The influence of protein concentration on key quality attributes of chickpea-based alternatives to cheese.

In response to consumer demands, plant protein ingredients are increasingly being used in the formulation of plant-based alternatives to cheese. The aim of this study was to determine the influence of protein concentration on key quality attributes of chickpea-based alternatives to cheese. Moreover, the age-induced changes in such attributes were assessed, with samples analysed after 1 month of storage. After characterisation of the ingredients, the chickpea-based formulations were prepared by blending chickpea flour and protein concentrate in different proportions to obtain four samples of increasing protein content (i.e., 8.68-21.5%). Formulations were developed at pH ∼4.5, and a moisture content of 50%, with shea butter used to obtain 15% fat content. The differential scanning calorimetry thermograms of the samples showed a main peak around 30 °C, corresponding to transition of the shea butter, and a smaller peak around 70 °C related to starch gelatinisation. Analysis of microstructure showed formation of a protein matrix with more extensive protein structure at high protein concentration. Furthermore, none of the chickpea-based samples melted under the testing conditions and all samples showed increasing values for adhesiveness, springiness and cohesiveness with increasing protein content. However, hardness was the highest for the sample with the lowest protein content, likely due to starch retrogradation. After storage, hardness increased further for all samples. This work improves our understanding of the role of chickpea protein in developing plant-based alternatives to cheese and the challenges therein.

Correlation analysis of protein quality characteristics with gluten-free bread properties.

The interest in gluten-free cereal products has increased significantly over the last number of years and there is still a high demand for high quality products. This study aims to establish possible connections between protein properties and dough and bread quality which could advance the knowledge for gluten-free product development. The objective of the present study was to correlate protein properties with bread characteristics. Therefore, a wide range of tests (solubility, emulsifying, foaming, water hydration properties) was performed to characterize a range of food proteins (potato, pea, carob, lupin and soy). Furthermore, the performance of these proteins in a dough matrix (pasting, rheology) and bread formulation (volume, structure, and texture) was analysed. Statistical analysis showed significant (p < 0.05) correlations between protein properties, dough properties and final bread characteristics. The addition of the proteins to the gluten-free bread formulation affected pasting rheological and bread characteristics such as crumb density, crumb hardness and specific volume. The addition of potato and soy protein resulted in the lowest volume with a dense crumb structure and a low consumer acceptance score. However, lupin, pea and carob containing gluten-free breads had a higher specific volume and softer and less dense crumb structure. The protein solubility (r, 0.89; p < 0.01) and its foaming properties (r, 0.97; p < 0.05) were found to be the most important protein properties with correlations significantly with dough properties and bread quality.

Control of Zymoseptoria tritici cause of septoria tritici blotch of wheat using antifungal Lactobacillus strains.

AIMS: This study explored an effective biological control agent based on lactic acid bacteria culture or culture supernatant, which was effective against fungicide-resistant Zymoseptoria tritici, which causes septoria tritici blotch (STB). METHODS AND RESULTS: Three lactic acid bacteria strains which exhibited broad antifungal activity were investigated for their potential to control Z. tritici. Plate assays, liquid culture growth inhibition assays and STB biocontrol seedling tests were employed. Lactobacillus brevis JJ2P and Lactobacillus reuteri R2 caused significant fungal inhibition as observed by large mycelium clearing on modified MRS agar. Cell-free culture supernatants of Lact. brevis JJ2P and Lact. reuteri R2 showed antifungal activity against Z. tritici, as observed by mycelial radial growth inhibition and liquid culture growth inhibition. Cell-free supernatants of these anti-Z. tritici LAB strains were assessed in vivo for their abilities to inhibit STB development in seedling tests. Lact. brevis JJ2P was capable of inhibiting disease development and significantly reduced the diseased leaf area covered with pycnidia. CONCLUSIONS: Biological control accomplished by beneficial micro-organisms such as Lact. brevis JJ2P may represent an alternative control strategy for reducing STB. SIGNIFICANCE AND IMPACT OF THE STUDY: Globally, STB is regarded as one of the most important diseases of wheat. Control of Z. tritici is heavily reliant on fungicide application. The recent emergence of resistance or reduced sensitivity to fungicides among Z. tritici populations has urgently called for the development of new control strategies.

Modelling the effects of orange pomace using response surface design for gluten-free bread baking.

The development of gluten-free bread creates many challenges; producing bread that will match the properties of its wheat counterpart can be difficult. Fruit by-products are know from literature to contain a high level of dietary fibre which could improve the bread properties and fibre contents of gluten-free bread. Therefore, a mathematical design was created; three variables were identified from preliminary tests (water (85-100% flour weight, OP 0-8% flour weight and proofing time 35-100 min) as being crucial in the development of acceptable bread. Results illustrated longer proofing times (p<0.05) and lower orange pomace levels (OP) (p<0.001) produced a bread with a greater specific volume. OP had the most significant (p<0.0001) effect on hardness at 2h and 24h post-baking. The optimised formulation was calculated to contain 5.5% OP, 94.6% water and a proofing time of 49 min. Total fibre content of the control bread (2.1%) was successfully increased t o 3.9% in the OP containing bread. Substituting gluten-free flours with orange pomace flour can help improve the total dietary intake of a coeliac while not negating on the quality properties of the bread.

