A novel method to assess heat transfer and impact of relevant physicochemical parameters for the scaling up of solid state fermentation systems.

Heat production during fermentation is undesirable. It can affect the growth of biomass, sporulation, products formation and the scaling-up. Physico-chemical properties of substrates influence heat and mass transfer in Solid State Fermentation.

Highlighting Protective Effect of Encapsulation on Yeast Cell Response to Dehydration Using Synchrotron Infrared Microspectroscopy at the Single-Cell Level.

In the present paper, the Layer by Layer (LbL) method using β-lactoglobulin and sodium alginate was performed to individually encapsulate cells in microorganized shells in order to protect them against stresses during dehydration. Higher survival (∼1 log) for encapsulated yeast cells was effectively observed after air dehydration at 45°C. For the first time, the potentiality of Synchrotron-Fourier Transform InfraRed microspectroscopy (S-FTIR) was used at the single-cell level in order to analyze the contribution of the biochemical composition of non-encapsulated vs.

Biophysical Stress Responses of the Yeast During Dehydration Using Synchrotron-FTIR Microspectroscopy.

During industrial yeast production, cells are often subjected to deleterious hydric variations during dehydration, which reduces their viability and cellular activity. This study is focused on the yeast , particularly sensitive to dehydration. The aim was to understand the modifications of single-cells biophysical profiles during different dehydration conditions.

Hemp (Cannabis sativa L.) Protein Extraction Conditions Affect Extraction Yield and Protein Quality.

The purpose of this paper was to study the extraction conditions of hemp proteins from undelipidated press-cakes. The effects of different hydration conditions on protein recovery yield and polypeptide profile were evaluated: pH (2 to 12), ionic strength (0 to 500 mM NaCl) and press-cake/liquid weight ratio (2% to 22%). pH was the most impacting factor.

Oxidative stress resistance during dehydration of three non-Saccharomyces wine yeast strains.

The development of new fermented foods and beverages requires more and more the use of new dehydrated yeasts species. In this context, the non-Saccharomyces (NS) yeasts Torulaspora delbrueckii, Metschnikowia pulcherrima and Lachancea thermotolerans are developed especially in winemaking as co-culture in the fermentation of the must or for the must bioprotection. However, during formulation-dehydration the yeast cells are exposed to several stresses that reduce cellular activity.

Dehydration stress responses of yeasts Torulaspora delbrueckii, Metschnikowia pulcherrima and Lachancea thermotolerans: Effects of glutathione and trehalose biosynthesis.

In food industry and winemaking, the use of active dehydrated yeast (ADY) Saccharomyces cerevisiae is a frequent practice because of the long-term stability and high efficiency of ADY. Nowadays, there is an increasing interest for new yeasts strains, such as Torulaspora delbrueckii (Td), Metschnikowia pulcherrima (Mp) and Lachancea thermotolerans (Lt). However, the yeasts transformation processes into the solidified form generate several stresses that reduce the cell viability.

Selected dehydrogenases in Yarrowia lipolytica JMY 861: their role in the synthesis of flavor compounds.

The presence of selected dehydrogenases, including alcohol dehydrogenase (ADH-YL) and aldehyde dehydrogenase (ALDH-YL), in Yarrowia lipolytica JMY 861, and their potential role in flavor synthesis were investigated. The experimental findings showed that using reduced form of nicotinamide adenine dinucleotide (NADH) as cofactor, the ADH-YL activity in vitro was 6-fold higher than that with reduced form of nicotinamide adenine dinucleotide phosphate (NADPH); however, under the experimental conditions used in this study, an ALDH-YL activity was not detected. The in situ hexanal reduction reaction was found to be instantaneous; however, when the yeast cells suspension was diluted 150 times, the initial relative hexanal concentration was increased by 84.

Optimization of the Hydrolysis of Safflower Oil for the Production of Linoleic Acid, Used as Flavor Precursor.

