces of 40 leaves (10 leaves per treatment) were taken after two weeks of growth. The mean spectra of the leaves (n = 32,000) were pre-processed by means of a Savitzky–Golay algorithm and standard normal variate normalization. Principal component analysis was then performed on a calibration set of 28 mean spectra, yielding an initial model for salinity effect detection. A second model was subsequently proposed based on an index computing an approximation to the second derivative at the red edge region. Both models were applied to all the hyperspectral images to obtain the corresponding artificial images, distinguishing between the 28 that were used to extract the calibration mean spectra and the rest that constituted an external validation. Those virtual images were studied using analysis of variance in order to compare their ability for detecting salinity effects on the leaves. Both models showed significant differences between each salinity level, and the hyperspectral images allowed observations of the distribution of the salinity effects on the leaf surfaces, which were more intense in the areas distant from the veins. However, the index-based model is simpler and easier to apply because it is based solely on the reflectance at three different wavelengths, thus allowing for the implementation of less expensive multispectral devices.The funding of this work was supported by the MICINN through projects Multihort (AGL2008-05666-C02-01) and QualityLeaf (AGL2013-48529-R). LPF-TAGRALIA is part of the CEI Moncloa Campus. We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI)

Innovative and sustainable solutions to reduce postharvest losses

Postharvest research must enable us to translate fundamental knowledge into innovative and sustainable solutions to reduce postharvest losses. These include genetic improvements by selecting cultivars with good flavour and texture and long postharvest life, sensor improvements to monitor and control the ripeness and the optimal maturity for harvest, and improvements in quality control and storage conditions. New packaging technologies using biodegradable and recycled materials are promising solutions for helping with environmental sustainability. However, they should also be adequate for fresh produce quality maintenance. The innovative actions should combine appropriate optimal temperature and relative humidity during storage, transport, and distribution to create the desired conditions around the commodity for freshness preservation. To achieve these goals, collaborative actions that integrate all the aspects related to postharvest losses are needed starting from the agricultural production activities to processing, marketing, distribution, and even consumers

Quality improvement of Pleurotus mushrooms by modified atmosphere packaging and moisture absorbers

11 pages, 7 tables, 3 figures.Quality of Pleurotus ostreatus mushrooms was compared during cold storage under various temperatures and modified atmospheres with and without moisture absorbers. CO2 production followed a non-climacteric pattern and was about 0.50, 0.99 and 1.23 μmol CO2 kg−1 s−1 at 0, 4 and 7 °C, respectively, after 12 h. At the end of 11 days of storage, the respiration rates were very similar for all the assayed temperatures (±0.37 μmol CO2 kg−1 s−1). The best mushroom appearance was found at 0 °C, although for optimizing modified atmosphere packaging (MAP), 4 °C was selected to minimize low-temperature damage. When prolonging the storage beyond 7 days, quality characteristics dropped sharply and the mushrooms were not marketable, except when kept at 0 °C. Therefore, 7 days was the maximum recommended storage period for Pleurotus mushrooms. MAP at 4 °C for 7 days was created using microperforated polypropylenes (MPP1 and MPP2), low-density polyethylene (LDPE) and polyvinyl chloride (PVC) films. Results were compared with macroperforated polypropylene (PP) control packages. In order to avoid condensation, sorbitol and silica gel were used to modify the in-package relative humidity. Moisture absorbers did not modify the gas composition of the packages. Sorbitol promoted tissue leakage and cannot be recommended. Lower relative humidity was observed in packages containing silica gel and this did not affect the quality of the mushrooms. However, increasing amounts of silica gel increased weight loss in Pleurotus mushrooms, and high weight loss detected in PP packages made these unacceptable. MAP (15 kPa O2+5 kPa CO2) was found beneficial for maintaining acceptable quality of Pleurotus for 7 days at 4 °C.The authors are grateful to UE, Project EUCRAFT QLK5-CT-1999-70010 for financial support.Peer reviewe

Quality improvement of Pleurotus mushrooms by modified atmosphere packaging and moisture absorbers

