Enhancement of Textural and Sensory Characteristics of Wheat Bread Using a Chickpea Sourdough Fermented with a Selected Autochthonous Microorganism.

A traditional Greek sourdough, based on the fermentation of chickpea flour by an autochthonous culture, was evaluated as a wheat bread improver. The dominant indigenous microflora (Clostridium perfringens isolates) was identified by 16S rDNA analysis, and a selected strain (C. perfringens CP8) was employed to ferment chickpea flour to obtain a standardized starter culture (sourdough) for breadmaking. In accordance with toxin-typed strain identification, all isolates lacked the cpe gene; thus, there is no concern for a health hazard. Loaf-specific volumes increased with the addition of liquid, freeze-dried, and freeze-dried/maltodextrin sourdoughs compared to control bread leavened by baker's yeast only. Following storage (4 days/25 °C), the amylopectin retrogradation and crumb hardness changes (texture profile analysis) revealed a lower degree of staling for the sourdough-fortified breads. Modifications in the protein secondary structure of fortified doughs and breads were revealed by FTIR analysis. High amounts of organic acids were also found in the sourdough-supplemented breads; butyric and isobutyric acids seemed to be responsible for the characteristic 'butter-like' flavor of these products (sensory analysis). Overall, the addition of liquid or freeze-dried chickpea sourdough in wheat bread formulations can improve the specific volume, textural characteristics, and sensorial properties of loaves, along with extending bread shelf life.

Inclusion Complexes of ß-Cyclodextrin with Salvia officinalis Bioactive Compounds and Their Antibacterial Activities.

In the present study, the formation of molecular inclusion complexes of Salvia officinalis (sage) bioactive compounds with ß-cyclodextrin (ß-CD) was evaluated. Sage essential oil (SEO)/ß-CD inclusion complexes (ICs) were prepared by co-precipitation at iso-molecular concentrations, and Fourier transform infrared spectroscopy (FT-IR) was applied for the confirmation of the ICs' formation. Quantification of the SEO in the inclusion complexes was performed spectrophotometrically at 273 nm using an SEO standard curve. The SEO and its inclusion complexes were evaluated for their antimicrobial activity against Escherichia coli, Staphylococcus aureus and Listeria monocytogenes. The results showed that ß-CD effectively formed inclusion complexes with SEO in satisfactory yields. The antimicrobial activity of the SEO in prepared complexes with ß-CD was exhibited against L. monocytogenes and S. aureus and was proportional to their concentrations but was less pronounced.

A sourdough process based on fermented chickpea extract as leavening and anti-staling agent for improving the quality of gluten-free breads.

The use of a sourdough (SD) preparation based on a fermented chickpea extract (FCE) starter as a leavening and anti-staling agent in gluten-free breads was explored in this study. The FCE starter was prepared by a submerged fermentation (at 37 °C for 15 h) of coarsely ground chickpeas and the gluten-free bread formulations, based on rice and corn flours, were made using a rice sourdough produced with the FCE starter as additional leavening agent; the FCE-SD breads and samples containing merely baker's yeast as microbial leavener (control) were both prepared at three different levels of added water, i.e., 85, 92 and 100% (flour weight basis). The loaf specific volume significantly (p < 0.05) increased with sourdough inclusion into batters and by increasing the amount of added water. Moreover, inclusion of sourdough into the gluten-free formulations resulted in a finer porous crumb macrostructure and a lower crust moisture content than control breads. Upon bread storage (25 °C for 5 days), water migration from crumb to crust was noted. Staling events were also monitored by compression testing and differential scanning calorimetry, showing an increase in crumb firmness and the apparent melting enthalpy (ΔH) of retrograded amylopectin during bread storage; the values for both parameters decreased with inclusion of FCE-SD and with higher amounts of added water into the gluten-free formulations. Kinetic data in modelling crumb firmness and ΔH values by linear regression analysis and the Avrami equation, respectively, revealed a slower staling rate for breads with sourdough, compared to control formulations; moreover, with increasing level of added water to the batter, the firming rate was reduced, while the amylopectin retrogradation was enhanced. Finally, in vitro enzymatic starch digestibility of the crumb was lower for staled breads stored for 5 days, compared to fresh products, while there was no pronounced effect by sourdough inclusion. Overall, the incorporation of FCE-SD into gluten-free bread formulations seems to be a promising alternative for improving quality and extending the shelf life of gluten-free baked products.

