This work evaluates the effect of 1-methylcyclopropene (1-MCP) on postharvest and fermentation of Manzanilla cultivar, processed as Spanish-style or directly brined table olives. During postharvest ...handling, 1-MCP (2.85 µL/L) reduced the number of colour-turning olives by 18.42% over the untreated fruits. In Spanish-style and directly brined fermentation, the 1-MCP treatment led to lower pH levels, higher titratable acidities, improved firmness and colour olives than untreated fruits. A panel of expert testers also gave higher scores, and overall acceptability to the 1-MCP treated fruits, especially in the case of Spanish-style fermented olives. Metagenomic analysis of olive biofilms at the end of the fermentation process (176 days) revealed that Lactiplantibacillus was the most abundant bacterial genus in both Spanish-style and directly brined olives (>72%). However, fungal biodiversity was higher than bacterial in all treatments. Saccharomyces was the predominant yeast genus associated with directly brined olives (>97%), whilst Wickerhamomyces (>37%) and Zygoascus (>18%) were with Spanish-style fermentations. The 1-MCP treatment doubled the presence of Wickerhamomyces in Spanish-style fruits (74%) whilst reducing the presence of Zygoascus and allowing the growth of Enterobacter (15%) in directly brined olives. Thus, the postharvesting treatment of table olives with 1-MCP could help reduce the maturation progress of olives and improve the organoleptic and quality characteristics of the products without affecting the microbiological evolution of the fermentations.
Saccharomyces cerevisiae isolates from grapes, soil, vine bark and buds collected at seven phenological stages of an annual growth cycle, were molecular typed by Microsatellite Multiplex PCR. ...Subsequently 30 S. cerevisiae genotypes were selected and the effect of vineyard environmental stressors, in both sublethal upper and lower levels, on their growth parameters was evaluated. The effect of low and high temperature (7–40 °C), pH (2.5–8.0), glucose concentration (3.0–300.0 g/L), nitrogen concentration (0.008–8.0 g/L), and copper presence (24 mg/L) were modelled individually using the reparametrized Gompertz equation. Multivariate ANOVA and Generalized Procrustes Analysis were used to determine the environmental stressor's influence over the lag phase (λ) and the maximum specific growth rate (μmax). Both parameters were significantly affected by the S. cerevisiae genotype, the treatments, and the interaction between them. Despite a generalized reduction in μmax and a variable answer in λ, the 30 S. cerevisiae genotypes were able to overcome all the treatments. Extreme glucose limitation, copper presence and low temperature had the highest impact over the growth parameters. Interestingly, ten genotypes mostly distributed in the vineyard were the least affected, suggesting a greater acclimatization fitness and the possibility to persist in the changing conditions of the vine annual cycle.
•Growth parameters A, λ and μmax are genotype and stress treatments dependent.•Copper and low temperature stresses produce the most diverse response in the strains.•Ten repeatedly isolated genotypes showed better acclimatization in the vineyard.•Strains' phenotypic diversity would allow them to acclimatize in the vineyard.
The use of bacteriophages for killing pathogenic bacteria is a feasible alternative to antibiotics and disinfectants. To obtain the large quantities of phages required for this application, ...large-scale production of bacteriophages must be optimized. This study aims to define conditions that maximize the phage yield of the virulent and polyvalent staphylococcal bacteriophage vB_SauM-phiIPLA-RODI in broth culture, using the food-grade species Staphylococcus xylosus as the host strain to reduce the risk of growing massive quantities of pathogenic bacteria and therefore, to ensure the safety of the final phage stock. The effect of four variables, namely initial bacterial concentration (5.66-8.40 log
colony-forming unit (CFU)/mL), initial phage concentration (5-8 log
plaque-forming unit (PFU)/mL), temperature (21-40 °C) and agitation (20-250 rpm), on phage yield (response) was studied by using response surface methodology (RSM). Successive experimental designs showed that agitation did not significantly impact phage yield, while temperature did have a significant effect, with 38 °C being the optimum for phage propagation. The results allowed the design of a model to describe phage yield as a function of the initial bacterial and phage concentrations at fixed agitation (135 rpm), and optimum temperature (38 °C). The maximum experimental phage yield obtained was 9.3 log
PFU/mL, while that predicted by the model under the optimized conditions (7.07 log
CFU/mL initial bacterial population and 6.00 log
PFU/mL initial phage titer) was 9.25 ± 0.30 log
PFU/mL, with the desirability of 0.96. This yield is comparable to that obtained when the phage was propagated on the original host, Staphylococcus aureus. Bacteriophage phiIPLA-RODI showed the same host range and very similar biofilm removal ability regardless of the staphylococcal species used for its propagation. The results presented in this study show the suitability of using a food-grade strain of S. xylosus for the propagation of S. aureus infecting phages and the application of RSM to define the optimal propagation conditions.