11 pages, 7 tables, 3 figures.Quality of Pleurotus ostreatus mushrooms was compared during cold storage under various temperatures and modified atmospheres with and without moisture absorbers. CO2 production followed a non-climacteric pattern and was about 0.50, 0.99 and 1.23 μmol CO2 kg−1 s−1 at 0, 4 and 7 °C, respectively, after 12 h. At the end of 11 days of storage, the respiration rates were very similar for all the assayed temperatures (±0.37 μmol CO2 kg−1 s−1). The best mushroom appearance was found at 0 °C, although for optimizing modified atmosphere packaging (MAP), 4 °C was selected to minimize low-temperature damage. When prolonging the storage beyond 7 days, quality characteristics dropped sharply and the mushrooms were not marketable, except when kept at 0 °C. Therefore, 7 days was the maximum recommended storage period for Pleurotus mushrooms. MAP at 4 °C for 7 days was created using microperforated polypropylenes (MPP1 and MPP2), low-density polyethylene (LDPE) and polyvinyl chloride (PVC) films. Results were compared with macroperforated polypropylene (PP) control packages. In order to avoid condensation, sorbitol and silica gel were used to modify the in-package relative humidity. Moisture absorbers did not modify the gas composition of the packages. Sorbitol promoted tissue leakage and cannot be recommended. Lower relative humidity was observed in packages containing silica gel and this did not affect the quality of the mushrooms. However, increasing amounts of silica gel increased weight loss in Pleurotus mushrooms, and high weight loss detected in PP packages made these unacceptable. MAP (15 kPa O2+5 kPa CO2) was found beneficial for maintaining acceptable quality of Pleurotus for 7 days at 4 °C.The authors are grateful to UE, Project EUCRAFT QLK5-CT-1999-70010 for financial support.Peer reviewe

Effect of Processing Techniques at Industrial Scale on Orange Juice Antioxidant and Beneficial Health Compounds

8 pages, 4 figures, 2 tables.Phenolic compounds, vitamin C (l-ascorbic acid and l-dehydroascorbic acid), and antioxidant capacity were evaluated in orange juices manufactured by different techniques. Five processes at industrial scale (squeezing, mild pasteurization, standard pasteurization, concentration, and freezing) used in commercial orange juice manufacturing were studied. In addition, domestic squeezing (a hand processing technique) was compared with commercial squeezing (an industrial FMC single-strength extraction) to evaluate their influences on health components of orange juice. Whole orange juice was divided into soluble and cloud fractions after centrifugation. Total and individual phenolics were analyzed in both fractions by HPLC. Commercial squeezing extracted 22% more phenolics than hand squeezing. The freezing process caused a dramatic decrease in phenolics, whereas the concentration process caused a mild precipitation of these compounds to the juice cloud. In pulp, pasteurization led to degradation of several phenolic compounds, that is, caffeic acid derivatives, vicenin 2 (apigenin 6,8-di-C-glucoside), and narirutin (5,7,4‘-trihydroxyflavanone-7-rutinoside) with losses of 34.5, 30.7, and 28%, respectively. Regarding vitamin C, orange juice produced by commercial squeezing contained 25% more of this compound than domestic squeezing. Mild and standard pasteurization slightly increased the total vitamin C content as the contribution from the orange solids parts, whereas concentration and freezing did not show significant changes. The content of l-ascorbic acid provided 77−96% of the total antioxidant capacity of orange juice. Mild pasteurization, standard pasteurization, concentration, and freezing did not affect the total antioxidant capacity of juice, but they did, however, in pulp, where it was reduced by 47%.This work has been funded by a Spanish CICYT (Comisión Interministerial de Ciencia y Tecnología) grant, Projects ALI98-0843 and AGL2001-1125. A.G.I. is holder of a predoctoral grant from the Spanish Ministry of Education and Culture.Peer reviewe

Overview of Hazards in Fresh‐Cut Produce Production: Control and Management of Food Safety Hazards