A natural approach in food preservation: Propolis extract as sorbate alternative in non-carbonated beverage.

Propolis extract was investigated as potential substitute for sorbate in orangeade. Extract was prepared by using aqueous solution of hydroxypropyl-beta-cyclodextrins. Propolis extract was incorporated in non-carbonated orange soft drinks and its antioxidant activity, microbiological stability and color changes were estimated and compared to those of orangeade containing potassium sorbate. l-Ascorbic acid (AsA) degradation at concentrations 0.13 and 1.3% w/w was investigated in the presence of propolis during storage using High Performance Liquid Chromatography-Ion Exclusion Column (HPLC-IEC). The results indicate that the rate of degradation decreased with an increase in ascorbic acid concentration, while addition of propolis affected the degradation rate of samples containing a high AsA concentration. The antifungal effect of propolis extract, potassium sorbate and their combination was assayed. Results showed the inhibition of Aspergillus spp. and B. bruxellensis inhibited in low combined concentrations antimicrobials, while Aspergillus spp. and T. macrosporus were inhibited at 450 mg/g propolis extract.

Sulfur dioxide response of Brettanomyces bruxellensis strains isolated from Greek wine.

Brettanomyces bruxellensis is the most common spoilage wine yeast which can provoke great economic damage to the wine industry due to the production of undesirable odors. The capacity of the species to adapt in various environmental conditions offers a selective advantage that is reflected by intraspecific variability at genotypic and phenotypic level. In this study, microsatellite analysis of 22 strains isolated from Greek wine revealed the existence of distinct genetic subgroups that are correlated with their geographical origin. The response of these strains to increasing levels of sulfur dioxide confirmed the presence of both sensitive and tolerant strains, which belong to distinguished genetic clusters. The genetic categorization of B. bruxellensis strains could be used by the winemakers as a diagnostic tool regarding sulfur dioxide sensitivity.

A comparison for acid production, proteolysis, autolysis and inhibitory properties of lactic acid bacteria from fresh and mature Feta PDO Greek cheese, made at three different mountainous areas.

Isolates of NSLAB were obtained from fresh (58 isolates) and mature (38) Feta cheese made at household level in three different mountainous areas, in order to study the effect of the area of production on NSLAB composition and their technological characteristics. Results obtained by SDS-PAGE of whole-cell proteins indicated that the microflora of the fresh cheese was composed of either lactococci (areas 1, 2), or lactococci and enterococci (area 3). The NSLAB microflora of mature cheese was composed almost entirely of lactobacilli species, differing according to the area of production. Species allocation by the SDS-PAGE method was confirmed by sequencing representative strains. Lactococci of cheese made in area 1 exhibited a narrow spectrum of antibacterial activity compared to isolates from areas 2 and 3, while for lactobacilli from all three areas a similar spectrum was noticed. Lactococci from area 2 exhibited higher (P<0.05) mean acidifying activity than lactococci from area 1. The isolates from the three areas also differed in respect of their caseinolytic activity, with preferences towards ß-CN (areas 1 and 2) or αs-CN (area 3). Mean proteolytic activity of lactococci from area 1 was stronger (P<0.05) than that of lactococci from area 2 and the same was observed for their mean aminopeptidase activity, as well as their extent of autolysis at pH5.1. Mean acidifying activity of lactobacilli after 6h was for strains of area 3>2=1. The strains from areas 1 and 3 degraded preferentially αs-CN, while a clear preference towards ß-CN was noticed for strains of area 2; their mean proteolytic activity was for strains of area 1 higher (P<0.05) than strains from area 3. The above results suggest that cheeses from the three areas differ in species composition of NSLAB and their technological properties. Principal component analysis of results on acidifying and proteolytic activities as well as autolysis allowed the distinction of lactococci according to their derivation area enabling the selection of appropriate strains as starters for cheese production in each area.