In situ production of human ß defensin-3 in lager yeasts provides bactericidal activity against beer-spoiling bacteria under fermentation conditions.

AIMS: To examine the use of a natural antimicrobial peptide, human ß-defensin-3 (HBD3), as a means of preventing spoilage from bacterial contamination in brewery fermentations and in bottled beer. METHODS AND RESULTS: A chemically synthesised HBD3 peptide was tested for bactericidal activity against common Gram-positive and Gram-negative beer-spoiling bacteria, including species of Lactobacillus, Pediococcus and Pectinatus. The peptide was effective at the µmol l(-1) range in vitro, reducing bacterial counts by 95%. A gene construct encoding a secretable form of HBD3 was integrated into the genome of the lager yeast Saccharomyces pastorianus strain CMBS-33. The integrated gene was expressed under fermentation conditions and was secreted from the cell into the medium, but a significant amount remains associated with yeast cell surface. We demonstrate that under pilot-scale fermentation conditions, secreted HBD3 possesses bactericidal activity against beer-spoiling bacteria. Furthermore, when added to bottled beer, a synthetic form of HBD3 reduces the growth of beer-spoiling bacteria. CONCLUSIONS: Defensins provide prophylactic protection against beer-spoiling bacteria under brewing conditions and also in bottled beer. SIGNIFICANCE AND IMPACT OF THE STUDY: The results have direct application to the brewing industry where beer spoilage due to bacterial contamination continues to be a major problem in breweries around the world.

Evaluation of exopolysaccharide producing Weissella cibaria MG1 strain for the production of sourdough from various flours.

This study determined exopolysaccharide (EPS) production by Weissella cibaria MG1 in sourdoughs prepared from gluten-free flours (buckwheat, oat, quinoa and teff), as well as wheat flour. Sourdoughs (SD) were fermented without sucrose, or by replacing 10% flour with sucrose to support EPS production. The amount of EPS depended on the substrate: high amounts of EPS corresponding to low amounts of oligosaccharides were found in buckwheat (4.2 g EPS/kg SD) and quinoa sourdoughs (3.2 g EPS/kg SD); in contrast, no EPS but panose-series oligosaccharides (PSO) were detected in wheat sourdoughs. Organic acid production, carbohydrates and rheological changes during fermentation were compared to the EPS negative control without added sucrose. Corresponding to the higher mineral content of the flours, sourdoughs from quinoa, teff and buckwheat had higher buffering capacity than wheat. Fermentable carbohydrates in buckwheat, teff and quinoa flours promoted W. cibaria growth; indicating why W. cibaria failed to grow in oat sourdoughs. Endogenous proteolytic activity was highest in quinoa flour; α-amylase activity was highest in wheat and teff flours. Protein degradation during fermentation was most extensive in quinoa and teff SD reducing protein peaks 18-29, 30-41 and 43-55 kDa extensively. Rheological analyses revealed decreased dough strength (AF) after fermentation, especially in sucrose-supplemented buckwheat sourdoughs correlating with amounts of EPS. High EPS production correlated with high protein, fermentable sugars (glucose, maltose, fructose), and mineral contents in quinoa flour. In conclusion, W. cibaria MG1 is a suitable starter culture for sourdough fermentation of buckwheat, quinoa and teff flour.

Barley malt wort fermentation by exopolysaccharide-forming Weissella cibaria MG1 for the production of a novel beverage.

AIMS: The growing interest of governments and industry in developing healthy and natural alternative foods and beverages that will fulfil the consumer drive towards a healthy lifestyle and clean-label, natural diet has led to an increase in traditional lactic acid bacteria fermentation research. In particular, this research aims to address the organoleptic modulation of beverages using in situ-produced bacterial polysaccharides. METHODS AND RESULTS: Weissella cibaria MG1 is capable of producing exopolysaccharides (dextran) and oligosaccharides (glucooligosaccharides) during sucrose-supplemented barley-malt-derived wort fermentation. Up to 36·4 g l(-1) of dextran was produced in an optimized system, which improved the rheological profile of the resulting fermentate. Additionally, small amounts of organic acids were formed, and ethanol remained below 0·5% (v/v), the threshold volume for a potential health claim designation. CONCLUSIONS: The results suggest that the cereal fermentate produced by W. cibaria MG1 could be potentially used for the production of a range of novel, nutritious and functional beverages. SIGNIFICANCE AND IMPACT OF THE STUDY: Using conventional raw materials and traditional processes, novel LAB-fermented beverages can be produced representing an innovative mechanism towards fulfilling the aim to decrease government and personal costs as well as potentially ameliorating consumer lifestyle regarding dietary-related disease.