This paper describes the dominant bacterial species metabolically active through the industrial production of Spanish-style Manzanilla and Gordal olives. For this purpose, samples (brines and fruits) ...obtained at 0, 15, and 90 fermentation days were analyzed by a culture-independent approach to determine viable cells by reverse transcription of RNA and further PCR-DGGE analysis, detecting at least 7 different species. Vibrio vulnificus, Lactobacillus plantarum group, and Lactobacillus parafarraginis were present in samples from both cultivars; Lactobacillus sanfranciscensis and Halolactobacillus halophilus were detected only in Gordal samples, while Staphylococcus sp. was exclusively found at the onset of Manzanilla fermentations. Physicochemical data showed a typical fermentation profile while scanning electron microscopy confirmed the in situ biofilm formation on the olive epidermis. Different Bacillus, Staphylococcus, and Enterococcus species, not detected during the fermentation process, were also found in the solid marine salt used by the industry for preparation of brines. Elucidation of these non-lactic acid bacteria species role during fermentation is then an appealingly challenge, particularly regarding safety issues.
: This work studies the effects of the initial brine concentrations of NaCl, KCl, and CaCl2 on the mineral content and gustatory and kinaesthetic sensations of fermented green table olives, using a ...simplex centroid mixture design augmented with interior points. The sodium in the flesh was linearly related to the mixture concentrations while potassium and calcium were linked by quadratic and special cubic models respectively. Acidity, saltiness, hardness, fibrousness, and crunchiness were expressed as linear funtions of the NaCl, KCl, and CaCl2 initial brine contents but bitterness required quadratic equations. The models can be used to produce table olives with specific mineral contents in the flesh and to predict their corresponding sensory characteristics.
Practical Application: The study provides the industry with models to estimate the Na, K, and Ca mineral contents in the flesh of fermented Gordal green table olives as well as their sensory characteristics as a function of the NaCl, KCl, and CaCl2 initial compositions in the brining solution. Therefore, the paper provides tools which are able to support the production of commercial presentations which not only satisfy consumer demand for low Na, but are also K and Ca fortified table olive presentations with specific sensory profiles.
Summary
Changes in the physicochemical and sensory characteristics of commercial plain (whole) and pitted ripe olives of the Gordal, Manzanilla, Hojiblanca and Cacereña cultivars were studied during ...a three‐year period in conditions that mimicking the storage of such products in real life. No spoilage was developed during this period. Throughout the shelf‐life, the pH of the cover brines had a marked valley decrease at the beginning of storage followed by a progressive further decline, the surface colour (measured instrumentally) and firmness of the olives followed a first‐order kinetic decay, mitigated according to the iron and calcium contents. Also, a slight browning of the cover brines at the beginning of the storage was observed. No significant changes in most of the sensory characteristics were observed by the panel test during shelf‐life except for a limited change in olive surface colour. At the end of the shelf‐life, most of the samples were classified as ‘extra’ category according to the IOC sensory evaluation method and only plain Gordal presentation was classified as ‘first, choice or select’.
The present work details the in vitro interactions between Lactobacillus pentosus and yeast strains isolated from table olive processing to form mixed biofilms. Among the different pairs assayed, the ...strongest biofilms were obtained from L. pentosus and Candida boidinii strain cocultures. However, biofilm formation was inhibited in the presence of d-(+)-mannose. In addition, biofilm formation by C. boidinii monoculture was stimulated in the absence of cell-cell contact with L. pentosus. Scanning electron microscopy revealed that a sort of "sticky" material formed by the yeasts contributed to substrate adherence. Hence, the data obtained in this work suggest that yeast-lactobacilli biofilms may be favored by the presence of a specific mate of yeast and L. pentosus, and that more than one mechanism might be implicated in the biofilm formation. This knowledge will help in the design of appropriate mixed starter cultures of L. pentosus-yeast species pairs that are able to improve the quality and safety of Spanish-style green table olive processing.