El capítulo 6 (Overview of Hazards in Fresh-Cut Produce Production: Control and Management of Food Safety Hazards) es una guía que describe y analiza los riesgos en la producción de productos frescos mínimamente procesados y cómo gestionar la seguridad de dichos productosThis chapter contains sections titled: • Fresh‐Cut Products • Food Safety Systems in the Fresh‐Cut Produce Industry • Fresh‐Cut Produce Production • Potential Microbial Risk of Fresh‐Cut Product Operation • Strategies to Reduce or Eliminate Hazards in Fresh‐Cut Products • Conclusions • ReferencesPeer reviewe

Procedimiento para la conservación de semillas de granada en fresco

Referencia OEPM: P9502362.-- Fecha de solicitud: 29/11/1995.-- Titular: Consejo Superior de Investigaciones Científicas (CSIC).El objeto de la presente invención es un procedimiento para la conservación de semillas de granada en fresco, mediante el cual se preserva la calidad inicial de la semilla de la granada, una vez separada del resto del fruto para facilitar su consumo directo. El procedimiento de la invención incluye el proceso de preparación de semillas frescas embolsadas así como el método para conservar las semillas (granos) de granada.Peer reviewe

Peroxyacetic acid and chlorine dioxide unlike chlorine induce viable but non-culturable (VBNC) stage of Listeria monocytogenes and Escherichia coli O157:H7 in wash water

The elaboration of guidelines for the industry to establish minimum concentration to prevent cross-contamination during washing practices based on operational limits is the core of the recommended criteria for the use of sanitizers. Several studies have evidenced that sanitizers reduced the levels of foodborne pathogens. However, they might lead to the progress into a viable but non-culturable (VBNC) state of the cells. This evidence has raised concerns regarding the effectiveness of the recommended washing practices for the inactivation of microbial cells present in the process wash water (PWW). The present study evaluated if the most commonly used sanitizers, including sodium hypochlorite (chlorine), peroxyacetic acid (PAA) and chlorine dioxide (ClO) at established operational limits induced the VBNC stage of Listeria monocytogenes and Escherichia coli O157:H7. Prevention of cross-contamination was examined in four different types of PWW from washing shredded lettuce and cabbage, diced onions, and baby spinach under simulated commercial conditions of high organic matter and 1 min contact time. The results obtained for chlorine showed that recommended operational limits (20–25 mg/L free chlorine) were effective in inactivating L. monocytogenes and E. coli O157:H7 in the different PWWs. However, the operational limits established for PAA (80 mg/L) and ClO (3 mg/L) reduced the levels of culturable pathogenic bacteria but induced the VBNC state of the remaining cells. Consequently, the operational limits for chlorine are satisfactory to inactivate foodborne pathogens present in PWW and prevent cross-contamination but higher concentrations or longer contact times should be needed for PAA and ClO to reduce the likelihood of the induction of VBNC bacteria cells, as it represents a hazard.The authors are thankful for the financial support from, Center for Produce Safety, and CSIC (Intramural 201670E056). Support provided by the Fundación Séneca (19900/GERM/15) was also appreciated. P. Truchado is holding a Ramón y Cajal contract from the Ministerio de Ciencia e Innovació

Nuevas Tendencias de Procesado y Conservación de Alimentos Vegetales de IV Gama

La OTRI del Centro Tecnológico Nacional de la Conserva y Alimentación junto con la OTT del Consejo Superior de Investigaciones Científicas, colaboran en el Proyecto AGROCSIC, el cual fue aprobado por el Ministerio de Ciencia y Tecnología y financiado por el Ministerio de Educación y Ciencia. El objetivo principal de esta nueva actuación es estudiar las distintas líneas de trabajo de los Centros del CSIC relacionadas con la alimentación, para transferir sus resultados al sector industrial.Los productos de IV gama están teniendo cada vez más importancia en nuestro país, debido al aumento del consumo de frutas y hortalizas que son claves en la dieta mediterránea, así como también debido a que son alimentos preparados y listos para su consumo o cocinado.Trabajo desarrollanoen el marco del proyecto "Control de microorganismos alteradores y patógenos bacterianos en productos vegetales de IV gama" (AGL2004-03060) financiado por el Ministerio de Educación y Ciencia.Peer reviewe