Analysis of bacterial community shifts in the gastrointestinal tract of pigs fed diets supplemented with ß-glucan from Laminaria digitata, Laminaria hyperborea and Saccharomyces cerevisiae.

This study was designed to evaluate the effects of algal and yeast ß-glucans on the porcine gastrointestinal microbiota, specifically the community of Lactobacillus, Bifidobacterium and coliforms. A total of 48 pigs were fed four diets over a 28-day period to determine the effect that each had on these communities. The control diet consisted of wheat and soya bean meal. The remaining three diets contained wheat and soya bean meal supplemented with ß-glucan at 250 g/tonne from Laminaria digitata, Laminaria hyperborea or Saccharomyces cerevisiae. Faecal samples were collected from animals before feeding each diet and after the feeding period. The animals were slaughtered the following day and samples were collected from the stomach, ileum, caecum, proximal colon and distal colon. Alterations in Lactobacillus in the gastrointestinal tract (GIT) were analysed using denaturing gradient gel electrophoresis (DGGE) profiles generated by group-specific 16S rRNA gene PCR amplicons. Plate count analysis was also performed to quantify total coliforms. DGGE profiles indicated that all ß-glucan diets provoked the emergence of a richer community of Lactobacillus. The richest community of lactobacilli emerged after feeding L. digitata (LD ß-glucan). Plate count analysis revealed that the L. hyperborea (LH ß-glucan) diet had a statistically significant effect on the coliform counts in the proximal colon in comparison with the control diet. ß-glucan from L. digitata and S. cerevisiae also generally reduced coliforms but to a lesser extent. Nevertheless, the ß-glucan diets did not significantly reduce levels of Lactobacillus or Bifidobacterium. DGGE analysis of GIT samples indicated that the three ß-glucan diets generally promoted the establishment of a more varied range of Lactobacillus species in the caecum, proximal and distal colon. The LH ß-glucan had the most profound reducing effect on coliform counts when compared with the control diet and diets supplemented with L. digitata and S. cerevisiae ß-glucans.

Inhibition of growth of Trichophyton tonsurans by Lactobacillus reuteri.

AIM: The aims of this study were to identify antifungal lactic acid bacteria (LAB) and characterize their activity against the dermatophyte Trichophyton tonsurans. METHODS AND RESULTS: A total of 165 different LAB were isolated and initially screened for anti-Penicillium expansum activity. Five strains, which exhibited strong inhibitory activity, were then tested against the dermatophyte T. tonsurans DSM12285, where they also caused inhibition as observed by large fungal clearing on agar surface. The strongest inhibition was seen with Lactobacillus reuteri R2. When freeze-dried cell-free supernatant powder from this strain was incorporated in culture medium at concentrations >1%, growth of fungal colony was inhibited. Conidia germination was also inhibited under these conditions as determined by microscopy. The anti-T. tonsurans activity of Lact. reuteri R2 was not affected neither by heat treatment nor by proteolytic treatment using pronase E and proteinase K, indicating that the responsible agent(s) were nonproteinaceous in nature. CONCLUSIONS: Lactobacillus reuteri R2 was identified as having strong inhibitory activity against the dermatophyte T. tonsurans DSMZ12285. SIGNIFICANCE AND IMPACT OF THE STUDY: LAB are naturally associated with many foods and are well recognized for their biopreservative properties. The use of these and/or their products may well provide alternative safe approaches for the inhibition of dermatophytic fungi.

The use of Lactobacillus brevis PS1 to in vitro inhibit the outgrowth of Fusarium culmorum and other common Fusarium species found on barley.

A total of 129 lactic acid bacteria (LAB) were screened for antifungal activity against common Fusarium spp. isolated from brewing barley. Four out of the five most inhibiting isolates were identified as Lactobacillus brevis, whereas one belonged to Weissella cibaria. L. brevis PS1, the isolate showing the largest inhibition spectrum, was selected and the influence of its freeze-dried cell-free supernatant (cfsP) on germination of macroconidia as well as mycelia growth was investigated using Fusarium culmorum as target organism.Addition of cfsP into the growth medium at concentrations > or = 2% altered the growth morphology of F.culmorum, whereas at concentrations > 5% the outgrowth of germ tubes from macroconidia was delayed and distorted. The presence of 10% cfsP completely inhibited the outgrowth of F. culmorum macroconidia. The activity of the compounds produced by L. brevis PS1 was higher at low pH values, i.e. pH < 5. Heating and/or proteolytic treatment reduced the inhibitory activity of cfsP, indicating that L. brevis produces organic acids and proteinaceous compounds which are active against Fusarium spp.