Spanish-style green table olive shelf-life SANCHEZ-GOMEZ, Antonio Higinio; GARCIA-GARCIA, Pedro; FERNANDEZ, Antonio Garrido
International journal of food science & technology,
August 2013, Letnik:
48, Številka:
8
Journal Article
Recenzirano
Summary
Changes in the physicochemical and sensory characteristics of commercial whole, pitted and stuffed with pepper, garlic or anchovy paste Spanish‐style green table olives of the Gordal, ...Manzanilla and Hojiblanca cultivars were studied during a three‐year period. No olives developed any spoilage during this period, and at the end of it, all presentations were classified as ‘extra’ according to the sensory evaluation methodology issued by the International Olive Council. Throughout the shelf‐life, surface colour index and firmness of the olives degraded in accordance with a first‐order kinetics, while a gradual browning of the cover brines was observed; however, products added with ascorbic acid maintained a stable colour, while those with calcium content showed reduced firmness degradation. No significant changes in most of the sensory characteristics were observed by the panel test during shelf‐life and only slight changes in firmness, and surface colour were noticed in samples with significant differences in these attributes when measured instrumentally.
•Convicted traffic offenders differ from no offenders in their psychosocial profile.•Road traffic offenders had similar psychosocial characteristics as other offenders.•Traffic offenders scored high ...on neuroticism–anxiety and activity personality traits.•Alcohol dependence was highly prevalent in the group of road traffic offenders.•The group of road traffic offenders scored high on the Driving Anger Scale.
There is very little information available about the characteristics of drivers convicted for traffic offences. The objective of this study was to perform a comparative analysis of the psychosocial characteristics of Spanish prison inmates convicted of road traffic offences (CRTOs), drivers serving a prison sentence for other types of offence (DCOOs), and drivers with no criminal record (DNCRs), in order to identify the psychosocial predictors associated with RTOs.
The study sample comprised 434 male participants divided into three groups: CRTO (n=240); DCOO (n=85); and DNCR (n=105). Instruments included an interview on sociodemographic data, driving behaviour, and past offences, as well as a set of tests to evaluate personality traits (ZKPQ-50CC), driving-related aspects (MDSI-S and DAS), and alcohol dependence (AUDIT).
A logistic regression analysis showed the following to be reliable predictors of RTOs: low education level (p<.05); having been involved in several road traffic accidents (p<.001); having received several fines (p<.001); a high score on the MDSI-S Risky subscale (p<.05); a low score on the MDSI-S Careful subscale (p<.05); AUDIT scores>8 (p<.05), and repeatedly driving whilst under the influence of alcohol (p<.05).
The results obtained have significant practical implications for designing and implementing traffic offenders programmes.
Table olives can suffer different types of spoilage during fermentation. In this work, a multi-statistical approach (standard and compositional data analysis) was used for the study of the volatile ...organic compounds (VOCs) associated with altered (butyric, sulfidic, and putrid) and non-altered (normal) Manzanilla Spanish-style table olive fermentations. Samples were collected from two industrial fermentation yards in Seville (Spain) in the 2019/2020 season. The VOC profiles of altered (n = 4) and non-altered (n = 6) samples were obtained by headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS). Ninety-one VOCs were identified and grouped into alcohols (30), esters (21), carbonyl compounds (12), acids (10), terpenes (6), phenols (6), sulfur compounds (2), and others (4). The association of the VOCs with spoilage samples depended on the standard or compositional statistical methodology used. However, butyric spoilage was strongly linked by several techniques to methyl butanoate, ethyl butanoate, and butanoic acid; sulfidic spoilage with 2-propyl-1-pentanol, dimethyl sulfide, methanol, 2-methylbutanal, 2-methyl-2-butenal, ethanol, 2-methyl-3-buten-2-ol, and isopentanol, while putrid was mainly related to D-limonene and 2-pentanol. Our data contribute to a better characterisation of non-zapatera spoiled table olive fermentations and show the convenience of using diverse statistical techniques for a most robust selection of spoilage VOC markers.
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