Selection of dominant NSLAB from a mature traditional cheese according to their technological properties and in vitro intestinal challenges.

Isolates (47) of lactobacilli from 5 different productions of Melichloro cheese were examined for potential use as adjunct cultures. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of whole-cell proteins classified 29 isolates as L. paraplantarum and 18 as L. paracasei subsp. paracasei. Randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) analysis differentiated the L. paraplantarum and L. paracasei subsp. paracasei isolates at strain level and both, RAPD analysis and whole-cell protein profiling provided useful information about the diversity of nonstarter lactic acid bacteria (NSLAB) in the different cheese productions. The isolates were slow acidifiers and about 70% of them degraded, preferentially α(s)-casein. The amounts of amino acids accumulated in the milk increased with the incubation time. A similar enzyme profile was exhibited by strains of both species, except for α-mannosidase and α-fucosidase, which were not detected in the L. paracasei subsp. paracasei strains. All strains grew in the presence of bile at 0.3% and the majority was able to withstand pH 2.5 and pancreatin at 0.1%. Moreover, all strains reduced cholesterol in vitro, with higher removal ability recorded for strains of L. paraplantarum. A narrow spectrum of antibacterial activity was recorded for 88% of the strains. Selected isolates with appropriate technological and interesting in vitro intestinal challenges could be used as adjuncts and deserve further studies.

Preservation of pears in water in the presence of Sinapis arvensis seeds: a Greek tradition.

In this research, the microbiological and physicochemical changes during preservation of pears in water in the presence of Sinapis arvensis seeds (PWS FL) according to the traditional Greek home food manufacture were studied. Pears preserved in water served as control (PW FL). The growth of lactic acid bacteria (LAB) coming from the pear surface was enhanced in the presence of Sinapis seeds, while Enterobacteriaceae and Gram-negative bacteria declined coincidently with the lower (P<0.05) pH of the PWS FL. LAB predominated over the other microbial groups in the fermentation liquids (FLs) of both systems. All the 49 LAB isolates from one fermentation experiment were identified as Leuconostoc mesenteroides subsp. cremoris by the SDS-PAGE of whole-cell proteins, while RAPD-PCR fingerprinting and partial 16S rRNA sequence determination of selected isolates did not discriminate them at the subspecies level. Fruit preserved in PWS FL had higher titratable or volatile acidity, phenolic compounds or antioxidant capacity as well as lower pH and firmness than the control fruit. All physicochemical parameters of the FLs increased except of the pH which decreased. Coincidently with higher population of LAB in PWS FL the levels of citric, lactic and acetic acid were higher than in control. Oxalic acid and related unknown substances were found at higher levels in PWS FL than the control and may be the agent(s) enhancing the growth of LAB and/or contributing partially to the decline of Enterobacteriaceae. The organoleptic test showed that fruit preserved in PWS FL had better overall acceptance than the control, and that it retained most of the positive traits.

Differentiation of lactococci from 2 Greek cheeses with protected designation of origin by phenotypic criteria and RAPD-PCR.

Seventy-six lactococci isolates from 2 protected designation of origin (PDO) cheeses were studied for their acidification ability, proteolytic activity, and inhibitory activities as well as their intraspecies characterization by randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR). Fifty-two of them were characterized as Lactococcus lactis subsp. lactis by the SDS-PAGE of whole-cell proteins. The test strains increased the amount of acid in milk from 6 to 24 h as well as the quantities of amino acids on incubation for 4 d. The majority of the isolates degraded preferentially αs-casein. The isolates from Feta differed from those of Graviera Kritis in respect of ß-casein degradation. This fragment was either not degraded or underwent a small degradation by lactococci from Feta. A stronger intensity of acidification for the isolates from Feta and a higher casein breakdown ability for those from Graviera Kritis were also recorded. Lactococci from Feta and Graviera Kritis inhibited, preferentially, the growth of Escherichia coli O157:H7, and Yersinia enterocolitica, respectively. A high heterogeneity among the isolates according to RAPD-PCR was determined, as well as grouping of the isolates according to their source of isolation. Selected isolates from each cheese could be used as starters to make either Feta or Graviera Kritis.