Rheological and Sensory Evaluation of Wheat Flour Tortillas During Storage

Texture of wheat flour tortillas over 15 days at room temperature was evaluated using an expert sensory panel, consumer panels, subjective rollability test, large deformation rheological methods (i.e., bending, extensibility [1‐D and 2‐D], and puncture tests), and stress relaxation method. Most of the changes in texture occurred during the initial 8 days of storage, while texture of tortillas changed slowly thereafter. Differences in texture between fresh and 1‐day‐old tortillas were detected by many objective rheological methods but not by either sensory panel. The expert sensory panel observed a rapid decrease in tortilla extensibility and an increase in staleness between 1 and 8 days of storage and smaller changes in sensory scores after 8 days of storage. Most objective rheological parameters changed rapidly between 0 and 5 days, and slowly after 5 days of storage. Significant correlations and factor analysis reveal that changes occurring in flour tortillas during staling are estimated better by subjective rollability, sensory evaluation (expert and consumer panels), and 2‐dimensional extensibility test than by other methods. Hence, some rheological methods are useful to estimate sensory properties of flour tortillas.     

Per os challenge of Litopenaeus vannamei postlarvae and Farfantepenaeus duorarum juveniles with six geographic isolates of white spot syndrome virus

White spot syndrome virus (WSSV) is one of the most important pathogens of penaeid shrimp. It is widely distributed in most Asian countries where penaeid shrimp are cultured, as well as in the Gulf of Mexico and SE USA. The virulence of six geographic isolates of WSSV was compared using Litopenaeus vannamei postlarvae and Farfantepenaeus duorarum juveniles. The six geographic isolates of WSSV originated from China, India, Thailand, Texas, South Carolina, as well as from crayfish maintained at the USA National Zoo. For challenge studies, virus infected tissues were given per os to L. vannamei postlarvae and Fa. duorarum juveniles. Resultant WSSV infections were confirmed by histological examination. The cumulative mortality of L. vannamei postlarvae reached 100% after challenge with each of the six geographic isolates of WSSV. However, the Texas isolate caused mortalities more rapidly than did the other shrimp isolates; the crayfish WSSV isolate was the slowest. In marked contrast, cumulative mortalities of juvenile Fa. duorarum reached only 35–60%, and varied among the geographic isolates of WSSV. Interestingly, in Fa. duorarum, the Texas WSSV isolate was also the most virulent, while the crayfish WSSV was the least virulent. The findings suggest that slight differences in virulence exist among geographic isolates of WSSV, and that susceptibility may vary with species and lifestages of the host.     

Genetic variability and diversity for protein and calcium contents in finger millet (Eleusine coracana (L.) Gaertn) in relation to grain color

Analysis of 36 genotypes of finger millet ( Eleusine coracana (L.) Gaertn) with varying seed colors revealed a wide range of protein and calcium contents. White seeded genotypes had higher protein contents, while brown seeded types had a wide range of values. The brown seeded genotype GE 2500 had the highest protein content. Although protein content had significant negative association with calcium content, white seeded types had moderate levels of calcium. The genotypic coefficients of variability were moderate and high for protein and calcium, respectively. High heritability coupled with high genetic advance indicated their governance by additive gene action. A negative significant correlation was observed between protein content and grain yield. Mahalanobis D 2 analysis grouped the 36 genotypes into eight clusters. Clustering pattern failed to indicate any relationship between genetic diversity and geographic diversity. Based on genetic diversity and performance, the genotypes MS 1168, MS 174 and CO 13 were found to be suitable for use as parents in a hybridization program for improving yield; the genotypes MS 1168, MS 174 and MS 2869 for protein and Malawi 1915 and CO 11 for calcium. Protein and calcium contents contributed less to genetic divergence.     

Contaminant seeds in imported crop seed lots: a non‐negligible human‐mediated pathway for introduction of plant species to islands

Contaminant seeds in crop seed lots constitute a pathway for plant species introduction into new areas, and these non‐native weeds may be an environmental problem if they become invasive. Seed certification is a process that regulates and guarantees the quality of seed lots, including their purity. In this study, we assessed weed contamination in certified and non‐certified seed lots (n = 116) from 12 crop species commonly cultivated in the Balearic Islands. Contaminant seeds were separated using sieves, and then manually under a stereomicroscope, before they were germinated to confirm taxonomic identity. Weight, number and diversity of the contaminant seeds per kilogram of seed lot, number released per hectare according to sowing rate, and taxonomic identity and biogeographical origin of contaminant species were recorded. Although certification reduced the number of contaminant seeds in the seed lots, it did not entirely eliminate contaminants, because we found up to 2000 contaminant seeds kg^?1 of certified ryegrass and sulla. Overall, contaminant seeds represented 118 taxa; of which, 82 were identified to species level, 70% of species were native, 19% were cultivated, and 11% were non‐native. Two of the identified taxa were first records for the Balearic Islands. In conclusion, contaminant seeds in imported crop seed lots represent a non‐negligible pathway for plant species introduction.     

Microwave-Assisted Extraction of Phlorotannins from Fucus vesiculosus

Microwave-assisted extraction (MAE) was carried out to maximize the extraction of phlorotannins from Fucus vesiculosus using a hydroethanolic mixture as a solvent, as an alternative to the conventional method with a hydroacetonic mixture. Optimal MAE conditions were set as ethanol concentration of 57% (v/v), temperature of 75 °C, and time of 5 min, which allowed a similar recovery of phlorotannins from the macroalgae compared to the conventional extraction. While the phlorotannins richness of the conventional extract was slightly superior to that of MAE (11.1 ± 1.3 vs. 9.8 ± 1.8 mg PGE/g DW_extract), both extracts presented identical phlorotannins constituents, which included, among others, tetrafucol, pentafucol, hexafucol, and heptafucol structures. In addition, MAE showed a moderate capacity to scavenge ABTS^•+ (IC₅₀ of 96.0 ± 3.4 µg/mL) and to inhibit the activity of xanthine oxidase (IC₅₀ of 23.1 ± 3.4 µg/mL) and a superior ability to control the activity of the key metabolic enzyme α-glucosidase compared to the pharmaceutical drug acarbose.     

Expression of the Antimicrobial Peptide Piscidin 1 and Neuropeptides in Fish Gill and Skin: A Potential Participation in Neuro-Immune Interaction

Antimicrobial peptides (AMPs) are found widespread in nature and possess antimicrobial and immunomodulatory activities. Due to their multifunctional properties, these peptides are a focus of growing body of interest and have been characterized in several fish species. Due to their similarities in amino-acid composition and amphipathic design, it has been suggested that neuropeptides may be directly involved in the innate immune response against pathogen intruders. In this review, we report the molecular characterization of the fish-specific AMP piscidin1, the production of an antibody raised against this peptide and the immunohistochemical identification of this peptide and enkephalins in the neuroepithelial cells (NECs) in the gill of several teleost fish species living in different habitats. In spite of the abundant literature on Piscidin1, the biological role of this peptide in fish visceral organs remains poorly explored, as well as the role of the neuropeptides in neuroimmune interaction in fish. The NECs, by their role as sensors of hypoxia changes in the external environments, in combination with their endocrine nature and secretion of immunomodulatory substances would influence various types of immune cells that contain piscidin, such as mast cells and eosinophils, both showing interaction with the nervous system. The discovery of piscidins in the gill and skin, their diversity and their role in the regulation of immune response will lead to better selection of these immunomodulatory molecules as drug targets to retain antimicrobial barrier function and for aquaculture therapy in the future.