Commercial lipases, from porcine pancreas (PPL), Candida rugosa (CRL), and Thermomyces lanuginosus (Lipozyme TL IM), were investigated in terms of their efficiency for the hydrolysis of safflower oil (SO) for the liberation of free linoleic acid (LA), used as a flavor precursor. Although PPL, under the optimized conditions, showed a high degree of hydrolysis (91.6%), its low tolerance towards higher substrate concentrations could limit its use for SO hydrolysis.

Aqueous two-phase system cold-set gelation using natural and recombinant probiotic lactic acid bacteria as a gelling agent.

The present study aimed to entrap probiotic lactic acid bacteria (LAB) in a sodium alginate and sodium caseinate aqueous two-phase gel system. The natural acidifying properties of two therapeutic probiotic LAB were exploited to liberate calcium ions progressively from calcium carbonate (CaCO3), which caused the gelation of the co-existing phases. Bi-biopolymeric matrix gelation of GDL/CaCO3 or LAB/CaCO3 was monitored by dynamic rheological measurements, and the final gels were characterized by frequency dependence measurements and confocal laser scanning microscopy.

Size measuring techniques as tool to monitor pea proteins intramolecular crosslinking by transglutaminase treatment.

In this work, techniques for monitoring the intramolecular transglutaminase cross-links of pea proteins, based on protein size determination, were developed. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis profiles of transglutaminase-treated low concentration (0.01% w/w) pea albumin samples, compared to the untreated one (control), showed a higher electrophoretic migration of the major albumin fraction band (26 kDa), reflecting a decrease in protein size.

For me the taste of soy is not a barrier to its consumption. And how about you?

This research investigates the cultural influence on beliefs about and attitudes towards soy foods (French from France vs. Vietnamese from Vietnam) and possible change of beliefs and attitudes and soy consumption habits with a change in cultural environment (French from France vs. French from Vietnam, Vietnamese from Vietnam vs.

A new alternative in vitro method for quantification of Toxoplasma gondii infectivity.

An in vitro method to determine the infectious potency of an unknown suspension of the protozoan parasite Toxoplasma gondii based on kinetics of host cells lysis was developed. Mic1-3KO a mutant strain of T. gondii RH tachyzoites was inoculated in 25-cm² flasks containing a 90% confluent monolayer of human foreskin fibroblasts.

Comparison of some new pretreatment methods for second generation bioethanol production from wheat straw and water hyacinth.

Pretreatment of lignocellulosic residues like water hyacinth (WH) and wheat straw (WS) using crude glycerol (CG) and ionic liquids (IL) pretreatment was evaluated and compared with conventional dilute acid pretreatment (DAT) in terms of enzymatic hydrolysis yield and fermentation yield of pretreated samples. In the case of WS, 1-butyl-3-methylimidazolium acetate pretreatment was found to be the best method. The hydrolysis yields of glucose and total reducing sugars were 2.

Toxicity of fatty acid hydroperoxides towards Yarrowia lipolytica: implication of their membrane fluidizing action.

Linoleic acid hydroperoxide (HPOD), substrate of hydroperoxide lyase, an enzyme of the lipoxygenase pathway, can be transformed into many aromatic compounds, the so-called "green notes". The presence of linoleic acid hydroperoxide in the culture medium of Yarrowia lipolytica, the yeast expressing the cloned hydroperoxide lyase of green bell pepper, undoubtedly exerted an inhibition on the growth and a toxic effect with 90% of yeast cells died after 120 min of exposition in 100 mM HPOD solution. The increase in cell membrane fluidity evaluated by measuring fluorescence generalized polarization with the increasing concentration of HPOD in the medium confirmed the fluidizing action of HPOD on yeast membrane.

Metabolism of phenylalanine and biosynthesis of styrene in Penicillium camemberti.

The occurrence of styrene in food may be an important aroma defect (celluloid odour), even at very low concentrations (Miltz et al. 1980) causing consumer rejection and is therefore a problem for the food industry. We examined the biosynthetic pathway leading to styrene formation by Penicillium camemberti using labelled compounds.